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Discussion Starter #1
‘97 7.3 ccsb, 235k miles. New to PSs, only had this truck a couple of months.



I’ve read through a lot of forums. I’m having a similar situation as a lot of people. Driving down the road, truck Lost power, bogged down when I gave it gas, died at idle at the next stop light. Cranks no start. No CEL.



Towed it home, originally had movement at the tach while cranking. Had a grey Motorcraft (MC) CPS on the truck. No DTCs on a cheap code reader. Fuel in the bowl, drained it and cranked it to fill twice. Batteries are both tested and good. CEL comes on while cranking and WTS comes on as well. Went through a complete rear tank of fuel with Lucas additive prior to switching to the front tank (doubtful that it’s bad fuel). ICP had oil in it, but it had been that way for a while (I didn’t know it was a sign of failure at the time). The fuses were all good except #4, trailer backup lamps. (Replaced, and all the parking lights stayed on, even when the key was removed. Removed the fuse, I’ll deal with that later.)



Replaced the CPS (blue MC), ICP (AA ignition), IPR (MC), Starter (DB electrical). Now the tach doesn’t move, still cranks, doesn’t start. Put the original CPS back on, no movement in the tach, put the new, blue motorcraft back on. No oil leaks, UCVH looks to be in good condition. I’ve checked the IDM and all the circuits are reading as they should. Not a wiring problem.



I had previously replaced the main wiring harness, fuel pump, rebuilt the fuel bowl and it was running fine when it died on me. Oil, coolant changed within the last 500 miles.



I’m thinking it could be the IDM or the HPOP. I’m waiting on an Edge CTS3 to show up so I can have some pressure values to aid in diagnosing this issue.



You guys have any ideas? I’ll buy another CPS if you think I should. It just wasn’t the problem before and I used a blue motorcraft to replace the grey motorcraft. My theory there is that it hasn’t started and had a chance to recognize the new CPS after disconnecting the pigtail.
 

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With the WTS light and CEL illuminating while cranking (along with fuse #4 issue), I think you have electrical issues somewhere. What's fuel pressure while cranking? It would be good to know what ICP and IPR% are during cranking as well. Cheers!
 

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Discussion Starter #3
I have no way of checking fuel pressure or any other values until I get the dash mounted digital gauge reader (it will be here Friday). I’ve been thinking electrical issues as well. Just don’t really know where to go from here.
 

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Fuel pressure is via the mechanical fuel pump in the engine valley and is not monitored by the PCM. You can measure it via the shrader valve on the Fuel Pressure Regulator attached to the driver's side of the fuel filter bowl. If you don't have a gauge to hook up, you can use a cheapo stick tire pressure gauge. Use a rag around the joint so you don't get sprayed with fuel. It should be a minimum of 25 psi at a minimum crank speed of 100 rpm. Cheers!
 

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Discussion Starter #5
Ah! I’m showing the green behind my ears. That’s a good trick with the tire pressure gauge. I’ll try that today and keep you posted. Thank you for the assistance.
 

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Discussion Starter #6
Fuel pressure didn’t register on a tire pressure gauge... think it could be the cheap fuel pump (Carter) I bought from amazon... that was the reason i had to get it towed the only other time I’ve had to.

Does it make sense that it still fills the bowl? It didn’t even do that the first time the pump failed on me.

I’m slowly learning my lesson about buying cheaper parts... they become expensive if you have to replace them.
 

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The fuel pump is a two stage pump. It draws fuel from the tank on the low pressure side and sends it to the filter housing. Then it draws it from the housing and sends it to the injectors with the high pressure side of the pump. What fuel isn't used by the injectors is sent back to the fuel pressure regulator on the filter housing before it is sent back to the tank..

Remember that you need to be turning the engine over to work the fuel pump.

So no fuel pressure could mean a bad high pressure side of the fuel pump.
 

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Discussion Starter #8
Remember that you need to be turning the engine over to work the fuel pump.

So no fuel pressure could mean a bad high pressure side of the fuel pump.
[/QUOTE]

thank you for the explanation. I was having someone crank the engine while checking the pressure.

As soon as it died on me, I thought it might be the pump. It did the same thing the first time. Only difference was the bowl wouldn’t fill last time.

You just explained why it might still be filling. I’ll get a new MC pump and update when I install it.

Thank you, gentlemen!
 

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Discussion Starter #9
I installed a new MC fuel pump, cleaned the fuel pressure regulator screen. Crank, no start.

Hooked up a CTS 3 gauge monitor and I can look at oil and trans temp, but while cranking, the screen shuts off, so no other values show. There are no DTCs either.

I’m back to thinking it’s electrical or HPOP. I just don’t know how to tell the difference. I’d really like to avoid buying more unnecessary parts.

Any help is appreciated.
 

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Discussion Starter #11
I looked through the battery terminals and they appear to be in pretty good shape after removing some of the buildup. I have one new Optima red top and a “good” autozone brand that was checked since it has been parked.

