90 s4 no start/run

[bjenkins]

You may recall, back in December I was heading to Georgia in my 90 S4. In Nashville, the belt service light came on and the car started running very poorly and was making some loud tapping noises under the hood. I trailered it back to Indy and it has sat since. A few weeks ago, I tore the front covers off and took a look. The timing marks were still dead on for TDC and 45, but the tensioner was loose and, I assume, flopping around. I was hoping the noises I heard were the tensioner banging the block and cover. I finally have the tensioner rebuilt and back in and the belt retensioned and am now trying to start it to see if there was any actual damage.

It will fire for a while and catch occasionally, sometimes running for a second or two, but very rough, and sometimes it will backfire through the MAF and once it even blew my flappy cap off! The fuel pumps seem to be working fine and I have good fuel pressure and I believe good spark. The plugs are new but a little oil fouled, I think because of leaky stem seals or something, and the plugs are probaly fuel fouled too from flooding. I have checked/swapped all pertinent fuses and relays.

While I was in around the fuse/relay block, I noticed that the plug that plugs into the board on the EZK/LH unit was unlugged and jumpered. Now, why would someone do this, and also, I fiddled around and pulled the jumpers out without making note of which ones were jumped. I did plug it back into the connection and pretty much got the same starting/running results.

Tomorrow, I will borrow a compression tester and check each cylinder and I'll probably replace all the plugs too, just to rule them out.

Any other suggestions or troubleshooting tips? I need to get this car out of my driveway and I'd rather sell it as a running machine than a parts car or project, more $$ that way.

Thanks in advance for any and all help.

[928ram]

Let us know how the compression test comes out.

With the basically being 2 ignitions systems on the 32V cars, it is possible for it to be running on 4 cyl. if something's failed; have you checked for spark and/or fuel wet plugs on each side?

[bjenkins]

I've only had time to check one bank so far. Here's the compression:

1-180
2-170
3-170
4-150

I think that's decent for a 190k mile car.

I removed the temp2 sensor plug and jumpered it and the car will now start and barely run if I hold the gas to the floor, but it is still knocking, so I think there is some internal damage.