BLM at 160. 1985 corvette
Drifting
Joined: Jun 2018
Posts: 1,678
Likes: 229
From: Michigan
False equivalency. New does not mean good. Something that has been on a well functioning car for 6 months is more proven to be "good" than just because it is new. I worked at a parts store at one point in my life. This is the main thing I learned.
This is more important than it being new.
It is almost like your ECM wants to be in power enrichment mode. It knows it is rich, but it wants to be richer.
It is almost like your ECM wants to be in power enrichment mode. It knows it is rich, but it wants to be richer.
Last edited by KyleF; Dec 12, 2019 at 04:24 PM.
Drifting
Joined: Jun 2018
Posts: 1,678
Likes: 229
From: Michigan
Understand that the CINJ ("9th Injector") can only be active or supply fuel when the key is in CRANK. It gets its B+ from the purple wire starter solenoid circuit. In no other key position is the CINJ powered. The CINJ is active at 95deg F or below. Once the engine is running, and key is not in CRANK, the CINJ is OFF, regardless of coolant temperature.
TLDR: 9th injector can only inject fuel when key is in CRANK. It is off at all other times.
TLDR: 9th injector can only inject fuel when key is in CRANK. It is off at all other times.
Edit: Never mind, was able to find it on Google pretty easy. It is only powered during crank cycle.
Last edited by KyleF; Dec 12, 2019 at 05:01 PM.
Drifting
Joined: Jun 2018
Posts: 1,678
Likes: 229
From: Michigan
Drifting
Joined: Jun 2018
Posts: 1,678
Likes: 229
From: Michigan
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Advanced
Joined: Aug 2019
Posts: 75
Likes: 8
Does the installed O2 sensor have a purple or black lead wire?
What color was the original sensor's lead wire? (I'm pretty sure it was black).
My recollection is hazy, but I don't recall that the two color sensors were interchangeable. Something else that costs nothing to check.
What color was the original sensor's lead wire? (I'm pretty sure it was black).
My recollection is hazy, but I don't recall that the two color sensors were interchangeable. Something else that costs nothing to check.
Drifting
Joined: Aug 2019
Posts: 1,339
Likes: 225
Interesting. If I am seeing this correctly....did you notice that the BLM came down at 3000rpm? That indicates to me that there is a vacuum leak that's big enough at idle, but not big enough at higher rpms because there's more air coming through the throttle.. Do you have vacuum at the egr at idle? If so, that might be the problem. I would try disconnecting it just to see what happens at idle. We actually did find something.
For the TPS, you can cycle the throttle with the engine off to see how the voltage changes. You should go from about .8 to about 4.5 volts and it should change smoothly without any dips.
For the TPS, you can cycle the throttle with the engine off to see how the voltage changes. You should go from about .8 to about 4.5 volts and it should change smoothly without any dips.
Last edited by Mrvettenick; Dec 12, 2019 at 05:20 PM.
Thread Starter
Advanced
Joined: Aug 2019
Posts: 75
Likes: 8
Side note, do you have the wiring diagram in a post-able format that shows this? I am not saying you are wrong at all, but this is different that I had been told in the past. Wiring diagram will clear that up. I have seen it posted previously the thermo switch is always powered. Never had an issue with mine so I have never dug into that circuit.
Edit: Never mind, was able to find it on Google pretty easy. It is only powered during crank cycle.
Edit: Never mind, was able to find it on Google pretty easy. It is only powered during crank cycle.
Thread Starter
Advanced
Joined: Aug 2019
Posts: 75
Likes: 8
Interesting. If I am seeing this correctly....did you notice that the BLM came down at 3000rpm? That indicates to me that there is a vacuum leak that's big enough at idle, but not big enough at higher rpms because there's more air coming through the throttle.. Do you have vacuum at the egr at idle? If so, that might be the problem. I would try disconnecting it just to see what happens at idle. We actually did find something.
For the TPS, you can cycle the throttle with the engine off to see how the voltage changes. You should go from about .8 to about 4.5 volts and it should change smoothly without any dips.
For the TPS, you can cycle the throttle with the engine off to see how the voltage changes. You should go from about .8 to about 4.5 volts and it should change smoothly without any dips.
blm goes to 140ish in gear as well
Thread Starter
Advanced
Joined: Aug 2019
Posts: 75
Likes: 8
Oil Producer
Joined: Apr 2014
Posts: 9,377
Likes: 2,737
tossing this in here. the 1985 is unique in that it forces itself to run with the parameters of “field test mode” while communicating with any scanner.
If you search it, there are a few things that are built into field test mode. rpm at 1000rpm is one. I think timing is pulled? there are others.
