The saga continues, but I felt the need to start a maintenance thread here. The EGR reinstallation did nothing for my KR readings, so we have to start looking at other factors. Fun, fun, fun :?.

im with will on this one

Get the PCM reprogrammed to unlock the torque converter sooner.

Tuning for both maximum power while expecting low KR under high load at low rpm with converter locked isn't going to do it.

I reallt doubt the cam timing is the problem. In case you weren't aware, the ZZP XP HOT cam is configured for 4* valve timing advance. I can't say I agree with that because advancing the valve timing skews the power curve towards the lower end while retarding it favours the top end.

In the case of the L67s, I would have preferred retarded valve timing since they have such a strong low rpm charactor yet taper off in the upper range.

I'll have to do a video of my tranny shifting one day, I should include a picture of the scanner running to show the TPS settings, gear, TC state and KR. It'* absolutely night and day the difference small adjustments make.

Further, you may want to have your Acceleration Enrichment (AE) changed too. It can be modified for certain TPS % settings as well it has a multiplyer value based on MPH, really usefull in the 48 to 64 MPH range.

Good luck!

Cheers,

I'm not sure I followed everything you wrote, Foghorn, but I feel I need to clarify a couple things.

I'm seeing as high as 10-12 degrees of KR when my TC locks in 3rd gear, under high load and low RPM. Throttle position is typically in the 10%-20% range when this occurs, though I don't believe the throttle position sensor has anything to do with the problem. It seems that this is false KR, mainly because there is no KR at low RPM in the bottom of 1st, 2nd, or 3rd gear. The problem only occurs once the car is already in 3rd gear and locks the converter. Additionally, the KR decreases and disappears as the RPMs climb, and there is no KR at wide open throttle.

To sum up, this isn't just an RPM/load related issue. It only happens when the converter is locked. This issue also has nothing to do with the EGR or the cam timing, because we already reinstalled the EGR and changed the cam timing. Results are exactly the same as before we made those changes. Something really goofy is happening.

Can there be a relation between a bad torque converter and false KR readings? Also, could my notorious surging/chuggle be a related problem?

Foghorn, you might be on to something when you say I should have the PCM reprogrammed to unlock the converter sooner. But I don't want a band-aid if this is a symptom of a larger problem.

Please help, guys. I'm due at Intense on April 14th for a dyno tune, and I don't want to drive 8 hours to Ohio to find out that it would be pointless to dyno my car because I have worn-out parts installed on it. I need to get this figured out, and if I need Intense to work on the car a little bit, so be it. But it is crucial that I get this issue isolated and repaired.


EDIT: Would my problem have anything to do with the conditions related in this service bulletin?

Just a suggestion: program out the converter lockup in third gear. I had my minimum lockup speed changed to 55 mph and it did a lot to help driveabilty in the 35-50 mph speed range. It had almost zero effect on fuel mileage. This suggestion may be a work around for a problem that can be cured in other ways, but if the car works well in all other conditions, you could just get rid of the problem area IMHO.

That'* a very typical situation described by many people in similar circumstances to you. It'* often referred to as Flash KR because, as you say, when accelerating from a stop you don't see KR, yet while accelerating on the highway with the TC locked you get oodles of KR.

It IS an RPM/Load issue and you comments above validate the circumstances.

The guys from Intense should be able to help you out with some custom tuning. Call Todd or Scott and explain what'* going on, I'm positive some transmission parameter changes along with Acceleration Enrichment (AE) adjustments will clear up your issues, it has for dozens of others like you.

Cheers,

Thanks for the insight, Foghorn! I have some questions. I want to understand this situation.

Can you explain a little more about what exactly is happening under those conditions? Does this mean it is real KR, because the engine is being loaded severely when the TC locks?

Why am I having problems with it now, as opposed to before my heads/cam swap?

Is there any problem with my TC, and would I benefit from moving to a higher stall converter?

Would it be smart to get rid of TC lockup in 3rd gear, as 2seater suggested? I like his idea of changing the minimum lockup speed, especially if it has little affect on mileage. Is this the same thing you would suggest?

I would really like to gain an understanding of the situation. Are you fairly positive my symptoms reflect flash KR? I want to make sure that the Intense guys are fully able to remedy to situation, because I would hate to drive all that way only to find it would be pointless to try and tune the car. Thanks!

I can't tell you for sure without seeing a proper scan of the car under the circumstances you describe, but it is either Torque Management (which manifests itself as KR) and/or you need a little more fuel under acceleration from the Acceleration Enrichment (AE - like the old accelerator pumps on carburators).

It'* a completely different setup than before, could be for many reasons.

I wouldn't think the higher stall torque would be of any help in this situation. As an aside, many turbo L67s and L36s have had to make extensive transmission parameter changes because of the load they are capable of exerting on the trannies at highway speeds, many of them fried their Torque Converter clutches.

I don't think so, it should be solvable without resorting to that.

Yes I am positive you have flash KR, but again, because of the tranny and/or you need a splash more fuel I can't tell exactly. In most cases I've seen with double digit KR in situations like yours it'* transmission related for most of it with some engine tweaking for the rest.

Talk to the Intense guys before you depart to see if there is some understanding of the situation to had beforehand. Have you done, or do you have the means the scan the car with something like an Autotap or something? If you don't own a scanner I think you're going to need one.

Cheers,

Thanks for the detailed reply. I'm glad you have heard of these symptoms; it makes me more confident that this problem can be easily remedied.

One other concern brought up by willwren is that the TC might actually be making noise, which could be the cause of the KR. My TC/tranny is all original (to my knowledge) which means it has over 128,000 miles on it. I wouldn't be surprised if the TC is starting to let go. But if physical TC failure is an issue, I need to let the guys at Intense know in plenty of time so I can hopefully get them to install a new TC before I tune. This is why I feel my situation is somewhat urgent.


To answer some of the questions that were posted in my 92-99 thread before it was locked: Yes, I'm running premium gas (91 octane). Fueling is fine; I'm actually running a bit rich at the times where KR becomes a problem. It all seems to be false KR, meaning the engine isn't actually knocking. If the sensors are hearing something else, I'll have to figure out what it is and change it.

False KR wouldn't be the right way to look at it. If it'* a Torque Management issue, and it could well be because Intense does not do that much with the tranny parameters in their PCMs, the PCM retards the Ignition Timing which is shown as KR which can be misleading.

Do you have a scan of your car that I can look at?

Cheers,