Need some help please!
11-30-2017, 04:43 AM
#21
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Good idea, I didn’t even think of that. Yesterday after work I stopped by and got my exhaust completely welded cause I had some pretty bad leaks thinking that would help after reading your post I thought maybe extra air was getting in and making it think it was running lean. It’s still doing the same thing though. Only misfiring once it’s warmed up. When I crank it in the mornings it sounds like a brand new truck. Also I noticed the surging I was talking about only happens when I press the brakes. When I let off the brakes it idles normal minus the misfire.
Last edited by Wesleyc_08; 11-30-2017 at 04:46 AM.
11-30-2017, 09:09 AM
#23
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11-30-2017, 09:34 AM
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11-30-2017, 06:16 PM
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it may very well be the issue, when u push the brake pedal in, the cabin air is allowed into the high pressure (atmosphere) side of the booster and if there is a leak in the booster diaphragm or plunger valve this would allow that air straight through the vacuum line to the engine leaning it out significantly.
It can still be the cause of the missfire without brakes as the rear atmosphere plunger is not a perfect seal and will often leak slowly when break pedal is at rest, and if theres a hole in the diaphragm this will pull a fair bit of air regardless.
in short, pushing the pedal just opens the floodgates to make the leak worse.
effectively this would be the vacuum leak that i talked about before, made worse when car goes into lean closed loop mode.
It can still be the cause of the missfire without brakes as the rear atmosphere plunger is not a perfect seal and will often leak slowly when break pedal is at rest, and if theres a hole in the diaphragm this will pull a fair bit of air regardless.
in short, pushing the pedal just opens the floodgates to make the leak worse.
effectively this would be the vacuum leak that i talked about before, made worse when car goes into lean closed loop mode.
Last edited by Thommo Thompson; 11-30-2017 at 06:19 PM.
12-01-2017, 04:52 AM
#27
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well y’all will probably think I’m an idiot but I think I may have found the problem. I have my idle screw on the throttle body screwed all the way in as far as it will go and I really feel like it is idling too high. I don’t have a tach and I’m working on getting one to test my rpms but to me it sounds high. Once I got it warmed up yesterday to where it was misfiring I got in and put it in 4th gear and let off the clutch enough to try and simulate what I feel like it sound sound like idling. Once I did that and held it to simulate a lower idle I could hear no more misfire. I don’t know if what I’m doing is accurate and as soon as I get a tach I can verify my idle speed. I’m guessing I need to take my throttle body off and clean it. What do y’all think? And I think i read somewhere where if your idle is too high when you press the brakes it cuts fuel to the injectors and if your idle is set too high it can cause surging due to something I can’t remeber what.
Last edited by Wesleyc_08; 12-01-2017 at 05:07 AM.
12-01-2017, 01:43 PM
#28
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On a fuel injected vehicle you should never adjust your idle, the computer handles that with the Idle air control motor and the fuel injectors. if it is not idling correctly you need to figure out what else is wrong, IAC, TPS, O2 sensor, crud buildup in the throttle body, VAFM, etc.You need to find the proper method to set the idle screw and let the computer do it's job.
12-01-2017, 03:18 PM
#29
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all u are doing holding then engine back like that is simulating load, so the ecu will increase air and fuel and thats why its not missing.
put the screw back all the way to fully closed unplug the ECU for a minute the plug back in, start engine and screw it in untill the engine will idle and stop there.
put the screw back all the way to fully closed unplug the ECU for a minute the plug back in, start engine and screw it in untill the engine will idle and stop there.
12-01-2017, 04:18 PM
#30
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all u are doing holding then engine back like that is simulating load, so the ecu will increase air and fuel and thats why its not missing.
put the screw back all the way to fully closed unplug the ECU for a minute the plug back in, start engine and screw it in untill the engine will idle and stop there.
put the screw back all the way to fully closed unplug the ECU for a minute the plug back in, start engine and screw it in untill the engine will idle and stop there.
like it’s still idling high after it warms up and I can’t go any further in with the idle screw.
