I replaced my 97 4.2 with a 99, they are suppose to match up, but my motor vibrates pretty good. The motor, coil, and flywheel have all been tested and are good. I think the camshaft sensor may be a couple of degrees out of poistion or the ecm may be bad. The voltage regulator on the alternator went out and blew out all the lights and the instrument cluster. Is it possible it could have messed up the ecm to and thats what is causing the motor to vibrate? I'm pretty good with motors, but this really has me stumped, please give your feedback

 

Brad,

Your stumped? Which is probably the same reason 33 people viewed this thread and haven't responded. I think this is one of those "ya gotta be there to see it" scenerio's. I can't tell what would cause it to vibrate without actually looking at it. I don't think your computer is bad, and what do you mean the voltage regulator went out and BLEW all the lights? Do you mean that it blew a fuse, or that the lights actually burned up? Because the fuse would trip with a sudden power surge before the lights would burn out. So I'm really not sure how to answer your question or solve your problem. When it's vibrating, is it still running good? Or is it hesitating and coughing. If it's running perfect but just vibrating, perhaps they did not install the motor mounts correctly, or at all for that matter. Usually an engine only vibrates because it's running rough, this is a problem we can address. But if your engine is running perfect and still vibrating, my guess would be that they didn't align the motor properly or installed the motor mounts incorrectly, or they used the OLD motor mounts instead of installing new ones.

Give me some more info please.

Tom

 

everything burned out including the gauges on the instrument panel and the reason being is that a ton of volts was being pushed through it and not amps, so the fuses did not trip. The motor runs good without any coughing or hesitating, just vibration. It feels like your sitting on a washing machine during spin cycle. On the other hand though after driving it for about fifty miles the check engine light came on, so I'm going to take down to autozone tomorrow and see what it says. This is somewhat good news because this means that the ecm must be doing something, hopefully its an easy fix like repoistioning the camshaft sensor. I'll post back after going to autozone tommorrow

 

hmm...it is possible it is the motor mounts not tightened or have their bolts put in at all...I could see them missing that on instalation
I am still curious about the lights burning out, if you increase the voltage you are also increasing the amps, and therefore the watts.

umm cant remember the exact formula something like

V x A
------
I

v=volts
a=amps
i = resistance

 

The formula is V = IR

I = current
R = resistance.

Therefore,

I = V/R

There is no way current woud stay the same and the voltage would increase unless the resistance were to increase, which can't happen.

Sounds like a fuse to me.

 

It is possible for the regulator to go nuts and burn out bulbs and such. The fuse should blow, but it would depend on how much the voltage went up.

I'm wondering if the torque converter may have been damaged during the engine install. Vibration will definitely be machanical rather than electrical if the engine is running well.

The moter mount idea was a good one, but I'm guessing something got bent. I've ruined a torque convertor myself trying to do an install with no lift.

Otherwise, it it's a standard, I'd look at the fywheel first.

By the way, you guys got ohms law right and if voltage goes up and resistance remains the same, current goes up. No doubt about it. He doesn't say how long it took for things to start going out. This is the main reason you never wire around a fuse.

 

Jimmy, I too can totally picture them forgetting to put the bolts through the motor mounts.

Let us know a soon as you find out what it is Brad.

Tom

 

Hey

Did you ever find out what it was. Don't leave us hanging now. inquisative minds want to know!!!

 

Yeah! It's like when the news harps on something for days and then suddenly you don't hear anymore. You never know how it turned out. I hate that.