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Discussion Starter · #1 ·
I just scanned my car for the first time with new motor aswell as it being the first time using the HPtuners scanner.

This is on a 98 gtp full rebuilt motor with heads, Intense S3 cam, balance shaft removed etc...

The car hasn't had a case learn done yet if that makes any difference.

I initially had a miniAFC on to lean out my idle a little bit because of the fumes are pretty bad (temp solution until I learned how to do it with hptuners) When I did WOT runs, the 02's weren't locking whatsoever as if it wasn't going into open loop.
I parked the car and was thinking that the miniAFC was causing issues so I removed it.
I did 2 other runs at WOT and the 02's locked. I was thinking that the miniAFC was shot.
Then on the third run and every run afterwards, same problem again, 02's won't lock.

What could be causing 02's not being locked at WOT?
The car felt strong when they locked but felt real weak when they didn't.

Please help!
 

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John,

What exactly do you mean that they don't lock up? At idle or cruising, O2's will fluctuate anywhere from 0xx to 9xx mv. At WOT, they should be in the low 9xx range, but can still move around a little bit. How much are they moving by? Check out this thread and see if it helps:

http://www.3800tech.com/forum/showthread.php?t=973

John
 

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I was with Big John while we were scanning his car.

His O2 sensor values were fluctuating between 0 and 1v at WOT instead of locking into a set value while in PE. The car as a result felt fairly dead compared to how it should.

Best guess is that something is being triggered so the PCM remains in closed loop and is adjusting for a leaner A/F mixture. John is having a problem with his Intense tranny that keeps throwing a P1801 I believe? code, this could very well be the problem, making the PCM stay in some torque management mode?

The car was fine when we first booted it approx 3 minutes after clearing the code and restarting the car in a parking lot, the problem resurfaced the next time he mashed the gas a minute later. Resetting the code on the highway did not cure the problem.

TPS was hitting 100%, MAP read 185kpa (12.5psi approx), all the numbers seemed otherwise normal.

John's main mods off the top of my head include:
-rebuilt raceprepped block, stock compression ratio
-ported heads, manley valves, 130 springs
-Intense Stage 3 blower cam
-LS1 TB with SLP 85mm MAF
-Lucas 42s
-Intense custom PCM based on Stage 2 (calibrated for 42 injectors and LS1 MAF)
-Intense tranny with 3.69s

Any good tuners able to verify the rationale on the tranny being the cause or suggest another reason O2 values wouldn't lock at WOT?
 

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Discussion Starter · #4 ·
Thanks for posting details Will.
Trans is getting rebuilt by Wednesday.
I hope someone can help me with my WOT situation so we can get it on the dyno soon
 

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P1801 is not listed in my '98 Helms manual. Are you sure that's correct? If the O2's are between 0 and 1V then it's staying in closed loop as you say, and is not getting into PE mode. The code could be causing the problem but I can't say for sure until I can find it. As an aside, one wacky thing that the stock PCM does in some of the abuse tables or TCS is to target a lean (15.5:1, 15.9:1, etc) AFR when those modes are invoked. I'm not sure why they would do that, but that could be it. I know you listed a DHP PCM but I don't know if they change those AFRs. If I had to guess, I'd say they were probably left stock but who knows? No flame intended towards DHP, BTW.

John

John
 

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Discussion Starter · #6 ·
Hi John

The code is P1811.
I don't have the DHP anymore, I currently have a custom Intense PCM (based on stage II with slightly different shift points, Lucas 42.5# + LS1 MAF table)

Any ideas?
 

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He actually swapped his DHP for a custom Intense PCM and I know he requested just about every torque management setting turned off which is why the tranny code could be causing the problem but also half doesn't make sense.

I can't remember the code, can you John? :( We're both new to the HP Tuners scanner, we couldn't save the log either.
 

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P1811 is when one of your shifts is taking longer that .65 seconds and the adapive modifier can't shorten it. According to Helm's, this will command maximum line pressure to try and protect the trans and will also disable the shift adapts. That's it. This must be independednt of your other problem.

I'd like to try and help. Do you have a scan or two you can send me that captures this behavior?

John
 

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Discussion Starter · #9 ·
Thanks for trying to help John.

I'm going to try to get it scanned and logged after I get my car back from the transmission rebuilders by Wednesday.

We were logging the run but Will couldn't find a way to save the log.
 

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Discussion Starter · #11 ·
Hi John,

I've replaced the o2 sensor and still no luck.
I've done 3 scans.
The first 2 show this behaviour and the 3rd one seems to be fine except for the fueling.

Is there a place I can send you the scans and possibly send you my .bin file for your review?

Thanks

johnt said:
P1811 is when one of your shifts is taking longer that .65 seconds and the adapive modifier can't shorten it. According to Helm's, this will command maximum line pressure to try and protect the trans and will also disable the shift adapts. That's it. This must be independednt of your other problem.

I'd like to try and help. Do you have a scan or two you can send me that captures this behavior?

John
 
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