I replaced the trans in my 95 Bonneville with a good used one. The axle ratios were wrong and it would not shift up to OD. I installed an ECM computer from another 95 Bonneville with the correct ratio and the trans shifts great again but now any time it is in OD with the slightest acceleration it has a constant engine detonation (spark knock,or pinging) I checked the EGR valve for carbon blockage and it was clean and closed when I removed it. I could use a pointer or two on this one. Thanks, Harry

Ok, what axle ratio do you have and what car did the trans come out of? Year and Model please. You may be totally hosed.

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Click here for mod list for both cars
93 SSEi, 95 SLE (supercharged) 97 Buick LeSabre Limited
PontiacDad at WCBF '04: Cruise control? That's like surrendering!
Comprehensive guide to troubleshooting, rebuilding, and modifying Eaton Superchargers

It sounds like you put in a L36/3.06 FDR trans and PCM and you're getting a ton of knock due to the n/a spark tables being too much for boost and the fueling being off.

You should have the original memcal recalibrated for your new trans ratio if you intend to keep it. Gmtuners.com can do that for you for relatively cheap.

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95 SLE... a keeper. 241k miles. Low and Slow.
97 BMW 528i
98 Infiniti vq35'd i30: 13.3@104mph, 30MPG Hwy (RIP)
02 Jag X-type
03 BMW M5
05 Chevy Cobalt LS
07 Infiniti G35s 6MT (Sold)
07 Ducati Monster S2R 800 with DS1000 swap
83 Yamaha IT175K
72 Yamaha DS7: '74 RD250 swap, JL chambers

Info on dropping a 92-99: Here.

Exactly what I was thinking.

Fuel tables are hosed due to the powerband being totally different. Keep you foot out of the throttle. No more than 50%.

Ultimately, if you want your performance back, you'll want to change that transmission again. In the meantime, reprogramming will solve PART of your problem.

_________________

Click here for mod list for both cars
93 SSEi, 95 SLE (supercharged) 97 Buick LeSabre Limited
PontiacDad at WCBF '04: Cruise control? That's like surrendering!
Comprehensive guide to troubleshooting, rebuilding, and modifying Eaton Superchargers

Wow! Sorry! the car is not the SSEI It is a normally aspirated 3800. The trans came out of a 95 LeSabre not sure of the exact ratio #s but something like 2.84. The original trans was a 3.6. The ECM replacement was out of a 95 Bonneville normal with 2.6 ratio.

Ok, 2.84 makes sense.

3.6 doesn't. That's 3.06.

What the heck is 2.6?


We need to know what ratio the PCM Donor vehicle came from, and what axle ratio it was? Most Bonnevilles came with 3.06 gears, so if you have a 2.84 trans, you aren't shifting right again. You have a messed up clusterfook on your hands. Either get your eprom re-flashed, or change your transmission to the proper one.

_________________

Click here for mod list for both cars
93 SSEi, 95 SLE (supercharged) 97 Buick LeSabre Limited
PontiacDad at WCBF '04: Cruise control? That's like surrendering!
Comprehensive guide to troubleshooting, rebuilding, and modifying Eaton Superchargers

Yes, the Bonneville came with a 3.06 ratio trans. That trans exploded and was replaced with a 2.84 ratio unit. This trans did not shift into OD. I replaced the ECM with one from a 95 Bonneville with the 2.84 ratio and the trans shift correctly again but now there is this spark knock issue in OD. If I need to have the EPROM reprogrammed is that done by GMtuners.com? Thanks for helping me get to this point. I now know that the correct ratio 3.06 trans should have been used in the first swap. I didn't have a lot of fun with this so far because the trans in the Bonneville now is actually the second 2.84 ratio I had installed and when it shifted exactly like the first replacement 2.84 trans and only then did I find out about axle ratios and needing the correct ECM programing. It has been an expensive and frustrating experience. Thanks for helping, Harry

I contacted Sinister Performance (GMTUNERS.COM) about the re-calibration of the mem-cal. Ryan said he would make the original mem-cal for the 3.07 trans ratio operate the replacement 2.84 ratio trans correctly. The other programing will remain and the spark knock will not happen.
I won't have the off the line pickup as before but the car will be usable again. It should be about as snappy as our Lesabre. I'm posting the mem-cal to Sinister in the AM. I'll let you guys know how it turns out. Thanks to all, Harry

I want to thank all who helped me through this problem I created by not installing the correct ratio trans in the first please. (If I had only known?)

Ryan at GMTuners.com reprogrammed the original mem-cal chip to control the 2.84 ratio trans with my Series 2 engine. I installed the mem-cal and the ECM and I have a very nice automobile again. All systems are back on line. My thanks to everyone, Harry

Sweet. Ryan is the man.

_________________

95 SLE... a keeper. 241k miles. Low and Slow.
97 BMW 528i
98 Infiniti vq35'd i30: 13.3@104mph, 30MPG Hwy (RIP)
02 Jag X-type
03 BMW M5
05 Chevy Cobalt LS
07 Infiniti G35s 6MT (Sold)
07 Ducati Monster S2R 800 with DS1000 swap
83 Yamaha IT175K
72 Yamaha DS7: '74 RD250 swap, JL chambers

Info on dropping a 92-99: Here.