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MG MGB GT V8 Factory Originals Technical - fuel injection

I just bought a Rover fuel injection manifold which appears to have all the mechanical bits, but none of the wiring. The plenam isw marked "4.2" and the unit is supposed to be from a 1996 Range Rover.

Rather than trying to find a Rover harness & computer, I am leaning toward a 1993-96 Mustang or 305 Chevy setup. Both are relatively inexpensive from the salvage yards. Anyone out there done this? Any advice? (don't need advice to stick with Rover stuff, that is not an option.)
Jim Stuart

Just a quick note...I know that the EEC IV system from Ford is easily tuned with either an EEC tuner or a Tweecer. Both systems will run you about $500, give or take a couple of bucks! Check with Jim, I believe this is the route he took.

Good Luck!

G.P. Copes

Oxygen sensors are easy, TPS shouldn't be too difficult either, nor will the IAC valve (aka stepper motor) the only ones that kinda scare me are the map sensor, the fuel and coolant temp, and the throttle body. You might luck out and find the same size threads for fuel and coolant temp senders, and the ford throttle body could probably be adjusted to work with your system. (I know they're tuneable, just don't know how) and maybe drill a hole for the MAP sensor somewhere in the upper plenum, maybe on the passenger side?

You can get entire mustang systems for dirt cheap, and painless wiring sells a harness for a couple hundred bucks to add fuel injection to a carbureted mustang. Sounds like *exactly* what you'd need for the project. Maybe check around on and see if anyone there can help you, or your local hotrod shop should know plenty about the system. If you wanna go *really* trick, you could get a haltech system, and run a laptop to adjust everything and completely maximize your system.


Not that I'm going to talk you out of anything, but I'm just curious about your objections to the rover system. I think your idea for a ford system is pretty damn good, and one I"ll consider some day in the future too.

You don;t need or want MAP.

Jim, If you are going to go that route you need a MAF (mass air) system. That means a 89-95 Era Mustang. The 89-93 are the better option as there at a TON of them and they are all the same with regards to TB and some other things.. The 94/95 are a touch different. Also lincoln's and mercury's of the same vintage with a 5.0 will match the 87-93 mustang parts most of the time. Also some Tbirds of that era.

The MA system is easy to tell upon site as it has a sensor in the air intake tuber between the air box and the TB. These systems read the actual air coming into the engine, so are much more adaptable to non ford or hopped up for applications.. You will have MAF, TB (with TPS and IAC sensors), ACT (air temp), Engine temp, distrib or crank fire parts, then any emissions garbage you choose to run. There is no fuel temp or pressure sensors. Your biggest hurdle will be the distrib/plug firing. Again, as mentioned talk to Jim Blackwood about that as he will tell you all the parts you need. In wreccking yards you will often find that the MAF sensor and ECU are gone. Ebay is the best bet. ECU's will run in the $75-150 range on Ebay, Stock MAF's are usually very easy to find on any of the mustang boards for real cheap.

On the twEECer, there are 2 versions. The standard and the RT. the RT add real time logging so you can see what the sensors and engine are all doing, that is a HUGE help in tuning. The Regular version is $380, the RT is $550. They have 100% support for mustangs 89-95 and partial and growing support for the 96+ mustangs. on the ECU make sure you get a mustang unit. The tuners do not support the non mustang ECU. Other than that ford was pretty good about keeping 99% of sensors using the same signalling, so grab pieces off the lincolns/mercs (it WILL be cheaper) and then buy a mustang ECU.
Larry Embrey

First, I don't know what system I have, MAP or MAF. What I do know it that I have a TPS, coolent sensor, fuel pressure sensor, & some other do-dads that take wire connectors. I also know how little I know.

So far, you have all been a great help. Maybe Jim B will chime in, if not, I will send him a note.

Looks like a '93 Mustang will be the donor. The reason I don't want to use Rover stuff is not because it won't work, too many have proved it will. It is because it is very expensive to buy & expensive to modify. Because it is designed to power a huge SUV, it is not optimum to power a small 2500 lb sports car. Mustang stuff is all over the place, & relatively cheap, & more fitted to a sports car in tuning.

