Crossfire Idle Mystery Solved
Thread Starter
Melting Slicks
Joined: Nov 1999
Posts: 2,461
Likes: 354
From: Madison Alabama
Crossfire Idle Mystery Solved
Like the title says – the mystery is solved! I’m posting this for any other cross-fire owner that is experiencing similar problems. Here is a link to the previous Crossfire Help thread where I’ve chased this as a fuel delivery problem, then an ignition problem after having exhausted searching for a vacuum leak through chasing hoses and tightening bolts on the intake and TBIs.
Turns out it was a vacuum leak at the gasket for the top lid on the intake. I discovered it while poking around earlier today. After all my hard work she was giving me signs/clues to look in the right place. I noticed she had sprung a small leak at the heater hose connection just under the distributor – some coolant had pooled in the low spot there. I had her running to see if I could tell where the leak was coming from and put my hand way down by the EGR valve to move the heater hose when I heard a clear “whistle” sound by the intake. Sure enough, that’s my vacuum leak and the reason for my rough idle.
I put some gasket sealer on it and let it set up for a few hours then took her for a cruise. She idles like new! You can see the area I’m talking about in the picture above – the blue sealant is where the leak is, a little over an inch long. I guess I overlooked this spot when searching for vacuum leaks because of the EGR valve. Also the way the top lid lips over the bottom you have to come at it at a weird angle to get it to whistle.
The good news, all of my hard work replaced 24-year old sensors and cleaned up the other parts.
My list includes: remove/clean both IAC valves, cleaned the air passages on the TBIs while they were out. Remove/clean the EGR valve and cleaned the intake air passage for that while it was out as well. New plug wires, plugs, rotor, CTS sensor, 02 sensor, fuel filter, MAP sensor and vacuum line. Verify timing (set +2 degrees at 8) and TPS volts. I also rebuilt the back TB unit (gasket kit) and disassembled the Fuel Pressure Regulator to clean it…all that and the problem was a gasket on the top plate…oh well, I’ll pull that off and replace the gasket and she should be good for another 24 years!
Turns out it was a vacuum leak at the gasket for the top lid on the intake. I discovered it while poking around earlier today. After all my hard work she was giving me signs/clues to look in the right place. I noticed she had sprung a small leak at the heater hose connection just under the distributor – some coolant had pooled in the low spot there. I had her running to see if I could tell where the leak was coming from and put my hand way down by the EGR valve to move the heater hose when I heard a clear “whistle” sound by the intake. Sure enough, that’s my vacuum leak and the reason for my rough idle.
I put some gasket sealer on it and let it set up for a few hours then took her for a cruise. She idles like new! You can see the area I’m talking about in the picture above – the blue sealant is where the leak is, a little over an inch long. I guess I overlooked this spot when searching for vacuum leaks because of the EGR valve. Also the way the top lid lips over the bottom you have to come at it at a weird angle to get it to whistle.
The good news, all of my hard work replaced 24-year old sensors and cleaned up the other parts.
My list includes: remove/clean both IAC valves, cleaned the air passages on the TBIs while they were out. Remove/clean the EGR valve and cleaned the intake air passage for that while it was out as well. New plug wires, plugs, rotor, CTS sensor, 02 sensor, fuel filter, MAP sensor and vacuum line. Verify timing (set +2 degrees at 8) and TPS volts. I also rebuilt the back TB unit (gasket kit) and disassembled the Fuel Pressure Regulator to clean it…all that and the problem was a gasket on the top plate…oh well, I’ll pull that off and replace the gasket and she should be good for another 24 years!
Thread Starter
Melting Slicks
Joined: Nov 1999
Posts: 2,461
Likes: 354
From: Madison Alabama
Quick update on this for the archives - here is what I found once the top plate was pulled off. The gasket had let go in two places. The blue sealant is from my quick fix to determine if this was the problem.
She's back on the road as of yesterday. Finally stopped detailing parts I'd removed and focused on getting her back together. Didn't take long at all thanks to a detailed, step-by-step list and digital photos.
No problems, she runs great, idles like a smooth-running Caddy and I fixed the coolant leak that pointed me in the direction of the vacuum leak. The love/hate relationship with my cross-fire continues…right now I’m loving it!
Thanks for all the help.
2TONE82
Z06/Z16 #165
She's back on the road as of yesterday. Finally stopped detailing parts I'd removed and focused on getting her back together. Didn't take long at all thanks to a detailed, step-by-step list and digital photos.
No problems, she runs great, idles like a smooth-running Caddy and I fixed the coolant leak that pointed me in the direction of the vacuum leak. The love/hate relationship with my cross-fire continues…right now I’m loving it!
Thanks for all the help.
2TONE82
Z06/Z16 #165
