idle woes

[mustangjon]

Ok so as most of ya know, im doing a speed density build, well car is back together and runs, yet wont idle for crap, it will just acts like a huge cam is in it lopes so bad almost stalling. under accel seems fine, only took it around block once. Black smoke running rich at idle, gets better under throttle. Base timing is between 10-12 degrees, with spout in, runs to roughly 20-25 degrees total. (seems lower than it use to advance to, thought was more like 30 before the mods) have adjusted the fpr to 35-40psi,

Had to redo some the vacuum routing due to removing the smog pump, thinking maybe a vacuum leak, but tried leaking a little propane around the vacuum fittings a bit, no noticeable change. So current thoughts, the vacuum rerouting isnt giving proper vacuum, where it should, or the mods are causing the SD comp to freak out searching for correct a/f ratio.

Any thoughts?

[DeckerEnt]

Some more info on the Lincoln. He just upgraded to GT-40 Heads, 1.7 roller rockers, 24 Lb injecters, explorer upper and lower, shorty unequal headers, off road h pipe. Details to make a good diagnosis.
Keith

[mustangjon]

i'm going to open up the plug gap back to .50 to force a stronger spark, might help burn some the richness out, going to check, double, triple check the vacuum lines again, also thinking since most the problem is at idle, im not getting enough air at idle, so thinking of drilling another small pilot hole in the throttle blade.

[facemelter71]

When you upped injectors did you get it tuned?

[mustangjon]

nope, running stock pcm, a few people i had talked to had luck with 24lb injectors on the sd without any form of a tune. Since the speed density computer runs off pulse width it really see's no difference in the injectors, but they might be too big, but the rough almost lopey stalling idle, i wouldnt think would be caused by rich condition

[Stangman]

well, when you are dousing out the spark with fuel... :lol: J/K

seriously though, have you disconnected the battery for an hour or so, to reset the computer so it will "re-learn"?

It may take a few startups and trips around the block at operating temp to see if anything changes...

[facemelter71]

Might want to swap out for some 19's and make a dyno run and see if goes lean anywhere.

[mustangjon]

well after taking a day off to think about it and relax, get my head back in game, i started at the basics. checked all vacuum lines, started at manifold and worked way out, then as i chased hoses.,... i found one the old hoses that went to smog pump was not capped or plugged in:eek: it was hiding in the wiring harness around coil, under intake hose. So problem 1... found and fixed... then continued, pulled plugs to examine and regap... opened gap to .52 instead of the .40 i had... well did 5,6,7,8 then 4,3,2.... got to 2 and noticed my brand new plug on number 2 had the center electrode isolater broke was resting on the outer electrode:eek::eek: so yah running on 7 cylinders and a vacuum leak... could cause issues... walked up to koi got a new plug, retimed it, double and triple checked everything again, readjusted idle... and it runs again! idle still not perfectly smooth, but being speed density i dont know if i'll ever get it like factory again with the 1.7 rockers, added air flow ect. Oh yah and turned fuel psi down to 28, just to check... unplugged computer let it clear, still appearing to run a little rich, but not near as rich. Going to run it to the gas station to get some gas in a bit, i've almost ran it out lol. Still have the one header to h-pipe leak to tackle too. :rockon:

[Stangman]

Sounds like you are back on track Jon! Gonna make it up to the cruise-in?

[mustangjon]

well just took it for a 20 minute beating... still has issues, my realtime fuel mpg guage shows me getting about 10mpg at 45mph in OD lol. Funny thing was the computer, settled down for about a minute... actually thought the car had died, i was driving at 30mph... and car went almost silent as i was basically coasting... i went to slow down car was pushing itself and running smoothly, i pulled over in a parking lot backed the idle down, and took off all was good... till i mashed on it hard again... then went back to lopeyness, either gonna let it cool for a few and take it for another run hoping computer will finish learning and stay that way.. or swap out back to stock injectors to see what happens... any thoughts?

and yes planning on making cruise by all means its driveable now just have to hit every gas station on the way:lol:

[facemelter71]

If you think it might relearn then i would let it idle for at least 15 minutes.And i alos run an E-cam with the typhoon upper and lower CAI and i still run the factory 19 pounders.

[mustangjon]

i talked to a buddy of mine, and said to try resetting computer again, backing idle down to where i had "reset" it after it had smoothed out, because when i had adjusted it when it was running after it seemed to smooth out, i just tossed it out window. But yes im going to try to set idle down low, let it idle for a bit, take it out for a few min, beat on it, see if it learns again, otherwise it'll be swap injectors and take 2.

[Stangman]

If you keep having trouble and get tired of screwing with it, read this website... It'll make converting to Mass Air the easiest thing you'll do.

http://www.fordfuelinjection.com/

Also I posted a link to a fuel injector comparison table. check that out too.

[mustangjon]

BOOOOOOOOOOYAAAAAAAAAAAAAH!!!!!!!

Car is fixed, back to the basics yet again, my whole original thoughts of vacuum issues messing with map got me thinking... started pulling vacuum hoses off while it was running.. the hose that was direct from my intake to MAP sensor had 0..... vacuum pressure. I guess its internally stopped up in the intake. Rerouted the hose and runs like a champ!

No more black smoke, idles great.:bigthumb
I did back the timing back to a safe 10 degrees since its running as suppose to now, and fuel pressure is set at 30psi. Now time to actually tune, well and fix all the small stuff such as exhaust leaks ect lol. :rockon:

Thanks for all the help and suggestions, it always seems to be the little stuff you never think of. I kept thinking vacuum leak.. not no vacuum period....

Oh yah and got about 16mpg even tho i was mashing on the throttle every chance i got. On a 6 mile trip on some back roads/town

[Stangman]

Rock on man!!! Glad you kept at it!! So how much difference is there now in power??

[mustangjon]

its mostly pullin top end... so i havent really opened her up that hard yet lol