Larry- I will check out the tweecer thing.
Jim Stuart

Rover systems are all MAF systems, I wasn't sure about the MAP thing which is why I brought it up. I figured Larry would chime in. The thing that *kinda* concerns me about the mustang thing, is their throttle body is a separate unit from the upper plenum, whereas on the rover, the throttle body is built right in. (the butterfly plate, and the tps) You'd really have to sit down with all the parts, but it's possible that you could adapt the mustang tps to our throttle body, and basically all your problems are resolved. Otherwise, probably cutting off the rover throttle body, and having a plate welded on to accept the removeable mustang throttle bodies would work very very well. At this point, you could always up grade to a bigger throttle body should the necessity be there. Tweecer gives the ability to adjust engine displacement and I think that is a CRUCIAL aspect of this conversion. Fuel maps for a 5L, 3,000- 3,500lb sports car will be about as bad as fuel maps for a massive suv, when used in our cars. The only parts that are hard to get for the rover systems is the throttle position sensor. I haven't found a cheap stateside alternative for that. Everything else is pretty widely available, and decently priced. I paid $300 for my last ecu and harness out of a junkyard, but I had to yank it myself. Kind of a hard job, but worthwhile.

Interesting stuff here.....

p.s. the electrical sensor on the back of the manifold that requires a 4 wire plug is the idle air control valve, or sometimes called the stepper motor. Not sure if you'll be able to reuse that, or if you'll hvae to use a mustang piece for that job as well.

Yeah teh TB on the mustang is bolted to the upper intake. This is actually a good thing. What happens if the bushings go bad, or you want more flow. With a mustang you unbolt you TB and buy a new or bigger one. The TPS AND IAC (stepper) both bolt to the TPS as well, so they are replacable and easily swappable and you will have to have them unless you replace the IAC with a plate to cover the holes in the TB. I have learned allot about them both from hanging with the mustang crowd here locally (They have taken me in as if I had a stang) and from the work I am doing to put a 5.0 into my 79 fairmont. All the ustang stuff is bolt on, so that if any one piece goes bad you just yank it off and buy another. The really cool thing is that if you fall in with the mustang crowd you can often scoop up thier stock take-off's for pennies when they go to upgrade..

Yes twEECer will be manditory for installing onto a 215/4.x rover. with twEECer you can change everything, make a auto trans ECU think it is a manual, change displacement, disable O2's, and all emissions controls, etc etc.. then you also get full modification of all the timing anf fuel curves and maps, so you could feasibly make it run anything from a 200cid V8 to a 500+CID big block V8
Larry Embrey

The preceeding comments are accurate, and Larry has given some very good pointers. I can add some information about the EEC-IV's capabilities, etc. For instance, it will interface with a distributorless ignition module to run a crank trigger ignition should you want to do that, and even if not there are a tremendous number of ignition parameters you can control through an electronic ignition system. It can control two separate radiator fans (this will vary by year) putting the fans directly under the control of the PCM, and in terms of injection tuning gives you a dizzying variety of ways to tweak the injection. All these parameters are accessible through the aforementioned "TwEECer" interface, allowing laptop computer control and 4 uploadable tune locations which can be selectively loaded on the fly. In other words, you can load the one you know works, a couple more you want to try out for making changes in different areas, maybe a 'valet' setting that won't let the car go over 5 mph, and still be able to switch to the stock calibration (or tune). Then you can switch between any of them while you are driving. You can set a rev limiter, a speed limiter, and so many other things that I'm nowhere near learning it all. If you run an automatic (Ford AODE) you can control every aspect of the transmission's behavior. I know, this is extreme for an MGB. But you could.

Bear in mind though it's experimental. Ford doesn't give out the secret info so things are still being discovered, and occasionally you might find a weird problem, but the guys doing the development are very sharp and continually upgrade the unit and the software. Last I checked they were in the midst of a instruction manual type project and a new software version is due out soon. There is a large and growing support group.

