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94 6.5 turbo starts rough!!!!

turbovanman

turbovanman

I has boost, :O)
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Ok, another bastard child 6.5, it starts but then miss's like its on 6 cylinders, belch's out white smoke, runs rough then after 5 secs smoooth's out and its fine. No smoke while running, lots of power and no blowby. Its a 94 K2500 extended cab long box, auto, turbomaster, Heath chip with longer glow plug duration, home made cold air box, 4 inch exhaust, pmd relocate. Customer brings it in a few months ago, starts rough and pukes out white smoke, I check out all the glow plugs and find a couple bad ones, replace them all, problem solved for now, or so we thought. He bought it back a few weeks ago, its worse, so I spend a few days unplugging one glow plug at a time trying to determine which cylinder, well that didn't work, :mad2:

So I pull out the injectors looking for a bad one, he put these in 1.5 years ago and aprox 20K on them. I find no wet injectors or wet cylinders and for shits and giggles, I cycle the glow plugs, look down the injector hole and they all light up. So on a hunch, I send the injectors out to get tested-good hunch, they are very bad-some the spray pattern is like half, pressures are all over the map AND the nozzles are done, turned blue??? Ok, so put the rebuilt injectors in and son of a bitch, it still does it, :mad2::mad2::mad2: SOOOOOOOO, to me, looks like something went thru IE bad fuel or water and damaged the injectors so I think the IP is damaged? I haven't done a compression test yet but I doubt that's the problem and it doesn't use a drop of coolant. TIA.
 
Gotcha. I figured that but was just checking.

Forgot to add, all scan data looks great, temps are inline etc. The only thing that throws me is the injector PW stays at 1.99 ms when first started, then it rumbles quietly, then clears up, gets loud and the injector PW jumps to 2.40 ish? :confused:

I am going to let it cool down and look at the timing.
 
1.99 is like the default before all the timing sources are reporting and adjusted for. It will set a constant of around there if you run the truck with the OS or CPS unplugged. When in backup fuel mode. So if your TDCO hasnt been set correctly it may add to this issue.

For extended glow time youd also have to unplug the IAT sensor.

I dont get anything that bad but my afterglows usually make the idling smoother faster. Do you get afterglows? If the advance from pulling the CTS helps it could be that you have stock advance and its not that great, or there is the theories that something in the IP gets worn and once moving it gets within tolerances and lubricated.
 
The TDO has been set at -1.94, no change. It already has the extended glow plug time, around 30-40 secs I think. I'll do the CTS unplug before I go home. Thanks everyone.
 
Wow, 30 seconds is too long for glow time. The PCM can only control up to 25 seconds. And the glow plugs can only get so hot which will happen in less than 20 seconds. Running them real long could be detrimental.

What smooths out the idle is the afterglow. The glow plug light should blink on once or twice a few seconds after it starts.
 
buddy said:
Wow, 30 seconds is too long for glow time. The PCM can only control up to 25 seconds. And the glow plugs can only get so hot which will happen in less than 20 seconds. Running them real long could be detrimental.

What smooths out the idle is the afterglow. The glow plug light should blink on once or twice a few seconds after it starts.
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It must be 25 secs then and yes, they cycle. This isn't my issue though.
 
Looks like its the pump, unplug the coolant sensor, starts and runs better, only a slight miss, plug it back in, miss's and blows out smoke so an IP is in his future. Thanks.
 
You can't adjust timing.....Maybe bad CTS?......Not the answer I was looking for, bad pump....why does the advance help the start?

Need DieselPro!
 
Dump a half gallon of 2 stroke or SAE30 in the fuel, something to lube that sucker up......Someone had mentioned that helping the rough start....I'm not sure who.
 
Brooklyn Tow said:
Dump a half gallon of 2 stroke or SAE30 in the fuel, something to lube that sucker up......Someone had mentioned that helping the rough start....I'm not sure who.
Click to expand...

He's tried all the band aids, nothing worked. He's trying to sell it so right now, he doesn't know if he'll fix it or sell it as is. Too bad, it runs awesome, smoothest, fastest 6.5 I've driven in awhile.
 
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