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That FSM test would give you 266F(or 130C) and the wiggle test would rule out the sender.

The open gives you -40F(C) to the PCM and makes the engine harder to start.and run due to timing and fuel will be way off.
 

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Discussion Starter #22
Yeah, with code 15, it's for the sensor on the water pump. When I unplug the connector, the engine light comes on and sets code 15. When I wiggle the wires for the connector, it will act up then if I bend the wire just right, it is fine again and light goes off. That will be my mission tomorrow to find the break and repair it. Thankfully it is just a weak wire that is causing the issue
 

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Yeah, with code 15, it's for the sensor on the water pump. When I unplug the connector, the engine light comes on and sets code 15. When I wiggle the wires for the connector, it will act up then if I bend the wire just right, it is fine again and light goes off. That will be my mission tomorrow to find the break and repair it. Thankfully it is just a weak wire that is causing the issue.
Get ready for more of this kind of stuff.
Our wiring was barely thick enough 26 years ago.
Now it's all old & brittle & ready to be replaced if not upgraded.
 

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Discussion Starter #25
Well, I drove the car for two days and took it on long drives. Code 42 no longer comes on after swapping coils and code 15 is fixed. Problem I'm still having is a intermittent misfire that happens when the car is warmed up during long drives. I went ahead and replaced the spark plug wires on the driver side. I got the otvc wires for it and now I have to do the other side and see if the misfire goes away. Yes, this is a new engine
 

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Discussion Starter #26
Put in a new coil which the car seem to drive fine. Only hiccup was going right and a slight hesitation happened. Either one the gas was low or the wire harness that is supposed to be attached to the driver side head is loose and hit the header possibly causing the hesitation. What sucks is that it's winter and I don't have a place to get under the car and unhook everything to bring it up top and check to make sure nothing got burned through even though it has a reflective heat tape wrapped around it. I'm almost sure a wire burned through and is probably grounding itself on the header. But all in all, it does seem to drive better. I will continue to keep driving it and see what happens.
 

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Discussion Starter #27
Anything. Quote DCT42 will set when: PCM detects 84 crankshaft revolutions without any "electronic spark timing" What this means to me is that if the engine slows down when the ICM is ordered to stay steady or increase RPM the PCM will store a 42.



The factory wire is 18ga temperature rated for 105C. Cheap car wire insulation could melt. If I ever had to do this I would use 16ga for physical strength and better signal. You could unplug both ends and use a ohm meter to do a wiggle test.


I would not mess with the optispark harness unless you have proof.

There are tests listed with the DCT42 in the FSM. They use a test light or volt meter. Short version is the ICM and coil, as well as connecting wires are all suspect. A good technician with a good scope would just check the PCM signal and the coil and see if they are sincronized. Not listed but on my list would be a bad high voltage coil to distributor wire. If it were spark plugs or wires I would think it would not get 84 revs without a single spark..

Something that will not cost any real time is to unplug and replug the PCM connectors.(battery off)

Tests are quicker that swapping things.
Got a question for you. I noticed that the white wire for the ICM is yellow in one spot under the wire loom. What does that mean? I've seen it before when I put in the new connector for the ICM and cut that section out but I noticed when I removed the bottom half of the loom towards the PCM, it was turning yellow in a small section that is bent. I know it can't be from uv rays of the sun because it is not seeing any sun light. I also noticed when I unplug the black connector on the PCM, the section that has the high and low signal for the optispark which is pin 2&3 had like a white cloudy plastic film on it that I could scrape off with a screwdriver and the same on the inside of that black cover for the connector. I have no clue why but I tried to clean it up. Any ideas? If you need a picture of the white wire and what I'm saying, I can take a picture of it and post it on here
 

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I am going to ask for the connector picture. If I see it I might describe it exactly like you have. I would be reaching for the 99% isopropyl alcohol or no residue contact cleaner to remove anything dry or flaky on the connectors pins/sockets.


The white wire that is yellow could be chemical or heat damage. I would want to test the wire with a ohm meter to be sure it is OK. This wire from the PCM to the ICM is a signal wire and should not carry enough energy to heat up.(ever)

Just to share information discolored insulation can mean the wire is damaged or corroded and then current has caused heat. Would make no sense for this wire.
 

