My Ranger has a problem with low power. I had to replace the original 2.9 because of a blown head gasket and oil contamination. I used one out of a 1988 Merkur Scorpio, switching all the Ranger external parts onto it. Since this switch just under a year ago, I experience uneven power from idle (uneven) up to approximately half throttle. The engine has all new tuneup parts and has had a chemical injector flush done (pressurized). A power balance test on SBDS at the dealership where I work indicates low power levels on cylinders 4, 5 and 6. None of the technicians whom I work with seem to have any ideas as to the cause of this problem. Any advice you folks could offer would be greatly appreciated.

E-mail sheaman71@hotmail.com

P.S. Just a thought... if I have to replace the engine AGAIN, will the external parts (intake, exhaust, distributor) and engine management (EEC IV) from the 2.9 bolt onto and work with a 4.0?

Im gonna have to think about your power prob, and get back to you. As far as the 4.0 swap, no, none of the 2.9 equiptment will work on the 4.0. The 4.0 is an EEC-4 also, but the comp is different.

I don't know if you changed the cam in it or not or if that could be the problem. What i am sure of is that the Merkur 2.9 came with a diffrent grind cam. I don't know if the grind changes lobe seperation or lift or both. I know that the cam has a different part # than any ranger or B2 2.9L and all the manuals say that the Merkur has 10 more hp than the ranger one. The reason that I bring this up is that your ECM may not be correct for the cam grind. The cam could make more or less power at certain rpms than the ranger cam and the ECM may not advance the timing at the right time giving you an uneven power band. Just a thought, run that by a couple of people and see what they think.

I'd think it'd be somthing with fuel, or wear..what's the compression like on those 3? It's really odd just to have low power on the left bank of the engine...Maybe there is restriction in the intake, is the gasket lined up? Rockers improperly ajusted on that side?

This is a wierd one!!

Paul

Thanks for the responses, folks. My compression (at last check) was even on ALL 6 cylinders, around 125 p.s.i. I believe. My fuel pressure measured at the fuel rail was about 30-32 pounds. Wouldn't the cam affect all 6 cylinders, not just 4, 5, 6? When we put the new engine in, we primed the oil pressure by cranking with the coil disconnected before starting. Would only 6 crank lobes get worn? I don't think that is very likely.

if the computer and the cam don't match then this could cause your problem. this of course does not explain why the power loss on those three cylinders only. if you play with the timing a bit does the loss in power switch to the other now good cylinders?
this is a wierd problem and i hope you figure this one out. let us know if you get an answer.

good luck

the 2.9L is a good engine and has lots of power compared to its chev competitor. if you look at my avitar its proof........still i can't wait to squeeze the 5.0L in there!!!!

Try replacing the head gaskets. Two different thickness gaskets will cause a change in cam timing from one side to another. The side with the thinner gasket will have advanced timing.

Originally posted by Rocketsled
Try replacing the head gaskets. Two different thickness gaskets will cause a change in cam timing from one side to another. The side with the thinner gasket will have advanced timing.


Could you explain this idea. I could see this having an affect on compression since you would have a different camber volume but don't quite see it changing the cam timing, assuming zero valve lash.