ICP Voltage vs PSI Chart

<table border="1" cellpadding="3" cellspacing="0"><tbody><tr><th align="CENTER" valign="bottom">Voltage</th><th align="CENTER" valign="bottom">PSI</th></tr> <tr><td align="CENTER" valign="top">1.0 v</td><td align="CENTER" valign="top">580</td><td align="CENTER" valign="top">
</td><td align="CENTER" valign="top">Minimum required at engine cranking speed 100 RPM</td></tr> <tr><td align="CENTER" valign="top">.88 - 1.19 v</td><td align="CENTER" valign="top">540-790</td><td align="CENTER" valign="top">
</td><td align="CENTER" valign="top">Normal warm idle voltage signal</td></tr> <tr><td align="CENTER" valign="top">1.38 - 1.53 v</td><td align="CENTER" valign="top">960-1088</td><td align="CENTER" valign="top">
</td><td align="CENTER" valign="top">Normal high idle voltage signal</td></tr> <tr><td align="CENTER" valign="top">3.22v</td><td align="CENTER" valign="top">2520</td><td align="CENTER" valign="top">
</td><td align="CENTER" valign="top">Snap accel or full load pressure signal</td></tr></tbody></table>

 

Yes, I now understand what you're trying to convey. However, what does the data point to as being the problem in your opinion?

 

From here ... http://oregonfuelinjection.com/pdf/f...diagnostic.pdf

NO START OR HARD START HOT

IPR (Injection Pressure Regulator) bad, will cause low ICP.

IPR o-rings bad, will cause low ICP.

Injector o-rings bad, will cause low ICP. Should also show up as black fuel (from oil in fuel) in fuel filter canister.

High pressure oil pump bad, will show up as low ICP.

Engine oil worn out or too thin.

Cranking speed too slow, should be 180 rpm minimum when warm.


Also Injector pulse width is 0.4 ms which means PCM and IDM are in sync and PCM is waiting for oil pressure to reach ~ 500 PSI at which point the Injector pulse width goes to 1-6 ms and the injectors will fire.

 

Update on this problem:
Replaced the IPR yesterday. I assumed it was original (stamped "1996" on rear of solenoid), so why not. After removing the FPR and the 2 bolts on the fuel filter, I was able to remove the IPR with a regular 1 1/8" box end wrench. Put it all back together and the truck started fine (cold). Ran for about 20 minutes, shut her down, and no restart.

Ran A/E again. KOEO test showed 1298 (IDM failure). Buzz test showed a 1298. Both codes have been present before, but I was just trying to eliminate other more likely causes first. I cleared the codes and performed both tests again. This time, they both passed without throwing any codes. Strange. Also, it sounded like a few of the injectors buzzed more loudly. I tried to start, but no only cranking and no start. Ran both tests again and got the 1298 code. Yep, definitely had some injectors that didn't buzz as loudly this time. Cleared the code, ran tests again...strong buzzing, no codes. Tried cranking then ran tests again...yep, some didn't buzz as loud and the 1298 came up again.

At this point, I believe replacing the IDM is the next logical step (and most likely the culprit). I removed it and openned the lid, but it looked good and clean on the inside. Guess I'll get one on order tomorrow.

 

I think that an idm isnt worth it especially if you pulled it off and you didnt hear anything sloshing inside of it and it looks all good. right now im in the middle of fixing my truck from a no start when warm issue, it ended up being the fuel bowl harness...i just recommend checking the pigtails on your ipr and icp really cood and look at your pins. i havent read the whole post so sorry if this has been brought up.

 

At this point, the IDM falls in line as being the next likely problem, according to the multiple diagnosis guides I use. The presence of the hard fault (which only shows up after attempting to start) has me more/less convinced. I've checked the wiring that goes to the IPR, and it's not chafed and they are seated in the plug. I've visually inspected the wiring at the fuel bowl, and can't really see any issues there. I have not unwrapped any of the wiring harness, but I would not expect that the shielded stuff would be damaged. There are no blown fuses and switching out the horn relay doesn't help either.

Looking back, the problem progressively got worse over the course of a day. I've replaced the CPS and IPR, both of which didn't fix the problem but still were good calls to replace. The truck runs like a scalded ape...when it runs.

I ordered a reman IDM from auto computer exchange in south FL, which appears to be pretty knowledgable about these things. The one I got is a higher voltage than stock. Should be here tomorrow or the next day, so we'll see.

 

sounds good, what was the bill for that idm? if you willing

 

$129 plus tax, free shipping, have to return core.

 

Well, here we are...
New IDM (reman unit) installed and the problem persists. Still no start when hot/warm. It did run just fine on the IDM for about 20 minutes. I have not plugged in A/E to see what's being read, but at this point I don't think it'll be very helpful. If it still reads "IDM failure" then what...???

I guess the next step would be to remove the valve covers and inspect the injectors, replace the o-rings. If I go that route, then I might as well replace the UVCH harness as well on both sides.

I'm at a loss as to what else could be causing this...

 

Problem(s) Found:
Injector #2 pours oil out like its an upside quart bottle. I broke a cardinal rule and puffed a hair bit of ether into her to start it. It wasn't enough to start, but was barely enough make it cough. When that happened, it literally shot a stream of oil 12 feet across my shop. With just regular cranking, it pours out. Tomorrow I'll remove the injector and inspect.

Another problem is that there is a burn spot about the size of a pencil eraser on the inside of the UVCH on the passenger side. I don't think its causing my problems, but it will be a problem if not corrected.

Sadly enough, this is the best I've felt about my truck for the last 2 weeks!

 

So its loosing high pressure oil from oring at the base of the injector?
If so ,that'll sure do it. 12' across the shop ? I would like to seen that lol
I will tell you,turning the engine over with a breaker bar when doing orings.
It will shoot the oil out the gp hole and cover your tool box. Really need to have the vc on lol

 

Those burn marks in the vch could cause problems as well. I would definatly replace them. But it sounds like your troubles run a little deeper than that. Where is the oil coming out. The deflector on the injector or the oring?

 

I don't think its supposed to be this way

 

Aaannnddd that is where you found your issue. It will never build hpo with that issue.

Holey moley that is the extreme end of the failure spectrum. Congrats...youo win! Lol

 

I ordered new o-rings to do all 8 injectors (plus one kit for a shelf spare). Also ordered new glow plugs too...might as well do those as well while I'm in there. Only ordered one new VC gasket and harness. This should be a fun little project for Saturday.

On a related note, I was able to remove the 2 oil plugs on top of the head to allow the oil to drain out. This is CRUCIAL when removing the injectors, but I only recently learned about it. This injector is on the front, and the truck is tilted back (pulled up into my shop), so about the only oil that went down into the injector bore is what was left in the injector, which was maybe a spoonful.

On another note, I did call the local rapist stealership to get prices on these parts. An o-ring kit from dieselorings.com is $7.45...they wanted over $15 Almost every part was nearly double the cost. The GP's were about $14 each vs. $11 online. Just another reminder that the dealership is only worthwhile IF you're in a bind AND IF they have the part you want. This local dealership DOES NOT carry parts for the 7.3's unless they are common to the newer diesels as well.