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Discussion Starter #29
I am going to ask for the connector picture. If I see it I might describe it exactly like you have. I would be reaching for the 99% isopropyl alcohol or no residue contact cleaner to remove anything dry or flaky on the connectors pins/sockets.


The white wire that is yellow could be chemical or heat damage. I would want to test the wire with a ohm meter to be sure it is OK. This wire from the PCM to the ICM is a signal wire and should not carry enough energy to heat up.(ever)

Just to share information discolored insulation can mean the wire is damaged or corroded and then current has caused heat. Would make no sense for this wire.
The pins themselves are fine it was just the black cover that goes over the female pins that had it. If the weather is nice tomorrow, I'll take the picture of the connector and the white wire with the discoloration. It definitely discolored in two spots on the white wire which I removed the one that was by the connector for the ICM. The other spot I noticed today after I removed the rest of the wire loom by the PCM.
 

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Discussion Starter #30
I am going to ask for the connector picture. If I see it I might describe it exactly like you have. I would be reaching for the 99% isopropyl alcohol or no residue contact cleaner to remove anything dry or flaky on the connectors pins/sockets.


The white wire that is yellow could be chemical or heat damage. I would want to test the wire with a ohm meter to be sure it is OK. This wire from the PCM to the ICM is a signal wire and should not carry enough energy to heat up.(ever)

Just to share information discolored insulation can mean the wire is damaged or corroded and then current has caused heat. Would make no sense for this wire.
As promised. Here are the pictures of the connector and the spots on the wire. I tried to see if there is a opening in the wire to ground itself to another wire but didn't see anything
197071
197072
197073
197074
197075
197076
197077
197078
197079
 

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Should look like the picture in post #2.(clean)

As a guess the plug was not latched to the PCM and something got around the seal.
As I said in the last post get some 99% isopropyl alcohol or no residue contact cleaner like CRC 02130-6 to clean that up.Use a toothbrush to clean the black plastic cover and just spray the contacts once or twice.

The insulation on your white wire looks like it has been rubbed hard and is a little thin but it may just be the picture. If it passes a wiggle test with the ohm meter I would just give it a little protection and put it back in the loom.
 

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Discussion Starter #32
Should look like the picture in post #2.(clean)

As a guess the plug was not latched to the PCM and something got around the seal.
As I said in the last post get some 99% isopropyl alcohol or no residue contact cleaner like CRC 02130-6 to clean that up.Use a toothbrush to clean the black plastic cover and just spray the contacts once or twice.

The insulation on your white wire looks like it has been rubbed hard and is a little thin but it may just be the picture. If it passes a wiggle test with the ohm meter I would just give it a little protection and put it back in the loom.
Yeah that white wire is stiff where it is yellow and I found it bent twice in the loom
 

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Discussion Starter #33
Should look like the picture in post #2.(clean)

As a guess the plug was not latched to the PCM and something got around the seal.
As I said in the last post get some 99% isopropyl alcohol or no residue contact cleaner like CRC 02130-6 to clean that up.Use a toothbrush to clean the black plastic cover and just spray the contacts once or twice.

The insulation on your white wire looks like it has been rubbed hard and is a little thin but it may just be the picture. If it passes a wiggle test with the ohm meter I would just give it a little protection and put it back in the loom.
Tomorrow I'm going to ohm the white wire between the pcm and ICM and wiggle the wires around. This sucks because with the car running in park and wiggling the wires, nothing happens but when I drive it, that's when it acts up. I wiggled the wires and connections and the opti harness and drove it and it got worse to the point of setting the light but then the light went off then came back on for a second then off. Just sucks when you hit the gas and it starts to act up before it clears up
 

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Discussion Starter #34
Should look like the picture in post #2.(clean)

As a guess the plug was not latched to the PCM and something got around the seal.
As I said in the last post get some 99% isopropyl alcohol or no residue contact cleaner like CRC 02130-6 to clean that up.Use a toothbrush to clean the black plastic cover and just spray the contacts once or twice.