Is there a down side? Well of course. It is a highly complex system with it's fingers into every aspect of the vehicle it was installed in. Not exactly the plug-n-play option. I do not know but I suspect that even with the Painless harness there would be a good bit of work to do. And there's no ironclad guarantee it will all work out fine either. For instance, on my system I still have a stumble at 2100 rpm which will occasionally cause a blower sneeze and is a little irritating to drive through. In fairness to the EEC-IV system, I have not run all the diagnostic tests and may yet have a bad component or other repairable problem. But in fairness to me, the tests are a smidgen intimidating the first time, if thorough. (During the engine run test there is a prompt to floor the gas from idle so the PCM can check WOT operation for instance, and there are some conflicting/incomplete instructions as to how to run the tests.)

However, this is one of the few systems that has an adaptive strategy built in. This means that as long as things aren't too out of whack the system will tune itself. So where are we going to be out of whack? Try the MAF transfer table to start. We're taking the airflow meter out of the system it was built for and giving it a totally new home so it's output is not going to be the same. Mine ran tremendously rich initially. However I was able to make some fairly minor adjustments to the MAF curve and get things a lot closer. Still not there yet. At the smog check it blows a 1250 where 850 is the limit for an MG, but mileage is up to about 18mpg. As I get closer on the tune that should go up.

As far as components are concerned, I think I'd at least attempt to stay with the Mustang stuff, in particular just to avoid having to load a MAF curve out of a Lincoln into the Mustang PCM. But it can be done and I've done it. For the PCM my choice was the '95 Mustang bacause it had the fan controls, but look at the features set and make your choice. Support for the '94-'95 (SN95 Mustang) PCM is not quite as well developed as the earlier ones. A factory authorized reconditioned '95 GT PCM can be had from an outfit in Fla for about $150 plus $50 core.

So if you get the junkyard system for a couple bills, the painless harness for a couple more, the tweecer for another 550 and possibly the GT PCM you're approaching $1500 by the time you put it all in. Not bad at all for what you are getting, but some would call it overkill. In particular among those would be DIY-EFI enthusiasts. Their own approach is a kit based system which is open source and much more basic, but will put you under a quite adequate electronic control for probably about a third of that for your completed system. Search DIY-EFI, that one's worth looking at too.

Jim Blackwood

Jim S.

If you're new to EFI you might want to look at the current issue of HOT ROD magazine. It has a article about tuning and mapping efi systems.
Edd Weninger

Tony's post about engine mounts made me think of this. Does your engine sit low enough in the car so you can shave the required .750" off the trumpet stack and fit the injection under your hood? I'm sure it was never an issue with the carb you have on there, but with the plenum that might cause some problems....


I am in the same situation. I plan to assemble and use a megasquirt fuel injection control system to control stock rover fuel injection. If you want to go through the trouble of assembly and programming it is cheap and adaptable.
If you want to check it out it is available at
Don Thorpe
Donald Thorpe

That's the one I was thinking of, megasquirt. I've got a partial kit but haven't ordered the rest of the components yet. Last time I tried something went haywire and the order never went through. Don, could you let me know if you go that route? I was going to use it for my truck.

Jim Blackwood

Will be looking for the Hot Rod issue this weekend.

I think I will have clearance once everything is machined, as I have a good bit of room above the air cleaner now, more room than most.

Looked at the megasquirt web page & was suprised to see that it is a MAP system & most of you think the MAF system is a better way to go. It does look like a very usable system, but assembled with the bits & pieces, it totals out around $500.00. & I still need sensors & such. Since I did my last breadboard project about 45 years ago, I think I need to buy assembled.

Wish I could find someone who had adapted the Mustang system.

Larry, look out for future questions.

Thanks to all for the great info.
Jim Stuart

If you're gonna spend $550, I'd just as soon get the tweecerRT and not have to invent any wheels. Obviously, conceptually the mustang setup will work on any motor (As Jim B proved) with the help of a tweecerRT. As far as I see it, and the more I think about it, this isn't a hard transformation. The worst part will be mating the mustang throttle body to the rover plenum. You'll need to purchase a mustang upper intake, chop it up, and have the mating surface welded to the rover plenum. From there, just bolt on the mustang throttle body, and you're good to go. Throttle bodies can be had easily for $30.00 on ebay. The painless wiring harness is $460.99 at jegs, and the eec IV computers are $30.00 on ebay. I saw the MAF sensors on ebay for about $30.00 too. Mustang 19lb injectors are sufficient for our cars, and you can get a set of them for $180.00. Oxygen sensor is $40.00(generic bosch 3 wire sensor). Can anyone think of anything else? Here's the same thing in list form:

mustang intake: $25.00
modify plenums: $150.00 ???
Throttle body: $30.00
MAF: $30.00
computer: $30.00
tweecerRT: $550.00
injectors: $180.00
O2 sensor: $40.00
harness: $461.00

Am I forgetting anything?

