GM-GMC: 88 Suburban with 6.5 upgrade, bosch injectors, diesel type

Question
Hello Harry,

I have an 88 Chevy Suburban that had a later model (98 or 99) 6.5 diesel replaced by the previous owner.  
The engine starts and runs fine when cold but after warming up it begins to idle rough and spew lots of blue exhaust although it runs ok while underway.  I suspected the injectors and am in the process of installing some recond Bosch injectors I bought off Ebay. If this does not solve the problem I would next suspect the injector pump.  I have read that the piston in the pump is a common problem and is easy to replace. Would the injector pump from the original 6.2 engine work on the 6.5 or would they have used the 6.5 pump? Are the pumps interchangeable?  Is it a critical task to replace the pump? I am asking this in case I need to locate a replacement pump.

Thanks very much for your help.

Regards,

Barry Miller


Answer
Unless someone went to a great deal of trouble, the injection pump that is on your engine is likely to be the original 6.2 (mechanical) diesel type.

A simple way to tell is by looking for the accelerator cable.  Mechanical 6.2s have a throttle cable from the pedal to the injection pump.  Electronic 6.5s do not use a throttle cable.  They are drive-by-wire where pushing on the pedal causes the computer to send a signal to the injection pump.

If you are describing the piston that operates the cold advance, the injection pump will have to be removed to repair it.  The bore it rides in will likely need to be sleeved and this repair probably should be left to a reputable diesel injection shop.