Help: 2001 Cobra Dying out after engine rebuild.

332cobra · 02-26-2006, 08:17 PM

Hey all,

I have a 2001 cobra that has 78k miles on it, i just had the conrod bearings replaced after hearing a bit of engine knock. Turns out piston 4 and piston 8 both were misfiring, and in the end the stock bearings had 2mm of play on sleeves of the rod bearings. they were replaced last week with a fresh kit. the pistons, piston rings, block, main bearing and cranks shaft were all inspected during the disassembley, they are all good to go.

Any how, after the rebuild the engine runs like a dream. It idles perfect and accelerates like new. Problem is it occasionally comes back down from about 3-4krpms below 400rpms and stalls. I'm still breaking the bearings in and have not gone above 3000rpms but a few times for testing, how long do you suggest i wait before opening her up? we're going to do a flush for oil next week to remove any shavings that are evident from the bearing break in.

It's a bit odd because the only way i can replicate the stall is after letting the clutch OFF from 3k rpms. does the engine just need to be tuned to be sure it does not go below the 700rpm mark? should i swap the fresh plugs that were put it last week? they were stock plugs to spec with the 2001 cobra.

any suggestions? any and all feedback from you mustang officianados is greatly appreciated.

it does seem to have an rpm flutter when cruising in neutral, almost as if the flywheel is making light contact. it does have a stage 2 spec clutch on it, and i can hear it grabbing a tad at idle. but when the car is stopped in place, it idles perfectly at about 700rpm, no missing.

Mr 5 0 · 02-27-2006, 03:48 PM

I would suggest that (a) you manually stabilize the idle at 700 RPM and, (b) post this in the Windsor Power forum.

Capri306 · 02-27-2006, 04:20 PM

Actually, this one belongs in Modular Madness.

Please read the sticky at the top of the Blue Oval Lounge.

332cobra · 02-27-2006, 04:58 PM

hi!

yeah so far i've been tapping the gas as the rpm's dip down below that 700hp mark, but before the rebuild i never had to do that to keep it running. i was wondering if a tune up or a particular brand of spark plugs might help with idle.

this only happens while cruising in neutral. the rpm's fluctuate, which is odd to me. as if the rotation of the drivetrain is affecting the idle rpm's of the engine. is something catching?

i posted in this forum as the engine is a 4.6 liter 32 valve, hope i got it right. do the windsor guys have better feedback on this type of stuff? thanks for the help thus far.

pny_p51 · 02-28-2006, 05:14 PM

Hi 332 Cobra,
nice to meet you! I hope you recieved the info. you needed..
I hope your car is ok too!!
My first love was the 84/85 Cobra... After that, any type of Mustang that I see, I love!
I own a 2006 V6 Mustang coupe, pitch black, charcoal interior, with pny pkg. Just bought it 3 weeks ago, and already had a problem with it!! The battery was defective! It had to be towed to the shop, and the battery replaced... That was last week! Crazy?! Ain't it?!
Good luck with your car, I hope it's all better now..

bigwhitecobra · 03-01-2006, 08:07 AM

Sounds to me like you have a small, but serious vacuum leak. Go over all the hoses, and make absolutely sure that all are connected. Check your vacuum lines and such. The problem is not related to plugs, or even your rebuild.

As far as break in goes, there are several opinions about it, but the fact is, if it runs......your good. Jump on her a few times and see if she holds together. If she has ran above 3K, she will run up to 7K.

Hope some of this helps. And for the record, I always break my vehicles in as per instructions, but common sense tells me that if it holds together on for the initial start up and warm up, she'll hold together for almost anything.

332cobra · 03-01-2006, 01:28 PM

thanks for the feedback guys, i setup an appointment with my mechanic this weekend to check the lines, connections and valves. i haven't heard any sounds that are abnormal other than the cold air intake tubing during induction.

in another forum the problem was pointed out as being the IAC or MAF/MAP. think it could be the idle air control valve? i could just replace it and see if it helps.

the problem only happens when cruising in neutral at 25-35 miles per hour. when in gear the engine runs perfect, and when parked and idle, it does not miss.

think we're getting close. thank you all kindly for the specifics.

