Code 42 revisited - ZR-1 Net Registry Forums

Subfixer · 03-14-2020

As discussed in an old thread, I get random detonation, followed by the SES light, secondaries are inhibited. Code 43 comes up as the problem. No other codes are set.

I had previously installed a new knock sensor which did not solve the problem. All checks in the FSM are good. Car is stock except for Mark's chip. Problem is present with or without Mark's chip.

While working on a radiator swap, I figured I would pull the plenum and have another look at this problem.

I found the secondary vacuum valve was leaking by, so I put in a good one, and installed a new vacuum check valve also.

I checked the ignition module for bent pins, but found none.

Any clue as to where I should check next before I button this up?
I do have a spare used Ignition module if I need it.

Thanks

Ccmano · 03-14-2020

I’m aware of one instance where the electrical connectors of the plug at the rear of the DIS (the ones the pins go in to) were opened too large causing an intermittent connection. At least that was presumed to be the case as the code stayed away for good after they were tightened.

The other thing that can happen at that plug is the pins go in next to the connector rather than through it. Once again causing an intermittent connection.
H

lfalzarano · 03-14-2020

How about the O2 sensors in front of the CATs? O2 sensors effect the adjustments to the ECU. The oxygen sensor relays information based on the ratio of the fuel to air being delivered into the cylinders via a sensing element. Faulty knock sensors can allow increased pre-ignition noises, misfires, backfires, and rough or jerky acceleration.

Just a guess and another place to look.

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Subfixer · 03-14-2020

I forgot to mention that I replaced both O2 sensors after the knock sensor replacement didn't fix the problem.

It seems that the knock sensor hears the detonation, but the timing does not retard.
I've checked all the wiring and grounds to/from the ECU and the DIS and to the O2 sensors and knock sensor. All ring out OK.

Everything is pointing to the ECU and I don't have a spare.....

lfalzarano · 03-15-2020

Is the chip firmly clicking into place in the ECU? I’ve heard that it can come loose causing this issue and other squirrelly issues.

If you are still having issues, You could also send the ECU to Jerry or Marc for testing.

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Jax ZR1 · 07-04-2020

Have you had any luck getting this fixed, my car is doing the same thing and I have not been able to figure it out, any help would be great. Thanks

Subfixer · 07-05-2020

I replaced the DIS module under the plenum and it seems to be better.
Only had an SES once since replacement.

I'm not convinced this is the final fix.

G8nightman · 07-05-2020

The knock sensor board on a 92 is on the ecm chip. I replaced mine fixed the issue.

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Subfixer · 07-06-2020

SES showed up again once yesterday and twice today.
First two times after a warm start.
Third time after running about 5 minutes.
All three times just normal in town cruising, no full throttle.
No codes stored......

Subfixer · 07-07-2020

Ok, got some codes today...

Code 43 is back, with Code 66(I had the switch in the "power" position when the SES light came on).
Reseated Prom again.
Is the knock circuit on the prom or on that other little circuit board next to the prom?
I'm using Mark's piggyback prom, but I have this issue with the stock prom also.
Mark's prom bypasses the original programmed chip, but still uses the circuit adjacent to the programmed chip.
Original post:
http://zr1.net/forum/showthread.php?t=30890

03-14-2020	#1
Subfixer Join Date: Sep 2018 Location: Groton, CT Posts: 381	Code 43 revisited As discussed in an old thread, I get random detonation, followed by the SES light, secondaries are inhibited. Code 43 comes up as the problem. No other codes are set. I had previously installed a new knock sensor which did not solve the problem. All checks in the FSM are good. Car is stock except for Mark's chip. Problem is present with or without Mark's chip. While working on a radiator swap, I figured I would pull the plenum and have another look at this problem. I found the secondary vacuum valve was leaking by, so I put in a good one, and installed a new vacuum check valve also. I checked the ignition module for bent pins, but found none. Any clue as to where I should check next before I button this up? I do have a spare used Ignition module if I need it. Thanks __________________ 1992 ZR1 #442, 2 tops, White, White, Haibeck 415, 3.90 gear, Coilovers 2018 Audi RS5, 2.9 V6 Twin Turbo, Auto, Black, Black 2021 Audi Q3, 2.0T, 8 spd Tiptronic, Navarro Blue metallic, Pearl Beige Last edited by Subfixer; 07-07-2020 at 07:16 PM.

03-14-2020	#2
Ccmano Join Date: Jun 2006 Location: Sparks, NV Posts: 2,852	Re: Code 42 revisited I’m aware of one instance where the electrical connectors of the plug at the rear of the DIS (the ones the pins go in to) were opened too large causing an intermittent connection. At least that was presumed to be the case as the code stayed away for good after they were tightened. The other thing that can happen at that plug is the pins go in next to the connector rather than through it. Once again causing an intermittent connection. H __________________ 90'ZR-1 #1461 Red/Black Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold 08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold 05 C6 Z51 Red/Black Sold 90'ZR-1 #1723 Black/Gray Sold but not forgotten 91' Z51 L98 White Vert. My First, you always remember your first. Sold.

