Engine/Transmission (1994 - 1998) 12 diesel shake

[Donno81]

i have 98 12 valve that i have recently changed injectors in and had the pump turned up and calibrated. the injection place says that the calibration stand says the pump is 100% calibrated but at an idle you can kinda hear a little ( i wouldn't call it a miss but kinda of a shake) when you rev the truck up to approx. 1200 or a little above you can really notice a shake. the truck doesn't smoke and i don't notice any oil consumtion. You can notice the problem alot more when the engine is warm. I noticed this problem before changing injectors and having the injection work done. One last thing the injection guys say that this pump is off of a 94. they also say that the govenor is tight and that there is nothing wrong . Does anybody have any ideas.

 

[98rammer]

was a governor spring kit installed though? 370 injectors with the stock delivery valves will make it stumble sometimes.

 

[Donno81]

the shop says they have never seen this problem... ... . at all. the have juiced a bunch of them up and said never. plus it did it before i replaced the injectors

 

[Got Smoke?]

Its probably his DV's because he sent me a PM reguarding injectors and said he had installed 370's.



Donno you might just have to upgrade to 191 Delivery Valves to cure this stumble. Do a search on 370's and you'll see we're telling you from other members past experiences.

 

[Donno81]

i understand you guys are just tryin to help. i just wanna make sure thats what it is before i spend the cash. you think even if the pump was was in specs on the stand that it could still be the valves???

 

[Donno81]

also i don't know what to think about this one, i have somone saying that it could be the clutch out of balance causing the engine to sound as if it where missing.

 

[power grizz]

check you gov springs! i would try adjusting the springs a hair tighter or looser a quarter click at a time before spending more money on parts. maybe some one else may have a better way to check governor. on my motor i had a similar shake, but i never took enough time to adj the springs correctly after the 4000rpm kit install.



i have been told by my diesel shop that the test stand cannot test the (gallop)of the governor because the machine is driving the pump regardless of throttle position, governor springs, etc.



play with the springs first, then i would still get the delivery valves. they make the 370inj much more powerful.

 

[Brandon]

just what I have heard, this is prone to 215 pumps, I cured it with a 160 pump, problem all gone... .

 

[Jim Fulmer]

Try the Gov springs as said above, it doesn't know what to do fuel or not fuel at that RPM. My guess is if you go lower or higher in RPM it quits, what about load, what does it do at that RPM in a high gear, is it smooth or bouncy. Yep mine does it too and it's dramatic but Piers say's he can cure that!



Jim

 

[GOODE11]

Donno81, does your truck also give off a vibration throughout the powerband? I've been chasing a engine "shake" and vibration for about 8mo now. I've been throwing quite a few parts at it and now I'm down to the pump. This is one thing that I really don't want to adjust, I tend to mess things up quite easily.



GOODE11

 

[Donno81]

you can notice the shake at an idle but when you accelerate it to about 1200 it becomes very noticable and literally makes the truck SHAKE. not like its gonna blow up but just like a raelly big cam in a gasser. when the truck is in motion you can still kinda hear it but once you get it up to speed you never feel it. i. e. under load. but at neutral at an idle it will drive you nuts just because you no its there. i am really siding with you guys about the gov. springs alot because thats what the diesel mech is saying it sounds like is that the governor doesn't know what to do... ... ... ... . are the gov. springs tightened easily???how??

 

[Sleeper]

Mine has shaken since it was new. Piers and I never did figure it out. Still shakes, but now it has a reason to. ;>)

 

[Donno81]

since getting juised up it feels like there is a lot of power but it takes for ever for the boost to build. the guys that did it say it will probably be around 390 hp but i just don't feel it. they say it isnot going to be eral noticable till i pull it or tow something to let the boost build. i want alot of boost really fast. is it turbo or governer

 

[drees1]

Do you have a combustion knock along with the shake? Mine makes a knock like the diesel knock, but louder on one cylinder. I pulled my pump and it was 100% as is. But I have stock injectors, and the pop test showed ok too. I think mine is injectors. Mine will shake the truck at idle up to about 1200 to 1500 rpm. but the knock is most noticable at 1750 rpm light throttle pedal. On mine as I slowly rack it up and down in speed, it does not shake when I let up on it so it is not balance. I think the knock is fuel knock. If you don't have a rythmic knock then I would try the governor springs as mentioned. If it started this when you changed injectors, you may have a bad injector.

 

[Donno81]

did it before to... ... ... ... ... i think. i never drove it enough before changing the injectors. i wanna say that when i first changed the injectors it didn't do it but by the time it ran for lets say 20 min. its done it ever since