Rover computer and harness: $300.00
Rover Throttle position sensor $115.00 in UK
injectors: $180.00
coolant temp sensor: $20.00
fuel temp sensor: $50.00 in UK
fuel pressure regulator: $55.00 in UK
Idle air control valve: $25.00

That should replace every single part of the rover system with what you need.

I'm not saying go one way over the other. But is the loss of fuel map control worth $750.00? I dunno. I averaged 21 mpg on the way from detroit to Townsend while spinning 3600 rpm's the whole way down. Cut that down by 1,000 and mileage should be stellar. Rover setup is super simple, and half the price. Mustang setup is ultra modern, 100% controllable, and capable of way more power then the rover setup.

Tough call.

You can save more money than that..

Forget buying a mustang upper intake. It would probably be simpler to take the rover upper and the mustang TB to a machin shop and have them either modify the rover upper, or make a adapter block. Again, I not seen a rover unit up close, but I may try to take a stock mustang TB over to a friend place to see what it looks like.

Forget the painless wiring it is not needed. Buy a 87-93 stock mustang harness and just weed out the unwanted connectors. I just did this on a car this weekend and while time consuming I also now have a harness that is tailored to the car. I spent 9hrs fooling around with it, and that was many trips inside to eat, etc.. They will be cheape too maybe $100??

The ECU are not that cheap on ebay, least not for the good ones. you want POST 88, so 98-93. They are often refered to a A9L among a bunch of others. The advantage you will ave being using twEECer is that you can get away with a manual or auto tranny ECU. MOST people want the A9L which is MA and manual trans. Otherwise there are check engine lights. YOu can disable that with the tuner. So maybe you can find one as cheap as $30. Injectors, don;t pay over $50 for a used set of 19's. Anything more is a ripoff. a NEW set of #24's can be had for $250ish, so why pay 90% of a guys upgrade for him? Worse case go to a JY and pull them from a wrecked car. OR give me a jingle in a month or two, I have like 2.5 sets of injectors, but have another car on the way I need to check injectors on before I give any up..

One thing to look out ford is some of the "kits I see people sell, maybe get TB, intakes, fuel rails, injectors and some wiring in one package, I see them go 80-100 sometimes. Just take time, and keep eyes open!!

The rest of it looks about right.
Larry Embrey

I went to a yard and paid $200 for the entire system including the distributorless ignition and all the wire and electrical components I could yank out of the car and any part suspected of being related, even took the engine home and brought it back later because I wanted some pieces from it including the intake manifold and crank trigger. (It had a broken crank) Then I bought a rebuilt '95 Mustang GT PCM to get tweecer compatibility for ~$150. (see my post below) I think that's pretty price competitive. I went back to the yard for extra chunks of wiring harness, spare fuel pump, stuff like that and spent maybe $30 more. You can clean your own used injectors easily with the right setup so junkyard ones are a good deal. I picked up a spare set for something like $20.

There is quite a bit you can eliminate in terms of wiring, but using the stock harness may take more than 9 hours to sort out. I spent days on mine, but then again it was for a 4.6L Crown Vic. The 5L Stang may be simpler.

The pieces -will- go on this engine, though it may take some ingenuity at times. Jim, considering your AC installation I wouldn't think it would be beyond you.

Jim Blackwood

Yeah I spent about 9hrs on mine, that was mostly stripping the harness and cutting out the emissions and Auto Trans wiring. I spent a good number of hours with a wiring diagram and pin-out chart to make sure the ECU and harness pin-outs matched..

Jim's pricing is right about what I would expect for a 5.0 EFI system..
Larry Embrey

I see mustangs with distributors, what's the story on those? Is it just a signal wire from the negative side of the coil, or is there more involved?

