Exciting Cobra Tech!! Sullivan upper & TB problem - IAC delete & issues?

[JA$ON]

I have the Sullivan upper that has been modded for an Accufab big oval TB (by Sullivan), where they close off one of the ports and hog out the middle. Now we have an IAC issue, the only option is to go to an earlier style IAC with a sample tube that goes in front of the TB. Theres already enough things going on in there and we are concerned about another tube wanting to blow off under boost. Has anyone deleted the IAC entirely and just adjusted the TB blade to get a good idle?

Its starting to sound like the car wont idle well without it, and drivability will be bad....stalling, etc.

What year and type (SOHC, DOHC) of IAC would I need to make this work??

Smart people help me please!

Thanks!

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[Bigturbonotch]

I think the main problem like you said will be idle, especially when cold. You leave the throttle blade cracked open just a little (adjust with throttle screw), then adjust the TP sensor to indicate idle voltage at this position. Set desired idle rpm via software and let computer add/subtract timing to maintain this idle. You can further smooth things via leaner AFR.

This is for a 5.0 dont know how different it is for a 4.6

 

[SVT SPEED 04]

consult the tuner and get his opinion? I think this would be your best answer big guy.

 

[batman]

bob should make a quick fix



thought i saw you were taking it there....

 

[Bob_Kurgan]

I think the main problem like you said will be idle, especially when cold. You leave the throttle blade cracked open just a little (adjust with throttle screw), then adjust the TP sensor to indicate idle voltage at this position. Set desired idle rpm via software and let computer add/subtract timing to maintain this idle. You can further smooth things via leaner AFR.

This is for a 5.0 dont know how different it is for a 4.6

bingo!! The IAC serves so many needs for the car with idle speed, part throttle, dashpot, startup, warmup, etc... it is doable to get a car to idle fine without an iac as long as the car recognizes that its going INTO the idle program.. now, add to the fact that your car doesnt have a working speedo and you just multiplied the issue.. Your computer will never be able know when it should be in dashpot mode or idle mode.. it will be very difficult to catch a "falling" idle now that the IAC is not able to increase airflow... typical startup is aided by the IAC allowing air into the motor while cranking (now you'll have to use your foot to add air)... best solution is to use what the factory gave you in the IAC and Speedo... if you cant use them, just be ready to have a higher idle speed etc.

 

[JA$ON]

bingo!! The IAC serves so many needs for the car with idle speed, part throttle, dashpot, startup, warmup, etc... it is doable to get a car to idle fine without an iac as long as the car recognizes that its going INTO the idle program.. now, add to the fact that your car doesnt have a working speedo and you just multiplied the issue.. Your computer will never be able know when it should be in dashpot mode or idle mode.. it will be very difficult to catch a "falling" idle now that the IAC is not able to increase airflow... typical startup is aided by the IAC allowing air into the motor while cranking (now you'll have to use your foot to add air)... best solution is to use what the factory gave you in the IAC and Speedo... if you cant use them, just be ready to have a higher idle speed etc.

crystal clear now Bob! I didnt know the IAC does so much at part throttle, etc. I dont want the car to idle high or else we won't hear those cams thumpin!!

I'll get with Hans and we'll figure it out. Theres a great thread that I finally found that addresses the problem with my Sullivan and Accufab TB. http://www.modularfords.com/forums/showthread.php?t=119615&highlight=sullivan+iac

I need to get the older style IAC with a sample tube and get it into the intake tube pre-TB. I just dont know exactly what year IAC I need So the sample tube goes pre-TB, now what I dont understand is where does this tube go? The original IAC hole is epoxied off by Sulivan, so how does it go through the IAC and enter the manifold?

Is it just an earlier N/A 4v IAC, or do I need a 2V IAC?

The car idled fine last year when I put the AUTO in and no additional tuning was done. Hopefully an older IAC and sample tube will remedy the problem.

Thanks for the good info Bob.

 

[twn-trbo-svt]

not sure if the problem got fixed but i had the same problem...i went to ford and ordered a 2003 mustang bullit 4v IAC...its turned 180 degrees more then the cobra's.... the plug will be on the passenger side....good luck