Engine/Transmission (1994 - 1998) Engine Shake

[Line-x1]

Hi All. New to the group. I have a 97 180 hp. (originally) in a 2500 4X4. I had a local shop increase the hp. They installed new injectors, governor springs, heaver exhaust springs (Pac brake) and some other non related things. When I got it back as soon as it went into overdrive it started shaking the whole truck. I took it back and they had no idea what was wrong (they were parts installers). They washed there hands of it and sent me to Canada to Piers Diesel Research. They worked on it all day (I watched) and got it drivable but it still has a problem. They changed to different injectors and tried governor springs, throttle springs and every thing else they could think of. I had it up to a local Cummins guy and he advanced the timing. That made a big difference in power and got rid of the black smoke. He has no idea what is wrong. Here are the symptoms. Under very light throttle pressure the truck gets a shake. The Trans is new and it didn’t do this until I had the parts installed. Every one thinks it is the engine. When I add more throttle it goes away. It also does this when backing out of the throttle. It will do it at slow speeds also. It doe’s it up to about 1900 rpm. No indication of a single cylinder misfire or tach fluctuation. Nothing strange on the boost gauge. I would take it back to stock but I am addicted now! I will take any questions and look at all answers. Thank you all. Mitchell

 

[jtwcummins]

What you are describing sure sounds like driveline/u-joints. Will shake on take off and around 50-55 mph and on decel is generally a bad ujoint, but the drive line might have been reinstalled 180* out when transmission was done. The drive line would more than likely cause shaking since rotational balance is off.



Problem is anything in the pwr train is possible problem area. You could have had a u-joint going bad and enjoying the new power finished it off.



Does the engine run smooth out of gear at the same rpm ranges?

 

[Line-x1]

There was no problem at all before the hp. increase. Yes the engine runs smooth with no load. This shake is the same at all speeds. It is allmost like it is a lugging thing but doe's not buck the truck and will be there untill the rpms are high enough you are pushing on the throttle past the throttle position that it causes a shake. I will look at the drive line and thanks for the reply. Mitchell

 

[jtwcummins]

Heard about similar issues w/gov spring adjustments. I think I would start at square zero, the fuel filter. Then I would bleed the air from the injector lines, the overflow valve might be flakey. How to can be found by doing a search. Then I would look at the injectors since seals and shims might be wrong or leaking.



If you mash the pedal out of gear does it rev smoothly?

Happening only under load makes it look like fuel mashing the pedal causing the engine to rev quickly will generally cause a shudder/stumble if this is a problem.

 

[Line-x1]

Good smooth, quick response when mashing the pedel in nuteral. This is only under light throttle pressure. I can maintain 50 mph in overdrive without the shake. As soon as I increse throttle slightly the shake starts unless I add a lot of throttle. It also doe,s it when I am backing out of the throttle at the same throttle positions. There has been several governor springs tried and new injectors. I will have to come up with the stock ones and try them. I have no idea as to what springs have been tried sense the stock ones were removed. I tried a new fuel filter and will look into the overflow valve ( whatever that is) Thanks Mitchell

 

[WZehner]

Mitchell,

I have a 95 that does a similiar thing. At light throttle settings between 1100 and 1300 the truck will shudder only in top gear whether in overdrive or not. It drives me nuts but I keep pushing the button to kick it out of overdrive until my speed gets over 45mph then I kick it in to overdrive. I'll keep watching to see what develops. Bill Zehner in Portland OR

 

[Line-x1]

Thanks, Bill. I changed the overflow valve and checked all the U joints to no avail. I am about ready to change the pump. It is hard to drive in trafic this way. I allmost bought a new Ram before I installed my utility box and did all this stuff to it and now I wish I had. Any one have any more ideas. Thanks Mitchell ( I still perfir the looks of the 97 body style!)

 

[Vaughn MacKenzie]

Sounds kind of similar to my problem, but I had a consistent slight miss on one cylinder. Finally pulled the head to discover the machine shop who did my valve job last year screwed up on one exhaust valve and it was leaking.



Might consider doing a compression test, and if that checks OK have the pump pulled and put on a stand for testing/tuning.



Vaughn

 

[Line-x1]

I do not believe it is a single cyl. miss. Any one know of the best place to have my pump checked out. Would like the seattle area. Thanks, Mitchell.

 

[DMcPherson]

sounds like trans to me. not sure which one it is, but most trand have some sort of device to adjust for throttle posistion. either increasing line pressure or lockup clutch apply pressure. when yo umake more power you make more at part throttle requiring less throttle to get to the same speed. the trans thinks its not much power and does not see the pressure required to lock the clutches up in the convertor and will shutter. seeing as you say it does it in od makes me beleive this more. when you apply more throttle the line pressure goes up and locks the clutches. this would explain why its only after you got more power. my opinion anyway

 

[Line-x1]

This was my thought too but I have had it back to the Trans guy several times and he thinks it is the engine and is sure it is not tork converter shutter. They made several adjustments including spring changes in the valve body that didn’t help. Every one who has looked at it thinks it is in the engine. It got better when PDR (Piers Diesel Research) worked on it but it is still there. I do not want to just keep throwing money at it if I can't get it fixed. I love the truck and have way too much time and money in it to change it now. Thanks to you all. Mitchell.

 

[RKraiza]

I had a much the same problem as your describing. It turned out to be a piece of debris in the delivery valve holder at the begining of the injector line. It partially obstructed the injector line, so when larger fuel amounts were required, the truck would noticablly vibrate and lug. But when I craked each injecter at idle, there was no noticable change between cylinders. I found this by accident when I started changinging out the delivery valves. The debris was a piece of broken spring from the delivery valve assembly. hope this helps.

Oo.

 

[Line-x1]

I will check the fuel system for such things. Thanks mitchell

 

[Driftwood Ram]

I know this is an old thread, but did your truck ever get fixed and if so, what was the problem??

Thanks,

Tracy

 

[Forrest Nearing]

it was governor springs, I promise you

 

[JAmos]

So, since you say it was governor springs, you mean that the tention/tightness of the springs wasn't equal right? Basically the cure for this is to put the pump on a test stand and set it up, where it would be easy to fine tune the springs?



Jordan

 

[Forrest Nearing]

possibly unequal, but probably just not adjusted right. I believe you need to go tighter if you've got governor bounce, but not sure. Have to play with it. You could back them off and count the clicks and make sure you've got an equal number of clicks on each side.



The only two times I've run into governor bounce were on automatic equipped trucks

 

[Forrest Nearing]

FWIW, you see this in automatics because the torque converter allows the engine RPM to vary at a given throttle/load/wheel speed, whereas a manual transmission you can only have one engine RPM at a given wheel speed

 

[JAmos]

I always do equal number of clicks and haven't had any problems yet. So, if I understand right-the gov is bouncing cause the springs are too loose? And so tightening them up decreases the sensitivity of the gov?



Jordan

 

[Forrest Nearing]

you'll have to play with it... I'd go one tighter and see how it does. might have to go looser. I'm sure someone w/ more experience will chime in after the holiday weekend is over (or after they wake up from the turkey coma)