Thanks for the info on Megasquirt. I found it a good set up and ordered it for my Rover 3.5
I inform you on the progress of the project. My engine ran very smooth with the weber/Carter 4 barrel so I will see what the difference iswith this set up. As intake manifold I will use the Federal EFI from Rover as used on early SDI engines imported in Canada.
Werner Van Clapdurp

Not sure what you mean about the distributors?? For the buick install it would be better to go with the coil packs. The reason being that distributor as you mentioned. The mustang ECU addjusts it's timing based on the signaling it gets form all it's sensors, including the Dist. Since the Buick Dist does not have the TIF modul, the ECU will not know what is happeneni ng with the Dist and that may cause issues. The coil pack and crank fire you mount the ring on the crank balaner and away you go..
Larry Embrey

So let me make sure I have this straight. You ditch the distributor, and attach the crank fire ring to the harmonic balancer, and attach some sort of sensor to the block/front cover and let it control the coil packs, which will fire the individual cylinders as necessary?

You could use a distributor, but it would have to have some sensors added and it would be different depending on the year. One setup Ford used was the TFI or Thick Film Ignition, I think that's what Larry was referring to. It's got a shutter and sensor setup, but I do feel the crank trigger is a better system. No doubt other systems could be adapted. You don't necessarily have to put the ignition under the control of the computer, it's entirely possible to run it as a separate system. this could be trickier with the SN95 systems as they swing the timing advance to control the idle speed. The ones used on the Fox bodied Mustangs didn't do it that way though so they might be a better candidate for that, depending on the ignition system. If your ignition can accept an external advance signal you should be able to use either PCM.

If you go distributorless you will still need an oil pump drive, but it's not too hard to modify the distributor for this by cutting off the head and capping it. A 1" copper tubing cap works well as I recall, and the cylinder ID sensor can be mounted there if you want to use it. You will have to pay some attention to orientation of the missing tooth on the trigger wheel as well as the location of the sensor. I may have a photo or two of that somewhere.

Jim Blackwood

Yeah Jim, the TFI is what I was trying to refer to but the name was just drawing a blank for me :-)
Larry Embrey

Contact they can help you with any thing you may need including the ignition, complete systems if you need one.
If you contact them via phone ask for Vince.
I have used their dual TBI set-up etc.
You want to use MAP and don't forget the ignition that works with the ECU.
also GM has a simple system etc etc.
Bill Guzman


Thanks for the cost comparisons. If I understand what all of you are saying, going back to the Rover set up will be cheaper & simpler. I already have the injectors & all the sensors on the list. I do not have the Rover computer & wiring. The 4.2 version of the Rover FI used a comventional distributer. This changed in later years, probably around 1996. I guess If I could find a Rover harness & computer for the right year, the only issue would be how to make it tunable.

Any sources for the Rover stuff & ideas for making it tunable?

Long run, I still believe the Mustang route is the best, but the Rover would be the easiest way to start. Damm, I'm right back where I started.

Jim Stuart

Probably simpler but not necessarily cheaper. It depends really on what you can do yourself, but if you calculate your own time at what it's probably worth then yes, probably cheaper as well.

I've done it Jim. If you want the help all you have to do is ask. I would guess that with the number of 302's going in these cars that the Ford EFI will become pretty popular and although doing it the first time was a brain twister, it turns out that it's not all that complicated. For instance, you can change the firing order in the PCM to match the engine and run injector wire #1 to cylinder #1 based on the GM cylinder location and all will be dandy. Or, you can switch the wires so the default firing order runs the injectors correctly even in limp mode. It's a small distinction because it'll still be getting gas either way but there are at least two ways to handle it. Wiring the EDIS ignition is way easy. All you need is the crank sensor, the module, and the coil packs. It takes one wire from the PCM, and you can use a CID sensor or leave it off.

I set my EFI up as a full featured unit, using all the inputs and outputs with the exception of the AODE automatic transmission controls. All the sensors, full closed loop and adaptive ability, control of two radiator fans, use of EGR inputs for a wideband oxygen sensor once I get that finished, and I even installed the cruise control. The new tweecer software due out now even has dyno capabilities. Think twice, you may be wishing you had made a different choice on down the road.

