97 7.3 Rough Running/Stall w/Diagnostic issues
10-26-2014, 03:38 AM
#1
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97 7.3 Rough Running/Stall w/Diagnostic issues
Not a Ford guy and I'm kind of worried that nobody here will have run into this issue. Got a 97 Powerstroke 7.3 that is having bad chugging/stalling issues. Owner changed fuel filter and it ran great for a couple of hours, then went back to it's old tricks. No water in the fuel. Has a performance chip on the PCM with adjustable power selector, stock setting doesn't run at all while max power setting chugs/dies.
I tried reading diagnostic information from the PCM via OBDII. Most requests were simply ignored by the PCM, while certain live data requests resulted in the engine either running on just one side or stalling altogether (while not providing the data). I pulled the power chip out of the PCM with no change. Currently I'm kind of stumped as I'm not a diesel guy.
Apparently the injector controller has failed and been replaced before. This doesn't feel like a bad injector controller though as normally I should be able to read codes, right?
I tried reading diagnostic information from the PCM via OBDII. Most requests were simply ignored by the PCM, while certain live data requests resulted in the engine either running on just one side or stalling altogether (while not providing the data). I pulled the power chip out of the PCM with no change. Currently I'm kind of stumped as I'm not a diesel guy.
Apparently the injector controller has failed and been replaced before. This doesn't feel like a bad injector controller though as normally I should be able to read codes, right?
10-28-2014, 10:05 PM
#2
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Ok first place I always start on strokes is a oil change. It can be low or diluted or just dirty. The level on the dipstick can show ok but the motor can be low enough on oil that the high pressure oil pump is cavitating and the injectors do not have a solid column of air free oil to operate properly. The high pressure pump is separate from engine oil pressure pump. The HP pump supplies engine oil to actuate the injectors.
Next put a scanner on it and look at the ICP pid. This is injection control pressure. When you crank the engine before it fires it should build pressure 150,250,350 then fire up bout 300+ and stay fairly stable at idle around 500-650 sometimes 800-1000 PSI at idle then as engine RPM increases it can build upwards to 2500-3500 PSI depending on engine RPM.
If the HP oil pressure is fluctuating a bunch at idle it generally is a pump failing. If you have the stroke service tools I usually pull the injection control pressure sensor screw a brass T in and then put my mechanical gauges on it to compare to what the pcm is showing.
The other thing the 95-97 strokes had tons of trouble with is the valve cover gaskets. The 110V power for the injectors is routed internal to the valve cover gaskets and will short to ground and can cause problems similar to what you describe. Usually but not always it will have injector control circuit codes stored.
If you have a ford scanner or snap on go to injector self test they may call it buzz test when it starts you will hear the injectors click like crazy as it fires all of them. Then you will hear it go buzz buzz buzz buzz buzz buzz buzz buzz. The PCM fires injectors 1-8 one at a time in cylinder order if you hear it buzz and then go silent and buzz again count real closely while its buzzing because that will be a dead hole you need to look at
Next put a scanner on it and look at the ICP pid. This is injection control pressure. When you crank the engine before it fires it should build pressure 150,250,350 then fire up bout 300+ and stay fairly stable at idle around 500-650 sometimes 800-1000 PSI at idle then as engine RPM increases it can build upwards to 2500-3500 PSI depending on engine RPM.
If the HP oil pressure is fluctuating a bunch at idle it generally is a pump failing. If you have the stroke service tools I usually pull the injection control pressure sensor screw a brass T in and then put my mechanical gauges on it to compare to what the pcm is showing.
The other thing the 95-97 strokes had tons of trouble with is the valve cover gaskets. The 110V power for the injectors is routed internal to the valve cover gaskets and will short to ground and can cause problems similar to what you describe. Usually but not always it will have injector control circuit codes stored.
If you have a ford scanner or snap on go to injector self test they may call it buzz test when it starts you will hear the injectors click like crazy as it fires all of them. Then you will hear it go buzz buzz buzz buzz buzz buzz buzz buzz. The PCM fires injectors 1-8 one at a time in cylinder order if you hear it buzz and then go silent and buzz again count real closely while its buzzing because that will be a dead hole you need to look at
Last edited by 01WS6/tamu; 10-28-2014 at 11:59 PM.
10-29-2014, 01:15 PM
#3
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Thanks for the help!
I can't pull any PIDs from the PCM because when I do it comes back as "not valid" and the engine goes into a odd half-firing-order or dies completely. I've tried two tools so far with the same result. Code requests just come back as the PCM failed to respond. I'm leaning toward a bad PCM but I don't hear much about these failing.
The oil pressure gauge is doing the wacky reading, slow fall then spike back to normal levels.
I can't pull any PIDs from the PCM because when I do it comes back as "not valid" and the engine goes into a odd half-firing-order or dies completely. I've tried two tools so far with the same result. Code requests just come back as the PCM failed to respond. I'm leaning toward a bad PCM but I don't hear much about these failing.
The oil pressure gauge is doing the wacky reading, slow fall then spike back to normal levels.
10-30-2014, 12:33 PM
#4
Thanks for the help!
I can't pull any PIDs from the PCM because when I do it comes back as "not valid" and the engine goes into a odd half-firing-order or dies completely. I've tried two tools so far with the same result. Code requests just come back as the PCM failed to respond. I'm leaning toward a bad PCM but I don't hear much about these failing.
The oil pressure gauge is doing the wacky reading, slow fall then spike back to normal levels.
I can't pull any PIDs from the PCM because when I do it comes back as "not valid" and the engine goes into a odd half-firing-order or dies completely. I've tried two tools so far with the same result. Code requests just come back as the PCM failed to respond. I'm leaning toward a bad PCM but I don't hear much about these failing.
The oil pressure gauge is doing the wacky reading, slow fall then spike back to normal levels.
My buddies 02 has a programer and it interferes when I try to read codes or see PCM data.
What are using to pull codes and see pids???
10-30-2014, 01:12 PM
#5
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Thread Starter
Used an Actron 9190 and a Solus Ultra. This was with the power chip disconnected from the PCM header.
It seems 01WS6 hit the nail on the head with the diagnostic procedure though- added enough oil to hit the full mark (wasn't below it very much) and the engine magically runs like nothing was ever wrong. Doesn't fix the inability to read codes though.
It seems 01WS6 hit the nail on the head with the diagnostic procedure though- added enough oil to hit the full mark (wasn't below it very much) and the engine magically runs like nothing was ever wrong. Doesn't fix the inability to read codes though.
10-30-2014, 01:20 PM
#6
It's a FORD... Just be glad it runs... 
I have not had an issue with the Snap On reading Ford except when it has an aftermarket programer. If it still has an issue you may need to check the wiring back to the PCM.
The aftermarket code readers similar to the actron will not read the diesel's PCM
97? Does it have an OBD1 style connector near the middle of the dash at the bottom?
I have not had an issue with the Snap On reading Ford except when it has an aftermarket programer. If it still has an issue you may need to check the wiring back to the PCM.
The aftermarket code readers similar to the actron will not read the diesel's PCM
97? Does it have an OBD1 style connector near the middle of the dash at the bottom?
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