Surging
Thread Starter
Heel & Toe
Joined: Dec 2010
Posts: 16
Likes: 0
Surging
Hello all,
1982 Corvette 62,000 miles
Was running fine but now won't run at all. When I start it, I get a backfire through the carburator, and wild surging until it stalls. It's like a bucking bronko to keep it running by attempting to compensate for the surging using the accellorator pedal. Then when it stalls there is a terrible stench of a fuel mixture way out of whack.
I've tried cleaning the IAC motors and replacing (adjusted to proper starting voltage) the TPS. I checked the injector fuses ... they were ok. When I removed the EGR to check it I found that it had been bypassed via a block gasket, so I removed it and installed a plate cover. Can't find a broken/disconnected vacuum line. Can't really check vacuum because engine won't run long enough. It is not throwing any Check Engine Codes. Wondering if I should spend the $150 on two new IACs.
Thanks in advance,
Cliff
1982 Corvette 62,000 miles
Was running fine but now won't run at all. When I start it, I get a backfire through the carburator, and wild surging until it stalls. It's like a bucking bronko to keep it running by attempting to compensate for the surging using the accellorator pedal. Then when it stalls there is a terrible stench of a fuel mixture way out of whack.
I've tried cleaning the IAC motors and replacing (adjusted to proper starting voltage) the TPS. I checked the injector fuses ... they were ok. When I removed the EGR to check it I found that it had been bypassed via a block gasket, so I removed it and installed a plate cover. Can't find a broken/disconnected vacuum line. Can't really check vacuum because engine won't run long enough. It is not throwing any Check Engine Codes. Wondering if I should spend the $150 on two new IACs.
Thanks in advance,
Cliff
Last edited by Clyfton; Dec 17, 2010 at 12:09 AM.
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
I don't think the problem is an IAC. Its most likely your fuel pump. maybe just the fuel filter but not likely. Don't mess with anything else. Did you set the TPS back to .525 again? The IAC's may no longer be functioning. they need the car running for a few miles at 35 mph to reset if you diconnected and removed them. You have three issures to deal with now.
Change the fuel pump first.
If it was a sensor you would be getting a code.
Jim
Change the fuel pump first.
If it was a sensor you would be getting a code.
Jim
Thread Starter
Heel & Toe
Joined: Dec 2010
Posts: 16
Likes: 0
Stingray1word ... I'm looking at my shop manual ... are you talking about the Fuel Pressure Regulator on the rear unit? I see there is also a Fuel Pressure Compensator on the front unit. I'm new to the Corvette world so it may be a stupid question.
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
Don't chase everything. I went down the same road. Same problem. It was the fuel pump. Only other remote possibility is the hose in the tank from the pump to the lid. It deteriorates. If its the hose an over full tank of gas will minimize the surging.
Jim
Jim
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
Jim
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Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
Le Mans Master
Joined: Jul 2000
Posts: 6,663
Likes: 162
From: columbia city in
i would look to see if the injectors are spraying fuel, if so are they spraying to much?if they are i would be looking at the coolant sensor at the front of the motor .that sensor talks to the computer not the gauge.http://www.crossfire.homeip.net/index.php?act=idx
Drifting
Joined: Jul 2009
Posts: 1,532
Likes: 14
From: Dallas-Fort Worth TX
Clyfton, I have a 82 fuel pump for sale if your interested. From the looks of it, it was replaced at one time, so I think its newer than the original 82. Never had a problem with it, just went to a mechanical and did not need it.
Thread Starter
Heel & Toe
Joined: Dec 2010
Posts: 16
Likes: 0
Terry82 ... when you say look at the sensor ... are you saying visually inspect it? replace it? or is there a way to test it? I tried clicking on the link in your post but that didn't seem to go anywhere related.
Le Mans Master
Joined: Jul 2000
Posts: 6,663
Likes: 162
From: columbia city in
if you are duming in a lot of fuel then the sensor is bad .yes you can check it when its cold an then check it when its hot .check with a ohm meter.that post goes to the cross-fire forum where you can get lots of help.
Thread Starter
Heel & Toe
Joined: Dec 2010
Posts: 16
Likes: 0
jdp6000 ... thanks a bundle ... you were right on
I replaced the fuel filter and fuel pump and she's purring like a mountain lion.
From the looks of things, they had never been replaced. So was well overdue.
I'm new to this forum. I know some forums allow for positive feedback points. I checked the forum rules and didn't see anything.
Thanks again,
Cliff
I replaced the fuel filter and fuel pump and she's purring like a mountain lion.
From the looks of things, they had never been replaced. So was well overdue.
I'm new to this forum. I know some forums allow for positive feedback points. I checked the forum rules and didn't see anything.
Thanks again,
Cliff
Melting Slicks
Joined: Jul 2005
Posts: 2,740
Likes: 3
From: Aurora Ontario
jdp6000 ... thanks a bundle ... you were right on
I replaced the fuel filter and fuel pump and she's purring like a mountain lion.
From the looks of things, they had never been replaced. So was well overdue.
I'm new to this forum. I know some forums allow for positive feedback points. I checked the forum rules and didn't see anything.
Thanks again,
Cliff
I replaced the fuel filter and fuel pump and she's purring like a mountain lion.
From the looks of things, they had never been replaced. So was well overdue.
I'm new to this forum. I know some forums allow for positive feedback points. I checked the forum rules and didn't see anything.
Thanks again,
Cliff
Jim
Thread Starter
Heel & Toe
Joined: Dec 2010
Posts: 16
Likes: 0
Looks like I'm not out of the woods yet.
I went to start it this morning and apparently, whatever controls the cold idle is busted.
I had to manually give it some gas and warm it up before it would run.
It used to maintain a fast idle until it got warmed up. I can't believe so much can break at one time. How do I fix that? Does crossfire have a choke?
Thanks in advance,
Cliff
I went to start it this morning and apparently, whatever controls the cold idle is busted.
I had to manually give it some gas and warm it up before it would run.
It used to maintain a fast idle until it got warmed up. I can't believe so much can break at one time. How do I fix that? Does crossfire have a choke?
Thanks in advance,
Cliff
Thread Starter
Heel & Toe
Joined: Dec 2010
Posts: 16
Likes: 0
Injector spray is conical with the cone the same size as the port. The spray clicks on and off rapidly with a slight dribble down the center. I made a 9MB Quicktime movie of it here http://cid-4054561e39209849.skydrive...1E39209849!159
You'll need Apple QuickTime available here http://www.apple.com/quicktime/download/ . If you have an iPhone or iTouch then you already have it.
You'll need Apple QuickTime available here http://www.apple.com/quicktime/download/ . If you have an iPhone or iTouch then you already have it.
Le Mans Master
Joined: Jul 2000
Posts: 6,663
Likes: 162
From: columbia city in
okay now you have a good spray.does this problem only happen when cold then goes away after warm up?have you pulled a plug to see how its burning ?did you check the iac?you may have one that is not seating well .did you sign up for the cross-fire forum.there is a lot of info there on how and what to check a cross-fire.