Help!
Hey everyone, i am having the hardest time getting my IAC off of zero. Here is my setup:
98 Ford 302 roller block with stock gt40 heads, ford racing manifold, ford racing E303 cam, pertronix flame thrower coil, ready to run electric distributor, fitech 600hp unit, aeromotive inline fuel pump supplied with the Fitech masterkit.
Previously i had a edelbrock 4 barrel carb on a torker manifold.
When i installed the Fitech, i was using the torker manifold, however i couldnt get the IAC off zero, so i figured i had a vaccum leak somewhere. I assumed it was the older torker manifold i had on it so i changed it out for the Ford racing unit from summit. I very carefully installed the manifold, i used a bunch of gasket sealant all around as i wanted to eliminate any possibility of there being a vaccum leak at the manifold. I torqued everything down per spec in the correct order. I used the supplied TB gasket from Fitech and torqued it down. I wanted to eliminate all sources of a vaccum leak. I plugged all vaccum ports at the TB unit.
When i first start it, cold engine, my IAC will hold at 4 to 5, then as it warms up, it drops to zero. Once it hits 170, the IAC stay at zero, with occasional fluctuations to 2 then back to zero. My target idle is set to 950, but it in no way hit that without dying out. The unit will hold the idle at 1200 to 1300, but if i try to dial back the idle screw it will die out.
I am at a loss here and appreciate any advice i could get. I uploaded a datalog at temp for reference as well as some photos of my setup.
Thanks again,
Jon
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What does your RPM say on the handheld when idling. Want to make sure we aren't dealing with interference. Also check codes. Better yet send a Datalog with all the data.
Hey Austin, I attached a data log to my previous post. Looks like RPM ranges from 1200 to 1400 from that log. Let me know if you don’t see it and I can attach it again. Thank for you help.
Quote from jmnjn on April 5, 2019, 11:26 pmHey Austin, I attached a data log to my previous post. Looks like RPM ranges from 1200 to 1400 from that log. Let me know if you don’t see it and I can attach it again. Thank for you help.
Ok, looked at the log. Data looks good. Unit is doing its job.
Check your secondary butterfly adjustment. Back primary screw to just touching and verify butterflies are closed, then repeat for secondary butterflies. Then use primary screw to set idle and IAC steps.
Are you running 18in or more exhaust past O2 sensor?
Ok thanks for looking at my datalog, I will make those adjustments and report back. O2 is located on my h-pipe, then from there it goes to back to axles where my mufflers are, which are more than 18 in away.
Send pic of O2 placement. H pipe not a good place....
Sure here are some pics
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That should work.
Update: So I’m still working on my IAC problem, going through the engine verifying no vacuum leaks. What I have done since last post is,
readjusted rocker arms,
retorqued intake bolts,
replace rocker arms with full roller rocker arms and adjusted again,
removed fitech to do a further inspection, because now I feel the unit has a vacuum leak somewhere and here is what I found;
Upon inspecting bolts for tightness, I found that the IAC bolts were finger tight. So I removed the IAC and found that the rubber ORing that seals the IAC to the throttle body was not seated correctly causing the ORing to become deformed. I corrected the ORing and reinstalled. I am reassembling the unit back to the engine and will update this thread.
Also I was advised by Fitech that my distributor was known to have issues so my next step would be to install a MSD unit that can be timing controlled. However I first want to set my IAC before moving to this step.
My goal is to get this to work and hope that my efforts will help out all others who may be having this problem.
Why did they have a problem with your distributor?