Recent problem.

[19Cutlass94]

Well as some of you know, I swapped in a cammed 3400 into my 94 Olds. I have the 1211 grind, p&p'ed intakes, and a 65mm TB, done to the motor. The problem Im having, is when coming to a stop, ( does not do this all the time ) it acts like its running out of gas and wants to stall but doesnt. The RPMS will drop from ~800rpm to ~300-400rpm and bounce back and forth. The other issue is that if your going down the road at lets say 30mph, give it half throttle, it barely goes anywhere, then all of a sudden takes off. Somestimes it doesnt even take off. the best way to describe it is as if you were pulling a trailer with a huge load, and punch it, vs punching it with no cargo at all. Whats odd is this started after I put the 65mm TB on. When the 56mm TB was on, I didnt have any problems at all. Also, sometimes it seems like it really just dies in the topend from about 80mph and on. Like somestimes itll hit 110mph FAST. Then other times it takes forever to hit 85mph. This weekend Im gonna try putting it back on to see what happens, but other than that what can I check? Fuel filter was just replaced, FPR is good, and pressure is good, fuel pump is good too.

Also, I have the data scans from everything, and it all looks good. LTFT is 127-128, STFT was 130 ( with a clogged fuel filter though ) BLM is 16 and my AFR at WOT was 12.4. At idle, spark is 15deg, but once you give it throttle, it jumps back to like 24 or 27 around there ( cant remember exactly what it was ) and I know the IPW at idle, but I havent check it at WOT. Theres no fault codes, nothing stored ot anything.


Thanks for any help guys!

[bszopi]

My 2 guesses is that you are still running the OBD1.5 PCM, which will never run the engine ideally (but I think you already know this). The other is that there is an issue with the TPS or IAC. Since you said it has come up since installing the 65mm TB, that would lead me to lean more towards one of those sensors. May not be that they are bad, but may need some tweaking with the new TB.

[19Cutlass94]

Well Ive also noticed that with this 65mm TB, it idles much higher than the 56mm TB. yeah I know about the OBD1.5, although I do plan on swapping in the future.

[IsaacHayes]

My 65mm TB idles perfect. It is not a CNC unit though, so maybe you need to adjust your throttle plate stop back some? Mine is from an LX5. Also I'd say since it acts strange with the TB swap, that maybe your TPS is bad. I had a bad TPS on the 65mm that I put on, it was idling way high. I hooked up my scannerPro definition, and it said 3% throttle. So I shut it off and pressed the pedal down to see the TSP % sweep on the analog gauge I have it set up to display. It never read 0% and would stop at 90%.. I took the TPS off (looked it up, it's a replacement brand) and put on a stock one from a 52mm TB out of a grandam. Bingo, 0% throttle, all the way up to 100%.

Check the TPS first. I doubt the bigger TB is making it act weird but who knows. Mine is running fine with the TB. My setup is original L82 3100 with 3400 LIM, 3500 UIM, LX5 65mm TB.

I notice my LTFT's pulls fuel rather than adding it. I've heard that means the motor is more efficient and making more power so you need less fuel, but I dunno. Posting 1 # for the LTFT's doesn't tell us anything, as it is constnatly changing # based on conditions. A log tells more.

If you want my ScannerPro and TunnerPro definitions, let me know. They really do help a lot for figuring out sensor problems and the like.

BTW what injectors are you running? The stockers or 3400 ones? I can't remember.

[19Cutlass94]

Im running the L82 3100 injectors, at ~45psi. I show 0% TPS angle at idle. The IAC is brand new, and the TPS is from the 3400, so its fairly new. I can check to see if I have the stop in too far. Although I duno if that would make a different or not, I doubt it. I have another TPS I can use. Maybe if I try an idle re-learn or something to see if it makes a difference or not.

I would use your definitions, but I duno what program I need, even though I have my laptop here I can hook it up to.

[IsaacHayes]

There is no real idle relearn for the 94-95 like there was for the older OBD1 cars. They pretty much learn right away. If they stall out then just retry and its good.

www.scannerpro.net and www.tunerpro.net are the sites.

[19Cutlass94]

ok so I need to download, the tunerpro, the aldl definitions, but what cable to I need to hook it up to my laptop to make everything work?

[IsaacHayes]

I use both programs. TunerPro to reset codes and view codes. Scannerpro to view sensor data and log.

TunerPro for some reason has a bug with recording our OBD1.5 code. Scannerpro logs it just fine and plays back fine, but has no .CSV export yet but moonwell has an online convertor, but somethings aren't working yet like RPM for it. Scannerpro deosn't let you select what mode you want to connect, so you have to make a separate def for code or sensor mode. and you cant send commands to clear codes unless you made a seperate def once again...

I have the defs on my website in the /aldlcable folder IIRC.

You need an ALDL cable, serial or USB or serial with usb adapter depending on your laptop. I have serial so I just build a serial cable. You can buy them too. You can try to make a 2 transistor cheapy one if you have a serial port I've heard most of the time that works. Then you plug the 2 wires into the ALDL port and connect it to the laptop and run the programs with my def loaded.

It can read trans temp to ac pressure and fuel pump voltage/etc. And display it as a graph, number, or analog gauge. I have BLM, INT, MAP, TPS%, Speed, Tach, Temp, Trans temp, IAT, etc as analog on my dash on scannerpro.

[19Cutlass94]

So new problem along with whats mentioned above.... I drive the car last night, and its idling about 1500rpm. I have an idea of were to look but cant really do anything until friday..

[19Cutlass94]

Problem is fixed. The ecm couldnt handle the 65mm tb.