I vaguely recall when i was scanning my 85 i was more or less unable to “catch my car in the act” because the very act of watching changed the parameters underwhich the car was operating. kind of like trying to observe a quantum particle.
anyway, thought i would mention this.
If you search it, there are a few things that are built into field test mode. rpm at 1000rpm is one. I think timing is pulled? there are others.
I vaguely recall when i was scanning my 85 i was more or less unable to “catch my car in the act” because the very act of watching changed the parameters underwhich the car was operating. kind of like trying to observe a quantum particle.
anyway, thought i would mention this.
Drifting
Joined: Jun 2018
Posts: 1,678
Likes: 229
From: Michigan
tossing this in here. the 1985 is unique in that it forces itself to run with the parameters of “field test mode” while communicating with any scanner.
If you search it, there are a few things that are built into field test mode. rpm at 1000rpm is one. I think timing is pulled? there are others.
I vaguely recall when i was scanning my 85 i was more or less unable to “catch my car in the act” because the very act of watching changed the parameters underwhich the car was operating. kind of like trying to observe a quantum particle.
anyway, thought i would mention this.
If you search it, there are a few things that are built into field test mode. rpm at 1000rpm is one. I think timing is pulled? there are others.
I vaguely recall when i was scanning my 85 i was more or less unable to “catch my car in the act” because the very act of watching changed the parameters underwhich the car was operating. kind of like trying to observe a quantum particle.
anyway, thought i would mention this.
I wish I had my log of some scans, but based on some of your scans that seems high on the IAC to have the throttle open that far.
Last edited by KyleF; Dec 12, 2019 at 05:49 PM.
Thread Starter
Advanced
Joined: Aug 2019
Posts: 75
Likes: 8
True. But BLM should be LESS than 128 for a leaky, drippy, faulty injector. Any 9 of them.
Your nose says it is rich. The O2 voltage is predominantly rich. But the BLM is high because the ECM thinks it is lean? You're receiving help from some good minds here. They haven't come up with it yet, but will.
Do you have access to the FSM for Codes 44 and 45? These two code tutorials have some good cues and suggestions for trouble-shooting O2 sensor input, and how to use the Check Engine Light to diagnose O2 sensor inputs and Open/Closed loop. Even though you don't have these codes, the diagnostic info for them is applicable to your situation here. Just a suggestion.
Your nose says it is rich. The O2 voltage is predominantly rich. But the BLM is high because the ECM thinks it is lean? You're receiving help from some good minds here. They haven't come up with it yet, but will.
Do you have access to the FSM for Codes 44 and 45? These two code tutorials have some good cues and suggestions for trouble-shooting O2 sensor input, and how to use the Check Engine Light to diagnose O2 sensor inputs and Open/Closed loop. Even though you don't have these codes, the diagnostic info for them is applicable to your situation here. Just a suggestion.
i do have fsm. I’ll read the 44/45 codes tonight and run the tests.
Thread Starter
Advanced
Joined: Aug 2019
Posts: 75
Likes: 8
tossing this in here. the 1985 is unique in that it forces itself to run with the parameters of “field test mode” while communicating with any scanner.
If you search it, there are a few things that are built into field test mode. rpm at 1000rpm is one. I think timing is pulled? there are others.
I vaguely recall when i was scanning my 85 i was more or less unable to “catch my car in the act” because the very act of watching changed the parameters underwhich the car was operating. kind of like trying to observe a quantum particle.
anyway, thought i would mention this.
If you search it, there are a few things that are built into field test mode. rpm at 1000rpm is one. I think timing is pulled? there are others.
I vaguely recall when i was scanning my 85 i was more or less unable to “catch my car in the act” because the very act of watching changed the parameters underwhich the car was operating. kind of like trying to observe a quantum particle.
anyway, thought i would mention this.
maybe just maybe this will cure some of my issues. Especially my early
lock up!!
It is unfortunate the field test mode is activated to where I can see what the car does at my normal idle rpm.
Drifting
Joined: Aug 2019
Posts: 1,339
Likes: 225
Just to satisfy my curiosity why don't you drive the car while looking at the BLM and O2 sensor voltage. Let's see how it drives under load, and what the data says.
Thread Starter
Advanced
Joined: Aug 2019
Posts: 75
Likes: 8
Looking at this snap shot indicates your O2 voltage has gone low, and the cross counts at 13 indicates the sensor is switching and is good.
Just to satisfy my curiosity why don't you drive the car while looking at the BLM and O2 sensor voltage. Let's see how it drives under load, and what the data says.
Just to satisfy my curiosity why don't you drive the car while looking at the BLM and O2 sensor voltage. Let's see how it drives under load, and what the data says.
I will drive it and report back.