Injector loom rebuild

[dreaminbohemian]

Looking for someone with a Renix injector loom on their bench to send me measurements and photos from the last injector plug to the TPS, knock, and O2 sensor. Mine got sheered off when the speedo cable and evap line wrapped around my drive shaft and the plugs  are no where to be found.

[87MJTIM]

I have one in a box in my garage.  I will have to dig it out.  It came from a 87 XJ.

[Gojira94]

Mine is 89-90, so no C101 but there should be no difference in dimensions from where injector 1 & 2 are and the end of the harness.

 

From inj. 1 & 2's exit from the loom, I measure 38" to the tips of the connectors for knock, CTS and O2. 87 and 88 manual agree that the knock sensor wires are Yellow w/ trace, Violet w/trace. I didn't want to risk peeling open my knock sensor connector just yet, but the wire colors on my CTS and O2 connectors match up with 87-88 manuals as well.

 

O2 (C229) - ABC is Orange, Black, Grey.

CTS (C222) - AB is Brown w/ trace, Tan.

Knock (C232) - AB is Yellow w/ trace, Violet w/ trace.

 

Knock female connector is the same as any Jetronic/ EV1 injector connector, O2 male is same as any GM MAP sensor (and Jeep Renix up to 95 2.5/4.0), or 3-wire OBD1 GM O2 connector. CTS is common to many GM connectors, and is usually available in parts house stores, failing all else if your local boneyards come up dry.

 

[Ωhm]

NOTE: Knock Sensor (KS) is a shielded circuit (dashed lines) tied to vehicle GND (G105). You'll need to wrap circuit with metal foil.

 

 

 

[Gojira94]

1 hour ago, Ωhm said:

NOTE: Knock Sensor (KS) is a shielded circuit (dashed lines) tied to vehicle GND (G105). You'll need to wrap circuit with metal foil.

 

 

I had no idea... and thanks for explaining. So he'll need to find the black ground wire in what's left of his harness nub, maybe 3 black ground wires, depending on how far up the splice with the O2 ground is? And make a total of 3 grounds, separate and distinct from the Brown w/ trace wire for the CTS sensor ground to ECU?

 

 

[Ωhm]

36 minutes ago, Gojira94 said:

So he'll need to find the black ground wire in what's left of his harness nub, maybe 3 black ground wires, depending on how far up the splice with the O2 ground is? And make a total of 3 grounds, separate and distinct from the Brown w/ trace wire for the CTS sensor ground to ECU?

 

What they do is wrap wires with metal foil and run a bare stranded wire. Somewhere along the line the bare wire will touch the foil. He needs to find that bare wire which should connect to GND.

 

@Billabob

 

[dreaminbohemian]

On 1/26/2024 at 9:30 AM, Gojira94 said:

Mine is 89-90, so no C101 but there should be no difference in dimensions from where injector 1 & 2 are and the end of the harness.

 

From inj. 1 & 2's exit from the loom, I measure 38" to the tips of the connectors for knock, CTS and O2. 87 and 88 manual agree that the knock sensor wires are Yellow w/ trace, Violet w/trace. I didn't want to risk peeling open my knock sensor connector just yet, but the wire colors on my CTS and O2 connectors match up with 87-88 manuals as well.

 

O2 (C229) - ABC is Orange, Black, Grey.

CTS (C222) - AB is Brown w/ trace, Tan.

Knock (C232) - AB is Yellow w/ trace, Violet w/ trace.

 

Knock female connector is the same as any Jetronic/ EV1 injector connector, O2 male is same as any GM MAP sensor (and Jeep Renix up to 95 2.5/4.0), or 3-wire OBD1 GM O2 connector. CTS is common to many GM connectors, and is usually available in parts house stores, failing all else if your local boneyards come up dry.

 

 

 

Thank you so much for this. I rebuilt the loom, connected the CTS and Knock sensor (but not the o2 because it is a 3 wire that was soldered together into a 2 wire and I'm waiting to hear from the PO to see why.) It started up, I think faster than it had before but was running rough and idling low.  The engine would shake the care at 2500rpm a little bit.  I have an REM and I got the following codes:

REM Codes:

Baro Pressure Low

Bat Voltage Low

Distributr Sync

 

ECU Codes

Injector 3 Short

Injector 4 Short

Injector 6 Short

Injector 2 Open 

Injector 3 Open

Injector 4 Open

Injector 5 Open

Fuel Not Primed

ICM Signal Open

 

One injector connector is slashed but I separated them so they definitely aren't shorting for my test.  Any help on trouble shooting this would be greatly appreciated

 

[Gojira94]

REM Codes:

A) Baro Pressure Low - probably expected with low RPM idle and running rough

B) Bat Voltage Low - not sure, but maybe from sitting since the night the incident occurred. Charge batt before next attempt.

