Ford Powerstroke Diesel Forum banner

Yet another no-start! 1997

3K views 13 replies 3 participants last post by  WFarms97HD 
#1 ·
Gtreetings Wrenchmen:
Many thanx for all the help that y'all have provided in the past. Pulled my tit out of the wringer more than once! lol
I have a 1997 F350, 7.3L PSD that will crank but won't start following a routine compression check with all new injectors. It shows no ICP pressure with the sensor connected, and goes to 2,400 psi when disconnected. Injector Pulse Width is low at .04ms - .19ms either way. Other parameters show the ICP voltage at 0.22V when connected to ICP and 0 when not; ICP duty cycle at 54.6V when connected and 35.5V when not; B+ 11.7V (glow plugs on) with ICP connected and 12.4V when not. The rest were about the same either way: RPM 154, EOT 68 deg., ECT 167 deg.
There is no smoke at the tail pipe but there is a faint odor of raw fuel. Fuel pressure when cranking is 50 psi, oil pressure is 38 psi. The KOEO self test revealed nothing. The oil level is full and appears undiluted. The injectors buzz individually and uniformly. There have been no DTCs set and none in memory. Truck is aged with terrific blowby at 254,00 miles. Did I overlook anything? lol Thanx!
 
#2 ·
If you just put new injectors in then you need to fill the hpop and allow everything to fill back up. It will take some cranking to get it done. Allow the starter to cool in between cranks.

If glow plugs and relay are good then it will fire when HPOP and fuel pressures are built.
 
#3 ·
Yes, I am inclined to agree with you White. I did fill the HPOP reservoir at the beginning, and checked it twice since then. Today I intend to plug in the block warmer just to aid in starting (not because it’s cold, it’s 79 deg. today) bleed air out at the shrader valve on the fuel pressure regulator, hold my foot to the floor and crank it, using 10 second cranks with a two minute rest in between. The battery charger will be on it the whole time, and I will continue to bleed the shrader valve in between cranks.
In regard to the ICP sensor, since I have to unplug it to get rail pressure, does that prove that it is bad? Or could there be some other reason the rail pressure reads zero when plugged into the system? A new one costs $160, so I need to be sure. Thank you for your input!
 
#5 ·
Well I don't know... I have cranked the holy hell out of that thing, as much as I felt the starter could take without overheating, and it never hit a lick. I rechecked all the parameters and there is no change. Curious thing tho- I checked the resistance of the glow plugs and they all read between 12 and 14 ohms, even the one new plug I installed. This is not at all consistent with the specs I have uncovered. But tech data is scarce and I never did find a really good source for specifications. I can't think of anything else to do for it. It's not going to run like it is, so I guess I will just have the owner bring a tow truck and take it away!
 
#6 ·
You say you relieved air from the fuel valve.

The fuel bowl is full correct? Pull the filter just to double check.

The glow plugs should be .2 to 6 ohms. Did you replace valve cover gaskets? You can check the glow plug relay for voltage across terminals when the key is on. Voltage should be around 11 volts.

New injectors mean everything has been drained from the heads, fuel and oil. The fuel bowl should be topped off and so should the HPOP. Good glow plugs and GPR should at least give it a hiccup if everything is working.

With a scanner you should see HPOP pressure as in ICP pressure. If you are not i'd crack one of the HPOP lines and see if you are getting oil out of them.

What lead to changing the injectors? I know i'm repeating a few things but just making sure. It's something simple, just finding it is always tough. The HPOP could have gone out or the fuel pump. The FPR screen could be plugged up too.

Valve cover connections should be clean and non burnt, IPR nut should be snug on the back of the IPR. ICP connector should be dry, if there's oil then it is bad.
 
#8 ·
Thanks White! I know you trying hard to help me and believe me, it is much appreciated. You seem to be the only one who is knowledgeable enough to help. Yes, I have checked everything you mentioned, new v/c gaskets, new harness pigtails, the works. The truck came in running on about 5 or 6 cylinders, so I had the injectors tested. They were all bad, producing anywhere from 20% - 70% of normal. So it got all new Alliant Power injectors, not remans.

I think I may have found a game-changer. I decided to put a gauge on the HP line going to the left head and it read 300 psi at cranking speed while the scanner showed 2500 psi. WTF?! lol I got the idea when I saw there was no oil being dumped out of the injectors. HPOP reservoir is full, and basic oil pressure is 28 psi at cranking speed. I'd say the HPOP is no good. But I don't know why the scanner is telling me there is 2500 psi. because there is not. This gauge is on the braided line that comes straight out of the HPOP.
I have used this gauge many times and I know it to be good.
 
#9 ·
There are many members much more knowledgeable than I am. They will chime in.
You can also pull one of the plugs in either head and put the gauge there. Odd that it's showing pressure on the scanner but not on the line.

Could likely be air still in the lines but if you've been cranking on it then it should be out.

Possible scenario is the HPOP has been on it's way out and the worn out injectors were starting to show which is why one went out.

With the age and mileage of these motors it isn't a bad idea to upgrade the HPOP now. With new injectors and HPOP that motor will run much better.
 
#10 ·
Yes, well I have an hypothesis about that rail pressure if you will indulge me. There are only two electronic components in the high pressure side of that HPO system, the IPR valve and the ICP sensor. Right? So the data link has to get the pressure reading from one of those two things. It can’t get it from the IPR valve because it doesn’t send a signal, only the ICP does. Therefore it must get it from the ICP sensor. And with the ICP unplugged, there cannot possibly be any rail pressure signal transferred to the data link connector. So the scanner software assumes full rail pressure when it doesn’t get a signal from the ICP and displays what would normally be full pressure for that engine. This is also evidenced by the speed in which it is displayed on the scanner. When you attempt to start the engine, the pressure is shown immediately. I’m talkin about by the time the starter engages the flywheel, the pressure is already there, showing 2400 psi. There is no build up time whatsoever. So the ICP sensor could be ok after all. With it plugged in, the scanner wasn’t showing zero rail pressure because the sensor was bad, it was showing zero pressure because there was no pressure in the rail! lol
 
#14 ·
If I remember correctly the injectors need idle pressure to fire so in the neighborhood of 500psi or more. Mine will not pop off in cold weather with original injectors until I see it's making over 500.

Sent from my HTC One A9 using Tapatalk
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top