707chance

iTrader: (2)

I have posted this information in two other places but I think the thread should also be posted here. I will trust that a moderator will move it to its proper place.
Last Monday I took my car to a large shop to be tuned by a respected tuner that is well known. An employee of the company placed the car on the dyno-wheel and worked the tap-shift feature during the pulls. The tuner was in the car for the first run and stood outside for the other runs. The first three pulls went OK with the performance of the car slowly being increased. However, there was an issue concerning the TC locking and unlocking. On the fourth pull I heard the car go through the gears to third and then they went WOT. At the very end of the pull I heard the car jump in rpms like crazy!!! The car was screaming. It was like a manual being put into neutral and then the gas pedal being pushed to the floor.
The tuner said that right after the pull, the car downshifted into second gear all by itself. He could not offer any explanation of this event. According to what I saw on the graph the rpm went off the screen and the speed of the car was around 137 when it was downshifted.
The car was towed home and we have removed the front head. We have done a seal test with two of the cylinders failing. This is as far as we have gone. We are trying to determine what to do next.
I have spoken to a really good transmission guy about the downshift event, the TC locking and unlocking and the TC being locked up during the 4th run. I will be contacting the TC Company next week.
The tuner has sent me 4 files, but I am unable to open 3 of them because they are HPTs and I don’t have the software.
Can anybody out there give me a hand with this situation? The shop will not return my phone calls, and the tuner was out of town last week, so I am hoping to hear from him this week.
I can forward the files to you via email.

01ssreda4

iTrader: (96)

Sounds like you possibly bent some valves from the over-rev.

Mattsv8

iTrader: (7)

Or pushrods

edcmat-l1

iTrader: (10)

Bent pushrods won't cause it to fail a leak down test. Unless by some freak chance they got jammed up top and ended up holding the rocker arm and pushrod open.

Chris10an

iTrader: (1)

But damaged valves will do. I have seen bend valves many time cause they over RPM the engines.

The problem with this is that I have also seen automatic trans downshift to sec even if we lock them with the software. There is always a risk, that's why every run on the Dyno is owners risk. "in my shop it is" if we have buil it it's our risk.

What was the RPM limit on this engine and did the Dyno operator/Tuner program the RPM limit?

That the shop don't answer is BAD. They should do, and try to solve this with you. Did you sign any papers before you test the car on the Dyno?

707chance

iTrader: (2)

[QUOTE=Chris10an;15057443]But damaged valves will do. I have seen bend valves many time cause they over RPM the engines.

The problem with this is that I have also seen automatic trans downshift to sec even if we lock them with the software. There is always a risk, that's why every run on the Dyno is owners risk. "in my shop it is" if we have buil it it's our risk.

What was the RPM limit on this engine and did the Dyno operator/Tuner program the RPM limit?

That the shop don't answer is BAD. They should do, and try to solve this with you. Did you sign any papers before you test the car on the Dyno?

I did not sign any documents. At this time I can not answer any questions about the RPM limit because I can not open the files sent to me and frankly this data is beyond my understanding at this time. I have sent the data tables to other experts in tuning and in this type of transmission and TC. I will post other peoples opinions/conclusions only if they give me permission.

2xLS1

iTrader: (25)

It doesn't matter what the rev limiter was set at in the tune. If it downshifted to 2nd, the dyno rollers mechanically over reved the motor. Tune rev limiters can't prevent that. It's a good practice when running an auto car on a dyno to put it in neutral immediately as soon as the pull is ended.

BOTTLE ROCKET

iTrader: (4)

You took the car to them for TUNING. This is not an issue of "who built the engine" since this was not an issue of the engine failing. (rod, rod bolt, etc)
The tuner is responsible for setting all of the "safety parmeters" (shift points, rev limiter, gear lock out, etc), as well as making sure their dyno is working properly, before they start so that this will not happen. Most customers have no idea what is involved in the tuning process, and that's why they take it to someone in the 1st place
The tuner should take care of this issue.

707chance

iTrader: (2)

I think you have made a good point. I wonder what the other professional tuners out there think about your point?

minytrker

iTrader: (13)

Something isnt right, if the shift tables were correct it shouldnt downshift into 2nd. I have had cars downshift before on the dyno and they downshifted into the correct gear and didnt hurt anything.
Like someone said already, no matter what the rev limiter was set at the spinning drum would have over reved it if it went into 2nd.

edcmat-l1

iTrader: (10)

Well duh. I know bent valves will. I only commented on the bent pushrod post. Bent pushrods will not cause a failed leak down test.

edcmat-l1

iTrader: (10)

How can you even comment without knowing what happened? Lynch mob mentality. And no, I'm not the one that tuned it.

How can anyone make any comment like this without knowing all the facts? Without a tune and data log to look at no one has the facts.

The fact that the OP did not sign a release form is bad on the shop/tuner. Instances like this is exactly why ALL car owners need to sign them.

2xLS3

iTrader: (3)

Actully looking at it from the vehicle owners view, instances like this are a good reason not to sign your rights away.

Over the years, I've seen many instances, where the dyno operator did something wrong, that could have ended with disastorous results and a few did and I'm not talking tuning mistakes, like getting it too lean or over-reving it. More along the lines of not properly strapping the vehicle down, or having a wrench fall during the run and having it go between the roller and tire, allowing it to be shot across the shop like a missle.

