GolfGTIforum.co.uk
Model specific boards => Golf mk1 => Topic started by: richandhazel on 28 July 2003, 13:42
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Hope someone can give us some inspiration as we're facing defeat with this problem :-[
Marcus (MK1_BOY) came round yesterday with a problem with his Mk1 GTI Campaign that I just can't fix. >:(
It starts fine when cold, however when hot and left for between 10 minutes to an hour and a half it just will not start. I've checked for the favourite, dripping injectors. Its definately not that. In fact it seems to be the opposite, no fuel. Pulled an injector out and sure enough, no fuel. Took the boot off the metering unit and lifted the sensor plate and sure enough fuel came out of the injector. The sensor plate is correctly positioned at the bottom of the cone and is central.
Cracked the supply line to the metering unit and we have good fuel pressure, so I'm guessing its something to do with the metering unit.
Anyone got any ideas? Just seems really odd that it only does it when the engine is hot. ???
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Or if its not the metering unit could it be wrongly routed fuel lines, ahd a similar problem before when a fuel line ran near the manifold causing fuel evaporation??
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Check that the fuel system is holding pressure when the engine is off. Had a fault like this, changed the pump and accumulator and this fixed the problem. Think it was the non return valve in the pump letting the fuel back, or the acc. was dead so could not top up residual fuel pressure when the engine was not running. Low fuel pressure causes the fuel to boil in the lines and you end up with a vapour lock, let the engine cool and the fuel vapour condenses and the engine starts. There was a mod for earley Porsche 924 that used a relay to fire the cold start injector while cranking to help this. (different circuit to normal cold start) Hope this helps, Steve.
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Cheers for all your help fellas, just to add insult to injury It misfires when I've been driving for a while, thought Rich and myself had sorted that one but it seems not.... its got to the stage the other day when it stared to misfire and within 10 minutes it actually cut out on me on a hill, turned the engin off, turned it back on and it was fine... Its as if my top water hose has burst and it spraying all over my dizzy cap( I know this cos it hapened to me the other month) but we've checked the Dizzy cap and it seems fine... Think you boys may have the right Idea, I'll have a check asap.... Again cheers for all your imput fellas... :(
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We do have a Mk2 one that we can try. I think the metering unit itself is the same, its just the airbox thats different.
The only thing i can suggest is going to a scrappy and getting hold of another metering unit. Gotta be worth a try.
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Thats a good one to look at, I'm sure they are routed correctly but its well worth double checking, thanks
Or if its not the metering unit could it be wrongly routed fuel lines, ahd a similar problem before when a fuel line ran near the manifold causing fuel evaporation??
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This could be it Marcus, its certainly been mentioned more than once before and well worth looking into, thanks Mk1.
Marcus, I also took the liberty of of posting the question at ClubGTI. This NRV has also been suggested there too:-
http://www.clubgti.com/forum/topic.asp?TOPIC_ID=26848
I think we ought to look at that, especially as you replaced your fuel pump recently.
Check that the fuel system is holding pressure when the engine is off. Had a fault like this, changed the pump and accumulator and this fixed the problem. Think it was the non return valve in the pump letting the fuel back, or the acc. was dead so could not top up residual fuel pressure when the engine was not running. Low fuel pressure causes the fuel to boil in the lines and you end up with a vapour lock, let the engine cool and the fuel vapour condenses and the engine starts. There was a mod for earley Porsche 924 that used a relay to fire the cold start injector while cranking to help this. (different circuit to normal cold start) Hope this helps, Steve.
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I had the same problem on my MK1. It turned out to be the fuel return valve. The fuel wasn't returning to the tank when i parked up thus causing vapour locks in the fuel lines due to the heat of the engine. When i restarted the car it either cut out straight away or misfired for a while afterwards.
Hope this helps.
Tom
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Worth a shot... Just need to find out what that is ??? ??? Gonna have a try of all these on Sunday.. 1 other thing, I took her out Wed night for 15 minutes and after 10 she started misfiring.. Now I've had this problem reciently in the past where it was misfiring and it turned out to be the ignition coil, after a very expensive route(I know my fuel pump will be fine for a few years) and it turned out to be the connection from the wires to the ignition coil BUT could this cause all my other probelms. Most syptoms make sence but the lack of fuel ??? ??? Any other last thoughts B4 I have to look at the metering unit?? Please??
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Hi Marcus, just found this:-
Starts hard hot- A couple things to look at are system pressure at rest, and CO setting. If the check valve won't hold rest pressure you will have a heck of a time getting going again after the car sits for 5 minutes. The spec for holding system pressure is that it must hold at least 20 psi for 1/2 hour
at: http://ncr-pca.org/tech/tech-cis.htm
Maybe something went wrong with your NRV when you changed your fuel pump???