I bought a new MC CPS. It registered for a few cranks after I recharged the batteries to full, but it isn’t registering on the Tach now. Still won’t start.

I visually inspected the UVCH, used a multimeter to check the batteries, IDM female connector. Both were within spec for the volt/ohms.

I’ll go through the IPR wiring and the PCM pinout today. My concern is it is an internal IDM or PCM issue and I have no way of checking those. Still no codes on my Edge CTS3 or cheap plug in. I’ve read on some forums, people have had bad PCMs with no codes. I do still have a WTS light, so it has power.

Confused...
 

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Discussion Starter #12
I used the attached document to do the following tests. IPR connector reads 12+ volts and I’ve checked the resistance between IPR connector Pin A and PCM relay terminal 361 (R) = 0.5 ohms.

I moved to checking the PCM connector because there is a brand new MC IPR in it. Pin 83 (circuit 552) and all listed test points for the IPR all registered OL on my multimeter. I assume the circuit is bad. The next step is to repair the circuit. That seems like an undertaking that may be beyond my skill set... Or maybe I don’t like electrical work.

Looking for an opinion regarding my next step. I have at least one bad circuit, probably more because I don’t even have any DTCs. That could be a problem with the PCM itself.
 

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I moved to checking the PCM connector because there is a brand new MC IPR in it. Pin 83 (circuit 552) and all listed test points for the IPR all registered OL on my multimeter. I assume the circuit is bad. The next step is to repair the circuit. That seems like an undertaking that may be beyond my skill set... Or maybe I don’t like electrical work.
I originally posted that document. If you IPR Power circuit has a problem it should set the P1283 code. It will crank faster than "normal" and the HPOP Reservoir will usually drain since the non-powered IPR will direct oil back to the pan. At any rate, if the tests mentioned above are the X3 tests in the document, you are good since those tests are checking for shorts (and your meter is showing those as open, so no short).

Cheers!
 

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Discussion Starter #14
Patrick,

I saw that you had posted that document (and many others I have used or referenced). Thank you for providing so much help with electrical issues! I didn’t want to single you out before by asking you, specifically. I appreciate your reply!

If I don’t have a problem with the wiring at the IPR, I’m going to check the CPS, ICP... and then I’ll be at a loss, in terms of looking for a short in my harness.

Any idea where I should check after that?
 

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Discussion Starter #15
So, moving down to X4, I checked the resistance between PCM Pin 83 and Point B in the IPR regulator harness connector. Ohms were 0.5... that leads to replacing PCM.

I did not have a breakout box installed for any of these tests. I had an OPEN circuit for all tests listed in the document (plus, I checked the resistance b/w the ICP, CPS pins and the grounds and power inputs in the same manner as the IPR).

This is a Hail Mary (just like all the others I’ve thrown at this truck in the last month), but do I replace the PCM? I don’t know anyone with an OBS SD that I could temporarily swap a PCM... there are places that will test them (diesel technologies of Chattanooga, flagship one...). Turnaround is a few weeks.
 

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I don't know that I would replace the PCM with the results of those tests unless you can actually verify getting the code P1283. Your IPR coil and wiring has "passed" all the tests, but currently you don't know if the IPR Power circuit is even the problem. In my case, I had 2 trucks, the 94 and the Cali 97. The 94 was fine, but I wasn't using it. I started it up, parked it out back and didn't use it for a month. When I went to move it, it would crank but no start, It was turning over faster than normal and CEL was on. Pulled the P1283 code with my EASE software on the laptop. Did all the tests, which passed, so it had to be the PCM causing the specific fault. Replaced PCM with one from RockAuto and it immediately started. Turns out the PCM was not providing the ground to power the IPR. I couldn't just swap PCMs either (5-speed Federal truck and 97 Cali E4OD truck PCMs are wired totally different). Have you been able to pull codes with the CTS3 on the truck before? Does the CEL stay illuminated when the truck is Waiting to Start? Cheers!
 

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Discussion Starter #17
Have you been able to pull codes with the CTS3 on the truck before? Does the CEL stay illuminated when the truck is Waiting to Start? Cheers!
[/QUOTE]

I have never been able to pull codes. The CEL is only on when it cranks, not during WTS.
 

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Discussion Starter #18
I unplugged the fuel bowl heater from the outside of the bowl. Started right up!

Thank you, everyone, for the help!

I taped over the connector and left it draped over the fuel regulator. I plan on rebuilding/ replacing the bowl (just because it’s old, and now has a broken heater wire). I’ve seen a lot of people say they just leave the heater connector disconnected... for years.

Anyone have any thoughts on how soon I should make this fuel bowl repair?
 

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Did you have a blown fuse? #22 under the hood is the one for the heater. While some have had a interment ground from the heater that causes the engine to die or not to start but the vast majority have had the fuse blown.

As for replacing it, it is up to you. I have been running for 10+ years with mine unplugged and other have been running a lot longer.
 

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I haven't had my fuel heater plugged in for 10 years now... doesn't seem to cause me any grief here in Utah during the winter.

Cj
 
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