AUTO XRAY help
Thread Starter
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
AUTO XRAY help
I have scanned my vette with a auto xray trying to find out why it runs so rich. This thing is putting out black smoke. Just dont understand the specs it shoots to me. Could someone help me with this. My O2 sensors are .783 on left and .721 on the right. block learn value is 108 on both sides.There are a total of 34 nos. here so if any others need posted please say so. This was scanned at idle with the engine at full tempature. The scanner can capture 2 scans per second for a 15 second run. I can run those as well and post if needed. Just need to know if it needs to be done at idle, cruise, or full throttle. I have ordered new heated O2 sensors for it, but I hate to put them in and ruin them if it keeps running so rich. Anyways, any help would be appreciated.
Thread Starter
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
Originally Posted by 65Z01
Is it in closed loop mode at idle and at say 2000-2500rpm??
Use the AutoXray's Monitor Mode to see if the O2 sensors are switching between ~300mV to ~800mV.
Use the AutoXray's Monitor Mode to see if the O2 sensors are switching between ~300mV to ~800mV.
Hey Jim,
I was hoping you would look at this post. The print out says it is in closed loop. temp. was 184. degrees. This was at idle in drive. 675 rpms. I will have to check it at the 2000 to 2500 range. should this be in nutral or cruising down the road not under a load. Thanks for your help.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
First I would check it in Neutral at both engine speeds to see if it stays in closed loop.
Then do the Monitor Mode scan and flip through the O2 sensor values to see if they vary over time. Though, since it's going closed loop and you have no codes, I suspect your O2 sensors are working to the satisfaction of the ECM.
Do you have any mods on the engine??
Then do the Monitor Mode scan and flip through the O2 sensor values to see if they vary over time. Though, since it's going closed loop and you have no codes, I suspect your O2 sensors are working to the satisfaction of the ECM.
Do you have any mods on the engine??
Thread Starter
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
I have long tube headers, ported heads, and LT4 Hot cam. I have a chip by Ski Down It, but he is very confident its not the chip. Im not so sure. It actually runs 1 to 2 tenths quicker in the 1/8 mile with a generic stage 2 chip from Fastchip.
I just got back in from my garage and I ran it in neutral and captured it. (actually between 2350 rpms and 2575 according to the readings) Anyways, I tried to throttle back and forth a little and the readings are from 228 to 726 on the left side and 83 to 721 on the right side.
And it is staying in closed loop.
I just got back in from my garage and I ran it in neutral and captured it. (actually between 2350 rpms and 2575 according to the readings) Anyways, I tried to throttle back and forth a little and the readings are from 228 to 726 on the left side and 83 to 721 on the right side.
And it is staying in closed loop.
Last edited by 93 ragtop; Nov 5, 2004 at 04:05 PM.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Since the O2 values are switching and the ECM is staying in closed loop, I don't think you would benefit from heated O2s.
It sounds like you are running stock fuel pressure and injectors so you might swap in the other chip and compare BLM readings, after the ECM has time to adapt to the new calibration.
It sounds like you are running stock fuel pressure and injectors so you might swap in the other chip and compare BLM readings, after the ECM has time to adapt to the new calibration.
Safety Car
Joined: Feb 2002
Posts: 4,212
Likes: 10
From: Sun City West Az
With both your BLM's @ 108, the ECM is maxed out.......it can't pull out enough fuel to lean out the mixture. I'll bet both your short term intergrators are maxed too. I agree that trying another chip may be needed...
Thread Starter
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
The left blm is 112 to 117 the right is 108 across the board. Tomorrow I will swap out the chip and compare. I am running stock injectors, and stock pressure. Thanks for your help and I will get back to you tomorrow.
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