fuel system trouble shoot

My '87 Jetta starts and runs for about 30 sec. Then sputters like there's no fuel. It starts right back up but then the same thing. Any trouble shoot suggestions? The car was overheating and I replaced the water pump and thermostat. I removed the intermediate shaft and had to reset the distributor. There are quite a few components to the fuel system. It has CIS (Continuous Injecton System) fuel delivery. It is a manual transmission 1.8 liter 8 valve. I checked for fuel flow from both fuel pumps and it was strong and steady. Would anything else but the fuel system cause the car to stall? :banghead:

But it runs when you step on the gas right? Sounds like the catalytic is clogged that would cause overheating, loss of power should be obvious. As long as it is not electrical, maybe your fuel filter is clogged; you need to check fuel flow AFTER the filter. Maybe, your fuel pumps are being strained. When this happens your fuel relay may melt right where the soldering is. It is number 65. Take it out and take it apart. See the solder on the main plug use more solder to fix. After it is fixed or OK plug back in without the box cover so that you can depress the magneto switch with your finger and listen for the pumps to work. Each pump can be unplugged where they are so that you can seperate the noises. I once hammered a catalytic after I confirmed that it was clogged and it fixed it but then might not pass emissions. However, fresh exposed catalytic rock will help. You could have a vacume leak. Right around the air flow sensor to the mainfold can be nasty leaks because they will seal until you drive, so man handle the rubber as if to open the leak up. By disconnecting the hose line under the manifold up to the rubber is enough to cause it to stall immediatly. If you went through all the checks up to replacing the computer make sure that it is not too lean because that is not listed in the check list before you buy a computer.

well i'm going to try to fix the same damn problem on a 96 jetta for my buddy he says it will go for a fewm seconds or so then cut off but start again and just keep doing it :( don't really know where to start :(

Following is a reply I just added to my post for my boys 92 Jetta. Not sure if that is the CIS system you mention. If your car has the flap typre air flow sensor, It may be possible that there is a NO contact swtich on that flap that has to make (close) to keep the fuel pump running after the engine starts. Ny boys symptoms sound familliar with what has been posted here. Not sure if these are the same injection systems. (Not real familliar with VW.) My Audis, have/had a round disk/plate that raises as the air flow increases. On one of them, it would not start or started then dies. (Bout 4 years ago, not sure on the details.) On this one, the plate was stuch down. Don't rember if I had to loosen it and recenter in the opening or if I carefully lifted and release it to free it up. Anyway, that took care of that one.

SO... With what is above and copy of reply below, heres 2 conditions that prohibited the fuel pump/engine to stop running after the engine has started and key repleased.

Good luck.
c150L

Went to pick up the car last evening. Prepared with an old tire to tie onto the back bumber so I could push it back here with the XT-6. (Kinda nice to have a height control to line up the bumpers closer..) Anyway, he tried starting the car. I could hear the FP kick in breifly, then he'd crank and it would start. Then it stops.

Popped the hood, I was expecting to see one of the KE-Jetronic continous injection systems (if that's what they are called) like my VW Rabbit and 3 Audis had. What I found was an eletronic (I didn't look too close) injection system. Looked for the air box and saw what appears to be a flap type intake air flow sensor on top of the airbox. just on the side of it, I see the hose clamp for the inlet tube to the throttle body is not on the tube. Closer look reveals that the inlet tube is not actually on the air box. Close, but about 1/4" gap on top and bottom. Appearently enough leakage that that minimal airflow at idle was not enough to deflect the flapper on the air flow sensor and in turn, keep the fuel pump running. Went and grabbed a screw driver from the Sube. Boy says he's going to be P@#$d if that was all that was wrong and that he got a $10 parking ticket for something as simple as that. Did luck out though. The ticket said if it were there one more day, it was going to be towed. That would have been another 100 bux.

Anyway, put the tube back on, started the car and drove it home. He still has major hesitation on exceleration when car is cold. Thinking he may have had a backfire or something that blew the hose off.

Have you tryed swaping the fule pump relay ?
you fuel pump starts to run off of the dis pulse sig after a few sec.
Not sure if it is related, I had the same prob on a 84 vw wabbit
and it was the relay.
worth a try.

panicx