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Triumph TR6 - TR6 Fuel Pump Bosch Replacement

I have just recently installed a Bosch Type 0 580 254 910 fuel pump on or TR6 (to replace the origianl Lucas Pump which was causing problems on hot days) and also a pre line 13mm inlet/outlet fuel filter Type 14001 on our TR6. After fitting the new Bosch pump the problem I have now is that it overworks for some reason - that is it runs with a high pitched sound and seems not under fuel pressure. The TR is still getting fuel and is still driveable
If you stop the TR, turn the engine off and leave a minute and turn it on again the fuel pump works fine. If you go for a run, then about after about 3 miles the overworking high pitched sound begins again. Has anybody had a similar problem when fitting the Bosch pump and is there a remedy to fix. The bosch pump has been installed just above the chassis rail under the back left-hand mudguard.
regards Kevin Farley
Kevin Farley

Kevin- Is your 6 a PI version?
Don K.

Yes it is a Petrol Injection model - 1969. I've been doing some work and road testing on it this afternoon (saturday) and I think I've narrowed down the problem. If "air" get into the fuel line the pump doesn't have the ability to clear the air, and the air tends to stay put in the pre filter. The Fuel tank has no baffles so if the tank is say on quarter full and you go round a left hand corner and the fuel rushes to the righthand side and then air gets into the line and the pump hasn't got the abilty to clear the line. Perhaps the filter should be in a "post" position. Have you got any other theories or solutiions what might be causing the problem. With the old system the fuel filter tends to hold a lot of fuel and therefore perhaps tends to support the old pump longer in operation before the lines fill again if you are doing a turn.
thanks for your comments...regards Kevin F
Kevin Farley

If you can post on the UK TR register site there are plenty of experts on PI pumps there, sorry I can't help you mine's on carbs.
R. Algie

Some tr owners have eliminated the noise problem you describe by fitting the longer fuel hose{pump to prv}from the saloon pi car.

Hi Kevin

The Bosch pump is really a high volume pump rather than a high pressure one. That said, it is adequate for most requirements of the PI system, with pressure up to about 100 psi before the volume 'curve' flattens out dramatically.

The consequence of this is that the pump wants to draw a lot of fuel, and you get problems if the supply is inadequate.

When I first installed mine, I used a braided pipe (after the pump) - it made one helluva racket!! To confirm Simon's advice above, I changed the hose to a longer rubber one, in the shape of a horseshoe (to diffuse any resonance) and it works fine.

But I think your problem may also be supply related. Bosch pumps are known for not sucking well. The 'K-tronic' injection system (Volvo, Porsche etc) use two pumps in line. I tried using a facet pump as a 'lift pump' pre-unit to help the bosch get more fuel but all it did was introduce cavitation and the bosch squealed constantly. I also installed a 3/8" feed from the tank outlet and that definitely helped. Long, sweeping lefthanders at speed caused the fuel to slosh away from the tank outlet and if air got in - disaster!! So finally, I added an anti-swirl tank (ex Jag V12) into the spare wheel well (also gives a few extra litres of fuel, but at the cost of a concealed spare tyre!).
I also re-routed the excess fuel return line into the swirl tank rather than the main tank.

In his (Triumph) Tuning Manual (1986), Gareth Thomas solves the problem by using both the Lucas and Bosch pumps in series, giving a total pressure of 130PSI!! (beautiful!!) I don't think much has changed since then!

I am considering doing this mod, as I still find that she runs better with a full tank than with less than a quarter. Day to day this is acceptable, but on a track it is extra fuel weight I don't need.

Hope this helps

Roger (in sunny Perth - PS you don't know a Peter Farley of Subiaco by any chance?)
Roger H

To all contributors and Roger...thanks for your input and it will give me a great start in fixing the problem. I've taken the Bosch pump off the TR and took it to the Melbourne Bosch dealer (Petro-Ject) who tested it for any faults. They advised that all seems OK with the pump. I'm not sure why I've got a problem whereis a mate with a TR5PI Bosch fuel pump setup in the same way as mine doesn't have a problem. As you would appreciate TR5s and 1969 TR6s PI lines are almost exactly the same. Your comments as to "supply is inadequate" may be the main cause. The pipe and union assembly and short hose out of the tank is only about 3 to 4 sixteeneth of an inch and then it leads into a hose that is about about half an inch internal some 4 inches from the bottom of the tank. Then the half inch hose travels slightly downhill for about 20 inches before joining the Bosch pump There is a line (14001)filter installed before the pump. Could it be that this is causing the supply problem thus the yelling for more fuel ? One small hose into one large hose doesn't work. Your mentioned about running the old Lucas pump (which I have left in the TR)in series with the new pump. The old pump which was the origianl pump from "69" tended to overheat and vapourise the fuel on hot days. Would this still happen if it was reconnected as a additional pump or would the Lucas run cooler. I still need to do a couple of things from the suggestions such as checking that the tank breather pipe is OK and that the tank outline pipe is not being blocked. What I might have to do is drain the tank and fit a bigger outlet pipe that will fit the "half inch" hose. I'm not real keen in the swirl tank option as I like the spare wheel where it is. We need the luggage room.
regards to all Kevin
(Roger: as to Peter Farley is he related to my uncle Colin Farley who lives in Spearwood and my cousin Warren Farley and they used to live in Palmyra Perth)

Kevin Farley

Hi Kevin - There is almost a certain problem with the filter before the pump. I use (of all things!) a Magna filter which is the same as a Volvo 240 filter - but definitely AFTER the pump - try that first.

