2001 Excursion, PHP tunes, BTS tranny 124k miles.

I replaced the CPS (from napa) no change
I replaced the fuel filter up there, no change no gelling as I ran Howes in it
Pulled the chip, no change but after recharging batteries and trying to start got P1670

It was showing a P1670 EF Feedback not detected, but now there are no codes or Check Engine lights. Parts store couldn't pull a code but a friend has a very advanced scanner we are going to scan on friday night hopefully. P1760 could mean IDM although I don't know if they are know to act like this or if they just go out.

Starts and idles fine. When you first go and push the pedal it sounds a little "clackity" for lack of a better word. It may accelerate a little while smooth or not and cut out. It cuts out for like a split second, multiple times. You can get up to speed but it still cuts out and I don't want to mess anything up.
It basically cuts out.

Idle and start video:
https://docs.google.com/file/d/0B6DV...V1OGtyNHc/edit


Driving video
https://docs.google.com/file/d/0B6DV...5XeG0yUU0/edit

thanks

 

Without the code, my best guess would be the UVCH. It isn't a hard thing to test, if you have an ohm meter. Also, a trick I saw was to take some wax or crayon and put it on the manifold by each exhaust port and see which ones don't start to melt. That would be a good indicator of which side to pull the valve cover on. (Of course this is on a cold motor that was started fresh.) If you can pull the codes, I would guess it might have a code of P1316. But that is just a guess.

 

Did you check the wiring to valve covers?

 

Haven't checked wires under valve cover yet, but mechanic where it was stranded said wires looked fine. I haven't confirmed but have towed it home as I wasn't sure of the competence of the mechanic where we were stranded.

I can still get up to speed so it hasn't completely come unconnected. I will check the wires on the drivers side valve cover for any chaffing.

 

I had a similar issue. Going to the store and all of a sudden it cut out, running on 7 cylinders. Still driveable, started fine, but there was a definately miss. Hooked up Scanner(AE) and pulled p1670(IDM). I knew it wasnt the idm because i just replaced it less than a year ago. Did an injector buzz test and injector 8 was quiet. Ended up being the UVCH. Some people will say its just the connection that is loose, which sometimes it is(look up 50 cent modification) but mine was pulling 6-7 ohms, normal is 2-3. So they do go bad. I figured with the valve covers off, the price of the harness is cheaper than taking it back to the mechanic the 2nd time.

 

Sounds like fuel. What is the fuel pressure?

 

FJ1 DIAGNOSTIC TROUBLE CODE (DTC) P1670 and P1668

DTC P1668 and P1670 indicates that a communication error has occurred between the PCM and the IDM.

Possible causes:
Open fuse
IDM relay
Open or shorted IDM enable circuit
Open/short in EF circuit
Open/short in FDCS circuit
IDM powering circuits
PCM

Check for other codes.
Key on, engine off.
Perform KOEO On-Demand Self Test and retrieve Continuous DTCs.

Was DTC P1668 present?

Yes- If DTC P1668 is present, GO to FJ2 . No- If DTCs P1667 and P1663 are set together with or without DTC P1668, GO to FJ6 .

If DTC P1298 is also present, REPLACE the IDM.

If DTC P1667 is also present, GO to KA1 .

If DTC P1663 is also present, GO to KF1 .

If DTC P1662 is also present, GO to NC1 .

If P1670 was set without any other DTC, GO to FJ10 .


FJ2 CHECK CIRCUIT 818 (GY/W) FOR OPEN

Install breakout box; leave PCM disconnected.
Disconnect the IDM harness connector.
Measure resistance on Circuit 818 (GY/W) between PCM Test Pin 48 and IDM harness connector Pin 4.
Is resistance less than 5 ohms?

Yes-GO to FJ3 . No- REPAIR open in Circuit 818 (GY/W). RESTORE system. CLEAR DTCs and RETEST.

FJ3 CHECK CIRCUIT 818 (GY/W) FOR SHORT TO GROUND
Measure resistance between IDM relay Circuit 818 (GY/W) and battery ground.
Is resistance greater than 10,000 ohms?

Yes-GO to FJ4 . No- REPAIR ground short in Circuit 818 (GY/W). RESTORE system. CLEAR DTCs and RETEST.

