Engine/Transmission (1998.5 - 2002) 275 Injectors

[hcpBILL]

I recently installed a set of the Bosch 275 Injectors. I am very pleased with the performance and economy improvement.

I noticed a very slight 'bumpy' idle speed since installing the new injectors. Everything else seems just fine. EGT goes to 1300+ in 4th pulling my 40' trailer over the mountains (if I dont watch it, I try to keep it at 1250 max).

Any reason to be concerned about the bumpier idle?

Thanks

Bill

 

[rkressg]

They will run a little lumpy for a while. The idle should smooth out after a few hundred miles. You might also notice some slight surges during acceleration, but again, this should smooth out.

 

[BillGotthelf]

If that lumpy idle does not clear up you probably have an injector that is not opening up at idle. Fuel pressure opens and closes the injector and sometimes the injector is a touch to tight to fully open at idle fuel pressure.

 

[Big_Daddy_T]

Sticky injector. I had one. I actually got to likin the lope. Felt like i had a lumpy cam. Got the chicks hot. Know what im saying.

 

[hcpBILL]

Thanks

Thanks for the advice. The injectors are a good addition. I got between 7 and 8% better mileage towing. I have not had a chance to check the mileage without a load.

Thanks again

Bill

 

[Jack in Alaska]

275's

My idle has a 300-400 rpm lope that was not there before. They have been in for approx. 80k miles and work fine at load.

I have not seen much increase in fuel economy when towing but much better performance.

 

[Crankshaft]

My 275s idled smoother when I put them in. But they were the BD Hi pulse.

 

[BillGotthelf]

Jack you might have more than 1 injector thats not working at idle. The easiest way to tell what injectors are not working at idle is 1 of 2 ways. One start the truck (cold) and let idle for about 15 minutes, then check temp at exhaust manifold for each cylinder. The ones not working will run about 40-50 degrees cooler. Second- run truck until normal temps are reached and then let idle for 10 minutes then check temps as in the first way. I used a infared heat sensing gun but you can use anything even an oven thermometer.

 

[RobertMiller1]

miss

could it be you're running too rich now, and the combustion is not as efficient?