High idle (Page 4/6) Scuba_steve45 SEP 20, 09:06 AM I did a vacuum leak test and came up with nothing. It just kept coming out the top of the throttle body even when I blocked it off. I did have a code 22 but I replaced the tps sensor and connector and it went away. quote Originally posted by 82-T/A [At Work]: Can you try to pull the codes and see what you're getting? I'm still thinking you have a vacuum leak... but I'd like to see what the codes say. Scuba_steve45 SEP 20, 02:37 PM Also I should add that the idle doesn’t hunt or anything it just stays around one rpm until the next time I start it usually. quote Originally posted by 82-T/A [At Work]: Can you try to pull the codes and see what you're getting? I'm still thinking you have a vacuum leak... but I'd like to see what the codes say. Yellow-88 SEP 20, 03:03 PM quote Originally posted by Scuba_steve45: I did a vacuum leak test and came up with nothing. It just kept coming out the top of the throttle body even when I blocked it off. I did have a code 22 but I replaced the tps sensor and connector and it went away. This was a smoke test? And smoke came out of the throttle body only. It should not be able to pass the throttle plate. Some one can add here. Does the IAC close fully when the ignition is off? If it does no smoke should exit any were. I like the hiss tube in this case, at this point because one can probe the throttle plate to "see" a tiny leak there. A worn throttle shaft can be another source of a leak. Scuba_steve45 SEP 20, 03:15 PM Yes I did a smoke test I apologize for calling it a vacuum test lol. I assumed it was supposed to because fuel sprays onto the “closed” throttle plate on idle so there has to be a way for it to reach the intake and such. I could be completely wrong lol I’ve never done anything with a tbi unit. Please let me know what you think I should do next? Thank everyone for their help so far!! quote Originally posted by Yellow-88: This was a smoke test? And smoke came out of the throttle body only. It should not be able to pass the throttle plate. Some one can add here. Does the IAC close fully when the ignition is off? If it does no smoke should exit any were. I like the hiss tube in this case, at this point because one can probe the throttle plate to "see" a tiny leak there. A worn throttle shaft can be another source of a leak. Yellow-88 SEP 20, 03:57 PM quote Originally posted by Scuba_steve45: Yes I did a smoke test I apologize for calling it a vacuum test lol. I assumed it was supposed to because fuel sprays onto the “closed” throttle plate on idle so there has to be a way for it to reach the intake and such. I could be completely wrong lol I’ve never done anything with a tbi unit. Please let me know what you think I should do next? Thank everyone for their help so far!! I have only 2.8 so I can't go look at a TBI unit. We need a TBI guy to jump in. I'll ask should the IAC valve be completely closed with ignition off? There is an air way that bypasses the throttle plate. The Idle Air Control, IAC valve is a needle and seat type valve controlled by a "stepper" motor so that the air way can be very accurately controlled. Crap in the valve seat from dirty air or carbon crud can screw it up. You didn't do anything to affect timing so I'll stick with Vacuum leak at the throttle body, either past the plate or through the IAC valve. Scuba_steve45 SEP 20, 04:18 PM quote Originally posted by Yellow-88: I have only 2.8 so I can't go look at a TBI unit. We need a TBI guy to jump in. I'll ask should the IAC valve be completely closed with ignition off? There is an air way that bypasses the throttle plate. The Idle Air Control, IAC valve is a needle and seat type valve controlled by a "stepper" motor so that the air way can be very accurately controlled. Crap in the valve seat from dirty air or carbon crud can screw it up. You didn't do anything to affect timing so I'll stick with Vacuum leak at the throttle body, either past the plate or through the IAC valve. Scuba_steve45 SEP 20, 04:19 PM How should I test this? Is the only method the “hiss tube” that was mentioned earlier? I did not mess with the throttle body or IAC itself besides replacing vacuum lines AFTER the iidling issue began. quote Originally posted by Yellow-88: I have only 2.8 so I can't go look at a TBI unit. We need a TBI guy to jump in. I'll ask should the IAC valve be completely closed with ignition off? There is an air way that bypasses the throttle plate. The Idle Air Control, IAC valve is a needle and seat type valve controlled by a "stepper" motor so that the air way can be very accurately controlled. Crap in the valve seat from dirty air or carbon crud can screw it up. You didn't do anything to affect timing so I'll stick with Vacuum leak at the throttle body, either past the plate or through the IAC valve. Yellow-88 SEP 20, 05:13 PM You've pretty much narrowed it down to the throttle body with the smoke test. The only way out is through the IAC valve or past the throttle plate. From the picture, a lot of dirty air got into where it wasn't supposed to. The throttle body is a place that needs to be clean and smooth. I use WD40 and a brush. The IAC does unscrew so you can easily clean it and the seat in the TB. Just don't plug it in when it's out. And don't change the distance the cone is from the body. If you do a search on this forum for IAC I think you'll find a lot written on it. A hiss tube can check if any air is leaking past the closed plate. With the engine running, the inlet to the IAC will hiss. It will take careful probing to be sure your hearing just the hairline crack at the edge of the plate. Scuba_steve45 SEP 20, 06:26 PM Alright I’ll try that out tomorrow when I’m back home and let you know what happens. I’m hoping I’ll figure out a solution soon!! quote Originally posted by Yellow-88: You've pretty much narrowed it down to the throttle body with the smoke test. The only way out is through the IAC valve or past the throttle plate. From the picture, a lot of dirty air got into where it wasn't supposed to. The throttle body is a place that needs to be clean and smooth. I use WD40 and a brush. The IAC does unscrew so you can easily clean it and the seat in the TB. Just don't plug it in when it's out. And don't change the distance the cone is from the body. If you do a search on this forum for IAC I think you'll find a lot written on it. A hiss tube can check if any air is leaking past the closed plate. With the engine running, the inlet to the IAC will hiss. It will take careful probing to be sure your hearing just the hairline crack at the edge of the plate. Yellow-88 SEP 20, 07:26 PM Thank you 82-A/T. Your Daughter does excellent work. Her attention to detail is obvious.