FJ4 CHECK CIRCUIT 818 (GY/W) FOR SHORT TO POWER
Key on, engine off.
Measure for voltage on Circuit 818 (GY/W) between PCM Test Pin 48 and battery ground.
Is voltage present?

Yes-REPAIR short to power on Circuit 818 (GY/W). RESTORE system. CLEAR DTCs and RETEST. No- GO to FJ5 .

FJ5 CHECK SIGNAL RETURN CIRCUIT 359 (GY/R)
Measure resistance on Circuit 359 (GY/R) between PCM Test Pin 91 and IDM connector Pin 2.
Is resistance less than 5 ohms?

Yes-GO to FJ6 . No- REPAIR open in signal return Circuit 359 (GY/R). RESTORE system. CLEAR DTCs and RETEST.

FJ6 CHECK IDM POWER
PCM connected, IDM disconnected.
Key on, engine off.
Measure voltage between IDM connector Pin 14 and battery ground.
Is B+ present?

Yes-GO to FJ7 . No- GO to NC6 .

FJ7 CHECK IDM GROUND
Key off.
Measure resistance between IDM connector Pin 26 and battery ground.
Is resistance less than 5 ohms?

Yes-GO to FJ8 . No- REPAIR open in IDM ground Circuit 574 (BK/PK). RESTORE system. CLEAR DTCs and RETEST.

FJ8 MEASURE FREQUENCY ON THE EF LINE
Connect PCM to breakout box.
IDM connected to harness.
Set up scan tool as follows:
Connect scan tool to the DLC
Connect test probe between scan tool common and breakout box Pin 77 (ground).
Connect second test probe between scan tool signal and breakout box Pin 48 (EF line).
Select VEHICLE and ENGINE
Select DIGITAL MEASUREMENT SYSTEM
Change level to 4 VOLT DC
Press the link button to choose a PID
Select PID/DATA MONITOR
Select RPM PID
Press START
Key on, engine running.
Measure frequency at 3 different RPMs.

RPM Frequency (Hz)
1000 66
2000 133
3000 200


For each rpm value, does the corresponding frequency match closely to the table?

Yes-REPLACE PCM. RESTORE system. CLEAR DTCs and RETEST. No- REPLACE IDM. RESTORE system. CLEAR DTCs and RETEST.

FJ9 DIAGNOSTIC TROUBLE CODE (DTC) P1316 INDICATES THAT CODES ARE STORED IN THE IDM
Possible causes:
Injector(s) or circuit(s)
Open or shorted IDM enable circuit
Open/short in EF circuit
Open/short in FDCS circuit
IDM relay
IDM powering circuits
IDM
PCM

Check for other codes.
Key on, engine off.
Perform KOEO On-Demand Self Test.
Are IDM or any other codes stored?

Yes-GO to the appropriate pinpoint test. No- GO to FJ10 .

FJ10 DTC P1316 OR P1670, CHECK FOR AN INTERMITTENT OPEN CIRCUIT
Key off.
Install breakout box, leave PCM disconnected.
Disconnect IDM.
Check for intermittent open in the following circuits:
Measure resistance on (FDCS) Circuit 821 (BR/O) between IDM connector Pin 17 and PCM Test Pin 95.
Measure resistance on (EF) Circuit 818 (GY/W) between IDM connector Pin 4 and PCM Test Pin 48.
Grasp the harness close to the IDM connector. Wiggle, shake the harness while working your way back to the PCM, while looking for a spike on the DVOM.
Do all readings remain below 5 ohms throughout procedure?

Yes-GO to FJ11 . No- REPAIR open in the suspect circuit. RESTORE vehicle. CLEAR DTCs and RETEST.

FJ11 CHECK FOR AN INTERMITTENT SHORT TO GROUND
Check for intermittent short to ground on the following circuits:
Measure resistance on (FDCS) Circuit 821 (BR/O) between battery ground and PCM Test Pin 95.
Measure resistance on (EF) Circuit 818 (GY/W) between battery ground and PCM Test Pin 48.
Grasp the harness close to the IDM connector. Wiggle, shake the harness while working your way back to the PCM, while looking for a spike on the DVOM.
Do all readings remain above 10,000 ohms throughout procedure?