12-01-2017, 10:37 PM
#33
Pulled and cleaned the throttle body and blew threw the lines to make sure there was no pluggage. Checked the VAFM and the TPS, both checked out good according to the FSM. Put the idle screw all the way in and reset the ECM. Cranked it back up andn let it warm up, still doing the same thing. I’m waiting for my tach to come in but it really sounds
like it’s still idling high after it warms up and I can’t go any further in with the idle screw.
like it’s still idling high after it warms up and I can’t go any further in with the idle screw.
Worth checking the gap in the throttle body to the plate, should be closed to slightly cracked (slightly being 1mm or so max)..
You replaced the vafm if I remember correctly, was that an exact part number match. Not really relevant to the vacuum leak after the idle air port.. But it could be an issue with the computer, they are factory calibrated (the internal by-pass for idle air).
12-02-2017, 06:47 AM
#34
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You have a huge vacuum leak post throttle plate, they aren't supposed to run with the idle screw bottomed out.
Worth checking the gap in the throttle body to the plate, should be closed to slightly cracked (slightly being 1mm or so max)..
You replaced the vafm if I remember correctly, was that an exact part number match. Not really relevant to the vacuum leak after the idle air port.. But it could be an issue with the computer, they are factory calibrated (the internal by-pass for idle air).
Worth checking the gap in the throttle body to the plate, should be closed to slightly cracked (slightly being 1mm or so max)..
You replaced the vafm if I remember correctly, was that an exact part number match. Not really relevant to the vacuum leak after the idle air port.. But it could be an issue with the computer, they are factory calibrated (the internal by-pass for idle air).
12-02-2017, 06:48 AM
#35
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12-02-2017, 07:10 AM
#36
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Had the throttle stop screw been messed with? If it has it could be holding the plate open,.
it should have yellow paint on it, if that paint is gone it could have been adjusted at some point. (Don't move it unless it has been moved from factory if it has you adjust it by screwing it in until it touches, then tighten it 1/4 turn more) a tps re calibration will be required if you move this.
is your throttle cable too tight not allowing the plate to fully close?
have you check the aux air valve or fast idle valve depending on which style 22re you have? They can both produce "vacuum"leaks that don't actually pull from outside the motor
it should have yellow paint on it, if that paint is gone it could have been adjusted at some point. (Don't move it unless it has been moved from factory if it has you adjust it by screwing it in until it touches, then tighten it 1/4 turn more) a tps re calibration will be required if you move this.
is your throttle cable too tight not allowing the plate to fully close?
have you check the aux air valve or fast idle valve depending on which style 22re you have? They can both produce "vacuum"leaks that don't actually pull from outside the motor
12-02-2017, 09:26 AM
#37
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Had the throttle stop screw been messed with? If it has it could be holding the plate open,.
it should have yellow paint on it, if that paint is gone it could have been adjusted at some point. (Don't move it unless it has been moved from factory if it has you adjust it by screwing it in until it touches, then tighten it 1/4 turn more) a tps re calibration will be required if you move this.
is your throttle cable too tight not allowing the plate to fully close?
have you check the aux air valve or fast idle valve depending on which style 22re you have? They can both produce "vacuum"leaks that don't actually pull from outside the motor
it should have yellow paint on it, if that paint is gone it could have been adjusted at some point. (Don't move it unless it has been moved from factory if it has you adjust it by screwing it in until it touches, then tighten it 1/4 turn more) a tps re calibration will be required if you move this.
is your throttle cable too tight not allowing the plate to fully close?
have you check the aux air valve or fast idle valve depending on which style 22re you have? They can both produce "vacuum"leaks that don't actually pull from outside the motor
12-04-2017, 04:27 AM
#38
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Any more advice on what to try? I pulled the brake booster vacuum line off and with it open it drops the idle. when I plug the vacuum line the idle speeds back up.
12-04-2017, 06:12 AM
#39
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If the surging stopped with the booster disconnected you need a new brake booster. then look for other vacuum leaks. put all adjustments back to stock, make sure you have good plugs/wires/cap/rotor and get back to us with an update about how it's running.
12-04-2017, 06:16 AM
#40
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One question I had was with the brake booster vacuum disconnected and not plugged off I thought it would cause a higher rather then idle down? Also what is the plunger looking thing on the throttle body suppose to do? I think its called the dashpot.
Last edited by Wesleyc_08; 12-04-2017 at 06:22 AM.
