90 Coupe, weird issue with the O2 sensor
Thread Starter
Burning Brakes
Joined: Mar 2010
Posts: 943
Likes: 15
From: Valdosta Georgia
90 Coupe, weird issue with the O2 sensor
Okay, a friend just bought a 90 Coupe, and she is having a weird issue
The car surges at cruise, so they replaced the plugs and wires, and that helped some, but didn't eliminate the issue.
Here's the weird part. If they disconnect the O2, the car runs great, hook up the O2, and the surge returns. I have an 82, so I'm not much help with TPI motors. Any thoughts or suggestions?
The car surges at cruise, so they replaced the plugs and wires, and that helped some, but didn't eliminate the issue.
Here's the weird part. If they disconnect the O2, the car runs great, hook up the O2, and the surge returns. I have an 82, so I'm not much help with TPI motors. Any thoughts or suggestions?
Last edited by Drawmain; May 5, 2011 at 09:07 PM. Reason: spelling
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
When you d/c the o2 wire you send the ECM into open loop . Not good for the best performance and it will set codes.
If its running bad, list the codes and go from there. These are totally sensor operated and do the tuning themselves...all you have to do is give it good parts and the ECM adjust fuel/air/timing constantly when things are set within spec. D/C any sensor, especially the o2 will not allow it to function and it goes to its emergency or cold run programming. Rich and dirty.
If its running bad, list the codes and go from there. These are totally sensor operated and do the tuning themselves...all you have to do is give it good parts and the ECM adjust fuel/air/timing constantly when things are set within spec. D/C any sensor, especially the o2 will not allow it to function and it goes to its emergency or cold run programming. Rich and dirty.
Melting Slicks
Joined: Sep 2008
Posts: 2,376
Likes: 111
From: Cherokee National Forest TN
Okay, a friend just bought a 90 Coupe, and she is having a weird issue
The car surges at cruise, so they replaced the plugs and wires, and that helped some, but didn't eliminate the issue.
Here's the weird part. If they disconnect the O2, the car runs great, hook up the O2, and the surge returns. I have an 82, so I'm not much help with TPI motors. Any thoughts or suggestions?
The car surges at cruise, so they replaced the plugs and wires, and that helped some, but didn't eliminate the issue.
Here's the weird part. If they disconnect the O2, the car runs great, hook up the O2, and the surge returns. I have an 82, so I'm not much help with TPI motors. Any thoughts or suggestions?
In addition a change to the exhaust system also created an 02 code. This was remedied by installing a 3 wire heated 02 sensor.
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
Get a scan tool or good data logging software if you are going to do your own work it is as basic as a timing light or screwdriver. Get the correct year factory service manual and a good digital volt ohm amp meter while you are at it. Working on cars and trucks newer than 1980 becomes guesswork and voodo without them and you will waste 90% of your time wondering what might be wrong changing parts as the next guess wha might be wrong rather than fixing the car.
Your current problem is emissions system related O2 sensor air pump egr exhaust system air pump hoses pipeing or wiring toy rhese systems related. When you disconnect the O2 sensor you are disableing most of the emissions equiptment. The problem with just reading codes is you can have incorrect operation but nothing completely failed or out of range to the point it has to be broken. What you need to be looking at id O2 voltage cross counts and integrator values. Used scan tools can be had for cheap money all over the place from various online auction and for sale web sites. I paid $90 for my Auto Xray a couple of years ago alone with $50 for a set of code reading plugs and a great manual that shows how to get almost every bit of information from every computer system on my 91.
Dave
Your current problem is emissions system related O2 sensor air pump egr exhaust system air pump hoses pipeing or wiring toy rhese systems related. When you disconnect the O2 sensor you are disableing most of the emissions equiptment. The problem with just reading codes is you can have incorrect operation but nothing completely failed or out of range to the point it has to be broken. What you need to be looking at id O2 voltage cross counts and integrator values. Used scan tools can be had for cheap money all over the place from various online auction and for sale web sites. I paid $90 for my Auto Xray a couple of years ago alone with $50 for a set of code reading plugs and a great manual that shows how to get almost every bit of information from every computer system on my 91.
Dave
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
Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
1. Send the injectors out every 3 years. I would do this when you are putting the car away so you have can leave it sit. Jon will have them tested and cleaned so you know they are good.
2. Post pics of the female friend if she is hot.
