I have a 1994.5 powerstroke that i was driving a couple of weeks ago, and it suddenly died like someone just turned off the key. Cranks fine but no start. Have snap on scanner that doesnt show any codes.
heres what i have tryed

new cam sensor
new icp
new ipr
new exhaust backpressure sensor
New hpop
new injector orings
new fuel pump
cleaned all fuel lines and bowl, no clogs (good fuel pressure too)
Tried good pcm
tried good idm
Replaced relays in fuse box
good 22 fuse, and all others good
have lots of fuel and oil

Injectors will buzz in buzz test fine, but not fire when cranking, have plenty of oil in resivour and plenty of fuel to inectors

am about to my witts end with it, and any help would be apriciated

 

Looks like you tried about everything. Do you get a wait to start light when first turning the key? You replaced fuse 22, but are you getting power to both sides of the fuse? My sons 99 died going down the road, long story short, the sockets that hold the 22 fuse had spread, and contact was lost threw the fuse spades.
Fuse #8 powers the PCM I believe. It has been quite a while, but someone reported the main wiring harness that lays on the drivers side valve cover fatigued and some wires broke. Just a couple of thoughts, and a bump to the top.

 

Like Tom said it looks like you tried about everything. Give this a read, you might find something.

https://drive.google.com/file/d/0Byb...1qRU1VVGc/view

 

You need four things for the truck to start:

1. Fuel pressure, of course. What is it when cranking?

2. HP oil, at least 500 PSI when cranking. What does the scanner indicate?

3. RPM detected from the cam sensor and reported via the PCM. Cold crank should be about 150 - 180 RPM range. What does the scanner indicated while cranking?

4. VRef which is a 5 volt signal to most of the sensors generated from the PCM. If you are detecting RPM via the scanner then VRef is OK.

One of these should show incorrect data and you can then focus attention in that area. You certainly have replaced a lot of parts and sometimes that's not a good idea , it's just guessing. Let your scanner guide you.

 

 

Hello again, and thanks for the response

All the sensors and parts are mototcraft from riff raff, so no worries there.

Looked at both the #8 and 22 fuse, contacts and fuse look ok. I did see a low reading while taking another look at it on the scanner. The icp was only showing .41volts max. The pigtail going to it appeara to be ok, no oil in contacts. Any idea what that low voltage means?

 

Also tryed unplugging the icp and ipr shut the pump down, psi showed zero after that. Isnt the unplugged icp supposed to set it around 725 psi by default?

 

If you unplug the ipr it will not start.

 

I tryed unplugging the icp not the ipr
I heard that if you unplug the icp the pressure should degault to 725ish in the system, dont know if this is true tho

 

Okay update on the no start. After much cranking to bring the oil and fuel pressure up after the work done, i discovered if you crank on it for 15 to 20 secs the injectors will fire, but it wont run. Immediately after they start to fire the check engine light comes on. Do not know how any of this is related, but tryed much more cranking, and still nothing

 

Well the CEL being on should be storing codes then, pull the codes and see what it says

 

The scanner isnt showing any codes though, thats the weird thing. I cant do alot of tests through the scanner with it not running, but nothing shows up in the tests i have run either.

 

Just going by what I read.

 

So, point 1 here.

You replaced the HPOP.

Which means it has to re-pressurize the whole heads and will cause a lots of crank no start scenario.

You also did injector o-rings, which will completly drain the HPOP rails. This will require a lot of cranking to clear the head.

Second point, IPR wiring can be a bit... Well, ****, if you're cranking a lot and its not fireing, make sure to watch to see what DC"s the motor is giving out. if its 0, then you'll never start as its got an IPR wiring issue. My best guess is you might not have plugged the fuel bowl wiring harness back in, or its damaged in some way due to fuel over time.

 

The low voltage means low High Pressure oil. You have some pressure, probably ~200 PSI or so, not enough to start. 0.88 volts is about 540 PSI. Your scanner should be able to read in PSI making it easier to interpret.

The actual pressure doesn't default if it's not available. The PCM makes a guess, since the ICP is unplugged. The value displayed in PSI is the guess while the value displayed in volts is real time, not a guess. You need to display PSI, not volts to see this. Actually while cranking the PSI (guess) will go quite high trying to fire the injectors.

Between 15 - 20 seconds of constant cranking the PCM will disable the the ICP, just as if you unplugged it. It's a built in programming thing, Confusing if you are not aware this occurs.

The PCM won't allow the IDM to fire the injectors without proper cranking RPM, EVER. These engines need to turn over pretty fast to allow that. You have not reported what the cranking RPM is yet making it difficult to address the issue further. If we can eliminate that area then we can focus elsewhere on the issue. Next we need to know the actual fuel pressure while cranking, I know you indicated it was good but what is good, the numbers?

Use the scanner for RPM, IPR% (some scanners call it ICP%) and ICP pressure in PSI, not volts. I've not used your scanner so no help here but I'm sure it's just a setup issue and others with the same scanner can chime in and help in that area.