Hello, Everyone.
I have a problem that I hope someone here can help me with.
I give a little background first if I may.
I have an 88 2 wheel, 2.9 custom.
The truck has 375,000 k's on it, runs real good except for my problem which is, a very severe vibration from the engine.
I did a compression test about a year ago and have pretty low compression all the way around but I don't burn a drop of oil, so I would guess it's the valves.
It always ran a little rough and I finally got around to replacing the motor mounts and now the rough running that was not that bad before has transferred itself right into the body and steering wheel.
It is not a driveline issue because it does it at certain idle RPM's and different driving RPM's.
I understand that bad injectors can create vibration but I think it has more to do with the valves but don't know if that's the case.
It has no miss at any RPM, just not a ton of power.
I love my little truck(first pickup I ever owned) and am hoping that someone can set me on the right path in tracing this thing down.
Thank you, all in advance of putting your minds to work with me.
mightymike

It sounds like you're already on the right track, get the heads redone and keep on truckin.

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From your words I would say check the timing. Did you do a compression test or a leakdown test? It could very well be that your base timing is off and your truck is retarded. No offense intended if your truck is a special needs truck.

I ROFLed!

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Lol. What?

Rofl!

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Gotcha. GYL

IT is NOT retarted! Although, it does have some special needs. As do I.
Thanks for the replies guys, I'll check that timing and get back.
It was a compression test but it leaked off pretty quick.
Thanks again.
mightymike

I do hope you understand I am in reference to tdc timing advance.

You might want to do an oil change and run 20w50 with a little marvelous mystery oil. I would say put a pint into the gas as well and possibly a pint of two cycle oil as well. This will clear out any removable build up from the fuel system. Marvelous is a very refined oil that can get info many smaller places and help move build up and help free stuck valves. The 20w will help restore a little compression and offer greater wear protection. Understand injectors are like headlight bulbs people often run them long after there lifespan i.e. headlight bulbs are rated for one year then they lose much of their light, but people wait until one burns out.

Well alot of people associate worn valve seals with compression issues. This should not be done, only if you have damaged springs or a really messed up head would this be an issue. If it leaked down fairly quickly then your rings are worn out, or possibly damaged. With your mileage this can be expected.
I would just step up to a 20weight oil and be gentle. I know there is a silver can that some Guru friends of mine swear by(clunker dragsters. . .10's 1/4mile). You may want to give it a try. I believe the premise is that when this additive is in the oil on the walls of the cylinders and the cylinder fires this additive hardens filling in vertical scratches in the walls helping to restore some lost compression "some". Just look for a stainless looking can in the additive section at you local parts haus. It's talks about something like "compression restorer".
G/L HTH

Hi, 02'4.04x4.
But if it were the rings, wouldn't you be burning lots of oil?
My timing light won't be here until tomorrow, so no progress has been made on finding an answer to this.
For 4 years now, I have been saying to myself, well maybe I should get a rebuilt engine.
But, for 4 years, it just keeps running along.
I'am sure, now that I have asked for help and am going to try a few things, that an understanding will come soon.
Thanks again for your energy and help.
mightymike

As an automotive service tech of 35 years I would recommend a wet and dry compression check before you pull those head's.
Remove all spark plugs.
With the engine warm and using the right compression adapter do a regular compression check. Record all the numbers.
Now with a pump type oil can squirt 4 pump's of oil into each cylinder. This will seal the ring's.
Do the compression test again, the oil will seal the ring's but not the valves.
Any low cylinders (Below 130)? they could have bad valves, blown head gasket's or cracked piston's.
With the engine running at the offending RPM try grounding each spark plug wire in turn.
Any cylinder's that didn't change the RPM? those are the one's to watch.
PM me with the result's.
Good luck,
Jim

Hmmm, it seems BwanaJim drives alot. . . That's impressive.
As for his recommendations, they are sound, I suppose it is possible that you have enough carbon deposit build up to keep the valve springs from seating the valves under compression, and it is totally possible that you have a blown head gasket without any tell tale signs of it like spark plug abnormalities, bubling resevoir, oil mousse, blowback in the intake, overheating, coolant loss, coolant in the oil, again I say it is entirely possible that you have just blown the head gasket between all cylinders allowing for an even display of vibration as opposed to an apparrent misfire.
Now that being said you could have a failed exhaust camshaft(seen it before), it could be that you are really inept about automotive happenings and cannot tell that your differential is causing the vibrations(happens), or even that you have a distributor and your cap traced causing misfires in 3 cylinders at a time, but typically with this kind of power loss you on't hear about people driving their automobiles for 4 years, in this condition, and I would assume you have atlest done 1 tuneup since it was noticed. Also burning oil is a sign of bad rings and yes bad valve seals, but when worn rings get partially lined up or just worn to an extent, it just fires past them. If you have the time I would recommend you doo the wet test but I would recommend using 90w.
G/L

Yo should be able to bump check the timing without a light. Simply loosen the lockdown nut and rotate the distributor "slowly" in most cases cases counter-clockwise to slowly advance the base setting you should notice the idle clean up and speed up a little keep turning slowly until it starts to stumble, then rotate it the opp. direction 1/8th inch and tight lockdown. This will leave it in a slightly advanced state improving performance. There are really quite a few factors that can affect advance on older cars such as your own, but this is one of the base checks to t-shoot timing issues. But as I mentioned before it is your best bet to just rebuild especially if your are mechanically inclined enough to pull the motor yourself.

02'4.04x4
Hello,
I timed the beast and it is tame.
Thank You big time for your timing suggestion. It still has a very tiny bit of vibration but I will check some of the other suggestions as well and hopefully get it running smooth.
Thank all you guys for your time and help.
mightymike