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97.5 H1 Hummer 6.5TD need help

M

mk1spyder

Member
Messages
51
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35
Location
charlotte
Where to start. Truck has about 160k miles on the original stock thin block engine. Ran fine before I tore the truck apart to do upgrades.

  • Wiring stock all in good condition all connectors in great shape no corrosion pins making good contact
  • Stock PCM no tune or anything
  • Original timing chain
  • IP replaced before I got it 10 years ago, truck sat for 8 years while I slowly did a frame off build in my garage literally every single thing is brand new including the bolts minus the engine and body
  • Just put a new IP on it (quality source) not sure if I could have moved the IP gear enough during install to put it off a tooth but I guess that is possible
  • 2x new PMD's
  • Feed the beast lift pump kit with manual switch
  • All new lines
  • New fuel filter housing and filter
  • New tank switch valve
  • New tanks
  • New pickup tubes and fuel level sensors new fuel gauge
  • New bosch injectors
  • New return lines
  • New turbo
  • New glow plugs
  • New CKP sensor
Basically everything is new. After the truck sat for 8 years it ran "ok" after I started it back up but wasn't quite right so I went through all the diag trees in the hummer service manual which only describes doing the TDC offset between -0.25 - -0.75 and nothing about a time set procedure or anything. I have a tech 2 diag tool not doing the koko method. But I wanted it to run perfect so I put all new shit on it, went to time it and now I have to basically max the pump all the way to the passenger side to get it to run half way decent. SO I am thinking I F'd up the TDC offset procedure I put the pump back towards the middle tried to relearn it ran like crap white smoke etc.... Figured I would check to see if there is air in the return line went to lowes got a clear hose came back, now the engine won't even start. Crank crank crank poof of white smoke no start. Hit the lift pump switch take the cap off the fuel filter and the fluid flows out the top freely. But I don't see any coming through the return line of the injection pump at all.

Prior to that my TDC offset was showing -2.46, if I moved it back towards the middle I could get it to show like -0.70 but it ran way worse. My actual timing went from 12.0 all the way at passenger side up to 14 as I brought it back to the drivers side a little, and then when I got to the middle of adjustment all the way back to 0.0-1.0 and if I get it to the 3.5 area it runs like shit. My actual timing will not follow the desired timing at all, the time set function doesn't do a damn thing because it isn't even trying to follow the desired timing. I took the stepper motor off hit the ON time set button and it did extend out so it does work but it isn't doing shit when controlled by the PCM.

At this point so much shit has been changed, so much of it is new, I don't even know where to start. And this PCM / Diag tool is one of the shittiest I've ever worked with, the original tech 2 tool was so bad you had to jamb cardboard into the cartridge slots to even make a connection with the candi module, atleast with the laptop tech2win I don't have that problem. Ready to throw this thing off a cliff and burn it as that would be the financially responsible thing to do at this point.
 
Like unplug the CPS and OS individually and see how it runs? I can't even get it to start now and no diesel is flowing in the return line with the lift pump on (do you have to crank the engine to get it to flow?).
 
Yes but you need to unplug before you try and start it. Not sure on the fuel out the return. I would try unplugging the CPS and try to start it and then the OS. Who did you get the pump from?
 
Wow, you did tanks, valve and all?!! I didn’t realize that. Possible flow issues or aeration issues at each location. That opens my mind some.

Remove the fuel line going into the ip, and engaging the LP, ensure good fuel flow to that point. and as I mentioned, ya need a pressure gauge there. If you don’t have one, harbor freight has one for like $20. My real preference is a dash mounted one, but I know you are frustrated to the point of wanting to sell it, so cheapy for now and some hose to
put gauge near windshield.

When you replaced the ip, how did you handle the 3 mounting bolts? Also did you just leave the gears alone from the timing cover side and just reach through the oil fill?

If you do get good fuel flow and pressure to the ip, maybe removing glowplugs and crank it to verify fuel misting out all cylinders.

