All right. This is the graph of what is going on during cranking... as you can see the DC is peaked around 40 and ICP at 2500.... wtf...

I will mention this is the ICP sensor plugged in...

 

Unplugged....

 

I will also state I was a moron and did not graph FPW when I logged as I was so focused on the oil....

 

Agreed its a simple negative feed back loop, I should have that voltage via mutimeter or readout from AE.

Its the negative side of the plug that provides feedback to the ECU via square wave pulse width modulation... IPR is the control valve for the oil is all...

I will let you know... Thanks for your help. I was simply trying to think through this as much as possible before taking it all apart.

Like I mentioned I forgot to record fuel pulse width, based upon these number I should have something correct? .3-.45 ms approx? If i get nothing i'm guessing a have an electrical problem vs mechanical...

 

I believe .3 - .45 ms is IDM is synced with PCM and waiting either for valid CPS signal or minimum high pressure oil ~ 500 PSI, then it should go up to ~ 1.0 ms. I can look it up for you if needed.

 

Almost right ...

Pulse Width; 0 ms means nosync, 1994-1997 .42 ms indicatesthat PCM and IDM are in sync (on99-03 it should be .60 ms) andthe PCM is waiting on the ICP to reach the minimum of 500 PSI. When min. ICP is reached PW should change to 1-6 ms

 

Right on man! thankyou! I'm going to take a bit of a lunch from the real job and go home and see what I get there... I'm making a wild guess right now we have 0.

 

AND ITS 0 ms all the time..... well that answers some questions... I want to check the IDM relay now... may be failing under load? Check the CPS just for chits as they have bearing on a non synch condition.

 

If buzz test still works then PCM - IDM are communicating. My vote is CPS, don't know what else would cause a no sync 0 ms FPW condition. CPS plugged in ? Guess it would be if it started once though.

 

Well I will take a look at both swap the relay for the blower motor, and toss a new CPS in for the heck of it, it was plugged in. I did check that. I am registering rpm though..

 

Man school is in session! Good stuff guys. Sounds like you're on the right track Nik. When we spoke the other night and I asked if you had a way to measure high pressure oil, what I meant was an external mechanical gauge. Not through a scan tool.

 

Well you all can riddle me this. Never seen it before either.......

Got home, fresh batteries, logged again, this time we had +3000 psi easily for quite some time, ICP voltage was 3-4 volts and remained constant around 3.2.. I wasn't paying attention to DC all too closely but I'll post the log. I cranked for 4 burst at 20 seconds... same thing... nothing

NO FIRE!!!! 0 MS FPW still.

Ironically the chip shows up today too.... so ran up to the house and grabbed it thinking it was easier than doing the CPS next. I swapped relays and plugged the chip in. Right as oil pressure builds she fires right off and idles nice and smooth... I almost crapped my pats. Turned the truck off after 15 seconds or so of running, and did a jig with the dogs super happy.

Going to eat dinner and go back to it. So freaking happy. I thought we had something bigger going on. The entire time my buddy kept saying chip and i affirmed it wasn't possible... will verify when I go swap relays again and see if it starts. If it doesn't I will swap them back and test again...If that is the case.... and it was the chip, I need an explanation... I have never seen a truck run without a chip, and only with one.... It has always been the opposite. I am starting to wonder if the lock out security deal had to do with the PATS system when it was disconnected... it did not reset till the chip was back in? I don't think thats possible either unless they truly pulled the security key off the PCM....somehow.

That all being said I have a hard time believing it was due to lack of oil. I think we had a solid 10 minutes worth of cranking on it over 3 days. The irony that it fired right as it built pressure baffles me, idled fine till I turned it off.

I will report back!

 

Not the relays...it was the chip. I swapped them and it was the same thing. Fired right up within 3 seconds of low pressure oil needle moving.... So I'm at an electrical loss. Unless its a cali model specific deal to have the PATS code on the chip, then I still don't believe it....

I will be calling gearhead to bounce a few questions off them.

 

Lord have mercy! Now the real question. How does it drive!?

 

Did not read the chip part in the post. Guess that could change everything in the diag portion on issue.