ECU Retune ceiling

[spoiledred94]

I don't want to laugh even though I feel like it. You are an amazing mechanic and a good teacher. The best part a good education is it's yours forever.

I put 2.5 gallons of premium 91/E10 Ethanol blend at 76 in with about 1/2 gal of 83 from fred meyer. Still got a KR of 4.

SpoiledRed94Wrote:
what would it tell me if the 93 octane produced no KR?

WILLREN WROTE
Not much. Higher octane fuel is simply harder to ignite. All it really tells you is that it's not False Knock. In your case, it's pretty clear it's real.

Does this mean it's false KR? I know you said it's likely real. I just don't know why?
If the fuel used in the first run was not the problem we know only that.

There must be numerous ways the wrong computer can give a KR. How long of a list is the possible causes for real knock? Do the EM cracks cause false or real knock?

Next steps
1) Replace TB Screen
2) Swap in the original PCM
3) TPS Check/Adj
4) Donut replace w/ new bolts and springs.

[spoiledred94]

Swapped in the STOCK computer.
Replaced TB screen
Ran sluggish. Not as quick, revs wouldn't climb fast enough

[00Beast]

Did you do them each one at a time, or did you throw them all in at once? I have a feeling your PCM is still thinking your gear ratio is different, and having issues with it.

[spoiledred94]

I did them 1 after the other. It was noticeable both runs. I didn't take KR readings-No rider today. I may be able to get KR readings tomorrow....

[spoiledred94]

Me and my friend made another run with the stock cpu and with the TB screen installed. we got a 4 but just once or twice. Most of the time it was 2 or 3. Always on acceleration

I can't ask sinister performance to wait any longer. I'm gonna have them burn asap with stock timing.

EDIT: I'll wait until morning in case someone has a better idea

[willwren]

You need to allow for several miles for the PCM to re-learn the fueling curves, etc.
You won't have good data right away.

Re-scan after several days of driving the way you normally drive. KR only when accelerating? Between what gears? 1-2 only? 2-3? All of the above? Or is it happening AT the shift?

Was it colder outside during the last scan? Or similar to previous scans?

When you said 2.5 gallons of 91, and a gallon of 93, what ELSE was in the tank? Give us the full contents please.

No, it does not rule out 'real' KR. Particularly in your case. It doesn't rule out false KR, though.

[spoiledred94]

KR is on acceleration only IIRC.
KR at like 4500.
KR would hit the max and hold like that for the last few revs.
It begins KR in the 1-2 shift (like KR=2) but mostly in the 2nd-3rd shift(KR=2).
Though Gary and I can look closer the next runs to see where in the shift/rev cycle the KR is happening.
The temps and humidity have been much the same for all the runs.
The 1/2 gal (ARCO, 76, FredMeyer 87) was already in there when I added the 2.59 gal of 91 octane 76

I put $10 Shell 93 in today. I am pretty loyal to 76, but it gets to be where I am and when I have the money.

[spoiledred94]

Did the last run until I get the new EPROM installed.

1-2 is 3 KR @ ~4500rpm
2-3 is 4 KR@ ~5500rpm

[spoiledred94]

If you guys will lend a hand with some advice on the KR and the EGR code Id take it very seriously.


Getting Code 406 (EGR pintle valve position) after above h.s. runs

Adjusted TPS. No effect on KR or Code

Then steam cleaned top end with one gallon water. (showed a much larger exhaust leak at the yoke than before). Still get code 406. Have not run checked KR yet. Would like to retry with Lucas or Sea Foam.

I saw a false knock eliminator shield kit on Intense for $12 Do you think it's worth a try?

Going to remove and clean my EGR when I get a new gasket.

I have the new finished Sinister Performance EPROM and am hoping I can clear up the code and KR before I install it.

[willwren]

Why would you adjust a TPS for an EGR code? And how is your TPS adjustable when the last year for that was 1992? Do you have the wrong one installed?

You are still getting KR, and at the WRONG time of year. Come summer, you're in for much more KR. No tuning until you know (scan on a hot, humid day, and work from there).

Lucas and Seafoam aren't going to do anything for you but empty your wallet. There is no such thing as a mechanic in a can in your case.

You don't have false knock. You have real knock, and that will prove itself by getting worse in the summer. You can't install INTENSE's kit without dropping the trans or pulling the motor.

Cleaning a linear EGR is generally not effective. The earlier digital units (ending in the 93 model year) are very responsive to cleaning. So don't expect much in terms of results.

[spoiledred94]

Thanks for the advice. I saw a thread where the same EGR code was present and TPS voltage was mentioned as a possibility for the Code 406. It was barely out of spec and I bent the pin very slightly to bring it into adjustment. I used my scanner to check TPS voltage. I had an EGR code years ago and I put a new one on but it turned out not to be the valve. Should I clean the old one and put it back on or try cleaning the newer one first? I won't install the new tune until KR is 0. How do you know it's real knock? And is there anything else I can do to to clear the KR before I wait for summer to do the EM's?

Kris

[willwren]

TPS has absolutely no bearing whatsoever on the EGR and never did, or ever will.

You BENT WHAT? You don't BEND crap in there to adjust a TPS. In fact, since 92, you don't adjust a TPS. This is a prime example of another little thing done absolutely wrong on your car that makes it nearly impossible and very frustrating to even try to help. We don't know what ELSE has been done wrong. I'd really love to know EXACTLY what it was you bent. It sounds to me that if you bent a pin, you bent part of the throttle body? First time I've ever heard of that one before.

You shouldn't do the new tune until NEXT SUMMER and that's ONLY if you have 0 KR by then. What you have NOW will be far worse by then. The reason I know it's real knock is because you can't prove it isn't. You have to go on the theory that it's real and chase it down.

The EM's should have been done a year ago before you started modding the car. Too late again.

In your case, I suspect this may be next to impossible now. I suggest you de-mod the car entirely, put the original PCM and Eprom back in, and see what the KR says.

[spoiledred94]

Just an update. I fixed my exhaust leak. The original donut had about 25% of it blown away and missing. I bought the stud/nut/spring replacement kit but I could not get the original studs out so I reused them along with the other new parts. I would think there is a chance the KR might be reduced by this. ( Loose metal to metal connection causing false KR). Waiting until I can get a rider to try more test runs.