Engine vibration at 2500rpm

[Sycostang67]

I recently completed a SMF conversionin my 93, I also just put back in my injectors. Two of the injectors are borg warners until I get my other 2 repaired, the other 6 are BB's I got from russ. I took the truck for a test drive today, everything seems to be fine except for a rpm related vibration. It starts out light at 2000rpm, gets worse at 2500rpm and then slowly fades past that. I know it's from the motor as it will do it if I just rev the engine while the truck is sitting still. What could I have done?

 

[rhkcommander]

could be offcenter flywheel, I've heard some quality issues lately.

are the two injectors known good? If not then they might be malfunctioning. If they stick open the fuel lines will get hot with the exhaust gases pushing back into the injector. Otherwise they can dribble and *** and other things that cause rough running

Check the engine mounts too. When I found out my driver side had busted the nuts through the plate my truck acted similar until I added washers...

 

[Sycostang67]

The other two injectors are brand new. Motor idles as smooth as it always has. I'll be a bit upset if I have to pull the flywheel back out. I will check the motor mounts just in case one was damaged while doing the clutch.

 

[rhkcommander]

good luck, I hope its something simple in your case

 

[icanfixall]

All the injectors need to be the same.. Think about this.... Differant injectors are supplying differant amounts of fuel to each cylinder... Thats going to cause vibration... No getting around that...

 

[88 Ford]

Maybe check your carrier bearing. Mine kinda vibrated like that when it all of a sudden went bad and then the driveline fell off.

 

[typ4]

He said it does it just sitting, and there have been some flywheel/ pressure plate issues.

 

[plywood]

When my old brown truck did that, it turned out to be the vacuum pump.

 

[BigRigTech]

I'm thinking flywheel/pressure plate issue, but until you have 6 matched injectors I wouldn't drive it. This is a new vibration from what I'm reading, so it must have been caused by the recent work you did...It just sucks that you did two jobs at once, makes it a lot harder to diagnose....

I just went through a similar issue at work....Sterling tandem plow truck with a Cat C12....Came in with no driveline noises, left with a severe noise/chatter and vibration on coast....I was asked to look at it with the guy who replaced the entire rear suspension. (Hendrickson Pri-maxx - junk for a plow truck) ...It only took me two seconds to see the pinion angles were all messed up as was the tandem alignment/spread.....Basic-basic stuff for most tech's but 1/2 the provincial shop wanted to replace the transmission.......It took some convincing from myself to get them to send it back to the alignment shop to have it corrected...They did that, came back the same so we took it to another shop and bingo - all fixed. They wanted me to check the driveline angles for them - I said I don't need an angle meter to see that the power divider is pointing at the ground and the rear diff is pointing to the moon........The last time this happened they had replaced a tranny and front drive diff before they would ask for help from two of us who worked at a dealership and had eaton driveline/trans training. Even then they still had to be convinced.

 

[88 Ford]

He said it does it just sitting, and there have been some flywheel/ pressure plate issues.

Ya just saw that now too. I was stuck on the fact that it started at 2k. Lol. My thought is that it could be either the pressure plates or the injectors or the pressure plates. It would be easier in the long run to wait til you get the other two injectors and put them in and if it fixes the problem good, if not, go from there and check the pressure plates.

 

[towcat]

drop Heath a pm. he went through hell diagnosing his flywheel vibration issues. your experience is very similar to his.

http://www.oilburners.net/forums/showthread.php?t=49774

 

[Black dawg]

does engine load affect the vibration?

 

[Sycostang67]

It vibrates the same sitting or under load. I have ordered another flywheel, was gonna have the balance checked before installing it. I would hate to go through all that just to find it was the injectors though. The engine does seem to idle a bit rougher than I remember, but cruises nice and smooth..under 2k rpm anyway. The injectors I got dont have codes on them either, they were in Borg Warner boxes. I got them just to get me by until my BB's were fixed. Two of them were leaking causing a pretty bad knock. I have noticed with the two BW injectors, that it knocks when the cold advance is on but goes almost completely away when it kicks off. I will see if I can't press my bro-in-law to get my BB's tested soon, before I pull my transmission again.

 

[RLDSL]

Did you use all matching bolts and washers when installing the flywheel and pressure plate?, If it's a new flywheel, it *should* be balanced out well enough to run smooth
Barring that, I'd be inclined to have the injectors tested

 

[towcat]

Did you use all matching bolts and washers when installing the flywheel and pressure plate?, If it's a new flywheel, it *should* be balanced out well enough to run smooth
Barring that, I'd be inclined to have the injectors tested

heath found his pressure plate was drilled slightly off-center.
once the Pp and disc was removed, the vibration went away. read the link to his post.