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Ok boys, here's the latest.. I tried to replace the metering unit the other day with one form a d reg gti we had, looked the from 1st glance but at a closer look its got a few differences, maybe could of adapted it but want to keep as much mk1 as possible, plus i was really oily and nasty. I decided to swap the bar that stops the air sensor plate from declining to far into the cone, oh year, broke the clip on mine trying to adjust it >:(.. Rich noticed the other day that the bar was the opposite way round on his unit, I swapped mine round so the tiny pin now makes contact with the metal arm now.. It seems to have problems starting full stop now, try once for about 5 seconds, nothing, 2nd time just about chugs into action, then when I go for a spin it splutters in high revs >:( >:( Good news is it seems to be starting when its hot same as when its cold so sort of fixed a problem.. Got home in it today and replaced the ignition coil with MK2 one, no better.. Someone please help me, I seem to be loosing my will to live now, Just want to take her out, its so nice out there and I'm at home on the internet... :'(
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You gotta look at that check valve Marcus. We've had too many people suggest it to ignore it. Feel free to come over...........I'm here all day.
My electric window switches are all done. I'm now fitting some speakers and wiring up the stereo and VDO gauges.
Hottest day ever today. 8) 8) 8)
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Is very very very hot dude.. went rounds bens old house and been in the pool, nice, then a nice air con car to get me home, been lovely... anyhoo, which valve is the non return valve, tried looking in my Hates manual but you know what there like >:( ??? Would have come over mate but I dont think my car will make it over to your, seems to misfire as soon as I go out in it and gets worse, didnt even make it round the block the other day. :'( Is a sorry state of affairs..
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DO YOU HAVE A FILTER BETWEEN THE TANK AND PUMP?
IF YOU DONT OR PREVIOUS IT DIDN'T YOU COULD HAVE ALL MANNER OF STUFF IN THERE. (RUST) YOU CAN REBUILD YOUR METERING HEAD... I DID ;D THERE IS A FINE MESH GAUZE IN THE MIDDLE, MINE HAD RUST PARTICLES IN IT. >:( BUT BE CAREFULL WITH TOP FUEL OUTLET CONNECTORS AS THEY ARE SOFT & KEEP THE TOO MATING SURFACES CLEAN. ON REBUILD MINE SEEPED FUEL FOR A SHORT WHILE THEN STOPPED. MUST HAVE THE FILTER THO.. TRUST ME. ;)
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Ok, We've sussed it, well Rich did...It turned out the be the tiny filter between the first fuel inlet pipe directly from the fuel tank to the fuel pump... Just inside the fuel pipe theres a tiny filter and it was clogged up with loads and loads of cr*p... Unbelievable, been out of action for about a month and it turns out to be a little bit of diry.. >:( :'( ??? Well I've heard about the fest, sound like there were a few good peps there, apart from techno freeks on Sat eve... I could have been there, been thinking with Rich, would have been inbetween Adams and Riches car, Nice car Adam, not sure about all the sound equ Rich says you have in there, weighs the car down a little... But looks good Esp in the pics next to Riches car, and no pink Photos this time.... Anyhoo, look out for me at the next fest, I'll be there for sure.... Keep your ears peeled... ;)
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P.S - I'm so going out in her after Top Gear...
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You're spot on mate, full credit to you ;). Whilst checking out Marcus's non return valve on the fuel pump we discovered the fuel pump inlet gauze was full of deposits/rust. Cleaned it all up and, touch wood, its all now behaving. Of course we now realise that this is leading us to another problem. Where the deposits came from in the first place. Looks like that fuel filler neck is going to need replacing ASAP.
Marcus, glad you're up and running now........sorry I didn't post last night, was just too tired and the pub was beckoning. Just sorting some stuff out with my website and the pictures will then follow soon.
DO YOU HAVE A FILTER BETWEEN THE TANK AND PUMP?
IF YOU DONT OR PREVIOUS IT DIDN'T YOU COULD HAVE ALL MANNER OF STUFF IN THERE. (RUST) YOU CAN REBUILD YOUR METERING HEAD... I DID ;D THERE IS A FINE MESH GAUZE IN THE MIDDLE, MINE HAD RUST PARTICLES IN IT. >:( BUT BE CAREFULL WITH TOP FUEL OUTLET CONNECTORS AS THEY ARE SOFT & KEEP THE TOO MATING SURFACES CLEAN. ON REBUILD MINE SEEPED FUEL FOR A SHORT WHILE THEN STOPPED. MUST HAVE THE FILTER THO.. TRUST ME. ;)