And thanks for sharing.
94 Cold Start Misfire Fixed.
Thread Starter
Drifting
Joined: Nov 2013
Posts: 1,572
Likes: 486
From: Loud, Raw and Dangerous 1968 327 4S in Southern California
94 Cold Start Misfire Fixed.
94 LT1 auto with 63K miles. Had a misfire when cold with no codes. Starts perfect and idled ok but until engine warmed up to over 140 degrees on water temp gage, would cut out when given gas and would not accelerate. Made a flub flub flub with some backfire sound. Once warm ran like a champ.
Dealer wanted $2,400 to replace Optispark and water pump but would not commit that this would fix the problem. Not being made of money decided to try to replace a few sensors first. First one I bought was a new MAF sensor for $54.95 off of EBAY (AM Autoparts - P/N 1AEAF00059). Easy install...first time out the car did the same but from the second time out problem was gone. Perhaps some information was stored in the computer still. After several months still running great.
Dealer wanted $2,400 to replace Optispark and water pump but would not commit that this would fix the problem. Not being made of money decided to try to replace a few sensors first. First one I bought was a new MAF sensor for $54.95 off of EBAY (AM Autoparts - P/N 1AEAF00059). Easy install...first time out the car did the same but from the second time out problem was gone. Perhaps some information was stored in the computer still. After several months still running great.
Last edited by Redvette2; Mar 11, 2015 at 09:39 PM.
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
I hunted the same issue on a 94 once. Exact same issue at the same conditions. Never did find anything exacting in all my testing. I could tell you what was NOT wrong with the car. MAF readings where all spot on by the book as was everything else.
Your guess might have just hit the nail on the head. I'll keep this in mind when I see the guy who owned it. It didn't bother him much and after extensive troubleshooting and finding nothing concrete I was not going to waste his money guessing.
I might try a hertz test or a test with a oscilloscope next I see the car. I've done that in the past to find bad MAF's that otherwise where fine. I even cleaned his MAF to. Son of gun for $60 its work a shot to replace it.
Thanks for the post.
Your guess might have just hit the nail on the head. I'll keep this in mind when I see the guy who owned it. It didn't bother him much and after extensive troubleshooting and finding nothing concrete I was not going to waste his money guessing.
I might try a hertz test or a test with a oscilloscope next I see the car. I've done that in the past to find bad MAF's that otherwise where fine. I even cleaned his MAF to. Son of gun for $60 its work a shot to replace it.
Thanks for the post.
Thread Starter
Drifting
Joined: Nov 2013
Posts: 1,572
Likes: 486
From: Loud, Raw and Dangerous 1968 327 4S in Southern California
Rain reply....
Could not tell if it was worse in the rain...the car always started fine. It rains so infrequently here and when it does I get a pond culture growing in the car so I tend to avoid it. This is my next issue to resolve. Changing the weather strip did not help...perhaps an adjustment on the window glass.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 207
From: Orlando FL
Sound like the fix is good. I have heard of a wide variety symptoms related to the MAF. Not like testing other components and having a high confidence factor for the test.
Seems like it is difficult to get a good test or check to verify that it is good or bad. Possibly using a scope might be the only way technically to get a handle on it (as said).
Seems like it is difficult to get a good test or check to verify that it is good or bad. Possibly using a scope might be the only way technically to get a handle on it (as said).
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Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 207
From: Orlando FL
Currently I don't not have a scope either at this time. I have been using scopes all my & life been in electronics since I was 10. Always had use of a scope from work but retired now so I'm on my own. Been looking around for the right scope, not too big or heavy at about 100 MHz which should take care of all my basic needs.
Le Mans Master
Joined: Jan 2006
Posts: 6,564
Likes: 6
From: Woodstock Georgia
Check for the coil to opti wire shorting out. Run the engine in a dark area and look for sparks.