I have a 1995 Volkswagen Golf III and it has been puzzling me as to whats wrong with it. I haven't had a chance or the money to do anything to it in a while but i'm hoping to start back on it sometime in the spring. Ok, what I'm leaning towards that could be the problem is a fuel pump. Like the novice car repair person that I am I bought a used fuel pump not realizing that this was a bad idea. The pump works but I do not know whether or not it is pumping at its full potential. My symptoms are this: The car will not idle, if you pump the gas it will run at the high end 2000-6000 rpms, but once it goes below the 2000 threshold, it will choke down and die. I have replaced the FPR, the MAF, the Fuel Filter, Air Filter, cleaned TB and Intake, replaced the intake manifold gaskets, (both of them) cleaned EGR (port in intake clogged with carbon, will a broken EGR cause a no idle condition, if so how to test it?) I have also replaced the spark plugs, wires, distributor cap and rotor. I will be getting a fuel pressure gauge from my uncle soon to test the pressure but I did notice this. Today I unplugged the MAF, even though I did replace it, to see what would happen. Unplugged it and the car idled. However it only idled without help (ie pressing gas pedel) for about 20 seconds.. which is 20 seconds more than it would idle with it plugged in. As it won't idle at all with it plugged in. Also, I've read on here that unplugging the vacuum line on the FPR will increase the idle fuel pressure, is this correct. I tried this incase I maybe had a weak pump and to see if this would positively affect the idle of the car (to see if it could be the pump) but I do not know if this is a good test or what. My question is does it seem like a fuel pump to you guys, (used pump) should that be the first thing I check? I was going to ask about temp sensor because my temp light was flashing but the car wasn't overheating but I put more AF in the system and it went away. Are there any sensors other than the MAF that would even remotely cause this problem or should I start with a fuel pump?Thanks for the help!

Also have a video of it: http://smg.photobucket.com/albums/v3...current=vw.flv

 

OK, so after you run the car, check under the car at the cat, and see if it's glowing red, that would mean that you're cat is plugged, which happens.
2) Get some MAF spray cleaner and spray the sensor. I unplugged my sensor and the car died. So I dunno why it runs better. When you spray the cleaner, the car will want to die, so you have to keep constant RPM's up.
3) Could be dirty fuel injectors, but I dunno. That MAF is totally weird and contradicts certain problems. The smoke that came out the exhaust would indicate that either runing really rich, or dirty cat.

I'm not really sure, I wouldn't think it would be the fuel pump.

 

As of right now the cat is gutted, (im gonna get a new one but i thought it was clogged and I wanted to eliminate that prob) I've tried cleaning MAF to no avail. Car does run better with MAF unplugged however if you do unplug the MAF while the car is running, it will shut the car off, but if you unplug it with the car off then start it should run, thats how it is for me anyway. This car is soo confusing.. lol

 

Ok,that makes more sense. unplug it first.Ok, so did you check vacuum lines?? Hidden leaks usually come from the throttle body, even little holes will affect idle. What's the story on the throttle body?? Have you tried any products like carb cleaner, GumOut, or any fuel injector type?

 

When you say TB, do you mean the gasket between intake and TB? and I ran some fuel injector cleaner through it back when it was actually running well enough to drive. This car is undriveable in its current state.

 

Well, yea, but I was talking about vacuum lines that come off the throttle body. Some hoses will dry rot, and crack and lose vacuum.

 

I shall check that tomorrow, but I don't think i've miss any lines, (I went through and replaced a bunch a while back) will double check tomorrow.

 

Alright, im stupid. I went out there this morning and thought to myself, self, double check everything you've touched on this engine to see if something is missing or isn't right. I look and look and look, and finally I find it. The hose that goes from the Intake Tube to the ISV or IAC whatever you want to call it, is not pushed into the intake tube therefore not being monitored by the MAF. I push tube in, start car, it bitches at me a couple times until it gets used to it, and i let the car run for 15 minutes until it reaches operating temp. It idles the whole time.

One question though, although the car did idle, I noticed that it wasnt idling at a consistent speed. It would idle around 1k (its cold out) for a few minutes then start wavering from 750-1000 then even back out for a few minutes. Could this be as simple as cleaning the ISV valve (got excited when she idled and haven't cleaned it yet) or should I look at something else to even it out. I have all my power back it seems, (haven't road tested it yet but something as simple as turning the A/C on would kill the motor and I turned it on while idling and the engine raised the idle speed as normal).

Please make suggestions, I want to know that I can trust this car before I start driving it. The last time I was actually able to drive it, it would drive great until I reached operating temperature and start sputtering on take off after that. The ISV tube was connected then, LOL. Since then I can't remember exactly what i've replaced but I have replaced the MAF, FPR, and all the goodies I listed in the first post.

Thanks for the advice, it has helped me and will hopefully continue to help me as I learn more and more about these interesting little cars.

 

I'm assuming the ISV (Idle stabilizer valve) came off or did you take it off?? Also, the FPR (Fuel pressure regulator) You sound like an eye chart..lol...and I'm in aircraft maintenance!! Should be good to go, I haven't seen too many of those regs go to crap.

Now, don't feel a helluva lot better, and happy that it works???!!!!

 

I took the line off when I removed the intake to do some work and it slipped my mind to put it back on. Like I said the idle isn't totally steady, was just wondering if the ISV needed cleaning. I've heard they can get dirty and not function 100% and that spraying it out with cleaner and dropping a bit of oil in it helps, can you verify this.