Question for the AE gurus???

[7MAGMIKE]

I started having issues with my 250 last week. It skipped real hard once and started running rough, then the RPM started hunting very erratic well then smoothed out but then at a stop it started running rough again then stalled twice but would restart easily. This roughness has been going on every time I would drive it but only after it was good and hot. I replaced the fuel filter and cleaned a good handful of sludge from the filter bowl. I ran my AE software on it and my CCT on cyl. # 8 was always high plus I had a P1280 ICP low code set with a ICP reading about 475 psi at idle. I replaced the CPS with one picked up from my local International dealer this morning. This truck had the recall done on it for the CPS about 2 years ago I removed a grey sensor and installed a new grey sensor. My CCT is now reading 0* on all cylinders (good I assume) and my ICP is reading 500 psi (better) and no P1280 code. The engine seems to idle better I am going to give it a driving test in a few minutes. I am hoping this is a good fix. All other parameters appear good except my question about my ECT reading. I have noticed it starts cold at 135* and goes up to 300*+ when hot but my temp gage on the dash reads normal what is going on with that?

[klhansen]

The coolant temp sensor doesn't report to the PCM, just the gauge, so AE is giving you bogus numbers. I don't know why they don't fix that, but it's been an issue for a long time. On the vans with 7.3L, the ECT sensor also goes to the PCM, so maybe that's why they still have that parameter on AE.

P1280 is actually ICP circuit out of range low, not necessarily that the ICP pressure itself is low.

from the service manual
DTC P1280 indicates injector control signal circuit out of range low was detected during KOEO Self Test or during continuous diagnostic monitoring.

Possible causes:

• biased ICP sensor/PCM
• open ICP sensor circuit
• short to SIG RTN or PWR GND on ICP sensor circuit
• open in VREF circuit

It could be caused by an intermittent open or short, so check the wiring to the ICP sensor.

[woodnthings8]

More than likely your ICP sensor is causing the problem. You should pull the connector and look for oil in the pin area.

ICP of 475-500 is normal for a warmed up idle.

#8 Will always have a higher PERDEL than the rest. You have a AE or LL injector in that position. Your PERDEL numbers being all 0's tells me the Enigine Oil Temp was not up to the correct range (over 126 degrees usually) or your idle was a little high. I don't think I have ever seen a truck with all 0's while running PERDELS.

As Kevin stated, the ECT sensor does not read correctly on auto trucks. The manual trucks get tied directly to the PCM, but the auto trucks do not. If you watch ECT as the truck warms up, it does all kinds of odd things. I believe the PCM uses the EOT sensor to come up with a reading that the OBD II port sees.

Here are a few tests I ran by disconnecting the ECT sensor and leaving it hooked up.

[7MAGMIKE]

The truck still does not run right. In further testing it still stumbles and bucks, oh well I do have the obligatory spare CPS in the glove box. During earlier testing I pulled the ICP sensor connector and sure enough it was wet, I cleaned it and today during testing in my OP it was wet again. So that is definitely an issue huh. I guess it is on the next list to International. I am going to run some more tests in the morning to look at the CCT. The engine was probably not hot enough. I am still learning this AE stuff as well as this diesel engine I have had it for three flawless years and added 35,000 miles to the clock. So far it has been a good truck but owning an old truck does not come without risks.

The second image looks like what I am seeing but starting at 135* then going to 302* for a while then back to 11* and then appears to read correctly at about 195*-200*.

Thanks guys
Mike

[RT]

If your ICP is ruptured- you've most likely found your problem. I'd start there - you're going to need to replace it anyway.

[klhansen]

Originally Posted by woodnthings8

As Kevin stated, the ECT sensor does not read correctly on auto trucks. The manual trucks get tied directly to the PCM, but the auto trucks do not.

I checked the wiring diagram (same year as 7MAGMIKE's truck) when I posted here originally, just to confirm what I was saying, and I didn't find a difference between auto or manual trucks (neither gets an ECT sensor wire to the PCM). When I first got my AE I noticed the weird readings and investigated on the 99 wiring diagrams and it was the same. I recall checking the van wiring diagrams and they did have an ECT signal connected to the PCM. Either way, even on my manual tranny truck, I still get weird ECT signals if I look at that PID).

[RT]

I know where he got that info, though - there is a one line mention in the Ford Powertrain Diagnostic Manual about ECT feeding to the PCM on manual trucks. It doesn't indicate why or what the signal is used for, just the difference.

[7MAGMIKE]

OK I'll Ignore it. What are the most common parameters to monitor. I am monitoring RPM Inj P/W, EOT, ICP, VPWR, EBP, Inj duty cycle and MAP.

[klhansen]

Originally Posted by 7MAGMIKE

OK I'll Ignore it. What are the most common parameters to monitor. I am monitoring RPM Inj P/W, EOT, ICP, VPWR, EBP, Inj duty cycle and MAP.

It depends on what you're trying to diagnose. The more parameters you stick on the screen, the longer that AE takes to refresh all of them. For instance, if you've got HP oil issues, monitor just Engine RPM, ICP and IPR duty cycle, and maybe EOT. If you've got a screen full of parameters that are only secondary to the issue you're tracking down, they just serve to confuse, IMO.

[7MAGMIKE]

klhansen, Which wiring diagram manual are you using. I looked at Alldata and they show the ECT supplying an input to the PCM I believe on manual trucks. On Auto trucks that input (pin 37) is for TFT sensor

[klhansen]

Ford Service CD for 99 trucks and Ford Service DVD for 01-03 vehicles.

I have found some errors, like 35 ft-lb on the water pump bolts in the 99 manual, but both sources agree on that circuit.

[7MAGMIKE]

Thanks, I appreciate the info.

[woodnthings8]

Take a look at the wiring diagram I have posted HERE The ECT sensor is on the lower side of the diagram and shows it goes to the PCM via TFT. You will see the auto trans input is actually from the TFT, but the manual transmission goes to the ECT sensor.

Here is the description from the manual I have.

[7MAGMIKE]

Yes sir that is what I was thinking. Just interested in clarification. At this time I am looking at replacing the ICP due to the oil residue found in earlier testing but that is going to have to wait til next Friday. Thanks for the input. I do have other items I am going to investigate though. Fuel pressure as measured on my gauge pod is consistently 68 psi so I think that is OK but I want to inspect engine harnesses so that is my goal tomorrow.

Mike

[klhansen]

Ken,

Did that diagram come off the '02 manual? That's what your colored wiring diagram says on your site, which would explain the difference, since the wiring was completely changed for '02 and later models.

My 99 CD doesn't even have a DM pinpoint test section, and the ECT definitely goes to the Instrument Panel only, even though it shows up on the engine control wiring diagram (attached).

99 F250 7.3L Pickup pg 27-10.pdf

I suppose it's possible that on my 99 it communicates to the PCM thru the instrument panel, but that's not the idea I get from my references. ECT isn't listed as a PCM input in the engine control narrative either. And I definitely get whacked out ECT numbers on AE whenever I've checked them.

But.....

I just checked the 01-03 Service DVD I have and the DM pinpint info shows up just like you posted, and the ECT shows a connection to the PCM on manual tranny trucks. I must have not looked close enough before I posted the first time about it.

I always thought the 99-01 trucks shared the same wiring, but apparently there was a change along the way. I learn something new every day.

[on edit] Another oops!! I just went back and checked that 7MAGMIKE has an 03. Sorry for the misinformation.