I made a post on LS1tech forums but no one replied.
Did a data log on Scan9495, can someone who knows what to look for tell me if anyhing seems wrong. I recently rewired the fuel pump because the connector was melted on the inside of the sender unit and the A/F has been in the 20+ range at idle. Also the car seems to be cutting out after I drive it a few miles, with no change in fuel pressure or A/F.
In this data log I did not get the cutting out problem but maybe there is something there to indicate what is going on. I can make another one try to recreate the problem I am just worried the car will die in the middle of the road haha It's a 1995 lt1 auto Camaro, lots of mods I bought it with, it was wired by a non car electrician so it's been a nightmare to get it sorted.

Video of starting warm

 

I'll take a look at it. A quick run through on my iPad (which is not really useful for detailed data review) shows four trouble codes as soon as the log starts:

11 - SES light inoperative
15 - ECT sensor circuit voltage high/temperature low (typically an open circuit)
33 - MAP sensor voltage high/vacuum low
34 - MAP sensor voltage low/vacuum high

Have you investigated any of those? Right at the beginning, the barometric pressure (derived from the MAP sensor on startup) is jumping all over the place, should be steady since it can’t be measured once the engine is running. Makes the MAP sensor wiring suspect.

I'll try and take a more detailed look tomorrow using my PC.

 

Hello thanks for the reply!

I saw the codes but didnt know what to make of them, being a modified car and everyone is always warning against Opti troubles so I was more worried about that.

I will have a look at the MAP lines as soon as I get home,

 

Preliminary - I will continue to look deeper.

The scan rate is very low..... about 2 frames per second. It needs to be much higher, or it hides a lot of detail in the readings. I can get the author of Scan9495 to take a look and suggest how you can increase the scan rate. I don't use Scan9495 because I run an aftermarket engine management system. I can read the data, but I'm not up on setting up the program.

Forget the comment about the erratic Barometer reading.... not correct. I do not see any signs of the MAP being erratic, but it is fairly high (= low vacuum) probably due to the cam. Do you know the cam specs?

You have to clear the trouble codes, to see how fast they come back. Check the SES light. Appears someone may have removed the bulb to cover up the codes. You can clear the stored codes by pulling the "PCM BAT" fuse for 30-deconds.

There is an erratic reading on the coolant temp sensor. At one point is drops 10-degrees in 1/2 a second, enough to kick the target idle speed up from 850 RPM to 900 RPM.

Idle air steps seem high, at 69 at idle. But maybe that was done to try and control the cam at idle. As a result, the engine is typically idling 100 RPM higher than the target at times.

When you indicate it is running lean, is that based solely on the wide-band readings? Have you ever checked the plugs for signs of running very lean? Where is the wide-band sensor located?

You do have knock retards, a couple places where you are leaning into the throttle fairly gently, and then oddly enough, with closed throttle, under decel. Hard to understand what would cause that, unless there is some mechanical noise upsetting the knock sensor.

The O2 data and the long term fuel corrections do not indicate a significant lean problem. But there is something weird in the data. I have never seen a data log where every cell is at 128 (0% fuel correction) in every operating cell. The left bank O2 is seemingly locked at 128, and the short terms are not showing any tendency to add extra fuel either. On the right bank O2 sensor, it is very slow to warm up and become active. And there are places on the right side where the PCM is adding up to 12% extra fuel. But the difference between the banks is not indicative of a fuel pressure problem.

I'll keep looking. Since the problem didn't occur during this log, it's not likely to be an obvious fault. Just ran out of time this morning.

 

Injuneer thank you so much for looking into my problem!

Not sure about how the program works, I just started using it so just trying to figure it out myself.

Unfortunately I have no idea of the cam specs, last owner didn't have the info so we are left to guess. It's not a super choppy one but that’s not much information...

The reading are based on the wide-band, the sensor is right after the left cat I believe. When I get home I will take out cylinder 5/7 spark plug and see how it's looking.

I did fiddle around the MAP sensor then I cleared the DTC's with Scan9495 and took it out for a drive, the DTC's did not come back apart from DTC 11 and the car did behave rather normal.
When it was cold the A/F idle was around 17-18, then once it warmed up around 14.8, I did a WOT pull and it was 12.3. It seemed fine, the only problem is my laptop ran out of battery and all the data is corrupted lol... I will do another scan today and try and get it on here, but it seems fine at the moment

I am interested in the other readings you mentioned so maybe they can indicate weird things going on with the car

 

You have to have the O2 sensor in front of the cat. Your hot idle and power enrichment (PE ~= WOT) A/F ratios are OK, maybe a bit rich in PE. Cold idle is very lean, according to the wide-band. That is easily corrected in the tune. I'll review your log but as I recall it wasn’t a completely cold start.

Do you know who tuned it?

 

For the slow scan rate, what exact device are you using for a computer? It looks like the program is taking too much time to write to the datalog file. That could be due to a slow pc, low amount of ram, low amount of free disc space. If nothing else works, I may recommend using an older version of the program (ver 1.xx) because version 2 uses more memory.