hi pny_p51, don't get me wrong, i absolutely love the cobra. my last kit was a v6 mustang as well and i ran it for 120k miles with 0 issues. it was a great and sturdy car. the bearings going on my current box were my fault, i ran low on oil and kept running hard. simple as that. beyond that the mustang is a worthwhile cause. they're a dream to run. i'm glad to have my weekends back, cruising up in mountains and along pch. fun fun.

i'm positive your new mustang will bring years of enjoyment to come. just watch your oil. haha. (if you run hard daily, it burns away quicker that you'd think)

pny_p51 · 03-01-2006, 03:54 PM

Hi 332 cobra,
Thanks for the tip! I'll keep it in mind!! Yeah! I just love my stang! and I agree with you, they really are a dream ride!!
And I was wrong about something... I thought I wouldn't be able to take it out today, because they were calling foe stormy weather...well, it didn't happen! Infact, the clouds broke up alittle bit, and I was able to get out with my Mustang for awhile!! Met a friend of mine for coffee...had to buy her coffee, so that she'd hang out with me though,...

ha!ha!
Have a great day!!

332cobra · 03-01-2006, 04:18 PM

radness.

yep, the best part of my days believe it or not are the drive in to work (only 3 miles, but worth it) and the drive home. love it.

pny_p51 · 03-01-2006, 05:20 PM

ditto!!

P.C. · 03-02-2006, 09:35 AM

Hi. The I.A.C.idle Air Control Is Usually Bad If..in The Morning,cold, When U First Start The Car It Loses The Initial Fast Idle/you Find Yourself Having To Push On The Gas Just To Keep It Running!Until The Car Warms Up.Then it idles normal when it warms up.Folks Have Had A Lot Of Problems With M.A.f.S. Mass Air Flow Sensors Because They Over Oil Their K&N Air Filters.Oil In The Mafs = Equals Trouble.Big white cobra has a good point.A possible vacuum leak or a hose in the wrong spot.Sometimes things dont get put back in the right place after a rebuild.Also make sure the conections from the maf to the t body are tight.Leaks in between there might cause that.Try not to replace parts on a hunch.Like the old saying goes test dont guess!

332cobra · 03-02-2006, 01:45 PM

thank you for the support. i definately won't jump to any conclusions. i can't wait to work on it with the mechanic this weekend and find out what the issue was. hopefully we'll get it resolved and i'll be able to post positive results by monday. thanks again.

pny_p51 · 03-02-2006, 02:08 PM

[SIZE=3]Good luck to you 332 Cobra!!
I hope you are able to get your car all set and running like new again! Best wishes!! Take care...[/SIZE]

332cobra · 03-04-2006, 11:38 PM

UPDATE:

hey all. i spent the morning today doing an engine fluish and clean before swapping out the engine oil with some lucas oil treatment. turns out the idle air control valve was filthy. we removed it from the throttle body and it turns out it was full of black particles of dirt. we fluched it out with about a full can of carb cleaner and re-installed. the engine does not die out in neutral anymore. but it does fluctuate a bit more than i would like around the 25 mph mark.

would a brand new IAC valve fix the problem completely? do they make custom high performance IAC valves that are more sensitive to the updated cold air intakes we use today?

thanks for the tips. problem solved. now it's down to fine tuning performance from this point on.

bigwhitecobra · 03-06-2006, 10:28 AM

I'd just get a new one and be done with it.

332cobra · 03-06-2006, 12:45 PM

just ordered it online, thanks for the advice.

http://www.latemodelrestoration.com/...0%201?comp=LRS

when installing it out of the box, is there anything i need to to to beyond hook it up? is it self adjusting?

pny_p51 · 03-06-2006, 07:17 PM

Hey Cobra332!

Congrat's on getting your car up and going! That's great!! I bet that made you feel proud!
As for me, all that stuff you were talking about on how you fixed it, well, I was lost... I guess you could say that I am automobile illiterate

So sorry about that, but at the same time, I was impressed about all that you've done!
Have a great night!!

Hey bigwhitecobra !!!!

That's funny!! because that's what I would have done

But, you do have to applaude the man!! It is pretty cool all the hard work he put into it!!

Take care!!

