5.0/nv3550...engine now dies at stops*help*

[blazinchuck]

hey guys, for some reason the bronco now wants to die when coming to a stop. we had our big trip April 12-14..starting on the 15th i started to notice the idle dropping every time i came to a stop. normally it would hold a 1000-1100 rpm til my speed dropped below 8 mph...its not doing that any more either. if i gear down it will stall out every time...so now i have to ride with clutch in or slap it in neutral and pop the throttle once and it will then hold its set idle. ive also notice it wont do this until engine come up in temp...if i start it up and go...i can make a few stops before it starts stalling out.






i was sure the VSS was taking a dump...so i swapped it out. i had another laying around. but its made no difference. a month ago i set the tps voltage and idle and none of that should have changed. im still running the A9P(which i thought was not dependent on a vss)


fyi, i did install cruise 2 weeks before that April trip...only putting that out there. it was a simple wiring hook up and it gets its signal from dakota digital cruise output (at 2K pulses output) ...plus i run 2 ford vss, the 1st one at the tcase is for the EEC and the 2nd is for Dakota Digital...so neither of the systems should know the other is even there.


if any of you have some thoughts...lemme know. this is becoming annoying to drive now%)

[broncomatt]

You know my number bud, Have you put a scan tool on it to check codes. The first thing that comes to mind other wise is a vacume leak. Try some propane around the back of the intake, I had some when i was at ford that the pvc line melted or broke.

[broncosbybart]

Maybe clean the MAF too. It is very important to use MAF cleaner to do it. (Ask me how I know)... I clean the MAF in the racer probably 2x a year.

[chuzie]

Don't worry Chuckles, I will fix ur junk when I get back from this mission. :thefinger:

[blazinchuck]

emoved the IAC and MAF, the was very dirty. Cleaned it with maf cleaner and sprayed some into the ports on the iac. With truck up to temp the first couple stops it tried to shut off...but recovered. A few stops more and it seemed to be better. I'll test some more today...but not once did I have to tap throttle to save it. Still not seeing idle staying up when coming to a stop. I know I wasn't seeing things....it used to do that.

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[Bronco Biff]

My first thought when I read this was the IAC......and still is!! It also seemed to point there when you said it did not do it when cold-when the computer should be telling to IAC to open up some more for fast idle.

[blazinchuck]

I swapped in a new IAC still doesn't seem like a sure cure...still tries to die

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[broncosbybart]

Did you take the plate off the MAF? (The one with the 2 torx screws?) I remove it when cleaning. Not sure if it'll help. All my idle issues have been MAF related so far. For an off road rig, efi is nice but isn't worry free...

[nhopman]

Shoulda bought a Jeep with a warranty :rofl:











Just Kidding DON'T BAN ME FOR LIFE - hopefully its as simple as cleaning the MAF real well. I seem to over oil my K&N when I clean it and usually have to clean the MAF shortly after, and it usually makes a big difference with idle. Although I don't run a VSS with my C4 and have not had the thing die on me when stopping, even when it's not running well.

[broncosbybart]

Chuck wanted a jeep, but Lisa made him buy the 77 for her, remember?