Ed, you'd be one of the last people I'd even think to suspect of being the tuner in this case, but I'm willing to bet, you know who it was, but in your typical fashion, if you can't say something good about somebody or their tuning ability, your normally don't say anything at all.

edcmat-l1

iTrader: (10)

I agree completely. But, in the best interest of the tuner shop, they should have people sign the release forms, and they should ALSO have a well qualified tuner/dyno operator. It takes alot of skill to operate these cars on a dyno and get repeated results, without hurting anything.


Thanks for the compliments. You're right, I try to stay as neutral as possible.

BOTTLE ROCKET

iTrader: (4)

He just told us what happened
Thanks, but no, I dont have a "lynch mob mentality", but yes, I do have experience with legal issue involving busnesses not taking reponsibility.
I (and you) can only go on what was described, SO FAR. If somthing else comes out, then this all means nothing anyway. But as it stands do far;

1. He took it to a "tuner" to be tuned, and was paying him for his ability.
2. He had no engine issues before the "tune"
3. DURING THE DYNO session, the car over-rev'd and engine damage was done

The only "unknown" is whether or not there was a mechanical based transmission failure that cause the over-rev. Other than that, the PCM (or dyno) is responsible. (Both under the control of the tuner)

If he is not telling us everything, then I retract, if he is, the TUNER is responsible becasue it happened while he had "control" of the car and thus the responsibility. Another way of looking at it. If he had taken it for a "test drive" and wrecked it, who do you think would pay for the repair????

Signed form or not, if the facts the OP presented are complete, and it was my car, I KNOW who would pay for the repair

SweetS10V8

iTrader: (4)

The responsiblity of the shop was for safety and some parameters, I agree. But a random shift into 2nd gear will destroy any car at the top of a dyno pull.

The shop sees it as the owners car having and causing the problem, so its the owners reponsibility.

The customer ALWAYS wants to blame anyone anyway they can in these situations. But when it comes down to it; unless you can prove that the dyno operator shifted the car into 2nd gear or did something else negligent, I think this is the customers responcibility. Its a chassis dyno test, a lot can go wrong in an instant. Heck I cant stand it when people stand anywhere near chassis dynos during a test.

I would get those .hpt files and check them over, but I dont think youll get anything proving he hit a button shifting the car into 2nd. You might see a shift change, but nothing saying what caused or commanded it to shift.

707chance

iTrader: (2)

First of all I would like to thank everyone who has helped me in working through this situation. I do not desire to "witch hunt" anyone therefore I have not released any names. The company where the tune took place, their employee who was there and the tuner all have reps that I desire to protect and bills that they have to pay. Everyone makes mistakes and sometimes the smoke has to clear in order for people to react professionally as opposed to emotionally.
The transmission was built up last June/July with the understanding that it was going to see a lot more hp/tq then what was being placed on it before the “over-rev”. The TC was also upgrade but there is now an issue about how it was ordered to perform during the run. I will be contacting the TQ manufacturer on Monday about their specs. The motor was refreshed and built up on last fall with the understanding that it was going to see more hp/tq then what was being placed on it before the “over-rev”. No n2o was used in the tuning session.
As for the responsibility issue I ran a tree business for over 20 years. I have seen easy jobs suddenly go very very bad. I was told that my tune would be an easy one. To not inform your customer that you do not have any insurance and that you will assume no financial responsibility if anything does go wrong was not ethical.
After the dyno disaster I was told by the tuner that he did not know why the car behaved the way it did. So I began to search for reasons, I have forward to him several emails about possible reasons why the car over-reved. I called the company but they will not return my call, the turner has now emailed me twice telling me when he was going to call me but I have received no phone calls. I am still willing to work with these two businesses to resolve this issue.

BOTTLE ROCKET

iTrader: (4)

Good points; but the shop operator was the "expert" in contol of the car's computer settings, and the computer controls the trans shifting
Bottom line,EVERYONE IS NOT QUALIFIED TO TUNE And if they attempt it becasue of the $$$ involved, they must be held responsible.

edcmat-l1

iTrader: (10)

That single unknown is all it takes.

Aparently, you've never tuned a car that would not stay locked up when commanded, or stay in the commanded gear. Just because you command a certain gear, and command TCC lock up, does not mean it will stay locked up. There are mechanical issues that sometimes over ride PCM commands. Especially at WOT.

2xLS3

iTrader: (3)

According to the OP's first post, they were having lockup issues, so I feel the tuner should have done something about it before proceeding doing the WOT tunes.

I do realize for various reasons, they do drop out of the gear you set them for, and the convertor can come unlocked, but it is an electronicly controlled transmission, and if it doesn't do what the ECM, PCM or TCM, which ever is running it, tells it to do, it should be fixed before tuning it. Its not any differant then trying to tune it with a bad injector, most shops wouldn't do that, but they'd continue to tune, with a tranny issue.

To the OP, HPT has a demo version of their software, if its not accessible from them web site, PM Bill (FOFF667) and ask him for a link to it, I think the demo allows you to open files. Best wishes to a suitible outcome on your issue

PS I see in the not too distant future, all dyno shops needing to be licensed or members of some organization, to not only help preventing things like this happening, but the issues with skirting the emission laws. Maybe SEMA or some other automotive based enity will step up to the bat, before the EPA decides its their job to control dyno tuning shops.