Bigger is better(!) with the supply line. If you are still in trouble after moving the filter, and assuming it is not the pump to PRV line, the outlet is the only basic thing left to do.

As far as the Lucas pump goes, I don't know - it was suggested in a racing manual but I agree that the temperature problems could knock that one on the head - I may do it one day just to see, but it involves a second PRV and return so I will wait for winter.

The Peter F I know was our old neighbour, ex UK, but I don't think any rellies here.


PS Make sure you check out R. Algie's link above - join up and use the search facility, making sure you search under 'all', not just 'this month' - it is a very useful forum for PI's
Roger H

Roger and All. I seem to have had some success. I've made sure that there is no air in the lines and filter between the tank and the Bosch pump and also made sure that the fuel lines are above the pump, thatis the pump doesn't have to drag fuel uphill. After two recent test runs covering some 70 miles flat running and hills I've had no problems. Fingers crossed.
Fuel Tank has been above half full. No doubt that the small tank outlet, the smaller tank hose into a larger hose is also unsatisfactory. I will probably have to change the outlet pipe on the tank so it's basically the same size all the way through to the Bosch Pump.
I'm taking it down to the "Healey Factory'in Ringwood in the next couple of days and we will have a look at the problem and any changes we might make. I'll print this out and they can have a look at all the members comments. I'll ask them about putting a "magna" filter after the bosch and see what their reaction is. I will also checkout member Algie's link.
The filter I've got on is a "14001" type from Petro-Ject and it's a "very low resistence filter" so this also tends to me to believe that the tank outlet and inward pipes are the problem. What worries me is that the problem is likely to come back when to tank gets low and I'm on a run with the car club ( the country somewhere. We are going out on a run on this Sunday to Narbethong so it's the moment of truth (Mine is the two-tone blue and silver TR6 in the club web site)
thanks to you and all and I'll keep you posted. Kevin.
Roger my GG grandfather was a convict from Sherborne in Somerset/Dorset England - shipped out in 1830 for sheep stealing and is buried in Rosedale Victoria - Col Farley in Spearwood WA is his GreatGrandson. Your old neighbour may not want to know us!)
Kevin Farley

Memebers and ALL
I've closely checked all the joins between the half full Petrol Tank, the line, the filter, the line and the Bosch petrol pump and all are nice and tight and clean. There is no sign of any leaks or smell of fuel in the section and a test paper tissue on each joint proves to me that they is no sign of a leak. Great !
Does anybody know why I'm geeting Air into the Filter.
If I go for a say 20 mile run, turn off the TR and leave it for a while, then have a look at the filter it's half full of Air.
To me Air is geeting into the "lines' when the TR is on the go over a bit of distance.

Is it coming from a back flow through the bosch pump after she has been turned off ?

Also when I leave her overnight and turn on the ignition key in the morning, she goes bbbbbbbBBBBBBBBBBBBBbbbbbb in other words for half a second it runs normally and overrace for half a second then back to normal.

Does anyone have any clues to the above.
regards to all Kevin Farley

Kevin Farley

Kevin - have you switched the filter to after the pump? The 'bbBBBBB' sounds like air in the line due to cavitation (restriction in supply).

Roger H

Roger...not yet, but I make sure they is no air in the line between the tanks outlet and the pump, but after a run and leave it for a while the filter end up half full of air. It's got me mytisfied how it gets there. To me the only way is via the pump or post lines. But there is no sign of any leaky spots anywhere
It certainly a slow task getting it right. I'm going to the Triumph experts (The Healey Factory in Ringwood) on Monday. I'll keep you posted
thanks Kevin
Kevin Farley

Hi Kevin - cavitation causes bubbles to be formed in the fuel itself without an external source of air. This is a problem with the bosch pump if it does not have enough fuel supplied to it. I am not an engineer, but my understanding is that the extreme pressure (suction) at the point of a constriction in the line (the 'impeller' in the pump) is enough to 'draw' out vapour, particularly in volatile liquids such as fuel. The air in your line is probably not actually air but fuel vapour. There will be a similar effect as has happened with your Lucas pump but the Lucas pump problem was most likely due to heat causing the vapour release. Unless you follow the steps outlined above, I'm afraid there is not much more I can help you with as my setup is as described and has been running for over 4 years.

Roger H

This thread was discussed between 24/01/2004 and 06/02/2004

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