1995 ZR-1 Check Engine Light
10-23-2016, 02:04 PM
#1
Instructor
Thread Starter
1995 ZR-1 Check Engine Light
Has 23,500mi. Installed Haibeck chip several months ago & has run great since, more power & cooler. All original except chip. Just put in new ACD battery & tested twice, all OK.
Went on cold start & heard a pop, engine light came on. Had to go out, but car ran smooth & strong, no odd sounds, no smoke, plenty of gas. Except for light, would never know something happened. Tried to reset by disconnecting battery, but light still came on. The only thing I can possibly say MAY have changed is that idle won't come down under 1,000-1,100. Maybe related?
I have a CAN OBD II for my '96, but I believe that will not work on the '95, altho the plug will fit. Can anyone recommend an inexpensive reader for OBD I? I wanted to see if I could get a code first, but any thoughts appreciated.
Thx
Went on cold start & heard a pop, engine light came on. Had to go out, but car ran smooth & strong, no odd sounds, no smoke, plenty of gas. Except for light, would never know something happened. Tried to reset by disconnecting battery, but light still came on. The only thing I can possibly say MAY have changed is that idle won't come down under 1,000-1,100. Maybe related?
I have a CAN OBD II for my '96, but I believe that will not work on the '95, altho the plug will fit. Can anyone recommend an inexpensive reader for OBD I? I wanted to see if I could get a code first, but any thoughts appreciated.
Thx
10-23-2016, 02:21 PM
#2
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When the LT5 pops it is a backfire, Map sensor vac line most likely came off, Map sensor is under the silver cover at the rear of the plenum.
https://www.corvetteforum.com/forums...-backfire.html
https://www.corvetteforum.com/forums...-backfire.html
Last edited by FASTAZU; 10-23-2016 at 02:26 PM.
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Silverfox1 (10-23-2016)
10-23-2016, 04:18 PM
#3
Melting Slicks
When the LT5 pops it is a backfire, Map sensor vac line most likely came off, Map sensor is under the silver cover at the rear of the plenum.
https://www.corvetteforum.com/forums...-backfire.html
https://www.corvetteforum.com/forums...-backfire.html
Marty
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Silverfox1 (10-25-2016)
The following users liked this post:
Silverfox1 (10-25-2016)
10-23-2016, 08:14 PM
#5
Instructor
Thread Starter
When the LT5 pops it is a backfire, Map sensor vac line most likely came off, Map sensor is under the silver cover at the rear of the plenum.
https://www.corvetteforum.com/forums...-backfire.html
https://www.corvetteforum.com/forums...-backfire.html
You are THE MAN. Absolutely correct & solved the high idle issue as well.
Was an easy fix. Question: the vac line is actually pretty short, but it starts out at the sensor as "wide" line which is connected to about 2" of narrower line (where it separated) & then back to the "wide" line (1") to the nipple. Why not just have 1 solid line of the same size, why bother with the narrow interim? Is that how it's supposed to be?
Thanks again!
10-24-2016, 09:39 AM
#6
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Yes that is how they are. As they get old they tend to get lose from oil, may be time for a new line.
One of the few and best parts suppliers.
http://www.jerrysgaskets.com/hose-ma...ew-90-95-13d4/
One of the few and best parts suppliers.
http://www.jerrysgaskets.com/hose-ma...ew-90-95-13d4/
10-24-2016, 09:20 PM
#7
Burning Brakes
You are THE MAN. Absolutely correct & solved the high idle issue as well.
Was an easy fix. Question: the vac line is actually pretty short, but it starts out at the sensor as "wide" line which is connected to about 2" of narrower line (where it separated) & then back to the "wide" line (1") to the nipple. Why not just have 1 solid line of the same size, why bother with the narrow interim? Is that how it's supposed to be?
Thanks again!
Was an easy fix. Question: the vac line is actually pretty short, but it starts out at the sensor as "wide" line which is connected to about 2" of narrower line (where it separated) & then back to the "wide" line (1") to the nipple. Why not just have 1 solid line of the same size, why bother with the narrow interim? Is that how it's supposed to be?
Thanks again!
10-25-2016, 12:43 AM
#8
Instructor
Thread Starter
Yes that is how they are. As they get old they tend to get lose from oil, may be time for a new line.
One of the few and best parts suppliers.
http://www.jerrysgaskets.com/hose-ma...ew-90-95-13d4/
One of the few and best parts suppliers.
http://www.jerrysgaskets.com/hose-ma...ew-90-95-13d4/
Good idea. I'm gonna flight test early next year & that would not be the time for a repeat. Cheap insurance. i actually got the black oil filter from Jerry's . Glad they're around.
Thx again !
10-25-2016, 12:45 AM
#9
Instructor
Thread Starter
Reason it's wide, narrow, back to wide is that wide portions are rubber vacuum line to connect to hard plastic line between the nipples. I replaced the OEM MAP sensor line with rubber vacuum hose once. It worked fine until oil and gas fume plus heat soften the rubber line to a point where it would collapse during high engine vacuum, cut off vacuum to the MAP sensor, resulting in false signal from MAP sensor to ECM making the motor cut off during deceleration. If and when you replace MAP sensor hose replace with OEM hose.
Ok, that makes sense. Thanks for the explanation.