332cobra · 03-06-2006, 08:30 PM

awesome. thanks.

yeah i was about to scrap the cobra and trade it in for an S4, but with only 78k miles on it and considering i was on a waiting list for about 6 months to get it, i felt a bit obligated to keep it and pay a little more attention to it's needs, like, oil. haha.

it was definately a learning experience to take the engine out and swap the conrod bearings. then as new problems arised, using the internet was key to problem solving.

i cleaned out the iac with carb cleaner and it solved the problem by about 90%, but it's a tad finicky when i force the rpm's to drop by letting the clutch off on a down shift. i'll just replace it and see what happens. i have a feeling the motor just has a stripped gear or the gunk got in places it shouldn't had. only a $90 loss.

thanks again. i hope this message board stays up for those inthe future that have idle issues.

pny_p51 · 03-06-2006, 11:03 PM

Hey Cobra!!!!
Thanks !! That is really cool!! I hope that this board is like
Great job~~~
HOVE A GOOD NIGHT!!

bigwhitecobra · 03-07-2006, 10:14 AM

no problem. Glad to have helped.

02-26-2006, 08:17 PM	#1
332cobra Registered Member Join Date: Feb 2006 Posts: 13	Help: 2001 Cobra Dying out after engine rebuild. Hey all, I have a 2001 cobra that has 78k miles on it, i just had the conrod bearings replaced after hearing a bit of engine knock. Turns out piston 4 and piston 8 both were misfiring, and in the end the stock bearings had 2mm of play on sleeves of the rod bearings. they were replaced last week with a fresh kit. the pistons, piston rings, block, main bearing and cranks shaft were all inspected during the disassembley, they are all good to go. Any how, after the rebuild the engine runs like a dream. It idles perfect and accelerates like new. Problem is it occasionally comes back down from about 3-4krpms below 400rpms and stalls. I'm still breaking the bearings in and have not gone above 3000rpms but a few times for testing, how long do you suggest i wait before opening her up? we're going to do a flush for oil next week to remove any shavings that are evident from the bearing break in. It's a bit odd because the only way i can replicate the stall is after letting the clutch OFF from 3k rpms. does the engine just need to be tuned to be sure it does not go below the 700rpm mark? should i swap the fresh plugs that were put it last week? they were stock plugs to spec with the 2001 cobra. any suggestions? any and all feedback from you mustang officianados is greatly appreciated. it does seem to have an rpm flutter when cruising in neutral, almost as if the flywheel is making light contact. it does have a stage 2 spec clutch on it, and i can hear it grabbing a tad at idle. but when the car is stopped in place, it idles perfectly at about 700rpm, no missing. Last edited by 332cobra; 02-26-2006 at 08:32 PM..

02-27-2006, 03:48 PM	#2
Mr 5 0 Conservative Individualist Join Date: May 1997 Location: Wherever I need to be Posts: 7,487	Re: Help: 2001 Cobra Dying out after engine rebuild. I would suggest that (a) you manually stabilize the idle at 700 RPM and, (b) post this in the Windsor Power forum. __________________ 5.0 Mustang Owner 1990 - 2005

02-27-2006, 04:20 PM	#3
Capri306 Moderator Join Date: Sep 1998 Location: Grand Rapids, Michigan, USA Posts: 1,001	Re: Help: 2001 Cobra Dying out after engine rebuild. Actually, this one belongs in Modular Madness. Please read the sticky at the top of the Blue Oval Lounge. __________________ Capri306, Moderator The Mustang Works Online 1979 Mercury Capri 1987 5.0L Mustang LX Notchback 1993 5.8L Eddie Bauer Bronco

02-27-2006, 04:58 PM	#4
332cobra Registered Member Join Date: Feb 2006 Posts: 13	Re: Help: 2001 Cobra Dying out after engine rebuild. hi! yeah so far i've been tapping the gas as the rpm's dip down below that 700hp mark, but before the rebuild i never had to do that to keep it running. i was wondering if a tune up or a particular brand of spark plugs might help with idle. this only happens while cruising in neutral. the rpm's fluctuate, which is odd to me. as if the rotation of the drivetrain is affecting the idle rpm's of the engine. is something catching? i posted in this forum as the engine is a 4.6 liter 32 valve, hope i got it right. do the windsor guys have better feedback on this type of stuff? thanks for the help thus far. Last edited by 332cobra; 02-27-2006 at 05:28 PM..

