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Topic: 1991 GTI 8v 5dr in White (Read 1791 times) previous topic - next topic

1991 GTI 8v 5dr in White

Hi everyone. I just wanted to say hi and introduce myself and my recent purchase. Im not sure how to add pictures but I'm sure I will figure it out and get some uploaded.
Anyway I bought this car as a kind of small project what with it having an MOT already and just needing alot of TLC. There is however an issue with the acceleration that I'm hoping someone can shed a bit of light on for me?
Basically the idle is a little high but not excessive at about 1200rpm and it allows you to gradually build the revs up to about 2000 at which point its almost as if you have stamped on the pedal and the revs suddenly and uncontrollably shoot up. This is even more noticeable when driving as it almost feels like the engine itself is rocking when you accelerate in every gear. If you use the clutch to ease into the gear its fine but its almost as if you can only accelerate or decelerate. If you do manage to find level throttle it chugs and splutters.
Does this sound like anything anyone else has encountered? All help is really appreciated as I am a complete novice when it comes to this kind of thing. Thanks in advance 😬

Re: 1991 GTI 8v 5dr in White

Reply #1 –
Hi and welcome... that’s a bit of an odd one.
2 quick easy things you can check.

1. does the accelerator pedal operate smoothly. Push it with you hand and make sure it’s not notchy and that it returns well of it’s own accord. When I got my current one the arm was bent and would catch on the side of the heater box.

2. Under the bonnet does the throttle arrangement move freely and return by itself. You’ll see the lever the throttle cable attaches to, give it a push and make sure it moves freely.

I doubt it’s either of those things but they are the most basic so a good place to start and at least rule out anything interfering with smooth operation of the accelerator.

Good luck

Re: 1991 GTI 8v 5dr in White

Reply #2 –
Hi mate thanks for the reply. The pedal is fine and so is the arrangement under the bonnet. Both move freely and smoothly. I replaced the accelerator cable just in case it was something to do with that but its still the same.
It seems to get to a certain rev range and then even though im not moving the pedal or the throttle arrangement any more its as if im accelerating sharply. Like it kind of bursts into life kind of thing. Very odd. Its not possible to find and even throttle pressure without it being under load but when it is driving and you find even pressure it chokes as if its going to cut out and judders 🤔

Re: 1991 GTI 8v 5dr in White

Reply #4 –
Well at least you've rules out the basics. I'm wondering if it could be an issue with the either injectors themselves not spraying equally or an Issue with the ECU giving bad instructions to the fuelling. But I'm afraid although I have same engine now in my Golf I'm not that familiar with the DIGI, all previous Golfs have been earlier K-Jet which runs a mechanical continuous injection system.

Another simple thing to try might be to clean the ISV (Idle Stabilisation Valve) . It's silver metal cylinder looking thing on top of the engine. Not sure if that would give the symptoms you describe though.

There was a how to on the old site, hopefully it was copied over when the site was updated.

Re: 1991 GTI 8v 5dr in White

Reply #5 –
Yeh no thats fine mate. I really appreciate your advice anyway. Ill give thst a go and see if ot makes a difference when I get home tonight. Ill keep you posted. Thabks again 👍🏻

Re: 1991 GTI 8v 5dr in White

Reply #6 –
Hi all. Quick update on the throttle surging. I had tue car over to a friend of a friend who is a VW master technician. Had a good look over the car and I'm pleased to announce that ive bought a decent car by the sounds of it. Just needs a bit of tlc and a few minor bits. Anyway he noticed that my vacuum pipes didn't seem to be routed properly and having done a bit of Google work found a few images of how they should go so I can have a look at that.
The HT lead that goes to the coil stripped itself when he removed it so for the sake of a few quid and the fact that they look a but old anyway I've ordered new HT leads, dizzy cap, rotor arm and coil to see if that has any affect.
He is going to change the timing belt and do a timing set up because he thinks it could be a bit out and that could be contributing to the problem.
Does anyone have a routing diagram for the vacuum pipes? Mines the PB engine digifant 8v gti.

Re: 1991 GTI 8v 5dr in White

Reply #8 –
If you search MK2 GTi vacuum lines you should be able to come across the factory sticker showing the routing

Re: 1991 GTI 8v 5dr in White

Reply #9 –
Awesome. Thanks. Mine is no where near as clean as that haha. I'll get googling now and see if I can sort it. I'll keep you posted.
On a different note, how do I add pictures to this chat so I can try and upload the progress on here?

Re: 1991 GTI 8v 5dr in White

Reply #11 –
Hi All. Update on the surging problem. After replacing the throttle cable, dizzy cap, ht leads and reattaching the vacuum pipes in the correct way etc. It turned out to be a dodgy connection/wire to the harness connector leading to the full throttle switch. Makes sense now I've sorted it because it was as if you were suddenly giving it full throttle 🙄 but hey ho at least the surging has stopped.
Thank you so much for ur help though guys.

Re: 1991 GTI 8v 5dr in White

Reply #13 –
Yeh definitely. There are a few other little niggles such as the electric windows dont seem to like going down and back up again on the same journey for sone reason I have to stop the car, turn it off and then go again which I am assuming has something to do with the immobiliser wiring perhaps? Also the interior light only gets dimmer rather than actually going off when the door is shut so there is obviously some kind of wiring problem somewhere but that is a job for another day. It runs fine at the moment so thats the main thing.