Engine Stammer

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MeatCleaverX86

MeatCleaverX86

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Hey Hey

1994 300 TDI Defender 90 Daily Driver

So two months ago I was accelerating hard then almost head butted the stearing wheel as the engine stammered i dipped the clutch and coasted the engine settled and kept running. Then for a few miles it had a few murmours / lumpy runs when under load the fuel level was low but not lower then i normally go but thought **** im running out of fuel went to the nearest station filled up 40 something litres so wasnt out / lower then normal. but the journey home still had a few murmours / missfires but doesnt completly conk out.

Then for a week it drove perfect put it down to maybe a bit of air / water.

Then out of know where towing a trailer had lots of moments but everytime i dipped the clutch and the load dropped the engine recovers and ticks over perfect.

got back home after driving on tender hooks thought is it water or crap in the tank. ran through another tank of fuel changed filter then it ran perfect for about a month driving as hard as you like. thought it was fixed

Yesterday under medium load it happend again and had a few moments and stammers if i drive steady i can almost stop it happening and again on light load / tick over / revving in neutral it runs happy.

the fault is defiantly load related.

I have also pulled out the pickup from the tank and tank is clean (like new) and no obvious sign of water or crap to block anything. I have emptied the fuel filter into a jug and no obvious water settled within 5 minutes will check again later.

I have also wiggled the 12v feed to the fuel pump and this has no affect.

Any Ideas ?
 
Last edited:
tottot said:
Probable the fuel lift pump going iffy.
Click to expand...
This one^^

Second not getting a cheap one, the cheap ones don't tend to last long and don't seem to like the bio in modern fuel. I like delphi, they are the best I have found but even then don't last as well as the original.
 
cheers yes did start to point that way with a bit research suppose 180000 for a fuel pump isnt to bad...... will get one ordered
 
OK so fitted a new lift pump a few weeks back and a few other little jobs and it ran perfectly for 200 miles. Then yesterday it stammered 3 times on my way home from work...... has the new lift pump failed or is there something else to blame.

had a wiggle of the the key and 12v supply close to the stop solenoid nothing wrong there.

again reving the engine in neutral it doesnt seem to happen needs a bit of load for the stammer to happen.
 
MeatCleaverX86 said:
OK so fitted a new lift pump a few weeks back and a few other little jobs and it ran perfectly for 200 miles. Then yesterday it stammered 3 times on my way home from work...... has the new lift pump failed or is there something else to blame.

had a wiggle of the the key and 12v supply close to the stop solenoid nothing wrong there.

again reving the engine in neutral it doesnt seem to happen needs a bit of load for the stammer to happen.
Click to expand...

What brand of lift pump did you fit? I use delphi because I have had britpart/bearmach/other aftermarket ones last less than a week.
 
If after installing the new Delphi lift pump and insulation block, and checking the 12v supply to the FiP solenoid [physically checking for no intermittent break in the wiring too] it sounds like excess crud in either the in-tank fuel pick up, crud in the fuel lines and/or crud in the fuel filter or sedimentor [if you've a sedimentor fitted].

1. Drain and remove the 2x filters
2. check the fuel lines for leaks and/or air being drawn into the fuel lines [replace lines if necessary]
3. if with no faults with existing lines blow back with a foot pump to clear/be 100% there's no crud
4. fit new fuel filters
5. bleed fuel system
6. start and take for a test drive.

If fault still present take a look at the intercooler hoses - is these start to break down/lose wall strength they can collapse due to vacuum causing sudden loss of power.

ETA: although unlikely, the FiP solenoid could have an intermittent internal short/break down under load. This would be difficult fault find "live..." and it's always worth carrying a spare for just this scenario. Buy a spare original G grade solenoid for fault finding/testing and on the road breakdown. https://www.lrworkshop.com/parts/STC3254
 
Last edited:
v8250 said:
If after installing the new Delphi lift pump and insulation block, and checking the 12v supply to the FiP solenoid [physically checking for no intermittent break in the wiring too] it sounds like excess crud in either the in-tank fuel pick up, crud in the fuel lines and/or crud in the fuel filter or sedimentor [if you've a sedimentor fitted].

1. Drain and remove the 2x filters
2. check the fuel lines for leaks and/or air being drawn into the fuel lines [replace lines if necessary]
3. if with no faults with existing lines blow back with a foot pump to clear/be 100% there's no crud
4. fit new fuel filters
5. bleed fuel system
6. start and take for a test drive.

If fault still present take a look at the intercooler hoses - is these start to break down/lose wall strength they can collapse due to vacuum causing sudden loss of power.

ETA: although unlikely, the FiP solenoid could have an intermittent internal short/break down under load. This would be difficult fault find "live..." and it's always worth carrying a spare for just this scenario. Buy a spare original G grade solenoid for fault finding/testing and on the road breakdown. https://www.lrworkshop.com/parts/STC3254
Click to expand...
Already done most of this

1. Drain and remove the 2x filters - my 90 only has the one up front
2. check the fuel lines for leaks and/or air being drawn into the fuel lines [replace lines if necessary] - no obvious leaking but will check a 2nd time
3. if with no faults with existing lines blow back with a foot pump to clear/be 100% there's no crud - didnt blow lines out but when i removed tank pickup pipe to inosect tank for crud the tank was so clean (like new) i dissmissed this then.
4. fit new fuel filters - done
5. bleed fuel system - done
6. start and take for a test drive. - now getting a complex about headbutting the stearing wheel lol
If fault still present take a look at the intercooler hoses - is these start to break down/lose wall strength they can collapse due to vacuum causing sudden loss of power. intercooler hoses and pipe replaced last year because old ones were tired.
 
ETA: although unlikely, the FiP solenoid could have an intermittent internal short/break down under load. This would be difficult fault find "live..." and it's always worth carrying a spare for just this scenario. Buy a spare original G grade solenoid for fault finding/testing and on the road breakdown. https://www.lrworkshop.com/parts/STC3254
Click to expand...

it is intermittent and did wonder about the stop solonoid / ignition barrel a wiggle of the key and 12v supply on the drive showed nothing obvious.

It does seem to be load related.
 
Okay, so you need to closely inspect the fuel solenoid wire and for logical fault finding change the fuel solenoid for a known good unit.

Load related faults can be a pain in the ar5e to find. For the solenoid 12v supply wire it would be worth running a new/temporary wire to eliminate fault.
 
Have you checked the turbo for sticking? Its a symptom of stuttering power if someone has adjusted the turbo pressure up too high. You get the kangaroo issue which you might refer to as stuttering. If the wastegate is sticking it doesnt adjust pressure correctly or the arm might have rust or muck on its shaft and be in need of a wire bruch and some high temp grease etc etc. Check it out as it works two ways one to much boost and stuttering and the other too low pressure and crap performance with no turbo assistance.
 
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