Hello all --

I've just finished installing a new timing belt for my 88 Trooper. The old one was so oil-soaked and cracked I am surprised it had not broken yet.

During the install, I noticed the old belt was mis-aligned by one tooth - when the cam was aligned correctly, the crank sprocket was one tooth counterclockwise from where it should have been. I am not sure whether it had slipped or whether the previous owner had installed it incorrectly (back in 2002 or so).

I replaced the cam & crank oil seals, installed the new belt correctly and put it all back together. Now, I finally have a correct 750 RPM idle (used to be 1000-1100, could not get it to idle correctly) but the truck is sluggish until about 3000 RPM or so at least. Not terrible, just not as peppy as it used to be.

My current theory is that the timing at the distributor may have been set while the belt was off a tooth by the old owner. Could this cause these symptoms?

Also, the crank pulley timing mark is not aligned with the keyway - maybe the balancer is failing and the outer ring is spinning a bit around the rubber core? Makes it hard to check the timing...

Anyone seen these issues before?

Thanks in advance...

Absolutely reset the distributor! It's driven off the back of the cam, so it's sensitive to changes in cam timing.



Very possible...

If I were in your situation, I would mechanically set cyl 4 at TDC and check the marks on the balancer.

Yeah, if you are absolutely sure the belt is on right and the cam and crank line up, you could use the mark on the cam pulley to get it right on 0 degrees (TDC) Then just put a dab of paint on the crank pulley lined up with the 0 degree mark on the timing belt cover. I'd put a mark across the rubber part of the pulley so you can see next time if it has shifted any more.

Well, I double-checked the timing belt alignment, adjusted the valves, set the distributor alignment (aligned the 2 marks on the body and bracket, and then aligned the rotor to the same marks as best I could - this is per Jerry Lemond's advice). The crank pulley was ok, either I imagined it had spun or it spun itself back. Probably my fault.

At any rate, the idle is back to its old 1100 RPM and I can't get the timing any closer than about 14* BTDC (this is with the distributor cranked all the way clockwise). Is it because the idle is too high? Or is there another possible issue? I am not inclined to spend too much more time on this POS, but if anyone has any ideas I'd appreciate the help.

Thanks...

The easiest way to check that would be to run the idle down to 900 and see what happens! I do know that when my idle is set correctly, the advance stays at 12, but the INSTANT I crack the throttle open, it jumps WAY to the left. I think this is because the ECU senses the TPS coming off idle and compensates.

Check your TPS switch... if the idle contacts are not contacting, your ECU could be confused!

Hey, I have an 88 Trooper LS and had similer problems, Timing was way out like you said, and the Idle was sitting at about 1500 cold and warmed up was about 1100, rather high for my liking. after the head blew up on it and a full on rebuild took place, it runs awsome. Now check for vacuum lines that are old, hooked to the wrong place, I found that my 2.6 was very sensitve to anything we did to it. and with all the vaccum lines and almost new everything on this engine it idles at about 800 to 900 RPM warm and about 1100 cold with a 180 degree thermostat. another thing you can try is unpluggine the battery for a couple of min to see if it will reset the ECU. I did so last week after the rebuild was done and had the CEL light come on and it was sputtering. also what octane of fuel are you running? mine does not like anything below 90. just throwing some ideas out there for you. working on these things is like being lost and slowly find your way back LOL but YES they are worth it very dependable once they are fixed right and maintained. Later

If the dist is adjusted as far as it can go. I suggest checking to see if it is off one tooth. I had this problem when I rebuilt my 2.6. Once I pulled it and and got it on the right tooth, I had no problem setting the timing.

The distributor being off a tooth is most likely, I think - it's hard to see whether it's aligned correctly during installation. I may pull it out and try re-aligning it.

The idle now seems to be correct at right around 900-1000, this after a good warming up, and it certainly runs much better now, so I am not going to dig much deeper. If you saw the truck, you'd agree it's just not worth the time.

Thanks for all the advice.