[Vettezuki]

Reset the codes, which are only P0037/38, HO2S heater circuit. I'm guessing this is an ECU problem as the driver for the heater circuit is direct from the ECU. LKQ looks like they have one for about $100 and they have a 30 day return, so an easy check.

[Vettezuki]

Replaced ECU today and it did something interesting. At first it didn't throw any codes, much longer than before. Then it threw only P0037 (usually it was 37 and 38 right away) but also P0131. So I *think* there was an issue with the ECU driver for the heater circuits and the new ecu doesn't have it, but there is some kind of wiring issue to the upstream O2 as it is brand new.

Hypothesis: Some wiring issue between ECU and HO2S 1:1.

As for 131

http://www.obd-codes.com/p0131

NOTE: this probably happened while sitting there idling and sucking in some more SeaFoam, it's pretty cool out and a little humid so that might be related.

Also, and more concerning, I seemed to loose a little coolant, but I think that was on Monday or Tuesday when I ran the AC a bit. Any reason running AC would cause you to lose coolant? I wouldn't think so, but I don't know.

Hypothesis: None


Taking off the oil cap I saw a little milkiness under it. The oil is clean and the head/cams are getting oild properly. Is that water? Maybe just from the atmosphere? Gulp . .

Hypothesis: Little condensation from atmosphere through an oil cap that's not completely sealed. Gulp, some subtle small crack or coolant leak in the head or block into the oil.

[Shaolin Crane]

Originally Posted by Vettezuki

Replaced ECU today and it did something interesting. At first it didn't throw any codes, much longer than before. Then it threw only P0037 (usually it was 37 and 38 right away) but also P0131. So I *think* there was an issue with the ECU driver for the heater circuits and the new ecu doesn't have it, but there is some kind of wiring issue to the upstream O2 as it is brand new.

Hypothesis: Some wiring issue between ECU and HO2S 1:1.

As for 131

http://www.obd-codes.com/p0131

NOTE: this probably happened while sitting there idling and sucking in some more SeaFoam, it's pretty cool out and a little humid so that might be related.

Also, and more concerning, I seemed to loose a little coolant, but I think that was on Monday or Tuesday when I ran the AC a bit. Any reason running AC would cause you to lose coolant? I wouldn't think so, but I don't know.

Hypothesis: None


Taking off the oil cap I saw a little milkiness under it. The oil is clean and the head/cams are getting oild properly. Is that water? Maybe just from the atmosphere? Gulp . .

Hypothesis: Little condensation from atmosphere through an oil cap that's not completely sealed. Gulp, some subtle small crack or coolant leak in the head or block into the oil.

You can use a sniffer to check for gasses in the coolant, Test strips can test for coolant in the oil.

[Vettezuki]

Originally Posted by Shaolin Crane

You can use a sniffer to check for gasses in the coolant, Test strips can test for coolant in the oil.

kdracer73 helped me with checking the coolant resevoir and it was fine (no hydrocarbons in the coolant). If I'm just using distilled water for coolant now, would the strips indicate "coolant" in the oil? I ask because I imagine the strips are might be checking for some chemical in anti-freeze that doesn't exist in distilled water. And where do I get said strips?

NOTE: "New" ECU is now throwing same codes (and now misfires for some reaon) the last one was, which indicates the primary problem is probably between the ECU and HO2S with some kind of short, as far as the heating circuit is concerned. Yuck. . . I wouldn't be bothering if the damn thing wasn't basically "running" fine. Just something fing up emissions.

[Shaolin Crane]

Originally Posted by Vettezuki

kdracer73 helped me with checking the coolant resevoir and it was fine (no hydrocarbons in the coolant). If I'm just using distilled water for coolant now, would the strips indicate "coolant" in the oil? I ask because I imagine the strips are might be checking for some chemical in anti-freeze that doesn't exist in distilled water. And where do I get said strips?

NOTE: "New" ECU is now throwing same codes (and now misfires for some reaon) the last one was, which indicates the primary problem is probably between the ECU and HO2S with some kind of short, as far as the heating circuit is concerned. Yuck. . . I wouldn't be bothering if the damn thing wasn't basically "running" fine. Just something fing up emissions.

I'm not sure, I use to get the strips from Eddy, but you can probably get them at Vatozone or NAPA

[Damian]

Im wondering if there might be some ECU differences, even with the same year car. For example, my old Eclipse. They offered the same manual trans 3.0l V6 from 2000 to 2005. BUT, they had many different variations of ECUs, even with Eclipses with the same exact options, plus you had the issues with the immobilizer as well. Some of the big differences were the locations of the pinouts on the ECU were swapped around. Maybe youre experiencing the same thing???

[Vettezuki]

No. It plugged right in and started right up. LKQ had a list of many ECUs for the year overlaps and there were options, but the matched service numbers. I think it was the right ECU, just didn't solve the problem.

I realized tonight I had, probably Paul's, spark plug wire tester (inductive light thingy) and so I fig'rd after swapping the ECU I'd see how the new wires were lighting up. Well, two of the four were fairly intermittant and a weaker light. Tomorrow night I'm going to swap out packs and see what that gets me. . .

In any event, after brand new OEM O2 sensors and swapping out computers and still getting P0037/8, in highly confident there is some sort of wiring issue between the ECU and sensors. It might just be the heater circuit wires, but it might be more and that's not providing good data to the ECU so it can't function correctly.

Checked plugs tonight while I was at it and they were pristine and there was no junk or wetness in any of the cylinders as one would expect. But they do still have carbon deposits. I don't know how clean piston surfaces are supposed to be under regular conditions though. I can say that I've done sea foam through the intake twice over a couple hundred miles and in both cases it has blown out a stunning amount of shit. So the engine may still be in a process of cleaning itself by running from its previous highly abused state.

[Shaolin Crane]

For most vehicles even a few weeks difference between build dates could have a different ECU, location of sale included. Vehicle might start, but it being the proper one, well that's different, power strokes have about. Different ECM's per year, usually interchangeable, but sometimes not,

[Vettezuki]

Originally Posted by Shaolin Crane

For most vehicles even a few weeks difference between build dates could have a different ECU, location of sale included. Vehicle might start, but it being the proper one, well that's different, power strokes have about. Different ECM's per year, usually interchangeable, but sometimes not,

LQK had a large list of possible ECMs for make/model/year. They matched the service number off the back of mine. It basically ran the same and was eventually throwing the exact same codes, plus misfires (you couldn't feel them, just codes). But I think that was a newly emergent phenomena.

[Vettezuki]

Major props to ls1z28 for helping me sort the issued. Turned out there was a section of the harness that had been impacted and melted, so basically just a short. Taped them up and loomed back together, cleared codes and . . no more codes! He also noticed exhaust leaks at the flex pipe and the muffler itself, which he said could easily throw off the sniffer as it would be cyphoning in air. So I'll get a new muffler and flex pipe this week and take it back for diagnostics and *hopefully* actual smog run next Saturday.