Aftermarket Cam idle woes

I imagine they control more though because when it did run it would have a hanging idle or rough idle sporadically.

I've been chasing a hanging idle in my daily driver for several years. I've had three different reman computers do it, so I think it is related to something else in the truck. The computer is commanding the high idle, but I can't figure out why. It is a learned trait. If I unhook the battery it's fine for a few days and then goes back to doing it again.
 
i never degreed the cam to verify the cam card. i just know it would not run that cam with maf or speed density. i then rebuilt the maf ecm and it still had the same problem. i put the five o cam in and it had zero issues and ran good with maf or speed density.

the speed density jog1 actually runs the system very well, with no noticeable deto at all, but im waiting for that to get back and therefor selling the maf kit/system in the classifieds.

what was going on was exactly what yours did, fuel pressure would just fall off randomly, and was intermittent. id watch fuel pressure drop, and kept replacing fuel pumps and relays for them to do the same thing, which was (or at least i hope) was the ecm all this time. i was blaming cheap china parts only lasting a couple days, then crapping out. the maf system has no issues at all with the truck so i know fuel pumps/relays etc are all good. fingers crossed, hopefully the rebuilt computer will fix that.
But you didn't degree the other cams right? That shouldn't make that big a difference. Defreeing it shouldn't gain that much as far as idle quality. It will be the top end that suffers when not degreed. But even then your talking low single digit hp differences.

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I've been chasing a hanging idle in my daily driver for several years. I've had three different reman computers do it, so I think it is related to something else in the truck. The computer is commanding the high idle, but I can't figure out why. It is a learned trait. If I unhook the battery it's fine for a few days and then goes back to doing it again.
These PCMs don't have learning capability. It's X input produces Y output. Now some other part may be failing that is fine with a reset then fails again later on. I'd be looking at IAC they are known to carbon coke and stick. Etc. Or a vacuum leak these things have miles and miles of vacuum lines. It took me 30 feet of DOT air brake line to replace all mine. The stock ones get really brittle. They look ok but if you touch them they crumble. At this age may be worth it to replace them all just to rule it out.

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while i shipped my jog1 off to get repaired, i installed my a9p and maf system since all my plugs/wires are still there, to see if it still did that strange cold start barely idle thing, which it hasn't yet. purrs like a kitten, check engine light comes on after about 10 miles which is egr related which the old ecm did.

so, im hoping it was the capacitor issue cuz this maf system runs this set up with less power. im lean, im deto'in at wot with this setup and power has fallen off compared to the speed density.

so i can richen it up with this stupid air adjuster which fools the maf signal to the ecm or swictc back to speed density. prob speed density.

does anyone know what the capacitors actually do? or control?

The A9P was a 5.0 Fox ecm snd had a higher timing strategy than the JOG1 and most other ECM’s. Pull the plug and back your base timing off 2° at a time until you get back to no pinging. This will help with power and may help with the lean condition too.


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The A9P was a 5.0 Fox ecm snd had a higher timing strategy than the JOG1 and most other ECM’s. Pull the plug and back your base timing off 2° at a time until you get back to no pinging. This will help with power and may help with the lean condition too.

The much more aggressive timing strategy was something I loved when I had the A9L in my truck. It was something that none of the mass air kits seems to be able to get right, even with all kinds of tuning attempts. My truck left and pulled harder with the A9L than any of the other computers that went in it (BIO0, VEX1, WAY1) and various efforts at tuning. The only thing we kept coming back to was that the timing in the A9L was simply more aggressive and the truck computers defaulted to pulling way more at higher throttle angles due to the expected load characteristics.
 
blackbeauty,
the only cam i degreed was the stock 95 f150 cam when i took it out, since i have 2 351's, cleaned the iac a few days ago, and all my vacuum lines are less than a year old.

asap,
with the "air adjuster" i can lean/richen the mix by simply turning a screw. it lowers/raises the voltage from the maf meter to the pcm. so i can leave base timing at 10, and richen until deto is gone, which i did yesterday and power was restored as well as throttle response. but if i couldn't do that, id have to set base timing to 8 in order to keep it from detoing with the a9p which is more aggressive than the jog1 or my hug2. but i just temporarily installed all this to make a video that everything works for the sale of the system, which i don't need anymore.

fmos,
i just know its lean because ive ran this system before and had to richen it. the 351 runs really REALLY well when slightly rich, but idle will choke you lol. once everything runs good, idle always seems to be too rich. and i can't tune that out with what ive currently got. BUT revs strong with the a9p, thats for sure.

