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Possible cause -The check valve(s) on the AIR system fails, and exhaust gasses enter the pump, it corrodes and seizes up. That causes it to draw excessive amps, and (usually) blows the fuse. Don’t know that I've ever seen one melt. Is it a 20 amp fuse?
What year is your car (always good to include that info) - there was a recall of 95-97 LT1 models for this problem. For some reason 93 and 94 weren’t included. But I've seen the 94’s with the same pump problem.
Temporary “fix” - disconnect the AIR pump harness connector, then place a new fuse in that spot. That prevents DTC 29 from setting in the OBD-1 cars. OBD-2 is different. Long range - you may need a new AIR pump. The AIR pump only runs for 2 or 3 minutes on startup, to help the cat(s) heat up faster and reduce emissions. After the timer times out, the pump shuts off and has no effect on the way the engine runs.
Possible cause -The check valve(s) on the AIR system fails, and exhaust gasses enter the pump, it corrodes and seizes up. That causes it to draw excessive amps, and (usually) blows the fuse. Don’t know that I've ever seen one melt. Is it a 20 amp fuse?
It looks like the fuse says it is a 25 amp and if that is correct, that may have play a factor why the fuse started melting. Pretty sure the fuse size should have been a 20 amp. People don't seem to understand that a fuse is more than just a direct short to ground protection, it also protects the wire from carrying an amperage higher than it is rated for. The longer a wire is exposed to a current flow higher then it's rated for, the more chances it could turn the wire into a toaster element causing this kind of damage. I would definitely check the rest of the circuit to make sure it wasn't damaged too.
It looks like the fuse says it is a 25 amp and if that is correct, that may have play a factor why the fuse started melting. Pretty sure the fuse size should have been a 20 amp. People don't seem to understand that a fuse is more than just a direct short to ground protection, it also protects the wire from carrying an amperage higher than it is rated for. The longer a wire is exposed to a current flow higher then it's rated for, the more chances it could turn the wire into a toaster element causing this kind of damage. I would definitely check the rest of the circuit to make sure it wasn't damaged too.
I bought this car not that long ago and am starting to see the jank stuff they did to this car. will the whole fuse box need replacing since that fuse melted? And by check the rest of the circuit can you elaborate? Sorry I’m Kinda new to a lot of this stuff.
Possible cause -The check valve(s) on the AIR system fails, and exhaust gasses enter the pump, it corrodes and seizes up. That causes it to draw excessive amps, and (usually) blows the fuse. Don’t know that I've ever seen one melt. Is it a 20 amp fuse?
What year is your car (always good to include that info) - there was a recall of 95-97 LT1 models for this problem. For some reason 93 and 94 weren’t included. But I've seen the 94’s with the same pump problem.
Temporary “fix” - disconnect the AIR pump harness connector, then place a new fuse in that spot. That prevents DTC 29 from setting in the OBD-1 cars. OBD-2 is different. Long range - you may need a new AIR pump. The AIR pump only runs for 2 or 3 minutes on startup, to help the cat(s) heat up faster and reduce emissions. After the timer times out, the pump shuts off and has no effect on the way the engine runs.
The car is a 93 z28 and I bought it not that long ago and the cats are deleted other than that it’s basically stock. Was told it has a 93 gas tune but no proof was given. Do I need a tune to delete the air/egr systems? I really want to delete it to get headers but don’t want to get a tune since I’ve heard it’s hard to find someone to tune the 93s.
If the cat (93 LT1 only had one) was deleted, the AIR system serves no useful purpose and can be deleted.
I can recommend a 93 tuner. 93 model year is significantly different than all other years of the LT1. That's why you need to include a “signature” when you ask for help.. What works on a 93 can be completely different than what works on a 94-97. The 93 has a different ECM (only controls the engine), as opposed to later year PCM (controls engine and transmission). 93 ECM tune requires a new chip to be burned and replaced. Later years use flash programming. You tell the programmer why you need done, he burns a chip and mails it to you, you replace the existing chip in your ECM.
Is you SES light on? It should be, and you should have code DTC 26 for the quad driver module that controls AIR, EGR, and EVAP systems. On a 93 you can pull the codes with a paper clip. All other years require a scanner. If the SES light isn’t on, the previous owner may have removed the bulb or cut the wire.
As stated in earlier post, if you disconnect the AIR pump harness connector and put a new fuse in (assuming the fuse block isn’t damaged - pull the fuse out and do a continuity check on the slots the fuse blades push into). That eliminates the SES light and code. Deleting EGR is a bit more difficult. There is an electric solenoid, and you can delete that and insert a resistor in the harness connector to avoid an SES/code. But the ECM also runs a test (DTC 32) to see if exhaust gas enters the intake manifold when it opens the EGR valve. The diagnostic doesn’t always pick up the missing EGR, so you could deactivate the EGR system (cap the vacuum Connection on the intake manifold) and see if you get the SES light while driving.
Or, you could have both AIR and EGR deleted in the new tune/chip. As noted, you don’t need AIR. But EGR is actually useful, in preventing spark knock (detonation) when lugging the engine at low RPM. And EGR does not affect performance because it isn’t used at idle, isn’t used above 3,500 RPM, and isn’t used at wide open throttle.
will the whole fuse box need replacing since that fuse melted? And by check the rest of the circuit can you elaborate?
