Huge miss I can't diagnose

[rodtheedge]

My 92 TSI has a bad miss. After trying to diagnose I found that cylinder 4 is not firing at all and cylinder 2 has a miss. So I thought it was an ignition problem. I changed plugs/wires and there was no change. So then I thought it was the coil. I replaced it with the dejon coil on plug setup and it changed nothing. Somtimes when I start the car it will run fine for awhile but then it will go back to feeling like a tractor trailer like 15 minutes later. What other things should I check for? Because the problem can come and go I would think it has to be electrical but I'm not a mechanic so I'll leave it to you guys to decide.

 

[staticbrainwash]

Try new injectors, or getting yours cleaned. When i first got my 92 it missed when hot and i could never figure it out. If you know you're getting spark, and if you've got good compression, check injectors. It worked for me.

 

[dsm-onster]

Somtimes when I start the car it will run fine for awhile but then it will go back to feeling like a tractor trailer like 15 minutes later.

Head gasket is the likely culprit. Or a cracked head or block... Also a bent valve may be the cause. However, usually all the valves on at least one side bend before you notice... Maybe a burnt valve... Best to run a proper compression check.

A blown head gasket AND a burned valve can have the same affect on the compression test here. I still lean towards a blown gasket, though, as the problem crops up after your engine "warms up"; i.e. start up and get a smooth idle, then later misses.

 

[4g63t]

TEST you CAS, Your cas is bad.

 

[rodtheedge]

I've never heard the term CAS. What is it and where is it located and how can I test it? And I'm not getting spark on cylinder 4 at all so I don't think its a bad injector. I got another set so if that CAS isn't the problem I'll pop the other injectors in.

 

[Cs4g63]

CAS refers to Cam Angle Sensor. It is located on the passenger side of the intake cam. It is the circle thingy with wires coming out of it.

 

[Cs4g63]

This thing.
http://www.slowboyracing.com/more.php?id=3772&

 

[dsm-onster]

I've never heard the term CAS. What is it and where is it located and how can I test it? And I'm not getting spark on cylinder 4 at all so I don't think its a bad injector. I got another set so if that CAS isn't the problem I'll pop the other injectors in.

Ok, so you're not getting spark on number 4. . . You never mentioned this. Even when running a new ignition setup, you get no spark; so thus here's another vote for the cas as already mentioned.

 

[rodtheedge]

How can I test if the CAS is bad? And what other things could cause this problem?

 

[rodtheedge]

Nevermind. I did another forum search and found instructions.

 

[Mitsubishified]

If youre not getting spark and its not your cas or coil pack, it could be your transistor pack. I didn't have spark and i changed all my plugs wires my cas and coil pack. The transistor pack was bad.

 

[Mikelb]

^I replaced my transistor pack and ignition coil at the same time. My ecu fried something and took the whole ignition with it. It also took out my AFC, and alternator(I'm assuming, I haven't tested it yet, but the lights are on, on my dash)

 

[4g63t]

did you test your cas? what have you found anything?