No acceleration question

[z06_vette]

I have had this truck for just over 1 year now with a few problems but all relatively easy to repair. First had a valve spring broke, removed head and found it cracked, replaced it with a good non-cracked head, installed 8 new SSD marine injectors, SSD glow plugs, and installed the SSD 4" ss exhaust.
I have added an emergency light bar and in doing so, drilled thru a wire harness behind the dash, just below the radio. Repaired the harness and haven't had any issues for some time. My family just left on vacation and during my time away a friend borrowed the truck. Today, when he brought it back he told me that during his time he drove it, he had the brake light come on, the speedometer read and stick at 85 mph, and the truck would not accelerate.
He checked all the fluids - good. Like I said, all he saw was the speedometer was pegged at 85 mph. He told me the truck just idled, even with his foot on the floor. He shifted the transmission from park to drive, with no change. However he tried from park to reverse then the speedo went back to 0 and the truck began to accelerate like normal. He tells me this happened 2-3x for him but each time he shifted from park to reverse it acted normal.
He also told me that today it didn't have any concerns.
I have not scanned it for any codes at this point. Just wondering if there is anything I should maybe look for once I get it scanned and if there were no codes left in the pcm.
I am expecting to see a throtte sensor code in the system but since he didn't see a check throttle light or ses light on ever not sure what to expect yet.
Thanks for any advise in advance.

[grancito]

Put a paper clip in the diagnostic plug and read the flashes on the SES light, saves stabbing in the dark.

[z06_vette]

ok, finally after several tough weeks at work i finally got around to scanning the pcm for codes. stored is 18, 86, 85. since my friend has told me of this issue, i personally have not experienced the no acceleration concern. not sure what to do at this point.
I do however have an alternate concern which i didnt think too much of several weeks ago but it does not seem to be getting better, only worse. after the truck has set overnight, go to start, glow plugs cycle fine, cranks over fine but lots of white smoke out tailpipe and the truck seems to bobble for about 30 seconds adn smooths out. it runs great the rest of the day UNLESS i let it set for 8+ hrs. then again it does the same thing. now just under a year ago i had a broken valve spring, removed the right cylinder head and replaced the spring, all 8 injectors, glow plugs and gp controller with ssd parts (not valve spring-that was local part)
i have not had time to check this out but another diesel mechanic tells me i have some injectors leaking down over night. how would i really tell without removing them? what is ssd's warranty on injectors since i know i have had them less than a year and less than 7.5k miles? if one is bad should i replace only 1 or replace the whole set since that is what is recommended?
i wouldnt think it would be glow plugs since the ambient temps are above 85F.
Any thoughts?

[grancito]

Does the white smoke smell of fuel or sweet, coolant. Codes are a confusing mix of IP and transmission, could be an electrical connection problem. Speedo stuck is probably an instrument panel bad connection.

[z06_vette]

the white smoke smells more of diesel fuel than coolant smell

[grancito]

How many miles on the engine? Did you replace the valve lifters?

[z06_vette]

127500 miles, i did not replace the valve lifters since i have owned this truck. i did take extra time when i did the head removal to replace the valve spring to make sure the rocker arms, placement pins, push rods and what i could see of the lifters were in good condition.
the only problem i had after the valve spring repair completed was when i finally got around to mounting my light bar switch box onto the dash. i drilled a hole and the drill bit went thru the dash wiring harness. at that point i had the chime go off, all the lights in the dash came on and tons of fuses blew.
i repaired the loom the next morning, replace fuses adn check how the thing ran....seemed ok except i got a check engine light on...waste gate solenoid problems.
after checking vacuum, wiring - i found that i had missed 2 fuses! i replaced those and the truck has been running perfect. started fine, ran awesome - no problems!
now within the last 3-4 weeks i have noticed this start up miss, engine bobble, white smoke concern. now today i did not drive the truck but the wife says when she started it this morning, it cranked fine but lots of white smoke, truck would barely run, acted like it wanted to die but didnt. it cleared up within 1 minute. she parked it for roughly 2 hours, came back and it started fine. no miss, smoke or anything...perfect. let it set after lunch for roughly 5 hours at that point she did notice a small white cloud and very slight engine bobble.
it seems to reason that after a 5+ hour set something is causing the truck to run sort of crappy...i am thinking leaky injector.
hopefully all this rambling gives you all the info needed to help diagnose my problem.
thanks everyone!!

[grancito]

If it blows the white smoke for a short time then continues to run rough, then that may be a leaking injector that has the line full of air. But if it continues to blow white smoke then it is a compression problem as it is injecting fuel and not burning it. The 94 and 95 years have bad valve lifters, and they leak when sitting for a while and don't refill quickly, so start up has bad compression. Does it have noise from the rocker covers when it is hot?

[trukdoc]

...crank it cold watch the oil pressure gage as you start it...if you have a sloooow response for gage reading,you could be having o.p.s.problems...key on system pressurizes..cranking ops takes over running fuel lift pump...if the ops is starting to run out of range,you could be getting air in system causing symtoms you describe till ops catches up and problem goes away till next time couple this with a fuel drain back issue i.e.leak at fuel heater,lift pump check valve going bad,etc. and you have a problem that occurs when unit sits for several hours...hope this helps...jd

[grancito]

...crank it cold watch the oil pressure gage as you start it...if you have a sloooow response for gage reading,you could be having o.p.s.problems...key on system pressurizes..cranking ops takes over running fuel lift pump...if the ops is starting to run out of range,you could be getting air in system causing symtoms you describe till ops catches up and problem goes away till next time couple this with a fuel drain back issue i.e.leak at fuel heater,lift pump check valve going bad,etc. and you have a problem that occurs when unit sits for several hours...hope this helps...jd

It's not the sugar in the coffee this time, IS IT!!!! Garth will remember.

[rooferwill]

just a quick queston, Have you checked the glow plugs to see if they are all working? A couple glow plugs dead could cause similar problems. Just cause the solenoid is cycling doesn't mean they are working.

[ZiGBlazer]

I second the OPS. Check the output, or try energizing the fuel pump before you try to start. You can jump the relay (pins 30 & 87) in the underhood fuse block. If it works make sure you get a Delco OPS. Otherwise wire up a switch to override the fuel pump and run it whenever. I did and found it made starting a lot faster.

[grancito]

I second the OPS. Check the output, or try energizing the fuel pump before you try to start. You can jump the relay (pins 30 & 87) in the underhood fuse block. If it works make sure you get a Delco OPS. Otherwise wire up a switch to override the fuel pump and run it whenever. I did and found it made starting a lot faster.

As well as a starting problem, he has unburnt fuel coming out the exhaust pipe, thats not a lack of fuel problem.

[z06_vette]

OK, finally time to get back here and update everyone with what has happened over the last 7-10 days. I was still experiencing concerns and then several of you suggested monitoring my oil psi guage for a potential ops concern.
This is exactly why I brought this concern to the forum. You are all the best. What I noticed is that even though my guage seemed to be functioning properly I went and check my oil level. Much to my surprise My oil level was 4 quarts low! OUCH!
I added 3 quarts since that is all I had at the time and from that point on again watched my guage and checked how it started. Lo and behold the next morning this thing started like a champ. NO misfire whatsoever!
Now I could not really believe that being 4 quarts low would have that much of an effect. However, since i was due for an oil change anyways, i changed the oil and started fresh. Since then i have had no concerns whatsoever.
Amazing what issues you can prevent if you check under your hood occassionally.

*smacks himself upside the head for being stupid*

Thanks everyone!

[grancito]

Mmmm, when the oil pump sucks air, the valve lifters don't open the valves properly.