Club G40 Forum
Technical => Engine and Transmission => Topic started by: Dougy on March 05, 2008, 12:06:40 pm
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Hi Guys
This could be linked to the fuel pump which is very noisey but I'll see if anyone knows the answer
Right car drives fine and no problems until i go over about 4.5k or boosting.
After that every 5 seconds regardless if its sat ideling or driving, the revs drop for a split second.
If I am driving then it only happens if the revs are under 2.5k which makes doing 30 very difficult.
Very annoying as the car jolts asif its running out of petrol.
The only way to stop it is turn engine off and take keys out.
Could this be the fuel pump? Any ideas
Thanks
Dougy
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a problem over 4.5k or on boost could well be fuel pump not up to the job. Do you have access to a fuel pressure gauge you can hook up while driving? Then see if the pressure suddenly drops at 4.5k or on boost? Could do with finding out pretty soon really as leaning out could cause you a whole load more problems!
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[quote pid=111 author=hayesey date=1204719015]a problem over 4.5k or on boost could well be fuel pump not up to the job. Do you have access to a fuel pressure gauge you can hook up while driving? Then see if the pressure suddenly drops at 4.5k or on boost? Could do with finding out pretty soon really as leaning out could cause you a whole load more problems![/quote]
Well as it is a conversion and was 1.0 and then a GT I can only suspect it has not being changed
Think I will be picking one up from dan tonight and fitting it then
Would this cause shit fuel consumption?
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no I wouldn't have thought so, that kinda suggests you've got a sensor or two down and the ecu is in limp home mode. Although perhaps the fact it goes a bit mad on boost or over 4.5k is giving the ecu the hump? I think you need to get the pressure gauge on it or try that spare pump first, see if that helps and take it from there. Could well be a non-MPI pump by the sounds of it.
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Cheers Hay
I'll stick it on tonight and report back
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When I first did my conversion the SPI fuel pump was pretty tired - and gave the exact same symptoms when booting it. Sorted it straight away by fitting a G40 pump.
You can normally pick up mechanical oil pressure gauges cheaply and use them as a pikey fuel pressure gauge. I ran with one for a while to keep an eye on things.
Edit to add...
Didn't get the same bucking around at idle though. Are all the vac hoses plugged in properly? Lambda all good?
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[quote pid=115 author=Andy date=1204720530]When I first did my conversion the SPI fuel pump was pretty tired - and gave the exact same symptoms when booting it. Sorted it straight away by fitting a G40 pump.
You can normally pick up mechanical oil pressure gauges cheaply and use them as a pikey fuel pressure gauge. I ran with one for a while to keep an eye on things.
Edit to add...
Didn't get the same bucking around at idle though. Are all the vac hoses plugged in properly? Lambda all good?[/quote]
Ye i think the pump will sort it hopefully as it whines like an hamster at the minute.
At idle you can hardly notice the drop it rev's as it is only a slight drop but noticed when it is doing the fuel pump whine becomes louder
The whole thing is very annoying when in traffic and travelling at 30mph as it tends to be low 2nd gear and low 3rd gear
I will check hoses tonight and all connections, I know the knock sensor connector is fucked so that might be causing problems too or might not even be connected but I have a spare
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Fairly sure you can unplug the knock sensor and still have the car run fine - but it'll probably use more conservative maps as it'll know that the knock sensor input is open circuit/disconnected.
Could probably get around it by sticking a suitable resistor in the wiring loom instead.
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Anyone know a easy way to get fuel line clips back on lol
Struggling like fuck
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put new jubilee clips on lol the original ones are slags
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are they those pinch clip things as standard? If so then they aren't really re-usable, fuel pipe clips are the best bet (screw on ones) but jubilee will do at least for the time being. The problem with jubilee clips is that you have to over tighten them to keep a seal under high fuel pressure whereas proper fuel pipe clips are designed to put a more equal pressure around the pipe and seal without being as tight.
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Well that was fun
Had trouble finding some small jubilee clips in the garage but finally got there
Put them on "thought" they were tight started it up and spayed fuel all over like Haysey said you need to overtighten them but unfortunatly he posted after I put them on.
So took them off and went to disconnect the fuel pump again distracted as I was talking to my friend on the phone.
And who can guess what happened?? Well put it this way now I know why birds don't like giving head!!
I got sprayed in the face with about £fivers worth of fuel and fuck me did it sting.
at this point still on phone eyes burning says to mate "I can't see i'll have to call you back"
Note to novices don't talk on phone whilst removing fuel pump
Anyway after a quick wash in ice cold water think I will do it again after this post anyway as I can still feel my eyes stinging. I put it all back together and took on the test drive to find I still have the same problem.
Any suggestions guys?
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id say sensor issue, unplug ecu, reset it, and the take out and see if it does it straight away, i dont know how quickly limp home mode kicks in, get raes laptop to check it...
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yeah was gonna say, get rae on the scene with his vagcom if you can.
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Well got up this morning started driving to work did 1 mile and smelt petrol it was pissing out of the fuel pump
Note to self never use jubilee clips
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[quote pid=160 author=Dougy date=1204799888]Well got up this morning started driving to work did 1 mile and smelt petrol it was pissing out of the fuel pump
Note to self never use jubilee clips[/quote]
ive had jubilee clips on mine and theyve been fine... so far lol
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sorry dougy, didnt reply to yr test... normal vag ones are single use.. get proper fuel pump clips if you can - far easier to work with!!!
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Hello guys I'm back again and i'm proper puzzled now really need some help
Changed the fuel pump and suprise suprise it didn't change anything but strangly it made an even louder squeel than my previous one.
Now car still runs like shit, unplugged lamba and sounded like it was running better but made no difference to the running still slight drop in rev's above 2.5k.
Now apart from the above other obvious faults is terrible fuel consumption I'm getting around 35 miles to £10, car smells of fuel all the time running very rich and when you put your foot down there is just loads of smoke which I presume is the fuel.
Has anyone got any ideas cos i'm all out
Thanks
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hmm does seem strange, id try a different lambda probe first, maybe the probe makes it run shit, and with it off, it will over fuel so run shit?
it can only be so many things really, all which can be swapped!
if not probe then do the blue temp one...
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Going to Rae's tonight
Hopefully get to the bottom of this
Will report back
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Well went to Rae's last night and hooked it up to laptop to try and find the answer to this problem
Alternator = Fine
Lamba = Fine but sluggish
Timing = Fine
Dizzy = Fine
Battery = Fine
Fan = Was wired up backwards explains slight temp issue (just another problem caused by the person who did the conversion)
Blue temp sender = Fine
Knock Senor = Disconnected
So we could not pin point the exact problem
But it did narrows it down to a few things to check
Coil
ECU
Fuel
Anyone want to take bets on which one it will be??
or can think of anything else to check
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my vote is on the ECU because that's what was making my car get the hump a while ago till I replaced it!
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Well suprise suprise its not the ecu
Car is running very rich and my money is not on the injector rail
It has to be some problem with the fueling system
Any ideas guys
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what chip does it have?
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had a standard one on before then switched it with a Jabba one
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Right this is starting to get right on my tits now
Only thing that it could be now is the Injector Rail or Intank Fuel Pump
Changed the fuel filter yesterday and made no difference
Could an injector rail cause this much trouble?
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in tanks are £20 new... i think i might have a fuel rail with injectors you can try if needs be
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I have injector rail to try its the intank one I don't have which I want to try first as the pump other fuel pump is still making a noise suggesting that theres a block intank pump