I recently bought a 1994 Jetta III GL 2.0 5 speed


Previous owner didn't seem to know anything but he said he bought a new computer (from the junkyard) and put it in but that didn't seem to help anything.

Car turns over but will not start. It doesn't even attempt to fire.

I have tested a few things and here are the results.



Compression:
1&4 had 165-170psi which is ok (especially for 294k miles)
2&3 were covered by intake manifold but I'm assuming theyre fine.

Previous owner said it ran great before.

It is not get spark.
The plug that plugs into the coil is getting 12 volts but there is no spark coming from the coil.

The electric plugs to injectors are getting 12 volts.


I'm not sure how to test if its getting gas

When you first turn the key, I don't hear the fuel pump. Idk about this car but on my GM cars you hear a little whirring of the fuel pump running when you first turn the key.


When the key is first turned, these lights light up:
Coolant, Seat belt, oil, battery, brake
Then after a few seconds those go out and only oil and battery stay lit up.

But the check engine light never lights up. I read this could be a possible engine computer problem??


Trying to find a way to diagnose these problems without spending money. If I can't figure out what the problem is, I'll be forced to junk it.

I'd hate to do that though because it is from Oregon and it SOOO clean.

 

Welcome to the forum.

As you can appreciate its hard to diagnose problems on the web.

So this problem arose and the previous owner decided to change the ecu to try and get the car going?

Is there an car has the yellow car/key symbol on the instrument cluster, the immobilizer? If yours is a 1994 model then probably not as these were fitted from 2000 on in the US models.

The thing thats worth checking and its worth having a spare in the glove box a 109 relay, these do go fualty. This is the main power feed to the ecu and if that it fault you can crank the engine all day and it won't start. Have a look in the fuse/relay boxes for a relay with 109 marked on top.

I would have thought that the fuel pump would have run when you turn the ignition on to prime the system.

The ideal tool would be VAG-COM\VCDS to scan for any error codes in the ecu.

https://volkswagenforum.com/forum/ne...gnature-34185/

 

its probobly your ignition coil, spark plugs, and/or your spark plug wires

 

Well he can multimeter the coil and leads out if those are suspect.

Kyle https://volkswagenforum.com/forum/ne...gnature-34185/

 

Yes, previous owner "said" he swapped the ECU and it didn't help anything. But according to what I found the last digits of ECU for 1994 Jetta 2.0 with 5 speed should be "AE" or "AH." But the last digit that is on the ECU that is in the car now is a "T." Not sure if that matters or not??


No, there isn't any car/key symbol that lights up. The engine turns over fine but won't start.


Isn't is a sign if the service engine light never comes on that the ECU is not working properly? And is there any definite way to test an ECU to see if it is good?

 

Well, to make a long story short. I pulled a lot of stuff apart. Wire brushed the battery cables and I was starting to test grounds. Pulled the ground off the coil and cleaned it all up, nothing.

Found a way to test coil by disconnecting ground and then touch ground to metal while trying to start. Somehow doing this the check engine light magically lit up and the car started to pop and fire. It ran a little but not very well.

Found it needed 2 quarts of oil, half gallon of coolant and gas (which was near empty). Still ran rough, found 2 plug wires had been confused so fixed that.

Motor was very loud but after adding more oil it seemed to quiet down a bit.


Now my problem is when it sits a little while (an hour or more). It will start up and run for maybe 15 seconds (have yet to time it). But then it stalls and it will keep repeating this.

But if you just rev it up and get it in gear and driving, after you get it driving then it seems fine, it wont stall out.

Only stalls one when you first start it and sometimes if it wants to stall you can just hit the gas pedal and that'll keep it running.

Any thoughts? The spark plugs didn't look very good (haven't had a chance to swap them out) And when standing behind the car if someone revs it up, you can definitely get a good wiff of oil out the tail pipe.

Why would it stall out but only when it is first started?

Also, I am having problem with windshield wipers. Sometimes they work fine an sometimes they malfunction and just keep running and there is no way to turn them off

 

You really need to get it scanned with VAG-COM\VCDS to see it there are any error codes. A cheaper EOBD II scanner with find error codes and erase them. If you find any error codes post them.

I will ask you again. https://volkswagenforum.com/forum/ne...gnature-34185/

 

specs were in first post

1994 Jetta III GL 2.0 5 speed

So I dont have OBDII. I know u can use a paperclip to retrieve the codes but the engine light is never on.


It'll be running good and then just dies out.


Sorry not familiar, what is Vag-com/vcds

 

I see your spec is in post 1 but if its in your signature users will see it on every post you make, it saves repeating it every post.

Well VCDS is the best tool you will buy for a VAG vehicle. Avoid the Chinese clones on fleabay. The cheaper EOBD II readers will read error codes and erase them.

 

Will that VCDS work on my car?

It is a 1994 so it does not have OBDII. I have OBDII code reader but this car doesn't even have that system.