Injuneer

A quick look at the data (the log has almost 440,000 pieces of data), couple quick comments:

Do you have a fan switch? Fans turn on low at 100-degF and high at 102-degF.

You have some huge knock retard numbers.... up to the 15-deg of retard that is the max allowed with stock programming. Often, the EVAP system is functioning at 100%. 15% of retard is going to be noticeable. There's a small amount of knock retard with just about many applications of the throttle, even mild increases in throttle position.

sactodreamer

If you are talking a manual switch, I don't. At least not that I know of.

We bought the car from a tow yard as a lean sale. The previous owner told them he had recently rebuilt the engine and transmission. I have a hard time believing the engine was rebuilt because of how dirty it is but maybe they just didn't clean the motor when it was out. The transmission seems to shift pretty hard so it may have been rebuilt with a shift kit.

Is there a chance the last owner did rebuild it with some mods and didn't have the pcm tuned?

Sorry for the large file I figured it would be a lot of data to look at that's why I tried to get the times when I felt the hick up. Thanks again for the help.

sactodreamer

Well it was nice we got it running for about a week. The transmission went out today. Nothing after 2nd gear. I guessing the original owner lied about the transmission being rebuilt.

Injuneer

squarehead

Hi Sacto,

Here is a link for transmission rebuilders in your area.

https://sfbay.craigslist.org/sby/ptd...733944706.html

Also Proline Transmissions (916) 990-7492

Good luck and don't be discouraged.

sactodreamer

Thanks. Life keeps getting better, my 96 Impala SS just developed a rod knock, sounds like a diesel engine. FML hahaha

sactodreamer

I've searched and I really don't want to start a new thread but does anyone know if a 4L60E out of a 2001 silverado will work in my 95 z28? Pretty much everything I've found searching are people asking about the opposite (using a 95 4L60E with a newer engine). Asking because I can get the 2001 trans for free.

Injuneer

sactodreamer

Thanks, hopefully I can get this back on the road so we can figure out the other issue. I'm definitely going to owe you some beers.......

sactodreamer

Almost two years later and I'm getting the transmission repaired next week. Hopefully we can get back to tracking down the problem with the engine.

sactodreamer

It's back! Transmission is great but the misfire is still there. I replaced the battery before sending it off to the transmission shop and it has a "service engine soon" light. I broke out the laptop and obd1 data cable but the software is saying it will not run on windows 10. I must have updated it since last time since the software worked 2 years ago on this laptop. Is there another option to scan the computer since Datamaster3.4.1 isn't working anymore?

Injuneer

You were using Scan9495 previously. If you have a problem w/ running it on Windows 10, you may need to update the software. Beyond that I can ask GaryDoug to help you sort it out.

sactodreamer

Yeah, I used Scan9495 before. OK, I found the right file and got it working. I'm going to clear out that CEL tomorrow and go from there.

Thanks!

sactodreamer

Well, I hooked up the laptop/scanner a few times since my last post and I can't get any connects to the PCM. ​​​​​​

I was able to get a hold of the previous owner and he told me it needs new spark plugs and wires and that the Catalytic converter is bad. He believes that's the cause of the misfire.

I took this video on the way home from work tonight showing the misfire.

Injuneer

I can never seem to get much out of videos, even listening w/ high end headphones. Tell me exactly when it's misfiring. At max RPM? Spotty or continuous? Is this the same as it was 2 years ago, or is this new?

I looked at the data log from 2018. Bank 1 O2 readings seem a bit lower than Bank 2 at 100% throttle, high RPM. That may be a sign of misfires, with the unburned air being read by the sensor. The MAP seem to have some spotty readings. Did you put fresh gas in it, after sitting for a couple years? Did you look at the plugs condition and wires condition?