EFI TO CARB

[Foxfan88]

i'd almost say the tuner did a bad tune. a mild 5.0 should have no problem running 30#ers on a mild combo, with a proper tune, it should idle and drive and run like stock. i use a tweecer have 42s currently i am using N/A until i get my turbo on, 42s are WAY oversized for my N/A motor that may be making 300rwhp is that, ive managed to make my car run and drive excellent with the big injectors, and i am just a DIYer not a pro. so a shop that specializes in mustang should have no problem.

if all the sensors are new and working and the ECU is good, the EEC is TRYING to work correctly its just that something could be amiss with the tune.

i'm would bet this is an issue with the injectors and MAF and the ECU not being tuned properly for them.

you could try removing the chip and putting a stock MAF and 19s back on and see how it runs just to diagnose.

 

[1987stangman]

ok i have had the car for a year mass air conversion was done when i bought it. As I was pulling off the highway the day i bought it i was down shifting then just puushed in the clutch doing about 10mph and it died. Never thought much of it. Then last winter came i did a trick flow kit 30lb inj. and all the goodies, was having idle surge problem then I did idle reset and it was ok but had a humming coming from t-body but it was all good otherwise it idled best around 900 to 1000 which was fine with me as long as it ran. So i took it to a dyno shop that specializes in mustangs they burned a custom sct chip turned the idle down then the surging and it dies again on deacceleration, only when the car is warm. here are the sensors ive changed used all ford sensors tps iac o2 tpi mod. and ive checked for vac leaks about a dozen times. When the car dies it fires right up and you can smell the gas. The guy at the dyno shop told me that its probabaly a bad wire somewhere, being that he charges 125 an hour and dosent know about how long it will take him said it could be 1 hour or ten hours i havent been in a huge hurry to take it back. thinking it could be the vss but my buddy is a ford mechanic and he said that would have nothing to do with it. Please help

If it were me I would find some infor on mass air conversions and verify that the previous owner did the conversion right and used the correct materials to install. You could have a bad install or something loose in that area. Once the conversion has been verified correct you can move on.

 

[2KsilverGT]

Try this gizmo 86-93 IAC ADJUSTER MUSTANG. I was having the same problems as you and this fixed it. It's alot cheaper than anything else and it works well.

 

[crookman10]

thanks for the info i was going through stuff today under the hood and found 3 plug wires with burn marks on the boots pretty deep but not all the way through, ordered new ones about a week out. ill try the iac adjuster and let you know how it works

 

[Gearbanger 101]

If you biggest problem is with the idle and low RPM, swapping out to smaller fuel injectors isn't going to make a difference. Hang on to your 30lbers and save your money. They're not going to improve your horsepower capability at this level over a set of 24's, but they're not hurting anything either. You tune the computer to work with the injector....not the other way around.

You need to remember....forced induction cars (Blower/Turbo) run under vacuum the same as N/A cars do under normal driving conditions and don't have any idle or low speed driveability issues, so why should yours? If big injectors caused drivabilty problems, how do you explain all of the blown high horsepower street cars out there with 42lb/hr...even 60lb/hr injectors running around with perfect street manners and knocking down stock fuel economy?

Hell...I run 42's in my Cougar and it runs and drive better than it did when it was stock...and with over 400hp on tap I still average about 25mpg too.