03-14-2020	#3
lfalzarano Join Date: Feb 2011 Location: Clayton, North Carolina Posts: 1,133	Code 42 revisited How about the O2 sensors in front of the CATs? O2 sensors effect the adjustments to the ECU. The oxygen sensor relays information based on the ratio of the fuel to air being delivered into the cylinders via a sensing element. Faulty knock sensors can allow increased pre-ignition noises, misfires, backfires, and rough or jerky acceleration. Just a guess and another place to look. Sent from my iPhone using ZR-1 Net Registry __________________ Lou[COLOR="Red"][B][SIZE="4"][/SIZE][/B][/COLOR]

03-14-2020	#4
Subfixer Join Date: Sep 2018 Location: Groton, CT Posts: 381	Re: Code 43 revisited I forgot to mention that I replaced both O2 sensors after the knock sensor replacement didn't fix the problem. It seems that the knock sensor hears the detonation, but the timing does not retard. I've checked all the wiring and grounds to/from the ECU and the DIS and to the O2 sensors and knock sensor. All ring out OK. Everything is pointing to the ECU and I don't have a spare..... __________________ 1992 ZR1 #442, 2 tops, White, White, Haibeck 415, 3.90 gear, Coilovers 2018 Audi RS5, 2.9 V6 Twin Turbo, Auto, Black, Black 2021 Audi Q3, 2.0T, 8 spd Tiptronic, Navarro Blue metallic, Pearl Beige Last edited by Subfixer; 07-07-2020 at 07:19 PM.

03-15-2020	#5
lfalzarano Join Date: Feb 2011 Location: Clayton, North Carolina Posts: 1,133	Re: Code 42 revisited Is the chip firmly clicking into place in the ECU? I’ve heard that it can come loose causing this issue and other squirrelly issues. If you are still having issues, You could also send the ECU to Jerry or Marc for testing. Sent from my iPhone using ZR-1 Net Registry __________________ Lou[COLOR="Red"][B][SIZE="4"][/SIZE][/B][/COLOR]

07-04-2020	#6
Jax ZR1 Join Date: May 2019 Location: Vanderhoof British Columbia Canada Posts: 34	Re: Code 42 revisited Have you had any luck getting this fixed, my car is doing the same thing and I have not been able to figure it out, any help would be great. Thanks

07-05-2020	#7
Subfixer Join Date: Sep 2018 Location: Groton, CT Posts: 381	Re: Code 43 revisited I replaced the DIS module under the plenum and it seems to be better. Only had an SES once since replacement. I'm not convinced this is the final fix. __________________ 1992 ZR1 #442, 2 tops, White, White, Haibeck 415, 3.90 gear, Coilovers 2018 Audi RS5, 2.9 V6 Twin Turbo, Auto, Black, Black 2021 Audi Q3, 2.0T, 8 spd Tiptronic, Navarro Blue metallic, Pearl Beige Last edited by Subfixer; 07-07-2020 at 07:18 PM.

07-05-2020	#8
G8nightman Join Date: Dec 2007 Location: NYC Posts: 1,188	Re: Code 42 revisited The knock sensor board on a 92 is on the ecm chip. I replaced mine fixed the issue. Sent from my iPhone using ZR-1 Net Registry __________________ 90 Chevy ZR1 LPE #2315 'SOLD' 90 Chevy ZR1 LPE #2774 'SOLD' 91 Chevy ZR1 Callaway aerobody 91 Chevy ZR1 #1512 91 Chevy ZR1 #951 95 Chevy ZR1 #338 'SOLD' 91 BMW 850i 94 BMW 850csi 95 BMW 850csi 94 Lotus Esprit S4 07 Benz CLS550 06 BMW M5 "SOLD" Last edited by G8nightman; 07-07-2020 at 11:20 AM.

07-06-2020	#9
Subfixer Join Date: Sep 2018 Location: Groton, CT Posts: 381	Re: Code 43 revisited SES showed up again once yesterday and twice today. First two times after a warm start. Third time after running about 5 minutes. All three times just normal in town cruising, no full throttle. No codes stored...... __________________ 1992 ZR1 #442, 2 tops, White, White, Haibeck 415, 3.90 gear, Coilovers 2018 Audi RS5, 2.9 V6 Twin Turbo, Auto, Black, Black 2021 Audi Q3, 2.0T, 8 spd Tiptronic, Navarro Blue metallic, Pearl Beige Last edited by Subfixer; 07-07-2020 at 07:18 PM.

07-07-2020	#10
Subfixer Join Date: Sep 2018 Location: Groton, CT Posts: 381	Re: Code 43 revisited Ok, got some codes today... Code 43 is back, with Code 66(I had the switch in the "power" position when the SES light came on). Reseated Prom again. Is the knock circuit on the prom or on that other little circuit board next to the prom? I'm using Mark's piggyback prom, but I have this issue with the stock prom also. Mark's prom bypasses the original programmed chip, but still uses the circuit adjacent to the programmed chip. Original post: http://zr1.net/forum/showthread.php?t=30890 __________________ 1992 ZR1 #442, 2 tops, White, White, Haibeck 415, 3.90 gear, Coilovers 2018 Audi RS5, 2.9 V6 Twin Turbo, Auto, Black, Black 2021 Audi Q3, 2.0T, 8 spd Tiptronic, Navarro Blue metallic, Pearl Beige Last edited by Subfixer; 07-07-2020 at 07:17 PM.