Back tidle problems again

KAWMAN2

Member
Aug 9, 2022
59
5
18
32962
1988 mustang lx 331 strokker ,bbk intake amd fi mainifold, msd ignition, unknown high lift cal long tube headers 3 inch exhaust. Ran great with banks tune chip . for almost a year, started having problem just shutting down and restart by it self, changed the ecu pulled the chip ran fine for 2 months its back to starting fine and idle a couple of revs stalls will restart, act like a IAC, installed new one no diferencee check TPS sensor 9.6, i,m about ready to carburate this thing except it really runs great when it runs. I was looking at the IAC inline diode cant see how that would keep the IAC from working. does anybody know where the salt and pepper shakers are on the bbk manifold? I have 2 more al9 ecu in the closet?
 
KOEO codes as follows31 81 82 85 84 80 the only thing i replaced is the IAC I had a new one in the closet? ha very similar problem about 2 month ago and changed the computer and pulled the banks chip off ran fine?
 
So you are running a stock ECU on a 331? We need to know a lot more about the build. Things like what:

Injectors
Mass air meter
Fuel pump
Cam shaft
Heads
Etc

As much as you can list will help.

The tables in the ECU are set up for a motor that moves the air volume of a 302 so I would say that without a tune it’s not going to run optimally.
 
  • Like
Reactions: General karthief
Camshaft specs unkown, heads appear to be stock, means nothing till i take one off, injectors go by color i think, but dont know what color they are have to look, all i know is when its running right its a handfull need to tub it and put bigger tires on!
 
Well if the camshaft specs are unknown it can be known by using a dial indicator but from what I see your car needs to run in open loop always given the LT hedders and no wideband controllers and another chip like a QH is definately needed...........



Heres the difference between my camshaft specs (Explorer cam) and injector timing numbers(top numbers) in my engine and whats in the stock A9L tune(bottom numbers) as Im running a 93 351w on an A9L w/QH

Screenshot 2024-08-03 222301.jpg Screenshot 2024-06-24 012849.jpg Screenshot 2024-06-24 013139.jpg
Knowing when your exhaust valve closes and the intake opens is important in dialing in the timing of the injector to the valve actions at idle or youll get a wet intake manifold and a hard to nail down lambda...

Most hard start situations are caused by the cylinders literally hydrolocking during a hot startup due to inconsistent spraying due to improper injector spray commands...........


Heres when the injectors spray in an X3Z tune (bottom numbers).............

Screenshot 2024-08-03 222325.jpg

Alls it takes is a dial indicator and a magnetic base and you can also use it to check your pushrod angle to see if the pushrods are too long or too short.

Screenshot 2024-08-03 221915.jpg

As far as the stalling etc it all needs to be adjusted in the tune..................Everything on the left is my tune and stock A9L on the right...

Screenshot 2024-08-03 224505.jpg Screenshot 2024-07-27 120924.jpg Screenshot 2024-08-03 230958.webp Screenshot 2024-08-03 224556.jpg

Screenshot 2024-07-25 230341.jpg Screenshot 2024-07-25 230248.jpg Screenshot 2024-07-25 230223.jpg Screenshot 2024-07-25 230055.jpg Screenshot 2024-07-25 230037.jpg Screenshot 2024-07-25 225857.jpg Screenshot 2024-07-25 225815.jpg Screenshot 2024-07-25 225752.jpg



Screenshot 2024-07-31 014316.jpg

Good Luck
 
Last edited: