1.8 Jetta Cylinders are full of GAS

[rabbit_diesel]

I just finished swapping the automatic tranny to a 5 speed on my '92 Mk2 Jetta.  When I tried to start it, it seemed like it had too much compression.  So I took the spark plugs out and I turned it over again with the starter and gas just sprayed out of the spark plug wholes.  I don't think that's supposed to happen.  I know this is a diesel website, but please try to help out.  I would like to know why it is doing this.  I wish I could just put a diesel in it already.

[the caveman]

Digifant FI will push tons of fuel when cold, even when there is no problem. But the most likely problem is the ground wires that normally are attached to the coolant flange on the side of the head. Even if they look ok , cut them and use a good connector and attach them to the side of the intake manifold,  or any other good spot on the motor. Also make sure the temp sensor is working properly.

[jtanguay]

THIS SAME CRAP HAPPENED TO ME!!!!!!  RIP THAT ENGINE OUT AND DROP IN A DIESEL 

no seriously... the car ran, and then dumped fuel into the cylinders to the point the starter couldn't even turn it over.  wait about 10-20 hours and it all drains to the sump, dilluting the oil to the consistency of near diesel.  its absolute garbage.  i absolutely LOATHE these engines.

[Vincent Waldon]

Typically this means the injectors are being left open... usually because the ECU is erroniously telling them to do so.

Some troubleshooting thoughts:

There's no computer to check for codes... gonna have to troubleshoot this old skool, starting with the ECU grounds on the valve cover, as Caveman suggests.

Next would be to get a multimeter on the injector electrical line (all 4 injectors come on at the same time) and see if in fact they have voltage full time.  If so, you suspect the ECU... yanking it should make the voltage go away.

The quickest way to test the ECU itself is to swap out one from the junkyard... the Bentley has a series of tests you can perform but they really only confirm that the ECU is getting the right signal... and no set of signals should cause the ECU to leave the injectors on full-time.

[rabbit_diesel]

I was looking at all of the grounds and I noticed there is a ground cable that runs from the valve cover back to the coil mount.  That must have broke in half during the tranny swap.  I reconnected it and tried it again with no luck.  How could that one little ground wire cause the whole ECU to be shot?

[Vincent Waldon]

I was looking at all of the grounds and I noticed there is a ground cable that runs from the valve cover back to the coil mount.  That must have broke in half during the tranny swap.  I reconnected it and tried it again with no luck.  How could that one little ground wire cause the whole ECU to be shot?

Well, I'd be inclined to hunt down a test ECU before calling the ECU a gonner... but in general if you feed power to a sensitive electronic circuit without a proper ground current will flow thru paths the manufacturer never intended, with unexpected consequences.

There should be a thick copper braid (which I believe just grounds the coil) *and* at least one thin brown wire with a white strip, usually two brown/white wires in fact.  Are they all there and connected to the valve cover ?

[rabbit_diesel]

Yes, I believe those wires are safely connected to the valve cover along with the braded ground wire that goes to the coil (the one I had to fix).  Did I mention that it doesn't have spark?

[Vincent Waldon]

Nope, that's new.

Sounds more and more then like an ECU that's gone to meet its maker... if you can find one to swap it's the quickest way to eliminate/confirm as a suspect.

[jtanguay]

just to let you know what fixed it was another ECU.  car was sold shortly after that... 

[the caveman]

There is 2 grounding issues with those models- if the motor was cranked without all the grounds connected, it's a sure fire way of toasting the ECU. Also if the spark plugs are not tight it can cause ECU grounding problems.

[jtanguay]

doesn't surprise me with the ground issues... those cars were rust buckets if not properly maintained.

[rabbit_diesel]

if the motor was cranked without all the grounds connected, it's a sure fire way of toasting the ECU.  

That's exactly what could've happened cause the tranny I put into it was painted and I was kind of in a hurry to get her back together and... well, right when I went to start it all lights on the cluster went out and it was making weird clicking noises.  I'm just glad that I have a good theory that this is what the problem is.  I ordered an ecu box online for 40 bucks shipped.  So, all should go well... hopefully  

[Jettagli16v]

My sister had a 92 Jetta 1.8 for a few years,
and one day it would not start for her.
When I got there, there was no spark at all,
and it ended up being the "Ignition module"
(small computer thing on top of the ECU on the metal cover).
The only reason I got it fixed quickly is I had brought an ECU, Ignition module, Coil, and distributor
from a donor car.

I think her hall sender was also troubled,
but that was years ago....

-Brad

[rabbit_diesel]

there was no spark at all,
and it ended up being the "Ignition module"
(small computer thing on top of the ECU on the metal cover).

-Brad

Well mine doesn't have spark and plus the injectors are malfunctioning.  Could I also need one of those little ignition module boxes?   I sure hope not 

[jtanguay]

there was no spark at all,
and it ended up being the "Ignition module"
(small computer thing on top of the ECU on the metal cover).

-Brad

Well mine doesn't have spark and plus the injectors are malfunctioning.  Could I also need one of those little ignition module boxes?   I sure hope not 

this is why you need to go diesel 

but seriously, you might just want to find the mechanical fuel injected engine, and swap that in.  those things are near bullet proof and don't fail like the one you have now.  plus during the nuclear war, your car will still run