Got a problem, need a answer. anyone???

[sgt.scared]

Ok , on my 91 5.0 5 speed: I have tfs tw 170 ported heads and E 303 cam , 1.72 RR tfs street heat intake , 70 mm bbk TB , BBk coldair , 24 lbs inj , bbk long tube headers and my timing is at 10 now , and also I have a sct 4 blank chip.
runs alright but it wont idle worth a poo from 1500 to 500 back and forth , and dies at times.
does it with or without the chip , also try changeing the timeing too check for vac leaks . cant find any. WHAT WRONG ??? PLEASE HELP ME AND THANK YOU !!!

 

[LarsD]

Does it get better when you unplug the maf? Have you pulled the codes yet?

 

[BlownFiveLiter]

http://www.stangnet.com/mustang-forums/698148-help-me-create-surging-idle-checklist.html

 

[GroverDill]

Ford Mustang IAC IAB - Solving your idle problems


Also helpful.

 

[sgt.scared]

Im not getting any codes , no check eng light. havent try to unplug maf yet but will .. sometimes i smell gas .. think Im getting to much or not enough pressure ect ...?

 

[Mustang5L5]

Only 11 actual codes trip the CEL...out of 90 or so. Obd1 is not like obd2 where everythig sets it off

So possible for light to be off and codes to be stored

 

[sgt.scared]

havent check the codes yet also my maf is a 76 mm C & L .

 

[sgt.scared]

I unhooked the maf and it droped from like 1400 to a 500 idle and loped hard.
does that help who ever ask if I try that yet ..?
i cant get it to idle steady under like 1400 if I turn it down to like 900 then it starts to go up and down over and over from like 2000 to 600.and then dies sometimes and sometimes ,not just up and down ect..

 

[LarsD]

Sounds like you still have a big vacuum leak, mine was acting similar when I had one. Double check all your lines. Even if they look good, twist them around and get a good look. The line that was sucking air on me looked fine until I handled it.

 

[sgt.scared]

I'll recheck again tomorrow [ for vac leaks ] or so tks for all the help so far. O posted some new pics of me redoing my paint and also the motor after the mods ,

 

[sgt.scared]

Raining too much to work on the car today. Will keep you update as I try to find the vac leak if there is one guys.

 

[90limited]

Is this a new problem on an old build or a problem with a new build.

 

[jrichker]

See the "Surging Idle Checklist for help with all your idle/stall problems.

The quick and easy way to dump the codes is in there too, and all you need to do it is a paper clip! The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

 

[90fox306]

Sounds like IAC to me!! I had the same prob on a 3.0 Ranger a couple years back. Unplug the IAC and if it idles dwn, thats prob it. (NOTE) if will still run like poo but it shud Idle dwn if thats the prob. If thats the prob dont let anyone tell you that you cant clean them cause you can. It may jus need a good cleaning.

 

[sgt.scared]

theres no vac leak check and check and check . unplug the iac idle the same but did drop the rpms even more then. clean it did no good , so just to rule it out i ordered one that will be here thrusday . could it be my fuel presure reg ?? o running 76mm mass air , 24 lbs sample tube , 24 lbs injectors , cold air intake , 70mm tb , 70mm egr and tfs street heat intake , tfs tw 170 heads ported out to about 185's , e-303 cam , 1.72 rr , bbk 1 5/8 long tube headers , stock fuel pressure reg , stock fuel rails , open tapit cover , so Im not running pvc valve right not because it would cause vac leak...
runs down the road good at speed 20 50 80 ect but cold or hot eng it wont idle steady up to like 1500 down to like 500 then up to like 1300 down to like 900. no set idle over and over changes all the time never over 2200 or down at times to 0. up down up down can set the tb to idle about 1500 or so give it a quick push on the peddle 3500 or so then it goes to like 2000 and slowly drops to 1500 and idle steady then. o after i let off the gas ped it takes a sec to the rpms to start droping.

this is a new build top haft atlest.

 

[hatchback88]

i agree with 90fox iac will surge normal ford problem

 

[sgt.scared]

I got new coming [ iac ]let u know tomorrow after work.

 

[Mustang5L5]

Or...you could check codes before spending money. Just a suggestion

 

[SteedaGT9150]

Or...you could check codes before spending money. Just a suggestion

is there an echo in here?

 

[jrichker]

is there an echo in here?

No... just wisdom from some guys who have been there and done that...