That's hard to say since the picture only shows the top of the block and with the fuse still in place, you can't tell how much damage was done to the fuse block. Checking the rest of the circuit would mean inspecting the wire from the fuse block out to the air pump for damage like melted insulation or bare wire spots that could ground out.
I've attached schematics from the 1993 Firebird Service Manual that should be the same as the Camaro. They may help illustrate what all is involved in the air pump circuit wiring.
If the cat (93 LT1 only had one) was deleted, the AIR system serves no useful purpose and can be deleted.
I can recommend a 93 tuner. 93 model year is significantly different than all other years of the LT1. That's why you need to include a “signature” when you ask for help.. What works on a 93 can be completely different than what works on a 94-97. The 93 has a different ECM (only controls the engine), as opposed to later year PCM (controls engine and transmission). 93 ECM tune requires a new chip to be burned and replaced. Later years use flash programming. You tell the programmer why you need done, he burns a chip and mails it to you, you replace the existing chip in your ECM.
Is you SES light on? It should be, and you should have code DTC 26 for the quad driver module that controls AIR, EGR, and EVAP systems. On a 93 you can pull the codes with a paper clip. All other years require a scanner. If the SES light isn’t on, the previous owner may have removed the bulb or cut the wire.
As stated in earlier post, if you disconnect the AIR pump harness connector and put a new fuse in (assuming the fuse block isn’t damaged - pull the fuse out and do a continuity check on the slots the fuse blades push into). That eliminates the SES light and code. Deleting EGR is a bit more difficult. There is an electric solenoid, and you can delete that and insert a resistor in the harness connector to avoid an SES/code. But the ECM also runs a test (DTC 32) to see if exhaust gas enters the intake manifold when it opens the EGR valve. The diagnostic doesn’t always pick up the missing EGR, so you could deactivate the EGR system (cap the vacuum Connection on the intake manifold) and see if you get the SES light while driving.
Or, you could have both AIR and EGR deleted in the new tune/chip. As noted, you don’t need AIR. But EGR is actually useful, in preventing spark knock (detonation) when lugging the engine at low RPM. And EGR does not affect performance because it isn’t used at idle, isn’t used above 3,500 RPM, and isn’t used at wide open throttle.
Thanks for the tip about the signature I’ll have it done for the future posts. It would be amazing if you could let me know of a tuner. Also my ses light isn’t on but the light comes on after driving at highway speeds for a little bit and kind of hesitates a little bit idk if this has anything to do with the air. This didn’t start till a little while ago. I’ll probably be doing the temp fix until I get the chance to delete it.
FWIW, my '94 Trans Am LT1 (now stolen) had a bad air pump, and the TA would not pass emissions as a result.
I got a new air pump for free, due to a factory recall. You can check for uncompleted factory recalls on your car at:
Do you remember the # of the recall? The only one I am aware of is #99083, which only covered 1995-1997. Was there an amendment?
Campaign - Air Injection Reactor Pump Replacement Product Emission - Air Injection Reactor (A.I.R.) Pump System Failures # 99083
99083 -- Air Injection Reactor (A.I.R.) Pump System Failures
1995, 1996, 1997 Chevrolet Camaro and Pontiac Firebird Model Vehicles
Equipped with 5.7L Engine (RPO LT1-VIN Code P)
Condition
General Motors has decided to conduct a Voluntary Emission Campaign involving all 1995, 1996 and 1997 Chevrolet Camaro and Pontiac Firebird model vehicles equipped with 5.7L (RPO LT1-VIN Code P) engines. The Air Injection Reactor (A.I.R.) pump emission control system on these vehicles may fail to operate and cause the Malfunction Indicator Lamp (MIL) to illuminate. This condition may be due to corrosion of a solenoid internal to the A.I.R. pump.
Correction
Dealers are to install a new A.I.R. pump assembly kit that is designed to protect the A.I.R. pump system from failing due to internal corrosion.
On the other hand, since this vehicle has no cat, emissions would not seem to be an issue.
PS: Just put my 94's VIN in, and got "error - GM has no record of your VIN".
Do you remember the # of the recall? The only one I am aware of is #99083, which only covered 1995-1997. Was there an amendment? PS: Just put my 94's VIN in, and got "error - GM has no record of your VIN".
Injuneer,
Sorry, but for me, all of the LT1 paperwork became moot when the TA was stolen. Now I have a Z28, no problems.
As for the VIN snafu, that .gov website has never failed me. I can only suggest asking a GM dealer directly, for any recalls.
.
I don't really care about recalls.... my car is so far from stock they aren’t important. I was just curious to find out if there was a recall in addition to #99083, so I could be sure I am providing accurate advice.
I had posted about the 93 z28 with the melted air pump fuse and I took it out and it looks pretty f***ed. What should I do about this? Would I be able to somehow re wire that to one of the blank spots above
Last edited by Logan Jones; 07-21-2019 at 07:48 AM.
07-19-2019, 08:06 PM