The insulation on your white wire looks like it has been rubbed hard and is a little thin but it may just be the picture. If it passes a wiggle test with the ohm meter I would just give it a little protection and put it back in the loom.
I check the white wire for ohms and it is showing .5 ohms. Gonna check online for a new dvom because I'm questioning mine
 

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Discussion Starter #35
Is there a test for the ICM like a resistance test or do you have to take it to a part store to check it
 

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Discussion Starter #36
I am at a complete lost with this. I have wiggled every wire for the ignition system and nothing. Tempted to say the hell with it and take it to the dealer
 

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I check the white wire for ohms and it is showing .5 ohms. Gonna check online for a new dvom because I'm questioning mine
In case you do not know.
In Ohm mode the meter measures the test wires/probes. So if you touch the probes together and the meter does not show zero the meter is usable.
For example if you touch the probes together and the meter reads 1.00ohm when you test a wire just subtract 1.00. So if you tested a spark plug wire and got 10001ohms the wire is really 10000ohms. So if you touch your probes together and get 0.5Ohms and then check a wire and still get 0,5Ohms it means the resistance of the wire is lower than your meter measures. Lower the better.

I am at a complete lost with this. I have wiggled every wire for the ignition system and nothing. Tempted to say the hell with it and take it to the dealer
You have what feels like a missfire. If your scanner has live data you can watch Lo Res signal and High Res signal (The outputs of the Opti). If you do not have live data
scan9495 and Eehack is free + you need to buy a cable and have a laptop.

You could do the OPTI and Spark Test:

If you want a pro look around for a shop that has a scope and knows how to use it. They can check the Opti signals and the ICM and coil. If the shop only has a pro grade scanner they may just fire the parts cannon on your dime.
 

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Discussion Starter #38
In case you do not know.
In Ohm mode the meter measures the test wires/probes. So if you touch the probes together and the meter does not show zero the meter is usable.
For example if you touch the probes together and the meter reads 1.00ohm when you test a wire just subtract 1.00. So if you tested a spark plug wire and got 10001ohms the wire is really 10000ohms. So if you touch your probes together and get 0.5Ohms and then check a wire and still get 0,5Ohms it means the resistance of the wire is lower than your meter measures. Lower the better.


You have what feels like a missfire. If your scanner has live data you can watch Lo Res signal and High Res signal (The outputs of the Opti). If you do not have live data
scan9495 and Eehack is free + you need to buy a cable and have a laptop.

You could do the OPTI and Spark Test:

If you want a pro look around for a shop that has a scope and knows how to use it. They can check the Opti signals and the ICM and coil. If the shop only has a pro grade scanner they may just fire the parts cannon on your dime.
Touching the test leads reads .3 ohms and when I check the white wire from pcm to icm I get .5 ohms which is telling me I have .2 ohms in the wire. I have wiggled wires to see if anything changes but nothing. I have in the past replaced the optispark distributor with a spectra brand and pulled out the optical sensor and replaced it with the one that was in my factory distributor. I also replaced the spectra cap and rotor with a accel cap and rotor and put rtv on the outside of the distributor because the metal base of the distributor was not flat causing a gap for any moisture to get in there. I also used my original Opti harness because the one that came with spectra was junk. I was able to pull the wire and see the pins move all the back in the connector which would cause me to lose connection to the optical sensor. The only thing I can come up with is that the mitsubishi optical sensor is finally going bad. I came across another forum that talks about this code and he had installed switches for the high and low res and when switching off the high res, he got code 42. But for me, I don't know where to go for a distributor let alone a optical sensor to replace it. I've thought about mad Opti distributor but have heard horror stories about it. Basically all it is doing is cutting out then finally starts to clear up with code 42 coming on
 

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Discussion Starter #39
The other thing that is frustrating is that sometimes it cuts out and sometimes it doesn't. I understand with a misfire that it's going to do it constantly but this is not constant and could happen at any time
 

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I logged nearly 10 hours in my Mom's car trying to find the problem with her ABS. No codes just went squirrely while coming to a dead stop every once in a while. Ford scanner finally showed that one wheel stopped showing data at very low speed. I still had to figure out if it was wire, sensor, or the ABS module.

The Opti is hard for DIY. and parts swapping is expensive.
 
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