failed emissions, L98
Thread Starter
Melting Slicks
Joined: Apr 2004
Posts: 2,778
Likes: 138
From: cyberspace NY
failed emissions, L98
My 1989 L98 pretty much sits for months at a time. It's all stock, excpet the 180 degree thermostat. when I started it, it wouldn't idle, I had to feather the gas. I finally got it to idle by blasting it down the highway. Ran fresh gas. Now it'll idle, but is idling very rough. It drives fine, and pulls all the way to red-line, but still idles rough.
Went for emissions testing, and
CO was 18.00, limit is 15.00 !!
HC and NOx are within range
75,000 miles, original o2 sensor. tuneup was done years ago, but the car is mostly in storage.
where should I start looking ??
I don't want to destroy cats, by dumping raw fuel in there. so I stopped driving it...
Went for emissions testing, and
CO was 18.00, limit is 15.00 !!
HC and NOx are within range
75,000 miles, original o2 sensor. tuneup was done years ago, but the car is mostly in storage.
where should I start looking ??
I don't want to destroy cats, by dumping raw fuel in there. so I stopped driving it...
Drifting
Joined: Feb 2003
Posts: 1,614
Likes: 163
From: Davis CA
Too many possibilities, right? It sounds like you have too much fuel being delivered or lack of spark to burn it. I don't think that you need to be so concerned about the high reading that you stop driving.
You might first try a good injector cleaner (I've heard that BG 44K is good), new plugs, wires and cap -- especially if its been several years.
However, you might find that it is OK after a few tanks of gas and some regular use. It sounds to me like you had some bad gas and that might have given your injectors a problem.
You might first try a good injector cleaner (I've heard that BG 44K is good), new plugs, wires and cap -- especially if its been several years.
However, you might find that it is OK after a few tanks of gas and some regular use. It sounds to me like you had some bad gas and that might have given your injectors a problem.
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
the blur: You have a suggestion above to use injector cleaner. Please read this service bulletin from GM:
Corvette years 89 - 91 have the Multec injectors and they have a history of early failure. I used Chevron Textron injector cleaner in my 89 just before my injectors began to give me problems. FYI.
Corvette years 89 - 91 have the Multec injectors and they have a history of early failure. I used Chevron Textron injector cleaner in my 89 just before my injectors began to give me problems. FYI.
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
The injectors with "low" resistance readings have shorted coils (injector coil turn to turn shorts). These injectors will not provide the correct amount of fuel to their respective cylinders. How low are your resistance readings? The spec is 16.5 +/-.3 ohms for each injector coil.
Please note the lower the resistance readings, the higher current draw for that injector. If you have low, single digit resistance readings, the high current draw can damage the injector drivers in the ECM.
The stock injectors have a flow rating of 22 lb/hr.
Please note that the L98 engine has one O2 sensor and this is located on the drivers side exhaust pipe. Data from this sensor is used to control the amount of fuel being placed in both the driver and passenger side cylinders. If you have bad injectors on the passenger side, the O2 sensor "assumes" they are good. The location of the injectors may be a factor in your problem.
Please note the lower the resistance readings, the higher current draw for that injector. If you have low, single digit resistance readings, the high current draw can damage the injector drivers in the ECM.
The stock injectors have a flow rating of 22 lb/hr.
Please note that the L98 engine has one O2 sensor and this is located on the drivers side exhaust pipe. Data from this sensor is used to control the amount of fuel being placed in both the driver and passenger side cylinders. If you have bad injectors on the passenger side, the O2 sensor "assumes" they are good. The location of the injectors may be a factor in your problem.
Last edited by Sam Lam; May 4, 2007 at 09:38 AM.
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
The injector reading 5 ohms is a problem! I do not know if replacing this injector would solve your CO failure. Suggest you get someone to scan your ECM to see what is going on with your sensors and control system. This should allow you to solve the CO emission failure.
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Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Good idea, that one injector is causing you problems, while you're at it replace that 02 sensor. Change the oil and filter along with the air filter...my bet is you'll pass with flying colors after that.And make sure the car is really warmed up before the test.
