Help diagnosing injector pump issues

[Turbomax]

Hey all,
I have a 1995 Chevy 6.5 turbo diesel truck. I've had it about 3 weeks & can't get a definitive answer. Please help. When I bought the truck the owner said the SES light had been intermittent for a while. He said he had put a PMD on it in February & figured it had gone bad. It was a Dorman from O'Reilly's with a lifetime warranty so I wasn't too concerned. I replaced the PMD & relocated it on a heat sink behind the front license plate. However, no difference on the SES light. I've had it scanned & 2 codes are always there. 35 & 36 which the scanner says is injector pulse width error - short response & injector pulse width error - long response. I've been told that I need a new injector pump but want to make sure that will fix the problem before I spend the money.

I don't know if it's related but when I start the truck first thing in the morning, it smokes like crazy for at least 5 minutes; sometimes more. The smoke is grey/white which I suppose is fuel. Of course I can't accelerate since the SES light won't let the cable-less accelerator work. It will finally clear up & runs fairly well throughout the day. If I plug in the engine heater, even in warm weather, the smoke is very minimal. I've checked the glow plugs & the glow plug solenoid. They are okay.

So, does this sound like an injector pump will cure the issues?

I have another injector pump but I don't know if it's good. It's not worth having it put on & find out that it's bad, too.

I have never replaced an injector pump but I do have the tools & quite a bit of mechanical experience. Is this something I can do? I've already had the intake off removing the PMD. I know the pump has to be timed with the engine when it is installed but is there something else I should know when installing it? If I do have to replace the pump, what recommendations do you have? I am VERY LIMITED on $$$. I've found good prices at Dieselcare.com but have been told they are not very reliable. Any suggestions would be greatly appreciated. I'm only wanting to put the truck back as close as possible to original as possible. I'm not interested in high performance or speed - just dependability!

Thanks very much for your help

[DmaxMaverick]

Injection pump replacement is not difficult, or too technical. If you put the new where the old was, you shouldn't need to "time" it in any way. The PCM will compensate for minute differences (advantage of EFI).

Solenoid timing issues often mean pump time, but not always. The lack of lubrication in the fuel (ULSD) can cause solenoid delays, triggering the codes. Try a good fuel additive with lubrication, and add a pint of 2 cycle outboard oil with each tank of fuel. So can poor electrical connections or low voltage. Start with cleaning and verifying all the grounds, especially the single ground wire from the PMD harness to the pump housing. It MUST be mounted there. Grounding this one wire anywhere other than the pump often causes issues, including what you are seeing.

It appears you've already solved your smoky start issue. HEAT. Adding cold start heat by plugging in helps, so your problem is primarily the lack of heat. Either your plugs aren't all good, or they aren't getting hot enough. If you are using AC60G plugs, it isn't surprising (and is typical, by your description). They only get about 1/2 as hot as OEM plugs in the same cycle time. Either change out the plugs for Quick Heats (instant, permanent fix), or extend the glow cycle time (adding a manual glow switch is simple). Try this: Cycle the key until the GP lamp goes out. Cycle the key again to trigger a second glow cycle. Try a start. There should be some improvement, with the added heat of the second full cycle. Also, weak/tired injectors make cold starts more difficult and can be very smoky (less efficient spray pattern and/or low pop pressure). Added fuel lubrication can help in this department, as well, sometimes. If the injectors have over 100K on them, they are suspect.