What is crank speed now? Maybe the starting and not running right has batteries not happy. Still presolite starter?
 
Has a high tq gear reduction starter from Jegs forget the brand but the starter is not the issue, 2x optima yellow top fully charged.

I don't see how it could not be getting a good supply of fuel but I can add a gauge in line I suppose. I'll check that, it is has the Leroy FTB kit with manual relay switch with like 10 miles on it.

When I replaced the IP I just used a wrench on 2x of the nuts socket and extension on the driver's side bottom one, easy enough. The timing gear I just used a socket through the oil filler hole.
 
And yes it was throwing a P0216 because desired timing was 8 warmed up and it was running 13 actual. My actual is not following the desired one damn bit, I verified the stepper can function and that it is installed correctly. I also moved the timing adjustment lever on the IP with my finger with the engine off to verify it moves and it does but it is also the most cheesy design I have ever seen. Toyota would point and laugh at it.
 
If read correctly you said not using KOKO method? I seem to recall that using the Tech2 you force a TDCO value for current pump position whereas KOKO has the PCM figure out the TDCO based on that position. Anyways I have always used KOKO with no issues and never tried forcing it from a scanner. Others will chime in hopefully if I am off base here but try KOKO you have nowt to lose at this point. Of course the bugger now is that you cannot even get truck running so you are going to have to put pump in middle or thereabouts and force a value till ypu get it running.

Cheers
Nobby
 
Yeah if I just straight unplug the PCM for 30 mins or the batteries will it reset? I did KOKO and forced it multiple times trying to get it to do something anything positive. So I could have very well confused the shit out of it.

I would have thought using the tech2 is the proper procedure that the dealer would do?
 
This is like 10 sec of having the lift pump on, seems healthy to me. I disconnected the PCM measured the resistance across both stepper motor coils at 48ohm which is in range. Opened the PCM up looks perfect no leaking capacitors or anything burnt.
 

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No I don't believe pulling batt or pcm will reset it. Once TDCO is learnt it stays that way till next relearn, makes no sense for it to be lost or reset if truck is sat without power for a period of time otherwise how would you hook a new batt and simply get on your way.

Just reread your post on the face of it sounds like the timing is a tooth off, assuming good fuel supply etc.

Cheers
Nobby
 
The starter and battery question was thinking maybe all the cranking drained the batteries and was maybe just crankin too slow now adding to the issue. The presolite would have amplified it how slow they crank and how much more power they draw.

Yes, the fuel volume You are seeing is plenty if that was 10 seconds.
No the scanner will not tell you fuel pressure, but at that volume I believe you are ok on pressure.

Do you still have a clear line on it where you can see fuel flowing out the ip return line when cranking? Yes, have to be cranking for it to flow out ip return line. I remember you said you checked for bubbles at one point, but leave the clear line in place and glance at it as you go through this to ensure fuel flow and no bubbles sporadically.

I believe the problem is in the timing and or electronics side of things, but learned to always verify these first.
Also, on the ip optic sensor- is the optic filter there? If so remove it and connect the harness without it. See pic for what to remove.
1CB7A4C3-9285-42A2-A175-ED7631842E39.png
 

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No there is no filter there, I moved the pump all the way back to the driver's side and it started running again but really poorly tons of white smoke. The laptop died half way through the TDCO learn before it wait running battery just died on it that might be part of the issue. I noticed the tech2 is showing 99% engine load all the time?

The batteries are fully charged trust me I put a charger on them over night.

I unplugged the CKP and it sort of ran, I unplugged the OS and it will not start at all. The CKP is brand new though. I don't see any air bubbles in the clear line but it is the reinforced vinyl hard to see I'm going to go back and get the straight clear stuff.

I think my PCM TDCO learn is way far off but I can't get it running well enough to warm up to operating temperature let alone learn it again. Do I need to put a resistor in the coolant temp harness?
 
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