Mitsu 2.6 Problem

Picked up an 89 Ram 50 with the 2.6 as a winter car for my son. Engine only 106,000 miles, but has a new head. Engine runs well, but runs out of steam at high RPMs (over 4500 RPM). This is problem when the truck down-shifts it falls out of its power band. I was thinking that when the reinstalled the head they didn't centerline the cam properly as the truck can't climb hills or pass on the highway very well.

I think I may have figured out the problem. Disconnecting #1 spark plug wire does almost nothing to the idle and the engine sounds better (exhaust makes a putt-putt note when #1 cylinder is hooked up). I am getting spark so I am thinking it is probably valve train related. Looking for input

leaky injector? how's the exhaust smell?

In reply to Raze:

Carburetor car and the plug and exhaust color and smell appear normal.

Sounds valve related or head gasket to my not so sharp mind

I agree. Just wanted to make sure I wasn't missing anything.

I do think you have an issue with the head causing a problem w/#1 BUT, I can also tell you from experience that the carburetors on those late 80's 2.6s have issues. Mine would be fine until you reached a certain load level and then the power would fall off sharply. Let someone follow you while you duplicate the symptoms. If it it starts blowing black smoke when you reach the point of losing power, you probably have the same carb. issue that I had. In other words, I think you may have two separate problems.

Those trucks just sort of...do that.

check the fuel pressure is in spec.

In reply to carzan:

Carb seems fine. No smoke under any condition. Besides, if it was just a bad carb, I would get a noticeable drop of rpm at idle when I pull a plug wire. Engine actually sounds better on the three cylinders and the rpm barely drops.

Cam timing could be off when the head was replaced or the distributor could also be off.

Moparman wrote: In reply to carzan: Carb seems fine. No smoke under any condition. Besides, if it was just a bad carb, I would get a noticeable drop of rpm at idle when I pull a plug wire. Engine actually sounds better on the three cylinders and the rpm barely drops.

Yeah, that's why I said I think you may have more than one problem. It may not be the carb, , but I'm not convinced that a weak or even dead cylinder is your only issue.

Maybe. I was thinking an incorrectly centerlined cam. but only #1 cylinder makes a difference.

Mechanic is convince the problem is in the bottom end. The noise goes away when you disconnect #1 cylinder plug wire. He still has not run compression check, but there is no smoke or blow by. I am thinking balance shaft chains, but the noise wouldn't go away if it was that (I don't think). I have located a 1986 2.6 replacement, but the seller says that it won't fit later trucks, but does not know why. Does anyone here have the answer to that question?

Found the answer to the model year question. Different bell housing. Still can't figure the bottom end noise. Good oil pressure too.

Apparently no.1 cyl is weak or the firing order is wrong. Compression test before anything else.

I agree with you iceracer. I will know more on Monday. In any event. Does anyone out there have a good used 2.6?