IMRC Problems

[F111D F]

Interesting connector round concentric accordion seals around each wire. Pull the plug and meter between the BK/RD and Brn/Wh you should see steady 5vdc. (key on) wiggle the wires? I know it's abit of a juggling act. You should have 12vdc between GRN/Wh and BK/wh.

I have run into conflicting info electrical diagrams on the CD manual, involving this Brn/Wh (Signal return) lead as to how it gets back to pin 91 on the PCM connector.
If should not have 5vdc you need to check for continuity between IMRC connector and the PCM connector. As previous Brn/wh should have continuity to pin 91 and BK/rd continuity to pin 42. While your at it go to chassis ground to each end verifying no continuity/open.
Hopefully it is only a bad connector plug ie broken wire inside the plug?
I believe several others have this same issue always operated P1518?
I'm having trouble finding S48 on the engine big help it's located on the engine ---besides the Sig return from the IMRC at splice 48(partial) is wire from sig lead from O2 front #21, the engine coolant sensor I'm assuming sig return, for those with a manual tranny the TPS , the EPT sensor Exhaust pressure Transducer, and still with the manual here comes splice S53 (also on the engine?)picking up power steering pressure switch sig return. AND the ACT air charge temperature sig return (IAT maybe) and both rear O2 sig returns #12 & #22, the knock sensor sir return.
Damn I just got lost!!! Oh the ATX
For all those with P1518 could it be possible from sensor bad say going to ground or I low enough resistance to ground interacting? For those with a continuing IMRC problem if you have 5VDC on the BK-RD lead the next thing is continuity to pin 91 on PCM plug AND NO resistance readings to chassis ground OPEN. IF otherwise start unplugging all the electronic engine sensors until it's clean. Just never know the possible interactions. Maybe something to CSVT 1214's problem????? It looks like all the signal returns come back to pin 91 on the PCM.
I'll post this for now any questions please don't hesitate I know my troubleshooting/thought processes are confusing.
Does anyone know where Splice 48 and 53 are located besides on the engine? It might help someone isolate easier if they're SIG RTN lead is not clean! Tony

All this before never mind my login timed out while I was re-re-editing.

Interesting connector round concentric accordion seals around each wire. I've having fun well it was until Fluke auto switch over from ohms to voltage well that's what I'm blaming it not mention I was looking plug wrong. Did mention it's cold in the garage.
Unplugging the connector and reading voltages (key on) battery voltage between grn/wh and grd BK/wh. The 5vdc is between BK/wh and BK/Blu.
With key still on resistance ---between Bk/Rd and Brn/wh was approx. 7.8k to 8.7k ohms turn the key off and it went to approx 12Kohms. This goes to 2-3 ohms when I use the scan tool to turn on outputs.
I've got to tell you it's not what I'd expect looking at the wiring diagram provided in the CD manual.
Because according to the diagram the monitor circuit BK/blu 5vdc from the PCM and it's return from contact closer (the motor has pulled the cable is on Brn/wh. That BK/rd lead is from the PCM to transistor the bias control to the transistor I'm guessing. This block diagram stuff makes it to hard troubleshoot the way I'm use to. It really gets interesting when the grandson interrupts to assist him with Star Wars . Seriously without the YES/NO troubleshooting section HU in the PC/ED manual this IMRC a real trip!!! Hmmmm maybe I didn't need the PC/ED cause in the CD with the proper DTC code takes you to HU tests.
Of course I never really had any codes on mind, until I start seeing others reporting codes.
I'm knocking on big chuck of wood black walnut cut down and milled and dry locally I hope and pray mine doesn't quit like yours did \
Clay SVT change the connector hopefully that fixes it and we'll all run like heck.

 

[Clay_SVT]

I changed the injector harness and it's still doing it I had 12 volts Grn/Wh and BK/WH but no voltage between BK/RD BRN/WH, resistance between BK/RD BRN/WH was 7.9

 

[Clay_SVT]

Had 20K OHM when I went from the IMRC plug to ground going to start going through everything!

 

[F111D F]

I changed the injector harness and it's still doing it I had 12 volts Grn/Wh and BK/WH but no voltage between BK/RD BRN/WH, resistance between BK/RD BRN/WH was 7.9

Clay_SVT this is my screw-up On the BK/RD & Brn/Wh I read no voltage either. I did have 5.0 vdc on the Bk/Blu to grd the Grn/wh that goes back to pin 8 on the PCM. That early mention of 5.o vdc has to do the PID# IMRCM but it looks like you have the the Ford test box. The software scan toool I have I looked at couple driving logs and replayed them an no such PID comes. I had three pids but no voltage reading pid?
Do you have the CD manual? Where in Ohio are you?

Ah this manual and it's apple and oranges HU20 measure VPWR which is the Grn/wh but then the next statement to B-
they do the same thing in HU 22 measure resistance from IMRC signal ckt I'm guess is Bk/Rd to B- one has to assume that B- is pwr gnd the BK/Wh i'm guessing? If so resistance greater than 10k ohms Or is the B- at the battery's neg post? Too much guessing maybe this is where the dealer tech calls Detroit "just what the heck does this mean?" Then some of HU's they switch reading IMRCm pids with the StarGen DLC scan tool. Not wonder we can't afford to take it to dealer!!! I'll keep digging maybe someone knows the meaning the B- for sure? And this is just one of many confusions.

 

[Clay_SVT]

I'm getting a manual on CD here soon, I'm in Lima Ohio

 

[F111D F]

Lab rat busy in the garage!!!

Lab rat busy in the garage!!!

Ah good Ole Lima been there many over the years I worked with many there at the phone company, however mostly remotely in Mansfield.
I went back to today and took readings at IMRC connector all 5 with key on and key off. First to simplify I'm going number the contacts.

Note attachment I was having trouble Cutting & pasting chart to here

Digital Fluke 12 auto switch from ohms to voltage (LoZ) the black/neg lead to battery neg post grnd.

"Blue" will be readings from 07/97 you will note the LoZ indicates small voltage Dc present interfering. Most where less than than >.1-.4 tenths very small leakage. Have no idea that;s why I'm not a EE. And same goes why the different between the two cars --Not EE again. I would love to know why but they both work so ?????

I tried experimenting since I don't have a break out box with the 40 zillion different adapters, I tried grounding (resistance grnd) thru back of the plug (connector plugged into IMRC). With key on I was able cause the IMRC open the Rgrnd applied to #3. Since you just spliced the new connector if you opened that wire it should dropped maybe HOWEVER I wouldn't guarantee it

NOTE: Commanding the IMRC to operate (open) with the scan tool (with plug unconnected) continuity exists between #3  = 2.2 ohms.
Hopefully this will be of some assistance, troubleshooting mass produced throw-away vehicles has got to rank high on the painful scale.