as an update so yall don't have to read everything.
i went back to the 5.o cam advanced 4 deg, running the jog1 which is speed density, with all the other performance parts still installed and it ran very very......very well. pulled strong at all throttle positions, in other words, no dead spots whatsoever at any rpm/gear or throttle..... i was pleased with the results, or at least for the next year. but it started to have a wierd issue at start up. after about 5 minutes, fuel pressure would fall off and it would barely idle, i could rev it up and it ran good but idle would be around 450, barely allive, engine shaking....... so i sent my jog1 off to get the capacitors replaced since its never been done, i kept replacing fuel pumps and relays only for the problem to remain, blaming china................ so in the meantime, i installed the maf kit to drive the truck, which ive installed many times, and the problem went away so im assuming it was the ecm the whole time.
so im driving the maf system for now, which the jog1 seemed better than the a9p until i richened the mix. its not a good way to do it but it works, gets you in the ball park and keeps everything happy until my jog1 returns. but by its self, the tables must be based on the amount of air a five o pushes through and not a 351? even though its maf, its lean by itself. but im running aftermarket tb, intake, ported gt's with 1.90's, 1 5/8 shorties, high flow exh. etc...... so it flows a lot more than a stock truck, or at least more than the NON lightning 351

if you watch the rev video i posted,......... thats before i richened the mix..... thats stock a9p rev, only wot for a brief second, a couple times. its even snappier when it rich lol
 
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These PCMs don't have learning capability. It's X input produces Y output. Now some other part may be failing that is fine with a reset then fails again later on. I'd be looking at IAC they are known to carbon coke and stick. Etc. Or a vacuum leak these things have miles and miles of vacuum lines. It took me 30 feet of DOT air brake line to replace all mine. The stock ones get really brittle. They look ok but if you touch them they crumble. At this age may be worth it to replace them all just to rule it out.

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Sure they do. If I put my stock injectors in it will run like crap for about 150 miles as it learns to put more fuel in and then it's fine until I unhook the battery and the process starts again. They aren't on the same level as modern stuff, but they do learn.

Again, the PCM is commanding the high idle. It's not the IAC, a vacuum leak, or anything else. When you look at the data and it shows the IAC position requested as 100% that means the PCM is requesting the high idle. Turn the key off and back on and it's usually fine until you stop somewhere and then it's back to high idle. Unhook the battery and it's fine for a few days until it relearns this behavior.
 
i thought they had a slight ability to learn but maybe its just a slight ability to adjust.
ive never monitored live data other than the transmission with a laptop.
 
i thought they had a slight ability to learn but maybe its just a slight ability to adjust.
ive never monitored live data other than the transmission with a laptop.
do a search on the net for the Ford LHBH1 strategy document and download it. it covers some Ford truck SD pcm's. SD truck and Gen1 Lightning SD pcm's have adaptive learning very similar (essentially the same) as the Ford MAF EEC IV pcm's.
 
got the computer back from having the capacitors replaced, took ecm apart to verify quality, sprayed both sides of the circuit board with battery terminal protection spray, put it back together after it dried and sealed the rear port with foil tape. removed all wires from the 60 pin and cleaned the females with a tiny file, blasted them with starting fluid, cleaned everything up real good, repined the connector back and so far so good........also replaced the 60pin grey connector due to several broken tabs that locked the pins in.

the issue it was having was a weird start up issue, after about 15 seconds, fuel pressure would drop and barely idle. i thought fuel pump and relay, but after replacing like 3 of each, it still did it....... like the computer was not sending enough voltage to the relay, then after a minute or so, everything would return to normal and be fine the rest of the day....

switched it to maf while I waited for my speed density to return back and it ran fine, so figured it was the ecm......so its either fixed for now or just coincidence lol,

which leads me to another question for the gurus..........
that custom ground cam i was running strait up.........let say i advance it 4*.......... strait up it would idle around16.5 to 17" of vacuum.........does advancing effect vacuum in any way? ive read that it will slightly increase vacuum........and if that were true..... i could advance that cam, idle would be tolerable for the speed density and id have the upper end power that cam made with the 32* of overlap at lower, more usuable rpm range that i use?????? any thoughts............id get pimpslut but i don't want to put more money into this thing just to tune a cam with minimal mods...i can't justify that.
 
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