Okay, one of the problems I am having with the engine is a hesitation in higher gears at low RPM (less than 2K). I have narrowed the problem to the ignition module and the #6 plug, which is oil fouled. To help find the cause of the fouling, I took a compression test on all six cylinders. Numbers 1 and 3 I am not going to post because of lack of accuracy (had to use the spark plug adaptor and couldn't get it tight enough), but all the remaining ones, with the exception of #6, were within 10 PSI of 160. However, #6 has a compression pressure of 181 PSI, when cold. Does this mean I have blown oil control rings or bad valve guides?

 

you more than likely have bad valve stem seals. does it smoke when you first start it up and not during driving? if there is some oil in the combustion chamber from sitting it will seal the combustion chamber a little better than the others that are not leaking oil and cause a slightly higher compression. try and check compression after you have been driving it for a little bit. that will give you your best readings.

 

You could go with a hotter plug in that section; increase it by one heat range just to see what happens.

The higher compression is probably due to carbon buildup in the cylinder- especially if the engine has been misfiring.

 

Misfiring seems to be the least of my problems right now. I am not completely sure what the engine is supposed to pull in in.-Hg of vacuum, but depending on conditions, I can get anywhere from 12-16 in-Hg of engine vacuum, and I have read that I am supposed to be getting close to 17 or something like that.

I have reverted to the 3.1 fuel rail (no CSI-CSI was on constantly killing my gas mileage, I left the injector in the manifold since I don't know what size freeze plug to use to plug the hole but disconnected the fuel line), and have since gotten worse gas mileage, but better vacuum readings . I know I need to replace the EGR solenoid (coming this next week or so) and the ICM and coil (ICM was tested bad at startup and might as well do the coil at the same time). What is the next heat range up from the AC/D R42TS plug?

I am looking to do a rebuild soon since I don't know how many miles the engine has on it. I need to replace the RMS anyways, and so I can degrease the poor thing... it's so dirty right now I can't look at it without getting grease on my hands... It also appears to have low compression in cyls 1 and 3 but I am not sure since I couldn't get the adaptor to seat properly. I read about just over 100 PSI in both.

:edit: Forgot to mention that the EGR solenoid hasn't worked since before the 3.1 was dropped in, and I supposedly had the engine decarbonized last September. I guess I'll have to get some Top End cleaner or something...

 

BTW, when I first had the engine dropped in it did smoke on startup, but it was BLACK smoke from the two leaking injectors (hadn't installed the old fuel rail with the CSI yet... found out that problem was a defective ECM IAC driver).

The exhaust stream does not appear to contain any blue smoke, and I have looked at it in the dead of winter against a piece of white paper, although it does kind of smell like its either running lean or its burning something it shouldn't.

When I get the damn catalytic convertor assembled again I can run a hot compression test.

 

Update:

Hot compression test: 185 PSI on cyl 6. That's +4 PSI. Have NOT checked hot PSI on other three cyls yet.

Installation of AC/D R43TS (next heat range up) spark plug: Too soon to tell. Will know more later this week or next week.

Installed AC/D ICM. Will know more about cold start issue in the morning.

Gas mileage still sucks. Will have EGR solenoid next week.

Will have helper look at exhaust stream at cold start ASAP.

Is it still a good idea to do a rebuild now or can it wait a while?

 

Supposedly (I haven't done it yet) you can break up carbon in a cylinder by filling an empty windex bottle with water. Then you remove the intake hose, and while the motor's running, you mist water in front of (not into!) the throttle body.

Supposedly the engine sucks that water mist in, and when everything fires in the cylinder, it makes the cylinder "humid" and breaks up the carbon in the combustion chamber and the top of the piston.

 

Figgered out the problem just a few min ago. Going back a little ways, I originally had to replace the valve cover gaskets because they were leaking and I had low engine vacuum (killed two birds with one gasket set). Well, the torque spec in my repair manual is sooo wrong--that number doesn't allow the gaskets to be compressed. So, I drove around for a while with leaking valve cover gaskets (vacuum leaks, not oil leaks, thanks) and I heard the valves chattering when I started poking around for vacuum leaks one day. Thinking it was normal wear, I dismissed it--until now.


Today I take the PS valve cover off and do a compression test on all three cyls on that side. Average PSI was about 150 on all 3. I tightened the rocer nuts a little bit, the compression goes up to an average of about 163-4 PSI, and I lose a lot of the high gear/high speed hesitation. Now I just have to do the same to the DS head, and I should be all set.