Idle questions.
07-05-10, 06:47 PM
#1
Idle questions.
Background on the car....
91 Coupe pulled out of the weeds and used a 90 Turbo II donor for complete drivetrain (sans motor) and interior. Motor is a S5 Jspec with complete new gaskets (external), coolant, oil, plugs, wires. Motor came with upgraded top mount intercooler (no info on it other than its a koyo and bigger than stock) I added a 3 inch downpipe (no exhaust yet), FCD, and HKS blowoff valve. Removed and blocked off ACV, BAC, and the tube that ran to the converter. I did not remove anything from the throttle body, but I did not run the coolant lines to the throttle body, instead just ran a hose from the front iron to the rear iron.
Problem....
When the engine first starts, it revs to 5000 rpm and stays there for about 15 seconds, then kicks down and slowly pulsates between 1000 and 2000 rpm. Revs fine when pressing the accelerator, but always goes back toslowly pulsating when it trys to idle.
91 Coupe pulled out of the weeds and used a 90 Turbo II donor for complete drivetrain (sans motor) and interior. Motor is a S5 Jspec with complete new gaskets (external), coolant, oil, plugs, wires. Motor came with upgraded top mount intercooler (no info on it other than its a koyo and bigger than stock) I added a 3 inch downpipe (no exhaust yet), FCD, and HKS blowoff valve. Removed and blocked off ACV, BAC, and the tube that ran to the converter. I did not remove anything from the throttle body, but I did not run the coolant lines to the throttle body, instead just ran a hose from the front iron to the rear iron.
Problem....
When the engine first starts, it revs to 5000 rpm and stays there for about 15 seconds, then kicks down and slowly pulsates between 1000 and 2000 rpm. Revs fine when pressing the accelerator, but always goes back toslowly pulsating when it trys to idle.
07-06-10, 06:36 PM
#2
Well, I fixed my own problem!
I took off the UIM and made sure all the vacuum hoses were still on. They were, so I decided to take off the hose that was on the backside of the UIM that ran from one nipple to the other nipple across from it (this was on there when I received the motor) and put a cap on each nipple instead. The hose was pretty hard, so this could of possibly been leaking.
Next, I noticed that when I originally bolted on the UIM, I smashed one of the injector plugs, so I cut that off and put on a new plug. Not sure if that was part of the problem.
Reinstalled the UIM and while I was bolting on the intercooler (as I said before is an upgraded top mount) and happened to look at one of the bolt holes that mount it, and damn if it doesn't go all the way into the intercooler. this is probably where the leak was. So I put a good amount of black sealant on the bolt before installing it.
Fired it back up and all is good! Perfect idle!
I took off the UIM and made sure all the vacuum hoses were still on. They were, so I decided to take off the hose that was on the backside of the UIM that ran from one nipple to the other nipple across from it (this was on there when I received the motor) and put a cap on each nipple instead. The hose was pretty hard, so this could of possibly been leaking.
Next, I noticed that when I originally bolted on the UIM, I smashed one of the injector plugs, so I cut that off and put on a new plug. Not sure if that was part of the problem.
Reinstalled the UIM and while I was bolting on the intercooler (as I said before is an upgraded top mount) and happened to look at one of the bolt holes that mount it, and damn if it doesn't go all the way into the intercooler. this is probably where the leak was. So I put a good amount of black sealant on the bolt before installing it.
Fired it back up and all is good! Perfect idle!
07-07-10, 11:43 PM
#3
Hey wild bill I would change that Intercooler or weld it before you go to far, because when you hit boost, your most likely going to blow that sealant out like a popcorn fart .
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