Jim Blackwood

I will stand behind Jim (as I have that the Ford is the way to go here in the US at least. I have a Ford motor so it would make even more sense but base don what Jim has done I would do ford EFI if I had a Rover. The tuning just makes it the best option. then the extremely large amount of parts in the JY and aftermarket with regards to sensors etc... then the price. The only thing that makes the Ford mroe $$ is the tuner itself really..
Larry Embrey

O.K., its back to Ford, but you guys are in for it. I'm going to have a lot of questions down the line.

First, is what book to start reading.

Thanks to all who have offered a lot of really good info & advice.

Jim Stuart

Start with Charles O.Probst SAE: How to understand, Service and Modify Ford Fuel Injection & Electronic Engine Control. Robert Bentley, Publishers ISBN 0-8376-0301-3 $29.95

Then have a look at this link:
You can get the service manual for the donor vehicle from Helm for 20 bucks or so and it has the wiring diagram spread out over multiple pages, pinouts, circuit descriptions, wiring harness routing etc. or the vehicle schematic for about 15 which also has a listing of circuits for each wire color and connector information. I use the wiring diagram the most.

The following information applies to those who decide they want to put together their own wiring harness using the stock components in an attempt to get a neater job than can be done with the existing harness parts. It is definitely possible, is not tremendously difficult, but does require some time.

It is pretty simple to remove the locks and reuse the ford connectors by pulling the pins and inserting different ones and they are excellent connectors so you should consider getting extra ones from the yard and also be sure you get both sides of any one you get if possible. Be aware of this. The PCM uses a different sized pin from anything else in the car so nothing else fits it even though different pins will go in. So it's not a bad idea to pick up a spare PCM connector just to have the wires. If you strip out a couple of harnesses you can get enough wire that you will have to make very few splices, but try to get as much grey/red and black as you can as you will run short if you run individual signal returns and grounds. Of course you'll have wire everywhere for awhile and in a very wide arrangement of colors. A clothes rack or something similar would make a handy place to organize them as the work progresses. Maybe at some point Dan Masters will chip in here with some wiring secrets though, my wiring job needs to be a whole lot neater so my advice may not be the best.

You will need to select a location for the PCM, bearing in mind that there will be a thick bundle of wires running to it. You may also want to install a power distribution panel. Although it is very tempting to adapt one from the yard, I would suggest having Dan make one up to your needs as the result will be much neater with less confusion as to what does what and everything will have a purpose. He can also provide the lead-out wires in colors better matching the MG scheme. It would be a good time to consolidate the fuses and relays and get them all in one place. Alternatively, you can just layer the EFI system over the MG system and that will work fine.

Depending on where you locate your coil packs you may be able to use the stock plug wires and just change the spark plug boots. This worked fine on mine.

Ultimately it's up to you how simple or complex you make it, but once you've done some reading and gone out and got some parts you can decide that. In any case, I think we'll have an answer for just about any question you run into. In most cases there will be an inexpensive solution as well as the more expensive one so it will just be a matter of choosing which way to go.


Jim Blackwood

Wiring shouldn't be a problem. I have already removed all the MG harness & installed a Centex 21 circuit panel, completely rewiring the car. There are seperate circuits for the ECM & some other components. If at all possible, I want to retain the stock distributer, at least for a start, & not get into crank fire & coil packs.

As I like a neat, uncluttered engine compartment, would it be possible to mount the PCM in the inner fender behind the mud panel behind the front wheel? Once installed, how accessable does it need to be?
Jim Stuart

It may not be the cleanest/driest area and that would be my main concern because of the attachment of the tweecer unit to the diagnostic port. (Opposite end from the main connector) The board itself has a protective coating and the main connector is waterproof, but the tweecer connection is not and that might be a concern. It also has a connector similar to a telephone cord which goes to the selector switch and water or dirt would not be good for that. You could put it all in a sealed box of course, but then heat dissipation might become a factor. I hung mine through the passenger side pedal hatch at the end of the footwell and put a stainless kick panel over it but as I recall you have a blower there for your AC. I don't know. If your seals are good it may be fine. Once it's in and working you should be able to leave it alone. One idea might be to suppliment the existing seals with a caulk of some sort.

As for the distributor, no reason you can't do it that way. Even with the SN95 systems I think you could probably turn off the functions that are used to control the idle with timing advance so there should be no reason why you have to put the ignition under computer control at all. In fact, I just checked and there is a scaler for spark ignition type. It is set to 1 for edis and I'd be willing to bet setting it to 0 allows for the use of a separate ignition system.

