Misfiring

simon clemens · 10-12-2005, 07:18 AM

Hi all, I need help to find out some info with my 1995 mustang engine, (stock standard, curved intake neck). Firstly need to know what the IAC (Idol Air Control) screw looks like. I know where it is supposed to be... as I have removed the grey rubber plug on the throttle body and there is just a hole with a thread inside.... NO adjustment screw in there at all!! I was told by the guy who tuned the engine that "maybe it came loose in the throttle body and was sucked into the intake" this sounds to me like a whole lot of BULL SH!T, however I am led to ask the question is this possible?.
I need to know because the engine now has a misfire on number 2 cyl. The engine had just been dyno'd by this guy and he said that is was running perfectly fine on the dyno. Now I have a missing number 2 cyl, and he is claiming it is not his problem. He performed a leak-down test and discovered air leaking back into the intake... which indicates the intake valve is not seating.
Symptoms when running:
-Cold exhaust temp on number 2cyl
-Can easily hear the misfire on the right bank (twin exhaust system)
-good fuel inj, spark/leads, dizzy cap, coil

What could have caused my engine to now be running on 7 cylinders??? The day I picked the car up there was this problem with it.

Is it possible that the IAC screw has gone through the engine and damaged the intake on number 2cyl?

Please... any help on this will be appreciated, Simmo

HoodStrype · 10-12-2005, 10:17 AM

If you've changed the plug, wire, cap, button... it seems to me you want to get the computer checked for an error code and if that doesn't tell you anything, tear the top of that motor down.

Capri306 · 10-15-2005, 07:55 PM

If it is the case that a screw was sucked into the #2 intake runner, and from your description, then maybe you got really lucky and it's just jamming the intake valve open, thus no compression on that cylinder. I would at least take the upper intake off and see if you can look down there. If not, remove the lower and be sure. Go from there. Good luck.

p.s. if this guy's so intent on it not being "his problem" i'd consider doing a lawnjob in his front yard not "your problem"

simon clemens · 10-15-2005, 09:44 PM

Thanks for the replies fellas, will add to my post when i have found the problem... Believe me I've thought about doing worse things than a lawn job! He has really pushed the wrong buttons

When I get it back from these idiots I'll do my own compression test, I just don't trust that they know what their doing, may still have to pull the head off, its not a big job, just extra unwanted hassle

Simmo...

10-12-2005, 07:18 AM	#1
simon clemens Registered Member Join Date: Oct 2005 Posts: 3	Misfiring Hi all, I need help to find out some info with my 1995 mustang engine, (stock standard, curved intake neck). Firstly need to know what the IAC (Idol Air Control) screw looks like. I know where it is supposed to be... as I have removed the grey rubber plug on the throttle body and there is just a hole with a thread inside.... NO adjustment screw in there at all!! I was told by the guy who tuned the engine that "maybe it came loose in the throttle body and was sucked into the intake" this sounds to me like a whole lot of BULL SH!T, however I am led to ask the question is this possible?. I need to know because the engine now has a misfire on number 2 cyl. The engine had just been dyno'd by this guy and he said that is was running perfectly fine on the dyno. Now I have a missing number 2 cyl, and he is claiming it is not his problem. He performed a leak-down test and discovered air leaking back into the intake... which indicates the intake valve is not seating. Symptoms when running: -Cold exhaust temp on number 2cyl -Can easily hear the misfire on the right bank (twin exhaust system) -good fuel inj, spark/leads, dizzy cap, coil What could have caused my engine to now be running on 7 cylinders??? The day I picked the car up there was this problem with it. Is it possible that the IAC screw has gone through the engine and damaged the intake on number 2cyl? Please... any help on this will be appreciated, Simmo Last edited by simon clemens; 10-12-2005 at 08:28 AM..

10-15-2005, 07:55 PM	#3
Capri306 Moderator Join Date: Sep 1998 Location: Grand Rapids, Michigan, USA Posts: 1,001	Re: Misfiring If it is the case that a screw was sucked into the #2 intake runner, and from your description, then maybe you got really lucky and it's just jamming the intake valve open, thus no compression on that cylinder. I would at least take the upper intake off and see if you can look down there. If not, remove the lower and be sure. Go from there. Good luck. p.s. if this guy's so intent on it not being "his problem" i'd consider doing a lawnjob in his front yard not "your problem" __________________ Capri306, Moderator The Mustang Works Online 1979 Mercury Capri 1987 5.0L Mustang LX Notchback 1993 5.8L Eddie Bauer Bronco

10-15-2005, 09:44 PM	#4
simon clemens Registered Member Join Date: Oct 2005 Posts: 3	Re: Misfiring Thanks for the replies fellas, will add to my post when i have found the problem... Believe me I've thought about doing worse things than a lawn job! He has really pushed the wrong buttons When I get it back from these idiots I'll do my own compression test, I just don't trust that they know what their doing, may still have to pull the head off, its not a big job, just extra unwanted hassle Simmo...

10-12-2005, 10:17 AM	#2
HoodStrype Rearview Mirror Haze Join Date: May 1999 Location: Huntsville, Alabama...a.k.a. "HuntsVegas" Posts: 387	Re: Misfiring If you've changed the plug, wire, cap, button... it seems to me you want to get the computer checked for an error code and if that doesn't tell you anything, tear the top of that motor down. __________________ 93 lx Notch 01 GT ...the epitome of Murphy's Law