02-28-2006, 05:14 PM	#5
pny_p51 Registered Member Join Date: Feb 2006 Posts: 39	Re: Help: 2001 Cobra Dying out after engine rebuild. Hi 332 Cobra, nice to meet you! I hope you recieved the info. you needed.. I hope your car is ok too!! My first love was the 84/85 Cobra... After that, any type of Mustang that I see, I love! I own a 2006 V6 Mustang coupe, pitch black, charcoal interior, with pny pkg. Just bought it 3 weeks ago, and already had a problem with it!! The battery was defective! It had to be towed to the shop, and the battery replaced... That was last week! Crazy?! Ain't it?! Good luck with your car, I hope it's all better now..

03-01-2006, 08:07 AM	#6
bigwhitecobra Huh? Whatcha said? Join Date: Oct 2000 Location: Fayetteville, NC Posts: 1,073	Re: Help: 2001 Cobra Dying out after engine rebuild. Sounds to me like you have a small, but serious vacuum leak. Go over all the hoses, and make absolutely sure that all are connected. Check your vacuum lines and such. The problem is not related to plugs, or even your rebuild. As far as break in goes, there are several opinions about it, but the fact is, if it runs......your good. Jump on her a few times and see if she holds together. If she has ran above 3K, she will run up to 7K. Hope some of this helps. And for the record, I always break my vehicles in as per instructions, but common sense tells me that if it holds together on for the initial start up and warm up, she'll hold together for almost anything. __________________ 2003 GT White---STOLEN May you burn in hell whoever took it. Dumbazz didn't even get the good engine that was in the garage.

03-01-2006, 01:28 PM	#7
332cobra Registered Member Join Date: Feb 2006 Posts: 13	Re: Help: 2001 Cobra Dying out after engine rebuild. thanks for the feedback guys, i setup an appointment with my mechanic this weekend to check the lines, connections and valves. i haven't heard any sounds that are abnormal other than the cold air intake tubing during induction. in another forum the problem was pointed out as being the IAC or MAF/MAP. think it could be the idle air control valve? i could just replace it and see if it helps. the problem only happens when cruising in neutral at 25-35 miles per hour. when in gear the engine runs perfect, and when parked and idle, it does not miss. think we're getting close. thank you all kindly for the specifics. hi pny_p51, don't get me wrong, i absolutely love the cobra. my last kit was a v6 mustang as well and i ran it for 120k miles with 0 issues. it was a great and sturdy car. the bearings going on my current box were my fault, i ran low on oil and kept running hard. simple as that. beyond that the mustang is a worthwhile cause. they're a dream to run. i'm glad to have my weekends back, cruising up in mountains and along pch. fun fun. i'm positive your new mustang will bring years of enjoyment to come. just watch your oil. haha. (if you run hard daily, it burns away quicker that you'd think) Last edited by 332cobra; 03-01-2006 at 05:27 PM..

03-01-2006, 03:54 PM	#8
pny_p51 Registered Member Join Date: Feb 2006 Posts: 39	Re: Help: 2001 Cobra Dying out after engine rebuild. Hi 332 cobra, Thanks for the tip! I'll keep it in mind!! Yeah! I just love my stang! and I agree with you, they really are a dream ride!! And I was wrong about something... I thought I wouldn't be able to take it out today, because they were calling foe stormy weather...well, it didn't happen! Infact, the clouds broke up alittle bit, and I was able to get out with my Mustang for awhile!! Met a friend of mine for coffee...had to buy her coffee, so that she'd hang out with me though,... ha!ha! Have a great day!!

03-01-2006, 04:18 PM	#9
332cobra Registered Member Join Date: Feb 2006 Posts: 13	Re: Help: 2001 Cobra Dying out after engine rebuild. radness. yep, the best part of my days believe it or not are the drive in to work (only 3 miles, but worth it) and the drive home. love it.

03-01-2006, 05:20 PM	#10
pny_p51 Registered Member Join Date: Feb 2006 Posts: 39	Re: Help: 2001 Cobra Dying out after engine rebuild. ditto!!

03-02-2006, 01:45 PM	#12
332cobra Registered Member Join Date: Feb 2006 Posts: 13	Re: Help: 2001 Cobra Dying out after engine rebuild. thank you for the support. i definately won't jump to any conclusions. i can't wait to work on it with the mechanic this weekend and find out what the issue was. hopefully we'll get it resolved and i'll be able to post positive results by monday. thanks again.

