LT1 Running super rich surging - LS1LT1 Forum : LT1, LS1, Camaro, Firebird, Trans Am, Engine Tech Forums
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post #1 of 19 (permalink) Old 06-24-2017, 01:48 AM Thread Starter
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LT1 Running super rich surging

Okay, so I've been searching online with no clue what's going on honestly, I have a 95 LT1 cammed comp cam 503, 1.6rr, exhaust, and intake. It has been tuned by LT1pcmtuning.com.

I have datalogged the car using $eehack and only get the code 34, my coolant sensor appears to be working, and my o2 sensors seem to be working as well. The car is running at an afr of 10.04-10.08 constantly, which I know is sickeningly rich. After it idles for a little bit it'll bog and surge and occasionally die. It only really seems to do this in park and neutral though. It has stalled twice in reverse.

I've attached my datalog which is about four minutes of idling. I don't know how to read everything yet so I'm still learning. ($eehack) https://ufile.io/48jij

Any advice helps.

New parts: (replaced within the last year)
O2 Sensors (Ac delco)
Injectors (Stock, oem)
Optispark (Delphi)
Wires (Jegs)
Plugs (NGK coppers)
Map Sensor (Ac delco)

And maybe more I've forgotten.
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post #2 of 19 (permalink) Old 06-24-2017, 09:08 AM
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Your dtc 34 indicates you map signal is high. Use your datalog to see how how it's reading is. If at under 1volt constantly then map sensor is not working correctly or way too much vacuum to sensor..

Check to see electrical connector is making a good connection. Unplug it and check terminals for corrosion, bent or backed out pins. Plug connector back in and datalog again.

You can download the 95 service manual at www.mediafire.com/?40mfgeoe4ctti

Section 6E is the driveability & emissions section. Starting on page 6E3-A-76 will be info on dtc 34. Having this code with pcm seeing low voltage/high vacuum on map, will cause over fueling of car.

I recently had the opposite map problem on my 90 daily driver. With high voltage/low vacuum shown ecm, car was running so lean that it wouldn't stay running when car was put into gear.
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post #3 of 19 (permalink) Old 06-24-2017, 09:09 PM Thread Starter
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My map sensor reads between 39 and 59 kpa, which I honestly have no idea what that means.
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post #4 of 19 (permalink) Old 06-24-2017, 09:31 PM
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11.5-17.4 in Mercury on an old style vacuum gauge, which is kinda low for idle. Should be 18-20" (for an old engine with carb)

Last edited by Karl Nancy Koenig; 06-24-2017 at 09:35 PM. Reason: correction
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post #5 of 19 (permalink) Old 06-24-2017, 09:50 PM Thread Starter
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Quote:
Originally Posted by Karl Nancy Koenig View Post
11.5-17.4 in Mercury on an old style vacuum gauge, which is kinda low for idle. Should be 18-20" (for an old engine with carb)

This is the fuel injected LT1 350 from 92-97
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post #6 of 19 (permalink) Old 06-25-2017, 06:24 AM
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This is the fuel injected LT1 350 from 92-97
A cammed engine will almost always have lower idle vac than a stocker, as well. Have you checked fuel pressure?

1995 LT1 Wagon. ERE 383
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post #7 of 19 (permalink) Old 06-25-2017, 07:26 AM
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Doesn't your scan program have an option to read map voltage rather than vacuum reading?
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post #8 of 19 (permalink) Old 06-25-2017, 08:48 PM Thread Starter
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Doesn't your scan program have an option to read map voltage rather than vacuum reading?
If it does, I don't know how to get to it.

it's $eehack and I'm still learning how to use it. I also have the app on my phone the aldlscan
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post #9 of 19 (permalink) Old 06-25-2017, 09:31 PM
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A cammed engine will almost always have lower idle vac than a stocker, as well. Have you checked fuel pressure?
<palm to forehead> Yeah, that's probably a reasonable idle vacuum. You can ask the cam manufacturer.
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post #10 of 19 (permalink) Old 06-25-2017, 10:56 PM Thread Starter
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A cammed engine will almost always have lower idle vac than a stocker, as well. Have you checked fuel pressure?
Just tested the fuel pressure regulator and it's not leaking. I tested after running the fuel pump then removed the vacuum line, no fuel came out.
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post #11 of 19 (permalink) Old 06-25-2017, 11:04 PM Thread Starter
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Quote:
Originally Posted by cocobolo95 View Post
Your dtc 34 indicates you map signal is high. Use your datalog to see how how it's reading is. If at under 1volt constantly then map sensor is not working correctly or way too much vacuum to sensor..

