jetski247
Member
This is a non lightning, f150 with the 5.8 and e4od. So there are many differences that may not be the same as the lightning. But you guys probably know this stuff better than the 4x4 forums. This truck has 1 ton axles with matching master cylinder and brake booster amongst a bunch of other mods.
Figured I'd start a new thread with my idle issues after an aftermarket cam swap. I've tried so many different ways running speed density as well as a maf system and still have similar idle issue problems. So far the closest I've gotten was to enlarge the small holes in the stock throttle body butterflies of the F-150 and got it to idle fairly smoothly with the idle stop screw completely backed out. The 351 with the maf system in the 112° lope separation cam does idle much more smoothly (then speed density) with the IAC and TPS disconnected in the idle stop screw completely backed out just idling on the enlarged holes through the twin throttle plates. This solved much of the engine dying when putting it in gear or sitting in traffic or any kind of idle issues not using the little IAC adjustment plate sold from LMR which was mentioned in a previous thread. So far after 2 days of testing have yet to have it die in traffic extended idle. For 20 to 30 minutes in gear out of gear AC on multiple things that I could think of it hasn't died yet the only tiny issue that I have found is the aftermarket cam seems to idle more like an aftermarket Cam and have a thump thump thump thump thump thump thump idle to it which it didn't do before, so what I believe is happening is it is either a little bit lean and it's causing it to idle lumpy like an aftermarket cam for some reason why I don't know, before I enlarge the holes in the throttle butterflies the idol was very smooth it would just fluctuate randomly on its own and sometimes hang and sometimes not and it was it was almost impossible to to trace and or diagnose but idol was very smooth and crisp it most times.
Going back to the stock twin throttle body so I can use it for testing purposes has severely choked the engine with the aftermarket heads and Cam and intake and all the other performance parts on the engine but the idle to 2500 rpm usable torque is much smoother and crisper with the smaller throttle body.
Figured I'd start a new thread with my idle issues after an aftermarket cam swap. I've tried so many different ways running speed density as well as a maf system and still have similar idle issue problems. So far the closest I've gotten was to enlarge the small holes in the stock throttle body butterflies of the F-150 and got it to idle fairly smoothly with the idle stop screw completely backed out. The 351 with the maf system in the 112° lope separation cam does idle much more smoothly (then speed density) with the IAC and TPS disconnected in the idle stop screw completely backed out just idling on the enlarged holes through the twin throttle plates. This solved much of the engine dying when putting it in gear or sitting in traffic or any kind of idle issues not using the little IAC adjustment plate sold from LMR which was mentioned in a previous thread. So far after 2 days of testing have yet to have it die in traffic extended idle. For 20 to 30 minutes in gear out of gear AC on multiple things that I could think of it hasn't died yet the only tiny issue that I have found is the aftermarket cam seems to idle more like an aftermarket Cam and have a thump thump thump thump thump thump thump idle to it which it didn't do before, so what I believe is happening is it is either a little bit lean and it's causing it to idle lumpy like an aftermarket cam for some reason why I don't know, before I enlarge the holes in the throttle butterflies the idol was very smooth it would just fluctuate randomly on its own and sometimes hang and sometimes not and it was it was almost impossible to to trace and or diagnose but idol was very smooth and crisp it most times.
Going back to the stock twin throttle body so I can use it for testing purposes has severely choked the engine with the aftermarket heads and Cam and intake and all the other performance parts on the engine but the idle to 2500 rpm usable torque is much smoother and crisper with the smaller throttle body.
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