2002 gets puny after a minute... finally quit...

cbuttre835 · Sep 2, 2017

My 2002 7.3 automatic has developed a deal where it gets weak after about 2-4 miles every morning. It acts like you let off the throttle, then starts missing and loping, smokes very faint blue, and then clears up. I live a mile from the interstate and at 70 mph it'll clear up after 15-30 seconds.

Well, today I take the back roads, get a half mile from home, and it quit. Didn't have enough speed to ride it out. Towed it home, got it started on ether (disconnected IAH and GPR) and after a few seconds it would run on its own.

If Iet it idle itll run for 15 min fine. If I run the throttle up, it'll do the same thing, and lope real bad for a while, before settling down.

Fuel looks OK, didn't check the oil level (its on a slight grade) but its not old. Amsoil 15-40. Cracking drain valve with key on indicates good fuel pump flow, but I haven't checked pressure. Where do I? (no schrader valve like on an OBS)

Tach never stuttered or dropped out, and I got no CEL. Haven't pulled codes yet.

What other easy stuff is there to check?

Arisley · Sep 3, 2017

Get it somewhere where you can check the oil.

cbuttre835 · Sep 3, 2017

Nothing unusual; no fuel smell, no foam, level is OK. Gotta look back through my records and see when it was serviced last. (Inherited this truck but I did the maintenance on it.)

redneck1 · Sep 3, 2017

How old your cps?

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Magnum PD · Sep 3, 2017

Need to see what your high pressure oil is doing. Could be IPR or pump issues.

TjMiller · Sep 3, 2017

redneck1 said:
How old your cps?

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Did you see if it is throwing any codes for the cps? Had one with a bad spot on the TPS that did weird stuff like yours too.

cbuttre835 · Sep 3, 2017

I had a P1211, a glow plug circuit low, iah circuit low, a P0340 CPS failure code.

Could not clear them with the scan tool I had.

I drained the bowl and changed the fuel filter. Thus far, has not acted up since (three trips).

lincolnlocker · Sep 4, 2017

wish the one i have been trying to help with was that easy..

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cbuttre835 · Sep 15, 2017

lincolnlocker said:
wish the one i have been trying to help with was that easy..

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Turns out mine wasn't easy after all.

I warmed it up with the APCM Monday, Tuesday, and Wednesday of this week.

Was in a hurry to get to work Thursday, didn't warm it up, quit a mile from home.

AutoEnginuity (Thanks RiffRaff Diesel) arrived Thursday night. Put it on there tonight (Friday).

It restarted after about 5-7 seconds of cranking. ICP Duty Cycle was 18-20%. Ran pretty rough.

As it warmed up, ICP Duty Cycle settled to 10%. 500 PSI ICP. Ran smooth as silk. The KOER Cyl Contribution test reported #8 bad 3 times. (Isn't that the cackling injector?) The engine never changed sound though. The CC Test on the OBS trucks, it idles up fast and you can definitely tell when a cylinder is dropped.

The 10% / 500 PSI values are what I'm used to seeing on my OBS 7.3s. Do the split-shot injectors make a difference? I'd think they would.

I had an OBS truck that went through two IPR valves, as they wore the ICP DC at idle would creep up to 14-15% and it eventually wouldn't start back hot, because it wouldn't build ICP.

I wouldn't expect duty cycle to drop as engine oil thinned as it did on this truck. But, it had been in a non-running condition and had set 36 hrs. So there's that.

Gonna let it cool, and try to log data and see if I can get it to act up again.

Interested in any thoughts.

lincolnlocker · Sep 17, 2017

cbuttre835 said:
Turns out mine wasn't easy after all.

I warmed it up with the APCM Monday, Tuesday, and Wednesday of this week.

Was in a hurry to get to work Thursday, didn't warm it up, quit a mile from home.

AutoEnginuity (Thanks RiffRaff Diesel) arrived Thursday night. Put it on there tonight (Friday).

It restarted after about 5-7 seconds of cranking. ICP Duty Cycle was 18-20%. Ran pretty rough.

As it warmed up, ICP Duty Cycle settled to 10%. 500 PSI ICP. Ran smooth as silk. The KOER Cyl Contribution test reported #8 bad 3 times. (Isn't that the cackling injector?) The engine never changed sound though. The CC Test on the OBS trucks, it idles up fast and you can definitely tell when a cylinder is dropped.

The 10% / 500 PSI values are what I'm used to seeing on my OBS 7.3s. Do the split-shot injectors make a difference? I'd think they would.

I had an OBS truck that went through two IPR valves, as they wore the ICP DC at idle would creep up to 14-15% and it eventually wouldn't start back hot, because it wouldn't build ICP.

I wouldn't expect duty cycle to drop as engine oil thinned as it did on this truck. But, it had been in a non-running condition and had set 36 hrs. So there's that.

Gonna let it cool, and try to log data and see if I can get it to act up again.

Interested in any thoughts.

what cps do you have in it? yes the 8 is the cackle injector and always fails cct and usually #3 is from cps. looks like ipr and icp are ok. thats what they do on a cool/cold start..

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