Engine/Transmission (1994 - 1998) Engine runs rough at 1100 rpm

[SMalafy]

I just had my injectors changed and have problems with stalling and the engine running real rough and vibrating at 1100 to 1200 rpm. It runs good at higher or lower speeds, but it does seem a little harder to start too. I had problems with the engine stalling before on and off but no vibration at 1100 to 1200 rpms:. All the air has to be out of the lines after about 100 miles of driving. Is my fuel pump going bad or is there something else I should be checking ? I changed the fuel filter but that did no good. :

 

[CodySanders]

i would say you should start with what you just did. beter a chance of that then luck that something went bad at the same time you did the injectors. mabey bad injectors or mabey the timing can do that im sure someone will chime in and let us know. i think that when you change injectors the timeing can change as well.

 

[SMalafy]

I did have a problem with it stalling out before I changed the injectors only it was once in a while. The company dynomite diesel that sold me the injectors said there should be no change in the timing and it should run fine.

 

[Rams-n-Hogs]

Are they stock injectors, or 370's, and what else is done to the truck?

 

[SMalafy]

Not Stock, Stage 2 injectors, 75 hp increase made by Dynomite Diesel and all I changed were the injectors and fuel filter. I had a #4 fuel plate installed 6 years ago along with a 4in exaust and a low stall tourqe convertor in the transmission. I am going to look over my lift pump and check for leaks.

 

[SMalafy]

No leaks on lift pump however the steel line going thru my exaust manifold going to the turbo waste gate is broken off. Maybe thats the problem, the waste gate on the turbo not working

 

[Lil' Dog]

I don't know if the wastegate line would be that big of a deal, but the stumble may indicate some air in the system. Have you changed the rubber fuel lines to/from the engine lately? Known failure point. .

 

[fest3er]

No leaks on lift pump however the steel line going thru my exaust manifold going to the turbo waste gate is broken off. Maybe thats the problem, the waste gate on the turbo not working

If that's the boost line from the intake, it shouldn't make much difference near idle. And near idle, the wastegate is closed anyway; it only opens at high boost. Unless it's stuck open.



Use a stethoscope (or long screwdriver) and listen to each injector. If your hearing is good, you should be able to tell if an injector isn't working right.

 

[Rams-n-Hogs]

Like Lil Dog said, possibly the rubber fuel lines. You also might want to check the lift pump pressure with a fuel pressure gauge.

 

[Missouri Mule]

More info on engine stalling before new injector install.

In the 3rd gen vibration at idle/hard starting is cause by a bad inector are you sure the injectors were installed correctly ( washers to be exact).

 

[SMalafy]

I checked the fuel lines and they seem allright

 

[SMalafy]

I have a diesel shop do the work so I am not sure. I will listen to each injector tommorow and see. I can't see why the engine would really vibrate badly between 1100 and 1200 rpm and not do it all the time.

 

[SMalafy]

I guess I'll have to buy a fuel gauge and check the lift pump pressure tommorow too.

 

[Grumpy John 4x4]

rough Idle

When mine did that , Had to replace the 7100 pump

 

[SMalafy]

Did you have the exact same symtoms. The people who did the injectors said it seemed like the pump was bad considering the symtoms with the low RPM vs higher (above 1200) rpm. I need to buy a fuel pressure gauge. THANKS TO EVERYONE WHO REPLIED. i'LL LET YOU KNOW WHAT IT WAS WHEN I FIND OUT