03-02-2006, 02:08 PM	#13
pny_p51 Registered Member Join Date: Feb 2006 Posts: 39	Re: Help: 2001 Cobra Dying out after engine rebuild. [SIZE=3]Good luck to you 332 Cobra!! I hope you are able to get your car all set and running like new again! Best wishes!! Take care...[/SIZE]

03-04-2006, 11:38 PM	#14
332cobra Registered Member Join Date: Feb 2006 Posts: 13	Re: Help: 2001 Cobra Dying out after engine rebuild. UPDATE: hey all. i spent the morning today doing an engine fluish and clean before swapping out the engine oil with some lucas oil treatment. turns out the idle air control valve was filthy. we removed it from the throttle body and it turns out it was full of black particles of dirt. we fluched it out with about a full can of carb cleaner and re-installed. the engine does not die out in neutral anymore. but it does fluctuate a bit more than i would like around the 25 mph mark. would a brand new IAC valve fix the problem completely? do they make custom high performance IAC valves that are more sensitive to the updated cold air intakes we use today? thanks for the tips. problem solved. now it's down to fine tuning performance from this point on.

03-06-2006, 10:28 AM	#15
bigwhitecobra Huh? Whatcha said? Join Date: Oct 2000 Location: Fayetteville, NC Posts: 1,073	Re: Help: 2001 Cobra Dying out after engine rebuild. I'd just get a new one and be done with it. __________________ 2003 GT White---STOLEN May you burn in hell whoever took it. Dumbazz didn't even get the good engine that was in the garage.

03-06-2006, 12:45 PM	#16
332cobra Registered Member Join Date: Feb 2006 Posts: 13	Re: Help: 2001 Cobra Dying out after engine rebuild. just ordered it online, thanks for the advice. http://www.latemodelrestoration.com/...0%201?comp=LRS when installing it out of the box, is there anything i need to to to beyond hook it up? is it self adjusting?

03-06-2006, 07:17 PM	#17
pny_p51 Registered Member Join Date: Feb 2006 Posts: 39	Re: Help: 2001 Cobra Dying out after engine rebuild. Hey Cobra332! Congrat's on getting your car up and going! That's great!! I bet that made you feel proud! As for me, all that stuff you were talking about on how you fixed it, well, I was lost... I guess you could say that I am automobile illiterate So sorry about that, but at the same time, I was impressed about all that you've done! Have a great night!! Hey bigwhitecobra !!!! That's funny!! because that's what I would have done But, you do have to applaude the man!! It is pretty cool all the hard work he put into it!! Take care!!

03-06-2006, 08:30 PM	#18
332cobra Registered Member Join Date: Feb 2006 Posts: 13	Re: Help: 2001 Cobra Dying out after engine rebuild. awesome. thanks. yeah i was about to scrap the cobra and trade it in for an S4, but with only 78k miles on it and considering i was on a waiting list for about 6 months to get it, i felt a bit obligated to keep it and pay a little more attention to it's needs, like, oil. haha. it was definately a learning experience to take the engine out and swap the conrod bearings. then as new problems arised, using the internet was key to problem solving. i cleaned out the iac with carb cleaner and it solved the problem by about 90%, but it's a tad finicky when i force the rpm's to drop by letting the clutch off on a down shift. i'll just replace it and see what happens. i have a feeling the motor just has a stripped gear or the gunk got in places it shouldn't had. only a $90 loss. thanks again. i hope this message board stays up for those inthe future that have idle issues.

03-06-2006, 11:03 PM	#19
pny_p51 Registered Member Join Date: Feb 2006 Posts: 39	Re: Help: 2001 Cobra Dying out after engine rebuild. Hey Cobra!!!! Thanks !! That is really cool!! I hope that this board is like Great job~~~ HOVE A GOOD NIGHT!!

03-07-2006, 10:14 AM	#20
bigwhitecobra Huh? Whatcha said? Join Date: Oct 2000 Location: Fayetteville, NC Posts: 1,073	Re: Help: 2001 Cobra Dying out after engine rebuild. no problem. Glad to have helped. __________________ 2003 GT White---STOLEN May you burn in hell whoever took it. Dumbazz didn't even get the good engine that was in the garage.

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