Jim B
Jim Blackwood

From earlier posts, it was my belief that the SN95 system controls the idle through the timing. Other eec IV systems do have IAC's, and dizzy's meaning you might be able to separate them, and run the computer and injection without affecting the timing, but wouldn't this serve to defeat the purpose of going through all this work? If the ford system is designed to adjust timing to achieve maximum output when and where desired, taking away one of the three necessary controls (fuel, air, timing) would seem to handicap the system. Personally, I like the idea of attaching a crank fire ring to the harmonic balancer, putting a sensor up there, and letting the system run the way it's supposed to. Now if the earlier mustang systems didn't control timing, then disregard my argument, but if timing control is a crucial element in all the eec IV setups, then I wouldn't want to disrupt that.


They all control timing. From the 89 to the 95 mustang at least. The older were the EEC-IV unit with the TFI module. 96 they went to the modular motor and the EEC-V. The Crown Vics had the DIS system with the 5.0 (unknown years) as did the explorer from 96-98.

I would recommend to stay with the crank fire, and let the ECU do the timing.
Larry Embrey

Yes they do, but I think you can probably tell it not to with the scaler I mentioned. I put a post on the tweecer forum to see if anyone has the answer.

Jim Blackwood

OK, here's the scoop so far. You have to have a signal of some sort to tell the system when to fire the injectors. In the older systems it came from the TFI distributor which had basically two sets of vanes and sensors to give a signal for each cylinder. In the SN95 and newer this was replaced with the crank sensor which uses a 35 tooth (36 minus 1 at TDC) wheel on the crank. As noted, this wheel can be attached to the damper without too much fuss, and can be indexed to put the sensor at a convenient spot. Mine is located at the location of the stock timing marks but required some 'soldering' of the timing cover at that spot.

The newer design gives a signal every 10 degrees of crank rotation as opposed to every 90 degrees for greater consistency in engine control. The EDIS ignition that goes with it has also gained a good reputation as a powerful and reliable system. If you wanted to use the existing distributor ignition you might be able to do that with the earlier system as long as you had a proper timing signal to send to the PCM for firing the injectors. Sorry I do not have more right now, it was not a system I considered.

Jim Blackwood

Yeah Jim, that jives with what I have been hearing also. I think you and I are together 100%, I guess my point was if it already is there, why not take advantage of the ECU controlled timing. Especially if you have a twEECer as you can then make it do whatever you want it to..

Larry Embrey

Anyone know the diameter of said crank wheel?

I can maybe get a measure tonight when I get home if Jim can't get it sooner.
Larry Embrey

Tough to measure on the car, but I came up with 4.960" or just a tad under 5 inches. Larry may be able to get a more accurate reading and knowing the bore diameter and thickness would be beneficial as well. I believe I bored one out to be a press fit to the balancer and then tack welded it into position. I used the Olds damper hub and the wheel sticks out past the hub as it is a larger diameter, but I also have spacers and a damped drive pulley for the blower so your arrangement will be different. Different engines will undoubtedly have different sized toothed wheels. The wheel was inside the timing cover on the 4.6L but it works fine externally. The sensors themselves are available in a variety of shapes and cost ~$10-15 at Autozone. The same sensor is used for both the crank wheel and the CID.

Incidentally, I mentioned the TFI distributor has two sets of vanes and sensors. One is for the individual cylinders and the other is for cylinder ID if I am not mistaken. EDIS will run without CID, it just gives a continual update for injector firing, making sure it is fired at the intake stroke rather than the power stroke. Not a bad idea to have it though.

On an earlier question, the SN95 systems also do have an IAC motor even though they use the timing to control idle speed. The IAC is the coarse control and timing is used for fine control because the response is so much quicker.

Jim Blackwood

Hrmm, I can;t get a measure on the Diam on mine other than it is over 6" diam. Like Jim said very had to get to it on the car. It is right in the same plane as the steering rack and my 6" Calipers jaws are not long enough to touch each side..
Larry Embrey

This thread was discussed between 26/05/2003 and 04/06/2003

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