Yes-GO to FJ12 . No- REPAIR short to ground on the suspect circuit. RESTORE vehicle. CLEAR DTCs and RETEST.

FJ12 CHECK FOR AN INTERMITTENT SHORT TO POWER
Key on, engine off.
Check for intermittent short to power on the following circuits:
measure voltage on (FDCS) Circuit 821 (BR/O) between battery ground and PCM Test Pin 95.
measure voltage on (EF) Circuit 818 (GY/W) between battery ground and PCM Test Pin 48.
Grasp the harness close to the IDM connector. Wiggle, shake the harness while working your way back to the PCM, while looking for a spike on the DVOM.
Did voltage ever appear on any circuit throughout procedure?

Yes-REPAIR short to ground on the suspect circuit. RESTORE vehicle. CLEAR DTCs and RETEST. No-GO to FJ13 .

FJ13 VERIFY DTC P1316 AND/OR P1670
Restore vehicle.
Clear DTCs.
Cycle key off, than start engine.
Road test vehicle.
Perform KOEO On-Demand Self Test and retrieve Continuous DTCs.
Was DTC P1316 and/or P1670 set in Continuous without any codes in KOEO On-Demand?

Yes-GO to FJ14 . No- REPAIR KOEO On-Demand DTCs. RESTORE vehicle. CLEAR DTCs and RETEST.

FJ14 ATTEMPT TO GENERATE IDM DTCS
Key off.
Disconnect one valve cover connector.
Start engine to generate IDM codes.
Perform KOEO Injector Electrical Self Test and KOEO On-Demand Self Test.
Are IDM codes retrieved?

Yes-REPLACE PCM, RESTORE vehicle. CLEAR DTCs and RETEST. No- REPLACE IDM. RESTORE vehicle. CLEAR DTCs and RETEST.

 

Shop said fuel pressure was 80psi.

I checked the wires on the outside of valve cover and they looked good, no chaffing. Pulled the IDM and it was clean (outside) no water leaking out, connector wasn't corroded. Going to try and get that scan at lunch today.

 

Took it to a shop at lunch.

Used a MAC tools scanner.

no codes showing. Did a BUZZ test and all buzzed but 5 sounded a little bit different, not much though.

Could it still be the UVCH?

 

It may very well could be...

Last fall before if got cold, I replaced all my glow plugs thinking that was my problem. I was astonished to find that I had burnt pins on BOTH my harnesses. As soon as I replaced both sides, I was good to go again.

While you're under the valve covers, start the truck and one by one unplug and replug the connector at the top of the injector. When the engine sound doesn't change as you unplug an injector, you've found your faulty injector.

 

i'm not a professional by any means.. hell, i'm barely a shade tree mechanic. but it sounds like the rest of these guys have you going in the right direction. buzz tests, valve cover harness, resistance checks.. i'm thinking if all these check out fine, is there any chance it could be his throttle pedestal? a guy i worked with backed his truck out of the shop and hit the gas with no response in RPM. just sat there and idled. could it be this sensor is on its way out?
thanks for posting the video too. helped to read AND listen

 

Did some testing yesterday and it appears that the drivers side UVCH is acting goofy. Haven't even tested the passenger yet. Pulled it apart and the connector was a little loose but would not stay clicked in place.

Tried the .50cent mod but I could still wiggle the connector enough to change the Ohm readings past the acceptable range. Have a new harness coming so hopefully thats all it was. Will have to test the passenger side and see if thats causing issues as well.

Will Torque down the rocker arms as well.

 

Any news yet? Sucks to be stranded on the road.
I wound up just replacing my harnesses when I replaced my glow plugs. Fixed quite a bit that I didn't realize was wrong.

 

Got the harness in today, Im going to try and put it in tonight. Hopefully that will solve this issue. Not looking forward to that back valve cover bolt.

 

Here's an update...

Tackled the passenger side valve cover last night. Found it was burned on the connector. STILL didn't fix the issue. Same problem. The only other thing I can think is the factory pigtail/connecter (one you plug into the outside of valve cover) was a little brown from the burning. So I guess thats the next step.

What a pain.

Where is the best place to get the pigtail connectors?


https://docs.google.com/file/d/0B6DV...BlNk1FSEU/edit


https://docs.google.com/file/d/0B6DV...IwU0NLeXc/edit