Ryann Chandler

@MatthewMiller Yeah I guess what I wanted to show was the symptom of the car. I don't think the sound is anything to worry about...then again, I'm not a mechanic. I really don't see or hear anything abnormal, other than the stuttering. Great info on the 02 sensor though. I think next steps might be the injectors as mentioned above.

Nomake Wan

Agreed, it's a very strange sound. It sounds fine at idle, then under any throttle at all it just...misses.

Do you have any datalogs from TunerPro RT or ALDLDroid or whatever you're using yet? If the problem is a sensor sending bad data to the ECM, it will be far easier to see in a graph with all the sensor values laid out than it will be trying to test every single sensor one by one with a multimeter.

MatthewMiller

I agree with everything you wrote after this: a data log would be really helpful. That said, the way you put the quoted part makes me wonder if this could be a TPS issue? That area just off idle is typically the area where these sensors fail first, as the "wiper" (not sure what it's called) inside spends most of its time in that range on any street-driven car. It would be interesting to get a voltage range across the sweep of the TPS.

Ryann Chandler

@MatthewMiller @Nomake Wan Yeah so i've got ALDL droid and a handheld tool from a friend that can also read OBDI, The problem is neither of them can connect to the ECU. I contacted the creator of ALDL Droid and he sent me a replacement adx file, but same issue. I think the one he sent just disabled the checksum validation. The only data I can get is by jumping the pins on the OBDI port and reading codes off the LCD. I don't know if this matters, but usually i'll unhook the battery after sunday because I usually don't drive during the week. My thought is, maybe it can't connect because it hasn't properly cycled through yet but..... i dunno.

I did replace the TPS sensor first and it had the exact same problem. This was a simple swap though. I've since put the original back on. I also swapped the map sensor and that also didn't fix it, so the original is back on. I think there is some reconfiguring that needs to be done if you switch the TPS but I don't have the device to do that.

Nomake Wan

The 'reconfiguring' when you replace the TPS or throttle body is for the ABS/ASR computer, not the ECM. The ECM automatically adjusts (though you do need to make sure that the cable actually goes the full range of motion from 0% to 100%, which is why the cable between the ASR motor and the throttle body has an adjuster on it).

Sucks about your interface woes. I'm not sure why it wouldn't be able to connect, but as I don't have a pre-94 Corvette around to mess with, I'm afraid I can't be of much specific help. My apologies.

EDIT: Do you have a vacuum gauge handy? I wonder what the vacuum gauge would look like connected when you blip the throttle like that? Without datalogs we'll need to do things old-school methinks.

jfa_C4_40th

Assuming you haven't deleted your Catalytic Converter, have you given any thought to checking that? Your symptom of running fine at idle but crappy under load and fuel odor can be a sign of a failing CAT. Just something else to put on the checklist before you get deep in to mechanicals and fuel injectors.

Galaxie500XL

I used a (possibly) bad method to troubleshoot the injectors on my ‘93.

I’d replaced the dead OptiSpark with a Petris unit, along with new plugs and wires, but still had a miss. Wasted hours trying to figure what I must have been doing wrong.

Since I couldn’t find anything wrong with the ignition, I moved to fuel...pressure was great, and my son asked me how the injectors were doing.

On the LT1, the electrical connectors are very easily accessible. Since I didn’t have a noid light, I simply started the car, let it warm up, then disconnected each injector in turn, noting what idle changes I noticed with that particular injector disconnected, then moved down to the next one.

When I got to #3, there was a slight change in idle, but not as noticeable. Bought a new OEM injector for #3, and replaced all of the O-rings on all 8 injectors where they plug into the manifold, and called it a day.

18 months later, and it still runs great.

Again, I may have actually done something terrible...seek other advice, but in my case, this did work very well, with no obvious issues.