GTi engine idling problem

Post by **iwan74** » 05 Apr 2008, 23:21

Hello everyone, this is my first post on the forum, hope someone can help!

The previous owner of my van fitted a golf GTI engine which I believe to be a 1.8 8v digifant engine (if it helps the engine code is 026103373AA)

It has been working fine until recently where it has developed an idling problem. It starts fine and runs for about 10-15 seconds before the revs suddenly drop and the engie stalls. It drives fine though as long as I keep the revs up when I stop at junctions etc.

looking at the engine, I noticed that a connector to a sensor? (VDO 037906457A) which is attached to the air intake and throttle body had come away. When I reconnected it the van no longer stalls, but revs at about 3000 rpm instead!

I'd be grateful if someone could

1) identify the part that I reconnected

and

2) give me some advice/ideas on how to tackle the problem.

Many thanks.

Post by **HarryMann** » 06 Apr 2008, 09:37

Have pointed someone at your question in the hope that you might get an answer

Post by **andysimpson** » 06 Apr 2008, 11:16

Reconnect wire so it idles at 3000rpm, now gently tap that vdo valve and see if revs come back down. If revs do come down, cleaning out the valve may cure it, leave it soaking in petrol overnight. If you still have no joy, try and find another valve at scrapys, was used on lots of audi/vw's. It's also possible it was never wired properly when engine was fitted, this will not be easy to find, depending on what engine type it is.

The number you have put down is just a casting number, the actual code is stamped into engine block below spark plug no 3, I would think its a PB. Is the injection system mechanical or electronic?

Post by **iwan74** » 06 Apr 2008, 21:53

Thanks for the response, much appreciated.

I'll try to get hold of another valve and give it a go.

I'm pretty sure the fuel injection is electronic, I believe the engine is from a 1990 mk2 golf.

The weird thing is that it has worked fine for the six months I've owned the van and I'm pretty sure it hasn't been connected up in that time.

Also, the air intake/air filter is a custom made job, could that be contributing to the problem?

Post by **andysimpson** » 06 Apr 2008, 22:02

iwan74 wrote:Thanks for the response, much appreciated.

I'll try to get hold of another valve and give it a go.

I'm pretty sure the fuel injection is electronic, I believe the engine is from a 1990 mk2 golf.

The weird thing is that it has worked fine for the six months I've owned the van and I'm pretty sure it hasn't been connected up in that time.

Also, the air intake/air filter is a custom made job, could that be contributing to the problem?

Sounds like throttle housing is dirty. Basically a fixed amount of air gets past the throttle, the ecu will then bypass the throttle with that valve to get rpm where it wants and to account for temperature alternator load etc. They can be set to get away without valve. If you remove the large pipe going onto the throttle you will see it has oil deposits, there is a screw on the throttle housing, remove it, clean down hole with carb cleaner, clean the throttle flaps especially the small one, refit screw, you should now be able to set idle speed with that screw.

Post by **iwan74** » 06 Apr 2008, 22:11

thanks again for the info, I will give it a try and let you know how I get on. I might try to adjust it and re-instate the valve. To be honest the throttle response is a bit funny, all or nothing, so it probably makes sense that it has been adjusted in the past.

Cheers.

Post by **andysimpson** » 06 Apr 2008, 22:12

iwan74 wrote:thanks again for the info, I will give it a try and let you know how I get on. I might try to adjust it and re-instate the valve. To be honest the throttle response is a bit funny, all or nothing, so it probably makes sense that it has been adjusted in the past.

Cheers.

that screw could never get it to 3000rpm, that valve is either sticking or getting bad instructions. The throttles are weird, the tiny open up to about 2/3rd pedal movement and then the big one opens suddenly.

Post by **Sir Chad** » 17 Apr 2008, 21:13

the temperature sender can cause idle problems too

Post by **HarryMann** » 17 Apr 2008, 22:24

the temperature sender can cause idle problems too

If that's the thing bolted to the middle of the engine block, then AndyS has mentioned that before too... think it might also cause cold-start problems.
Overall not brilliant examples of design...

Not for longevity anyway, can be very annoying when getting aged

Post by **Sir Chad** » 18 Apr 2008, 21:08

don't get it confused with the other thing bolted to the engine block i.e the knock sensor.
the temperature sender is held in to the plastic elbow at the top of the block adjacent to the dizzy. the water pipe from the water pump connects to. It's held in with an R clip and seals with an 'O' ring.
I agree design is pants, the plastic elbows are renowned for leaking to.

Post by **HarryMann** » 18 Apr 2008, 21:15

Right, thinking of an earlier engine temps sensor that's a pain, on the PB series maybe? Picks up block tempreature...

Post by **iwan74** » 05 Jun 2008, 22:30

Many thanks for all the info, had some trouble getting hold of a second hand idle valve, ended up winning 3 of them off ebay!

Anyway, I changed the valve over and reconected it only to find the same high revving problem. So I guess it's a problem with the ecu, or rather how the bloke who did the conversion wired it up.

Is it worth trying to diagnose the fault or do you think my best course of action is to try to set the idle using the csrew in the throttle body?

Any info greatly appreciated

Post by **nindy** » 10 Jun 2008, 21:39

have you tired the club gto forum they are great on there dude i have a 16 v ecu if thats any good? pm me