1/4 TANK COUGH AND SPLUTTER

[marki]

Evening All.

Had an enjoyable run today, until I got down to 1/4 tank then the odd cough pump wasn't happy then a couple of miles later complete cut out for a few seconds.

Am I right in thinking it can't be PRV or filter and should be looking in the tank, as it runs great until the tank gets lower. Or should I be looking at the pump, it's a Bosch fitted in the boot but wasn't hot when I stopped.

Mark

[snowric]

marki,

 

If you have an original fuel tank and a bosch pump then you have the same symptoms as I had. There are several threads on the Register forum on this.

 

1. The Bosch pump needs to be gravity fed - it does not suck whereas the Lucas pump draws fuel and uses the original reservoir as a reserve

 

2. So you need to get the bosch pump at the bottom of your set up (some bosch pump kits have it at the top).

 

3. You can widen the fuel outlet to help - Malcolm at Prestige sells these (but I did my own so cannot say good or bad but people regualrly recommend his work). You can also do this your self using fittings off the web.

 

4. You can replace the tank with one with baffles in to stop the surging - Andy Wiltshire and Revington supply these in alloy.

 

You may just have something in your tank blocking the outlet and one other simple thing, check your pipe from the tank to the filter, if it has a kink in or restriction this could be makin tyhings worse as the tank runs lower.

 

others will send in better answers I expect - all the best.

 

Snowy

[marki]

Thanks for the reply.

I've searched a couple of times and a few people have had dirty pre filters. I have the set up you say with the original tank and a Bosch pump, I've had no problems ( with this ) in the last four years so it may well point to the filter. I've ordered one and will report back. I haven't taken the old one off yet do you know if they can be stripped to see if there is any crud in them ?

Thanks Mark

[snowric]

It depends on your pre filter - mine is a sytec and if you detach it you can take the filter apart an look. If you have the TR shop atyle bosch pump and filter I think it is fairly cheap to just buy another filter and replace it. But perhaps worth doing the standard things like check the earthing and fuel pump connections and the pressure at the metering unit too. Good luck

[triumph69]

Hi Marki

 

Check your pre filter - I have had problems for a month or so with the car cutting out after 10+ miles. Went to Revingtons open day and bought a new Coil, condenser and rotor arm. No problems for 50 miles so thought I had nailed it. Then it played up after next 40 or so miles - on drive it day Sunday. I noticed that the pump changed tone as the engine stuttered. I Limped home and took off the pre - filter - there is no label on it but its a Sytec. On unscrewing the end cap, I found this seal stuck in the inlet! (see photo attached - hopefully) cant believe the car even ran with this stuck in it! If you have a pre filter it may be blocked with crud from the tank and then when the tank is low on fuel, it has some effect upon supply? Who knows! Give it a go - it doesn't cost anything to check the filter.

 

Regards

 

Alan

 

 

 

 

 

[Graze]

I've had a similar occurrence on the last two weekends.

 

Bosch pump in behind rear wheel arch

 

First was with about 40% fuel after driving up a 1km Very steep driveway ( needed to rev above 3000rpm in first to get up it) as soon as I got to the top and backed off the pedal it stalled. Pump was whining horribly. Suspect a combo of load and lack of gravity feed. Left it 2 hours and started and ran 450km home fine the next day.

 

Last weekend after a 2 hour high speed 110-120km drive through country roads and freeway with a bit under 25% fuel I decided to go straight to the petrol station on way home. Got stopped at the lights opposite the station and it spluttered and cut out. With help of a young guy and girl (she was thrilled she got to steer car into station) whe pushed it up to the pump. Filled, started, all good.

 

I was starting to think the pump might be aging and was thinking of buying a spare. Apart from buying the Moss or Rimmer kit at £300 does anyone know the actual part numbers of the pump to buy direct from Bosch?

 

Will check filters etc this weekend

 

Graze

[stuart]

Pump is part number 0580 254 044 http://www.ebay.co.uk/itm/Genuine-New-Bosch-044-High-Performance-Fuel-Pump-/271823737826?

Be aware there are two versions this is the high capacity version.that will cope.

Stuart.

[snowric]

Stuart, I appreciate you are an expert ! But my pump was a Bosch 979 not a 044.

 

Here is a 979 Sytec equivalent from Glencoe.

 

http://www.glencoeltd.co.uk/hi-otp979-out-tank-fuel-injection-pump-o-e-0580254979/

 

The 044 is a great pump, high flow and pressure but is a massive current hog and very noisy.

 

The flow charts are on the Glencoe web site.

 

Note the input threads are different.

 

Snowy

[TR NIALL]

Snowy/Stuart,some Price difference in the 2 Pumps,some of that Glencoe stuff looks good.

Edited May 6, 2015 by TR NIALL

[Graze]

Stuart, Snowy

 

Bith pumps are listed as 72.5psi operating pressure

 

I thought we needed 105psi

 

I understand pressure can be increased with smaller dia pipes - is this the explanation For this pump being adequate?

 

Or am I missing something

 

Graze

[Peter Cobbold]

http://www.glencoeltd.co.uk/media/wysiwyg/P3979.1_MS_.pdf

 

Will the prv dump 3 litres per minute?

The pump makes that flwo at 7 bar, ca 105psi. And the PRV has to dump almost all that flow at low loads.

 

I think the pump is too big for the task.

Fuel flow needed is HP x 5.6 ml per minute. ( A Graham Bell Forced Induction Performance Tuning p 199)

So 3000 ml per min = 535hp

 

Peter

[snowric]

Peter, I have used both in a standard/kanckered TR5 engine.

 

Both do the job.

 

The 979 used much lower current to deliver and less noise so I have stuck with this one for the time being.

 

Frankly I would have saved had I just gone for Malcolm's set up at prestige but i enjoyed experimenting.

 

And of course there is nothing more fun to do than fill you wheel well inadvertently with petrol.

 

As you said you need less flow for lower HP at peak power.

 

Graze, the flow charts for each are on the Glencoe web-site.

 

Both pumps operate at 104-110psi. This is above their 'nominal' range and thus draw more current.

 

One day i will revert to the Lucas set up as I suspect, well cared for, it does the job nicely.

 

it will also give me the chance to screw up my plumbing and finish stripping my bootfloor of pain !

Snowy

[Peter Cobbold]

Snowy,

As long as it works ...........I was concerned the prv would not cope at that flow...,but you've shown if does.

Nothing like an experiment to test the theory.

Peter

Edited May 6, 2015 by Peter Cobbold

[snowric]

I haven't taken the return from the PRV to the tank off to measure the flow....yet :-)

[Peter Cobbold]

If the filter is restrictive, or even the hose bores and length before the prv too small, the flow might not be as fast as the pump could go on that chart...