C) Distributr Sync - also not sure, maybe because the low RPMs are below what the ECU uses to confirm distributor sync signal (out of range to be useful)

 

ECU Codes - 1 through 7 below suggest the ground wires got tugged pretty hard and taking the corrugated loom off the harness up as far as just past the engine speed sensor and posting some pics might help us spot some damage not seen before.

1) Injector 3 Short

2) Injector 4 Short

3) Injector 6 Short

4) Injector 2 Open 

5) Injector 3 Open

6) Injector 4 Open

7) Injector 5 Open

8) Fuel Not Primed

9) ICM Signal Open

 

8-9 above not sure, possibly #8 related to low batt voltage at start, #9 due to lack of signal as a result of distributor sync signal not valid/ available due to C) above.

 

[dreaminbohemian]

I finally got back from tour and am trying to get the truck running again.  I purchased a loom from a 90 xj installed it. 

I'm wondering if it's possible that my REM got shorted and is sending faulty reeding because I have replaced the engine loom and am getting the exact same codes.  It's starting up and seems to be running fine.  One time it was running VERY rough but out side that it seems pretty ok.  There are to connectors from the loom that I haven't found their mate to. One single pin connector near the diagnostic ports, and one single pin connector by the firewall near the passenger side of the block. But one looks like it is labeled as 4 w/d switch on a manual. 

[ja_racing]

On 1/26/2024 at 11:54 AM, Gojira94 said:

 

I had no idea... and thanks for explaining. So he'll need to find the black ground wire in what's left of his harness nub, maybe 3 black ground wires, depending on how far up the splice with the O2 ground is? And make a total of 3 grounds, separate and distinct from the Brown w/ trace wire for the CTS sensor ground to ECU?

 

 

So does the knock sensor need to have that bare cable all the way to connector and duct taped all three wires together?

mine doesn't can i add something that will work the same so i don't have to tear my harness loom to chase it back and add it?

[Ωhm]

13 hours ago, ja_racing said:

So does the knock sensor need to have that bare cable all the way to connector and duct taped all three wires together?

No. 

 

 

KNOCK Sensor (KS) shielding prevents or attempts to prevent the KS circuit from becoming activated by outside EMF. Examples of EMF include High Tension wires, near airport radio waves, illegal CB radios (wattage), etc, etc. Sudden EMF without shielding, will cause vehicle to stumble, hesitate usually for only a short period of time, the time it takes to drive under the wires or during a transmission signal, as examples. ECU is fooled by the KS and retards timing very suddenly and quickly. Generally speaking, this is not a problem, but it can/has occurred.

 

 

13 hours ago, ja_racing said:

can i add something that will work the same so i don't have to tear my harness loom to chase it back and add it?

 Yes

 

[ja_racing]

22 hours ago, Ωhm said:

No. 

 

 

KNOCK Sensor (KS) shielding prevents or attempts to prevent the KS circuit from becoming activated by outside EMF. Examples of EMF include High Tension wires, near airport radio waves, illegal CB radios (wattage), etc, etc. Sudden EMF without shielding, will cause vehicle to stumble, hesitate usually for only a short period of time, the time it takes to drive under the wires or during a transmission signal, as examples. ECU is fooled by the KS and retards timing very suddenly and quickly. Generally speaking, this is not a problem, but it can/has occurred.

 

 

 Yes

 

Oh ok if i don't need the bare wire and they all don't need to be taped isolated

if I'm understanding right its just so outside emf doesn’t throw it out of wack i doubt ill run into that so i should not worry about opening my harness to fix that

[Ωhm]

1 hour ago, ja_racing said:

 

if I'm understanding right its just so outside emf doesn’t throw it out of wack i doubt ill run into that so i should not worry about opening my harness to fix that

 

Knock sensors are piezoelectric in function. Knock or EMF can cause the same reaction (both being high frequency). Knowing this should take away any worry.