Check to see electrical connector is making a good connection. Unplug it and check terminals for corrosion, bent or backed out pins. Plug connector back in and datalog again.

You can download the 95 service manual at www.mediafire.com/?40mfgeoe4ctti

Section 6E is the driveability & emissions section. Starting on page 6E3-A-76 will be info on dtc 34. Having this code with pcm seeing low voltage/high vacuum on map, will cause over fueling of car.

I recently had the opposite map problem on my 90 daily driver. With high voltage/low vacuum shown ecm, car was running so lean that it wouldn't stay running when car was put into gear.
Replaced MAP sensor, no MAP code so far. Still running ultra rich.
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post #12 of 19 (permalink) Old 06-26-2017, 07:07 AM
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Could your pcm for less tune be the problem? eehack can compute a tune for your car based on the mods it has. Since our member Steveo wrote the program, you might want to pm him and get some tuning advice.

I've never used eehack, but I have used tunercat obd1 tuner and Tunerpro rt. Both those programs will read the variables in your pcm and list them.

I'm guessing that eehack can do the same thing. With the reading of your pcm, you can compare the tune provided by pcm for less to the stock bin file for your car. You can see what was changed in the tune. Steveo is the person who can help you the most here.

eehack will create a tune for your car based on the mods. You will probably need the program called "winflash" to upload it to your pcm. Winflash is available at the tunercat web site. It has a 30 day free trial. Or you can keep it forever for $20.

You should be able to save the pcm for less tune bin file, and reload it to your pcm, in case eehack tune bin doesn't improve running condition of your car.

So get with Steveo to discuss eehack and your pcm's tune.

Stock bin files are available on Stevo's website and at the gearheadefi forums. You will need a stock bin file for your camaro that is correct year, trans type, rear gear ratio.

Last edited by cocobolo95; 06-26-2017 at 07:10 AM.
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post #13 of 19 (permalink) Old 06-26-2017, 07:13 AM
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The only other things I can think of that would make your car run that rich would be vacuum and/or exhaust leaks.

Also learning the sensor data and what it should read would help you to determine what is wrong.
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post #14 of 19 (permalink) Old 06-26-2017, 09:36 AM Thread Starter
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Quote:
Originally Posted by cocobolo95 View Post
Could your pcm for less tune be the problem? eehack can compute a tune for your car based on the mods it has. Since our member Steveo wrote the program, you might want to pm him and get some tuning advice.

I've never used eehack, but I have used tunercat obd1 tuner and Tunerpro rt. Both those programs will read the variables in your pcm and list them.

I'm guessing that eehack can do the same thing. With the reading of your pcm, you can compare the tune provided by pcm for less to the stock bin file for your car. You can see what was changed in the tune. Steveo is the person who can help you the most here.

eehack will create a tune for your car based on the mods. You will probably need the program called "winflash" to upload it to your pcm. Winflash is available at the tunercat web site. It has a 30 day free trial. Or you can keep it forever for $20.

You should be able to save the pcm for less tune bin file, and reload it to your pcm, in case eehack tune bin doesn't improve running condition of your car.

So get with Steveo to discuss eehack and your pcm's tune.

Stock bin files are available on Stevo's website and at the gearheadefi forums. You will need a stock bin file for your camaro that is correct year, trans type, rear gear ratio.

My tune was done by LT1pcmtuning, Solomon. I sent off my log to him and he doesn't seem to think it's an issue with the tune but something mechanical. I've checked my fuel regulator, map sensor, o2 sensors, etc.
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post #15 of 19 (permalink) Old 06-26-2017, 10:09 AM
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Quote:
Originally Posted by cocobolo95 View Post
...eehack can compute a tune for your car based on the mods it has...
it doesn't do that,

you're thinking of a web based tool i wrote before. it's over here Free Online Tuning Service ? fbodytech

eehack is a datastream tool. it doesn't tune your car or modify your tune, instead it does nearly every possible thing you can do with the lt1 datastream.

you should really try it sometime

$EEHack Features and Screenshots ? fbodytech
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