88 Golf starts but won't stay running

"David Craig" wrote

thinking some kind of fuel pressure regulation is faulty but what do I

Cold start stuck on? Digifant module might be defective? Check all the signals and sensors that go to the digifant unit. Failed electronic injectors?. I think if this was my car I would shotgun fix it and just go to a pull it yourself and pull the Digifant unit and the electric injector rack with the 4 injectors that comes off. Rather than spend hours troubleshooting unless it is simply the cold start system stuck on, including the cold start injector (I forget, have not worked on mine for a long time as it runs perfect - have, among other cars an 88 Golf with an Audi engine I put in it running Digifant). My Digifant has run flawlessly for years. There may be error in my remarks as I have not looked at the Digifant config in a long while.

Harry

What kind of injection has it? CIS or digifant?

SFC

"David Craig" schreef in bericht news: snipped-for-privacy@4ax.com...

Here in the USA there is no "cold start injector " for that FI system. Doing a "blanket" replacement of parts isn't the way to fix things, especially after a bunch of parts are replaced and it still has the issue.

Is it Digifant with electronic injectors or the older CIS-E system.

Woodchuck, It has a fuel rail with injectors....so according to my Bentley manual, it is a Digifant II system. I don't think it is an injector problem though, because when it runs (albeit for about 4 seconds) it appears to be smooth....although is sounds a liitle like an old fashioned air cooled VW bug when it does. Hope this helps.

Thanks again, Dave

Also, I noted that the engine would only start if I disconnected the boot that connects the air filter box to the engine intake. If I reconnect the boot, the engine won't even try to crank. When I disconnect it, after only a few seconds of cranking, the engine starts. I am reading my Bentley manual and will post any more clues that I can think of.....again, thanks to everyone for their help!!

Dave

I can now crank the engine with the boot on. The air flow sensor was stuck. It still only runs a few seconds before it floods out. I also changed all of the vacuum lines from the air box, the carbon canister bypass valve, the fuel pressure regulator and all of there connections to the intake manifold.

I would pull the small vacuum hose off of the fuel pressure regular which is on the fuel rail and check for fuel present. I have seen the diaphragm rupture and fee fuel into the intake manifold. Since the exhaust manifold is near I would run the hose into a rag when you start the engine briefly.

Woodchuck, Funny you should mention that.....I replaced the vacuum lines this morning with clear tubing and just 5 minutes ago noticed fuel in the vacuum side of the fuel pressure regulator when I was attempting to start. It was moving slowly toward the intake manifold. (I could tell because there was a bubble in it). When I disconnected the fuel pump(s) and then cranked it over a few times....it overcame its flooded condition, ran as usual for a few seconds and then died....but I noticed that the fuel in the vacuum side of the fuel pressure regulator was then gone. I did go to a U-pull-it parts place this morning and tried a digifant II ECM (the brain), an engine temperature sensor (the one on the gooseneck at the front side of the engine) and an Oxygen sensor. None had any effect. I am off to the store to pick up a new regulator. I will keep you informed, but please keep mulling things over and continue to offer suggestions. You obviously know what you are doing.

Thanks again,

Dave

Thanks to all with a special thanks to Woodchuck. You were correct!! I replaced the fuel pressure regulator and she cranked right up!!

But, I have a new problem, the transmission intermittantly goes in gear .......sometimes it will and sometimes it won't....and it doesn't matter if it is Drive or Reverse. I changed the fluid and strainer and found alot of gunk......and the fluid was dark brown like muddy water. It seemed a little better after changing the fluid but I am still having issues. I am going to take it to a transmission shop to have it diagnosed unless anyone can offer a suggestion. By the way, the vehicle sat without running for 2 years before I bought it.

Thanks,

Dave

Excues me, I beg to differ. In depends on the situation. He did not replace any digifant parts. Had he not be able to diagnose the part and swapped the rail like I said, it probably would have fixed it also with the different part affixed. I can go either way and have rebuilt tons of engines and automatic transmissions and lots of electrical service. Sometimes on old cars it is easier and cheaper depending on the situation to replace parts or swap parts it they are handy and cheap. I go by time. Though I usually find the problem right away I would not hesistate to try a swapped part if it saved time.

Harry

Start searching for a tranny on the junkjard. Much cheaper that trying to rebuild yours if it is shot.

It maybe just had the valve body plugged up. A shop should be able to take it out and clean it..

Nice.

I don't use the "shotgun" method to fix cars. Can one imagine if a customer comes in the shop and I say... well you need everything replaced and it may fix the issue. Most of the time it's best to check all the easy things first to reduce what may be wrong. Then you know what it isn't! The ask what's left that could cause the issue?