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Engine Vibration in Reman Engine

I had a remanufactured 2.5 Liter engine installed in my '88 Chrysler LeBaron Convertible. The engine vibrates and starts and dies in the AM until it warms up.
I also had the engine and transmission mounts replaced; it made the vibration worse, I can realy feel it in the steering wheel.
The two balnce shafts have not been checked, in addition to that, what else should I check for to resolve this problem?

Does it vibrate after its warmed up?

Do you notice this vibration only at idle, only when driving, or both? If you are lucky it might be in the drive shaft. This is a rear wheel drive, right?

Balancing engine parts to prevent this kind of problem is time consuming and maybe the remanufacturing shop tech just didn’t take the time required to do it right. The problem could be anything between the balance shafts, the crankshaft, the pistons, and the rods. It’s also possible the engine or transmission is not properly secured in the mounts, quite possible since everything presumably had to come out, then be put back in, maybe some attachment point is missing or loose, etc. Do you have the shop manual for the car, so you can sus out the location of all the mounting points?

It’d also help to know if you installed a reman long block (with the heads) or short block (used the existing heads).

And to find out if you’ve checked the temp sensor.

Did the new motor come with an ECU, or did you use the existing one?

And lastly, why is the shop that did the install not addressing the issue?

88 Lebaron is fwd leftover from k-car era. Ugh. Just a fancy omni. Why would u want to resuscitate this thing?

I drove a 1987 Dodge Mini Ram Caravan with the 2.5. It shook all the time, I always thought this was normal for these engines, even when new.

Keith, GeorgeSanJose and the same Mountainbike,
Thanks for your reply!! Yes, the vibration continues at higher speeds, just not as much. When I put it in neutral, the vibration is less.

I had a Sparton long block installed. The mechanic in Des Moines did a terrible job with other work he did at the same time - this was confirmed by other shops. I took it back to him 3 times with no improvement. I’ve filed a fraud compliant with the Iowa Attorney General’s offic, currently waiting for the shop’s reply.

At this point I don’t know if the problem is with the installation or an internal problem with the engine. Are there any diagnostic tests that can be done on the engine - for the crankshaft, pistons and rods? The Lebaron has two balance shafts - havn’t had those checked yet and yes I do have the owner’s manual and the Chillton Manuel. The compression test at the Chrysler Dealership was 140 psi on each cylinder. I understand the compression should increase as the rings, ect. seal.

What should I check first - more tests - have the balance shafts checked - have all the bolts, ect checked - the new engine and transmission mounts made the vibration worse - instead of the car absorbing it, it comes through the steering wheel. The car is imp0ortant because it’s a convertible, used in parades. I work on animal welfare and cruelty cases.

Thank for your replies

There are diagnostic tests that can be performed. They include
vacuum testing, which should indicate a valve closure problem if one exists,
checking of the valve lash, that allowance for the valves opening and closing properly at temp and at speed,
checking the timing of the camshafts, timing, an other things relevant to the crankshaft position,
ignition testing on an analyzer…although I don’t think that’s your problem,
fuel pressure testing and testing of the throttle body injection,

And, and I emphasize this, checking the signals from the various sensors including the temp sensor.

My gut is telling me that either there’s a valve adjustment problem, a vacuum leak, or a fuel delivery problem. These are all areas that the engine installer (I’ll refrain from calling him a mechanic) would have/should have disassembled from your old motor and reassembled on your new motor, except the valvetrain, and he should have tested the engine after installation and made those adjustments if necessary.

I recommend that you get the vehicle to an independent with a good reputation, give him the whole story (perhaps even print this thread), and have him take a good look. Assuming he finds the cause, if it’s related to the installation he can document it and you can use that in attempting to recover damages, in small claims court if necessary.

I wish you sincere best in getting this all resolved. It truly makes my heart sink to read stories like this. But know that you will get past this. In the end, it’s only a piece of machinery. You will recover.

Let us know how you make out. We do care.