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i borrowed a matco obd1 scanner, pulled KOER self test and only got code 34 which is for EGR. (i always get this code since its blocked off) i did some messing with the VSS and this truck seems to have both the one at the trans and the one at the rear axle? i thought it was one or the other? i unplugged the one on the tailshaft and drove it, very delayed shifts and hard downshifts. i then plugged it back in and unplugged the rear diff sensor and no change to how the truck drove.
I have a 94 F150 351W E4OD with the exact same problem and have been chasing it for almost two years now. Also have shorty headers and emissions removed. Will be following these posts to see if you're able to make any progress. I've tried about everything you listed in your initial post as well. I sent my ECU off to get repaired a few weeks ago - will let you know if that makes a difference for me. Good luck
If you threw the parts cannon at it, 'same as he', then your in the same boat, if you didnt test any of the parts you removed, or the 'new' ones you put on, too many times people have gotten bad parts right out of box, and assumed(including my knucklehead sefl) and it bites you in the keester every time. check for stored codes.
i borrowed a matco obd1 scanner, pulled KOER self test and only got code 34 which is for EGR. (i always get this code since its blocked off) i did some messing with the VSS and this truck seems to have both the one at the trans and the one at the rear axle? i thought it was one or the other? i unplugged the one on the tailshaft and drove it, very delayed shifts and hard downshifts. i then plugged it back in and unplugged the rear diff sensor and no change to how the truck drove.
On 8th gen trucks, I believe the sensor in the transmission tail housing (output shaft sensor) goes to the ECU. The VSS in the differential is for the abs brakes/cruise control.
If you threw the parts cannon at it, 'same as he', then your in the same boat, if you didnt test any of the parts you removed, or the 'new' ones you put on, too many times people have gotten bad parts right out of box, and assumed(including my knucklehead sefl) and it bites you in the keester every time. check for stored codes.
initially i was working on this truck for someone else, and ended up buying it. he told me "just start changing parts until its fixed" he didnt care what it cost he just wanted it fixed. everyone loves to call people parts changers when in reality, this truck is 32 years old. i had to pull the motor to replace someone elses hack job of an oil pan gasket leak. all the vacuum lines and bull**** for emissions were failing and cracking. the range sensor was cracked. no i did not test it i replaced it. i only deleted the emissions stuff because it would of been too costly to repair them to factory standards. (truck does not have to pass an emissions test in my area).
the truck started this idling issue shortly after the headers/oil pan gasket/emissions delete was done. im not saying it was or wasnt related... but possibly. is it possible the deleted emissions can cause this? although hundreds of others have deleted the emissions and have no issues..... if i wanted to just change parts i would do so but im asking for advice, because im not the most knowledgeable on these older obd1 vehicles. most shops dont even wanna touch it.... they do the same ****. throw parts at it.
PCV valve was new when motor was out. truck does not have ABS to my knowledge its a bare bones work truck f250..... no light comes on for ABS when first turning key.
PCV valve was new when motor was out. truck does not have ABS to my knowledge its a bare bones work truck f250..... no light comes on for ABS when first turning key.
Then the ABS light is burned out. He wanted you to check the PCV to see if it was still in the grommet on the valve cover. If the grommet was not replaced it very well could be out of place. New parts don't mean they are good in this day and time.
Youre at the point where you need to grab a multimeter and start back probing the ECU connector. This is the sure-fire way to confirm the ECU is actually getting the signal from the Sensors.
Youre looking for the:
Engine Coolant temp sensor, key off. Check when cold, Ohms should be ~33k. Then start the engine for 2 minutes, key off and check again. Ohms should ~3k-16k.
Throttle Position Sensor, Key on engine off, Volts. at idle and WOT, Idle Should be around 1V and WOT should be ~3.8V higher than idle.
Speed sensor: Ohms while stopped. ~800-1600ohms
MLPS (Transmission shifter sensor) Cycled through its whole range. p=3770-4607 OHMS, r=1304-1593 ohms, N=660-807 ohms, D=361-442 ohms, 2=190-232 ohms, 1=78-95 Ohms
Then the ABS light is burned out. He wanted you to check the PCV to see if it was still in the grommet on the valve cover. If the grommet was not replaced it very well could be out of place. New parts don't mean they are good in this day and time.
Im guessing you have ABS but the fuse is burnt out. Look on the inside of the driverside frame rail, right under where the driver's feet sit on the floor pan. You may see a torpedo shaped device about 7" long with 2 brakes hoses and a wire harness coming out. Thats your rear ABS module.
As for the PCV valve, I was more concerned that the PCV is in place, the hose isnt split, and the other end of the hose is actually connected to the intake manifold. It would be a shame if you just have a massive vacuum leak because the PCV hose was disconnected. The engine doesnt really care if the PCV valve is in the crank case grommet; itll just suck outside air instead of sucking out the crack case fumes. Photo borrowed from Ford-truck forum
initially i was working on this truck for someone else, and ended up buying it. he told me "just start changing parts until its fixed" he didnt care what it cost he just wanted it fixed. everyone loves to call people parts changers when in reality, this truck is 32 years old.
if i wanted to just change parts i would do so,I'm not trying to bust your chops(I said, I did it), but you said you did, now you can go back and test them.
Did you know there's 3 different IAC's that fit our truck, parts stores only see it says it fits, not having engine size next to it, all you see is price which one will you(everybody) buy, the cheaper ..damn near always,
IAC=Idle Air Control, the holes on the 4.9L, and 7.5L are bigger, so the 5.0/5.8 will start surge/hunt idle, I found out hard way like everyone else, until I found FTE.
cx-1867-$62--4.9L
cx-1828-$57--5.0/5.8L
cx1823-$52--7.5L
quality control is nil and void on these and any other parts you buy for any vehicle.
There's also a TSB--click attachment below
Did you know there's 3 different IAC's that fit our truck, parts stores only see it says it fits, not having engine size next to it, all you see is price which one will you(everybody) buy, the cheaper ..damn near always,
IAC=Idle Air Control, the holes on the 4.9L, and 7.5L are bigger, so the 5.0/5.8 will start surge/hunt idle, I found out hard way like everyone else, until I found FTE.
cx-1867-$62--4.9L
cx-1828-$57--5.0/5.8L
cx1823-$52--7.5L
quality control is nil and void on these and any other parts you buy for any vehicle.
There's also a TSB--click attachment below
I was not aware of the different engines requiring different IAC valves. Hadn't heard that before.
I do know that there is an early style and later style IAC depending on the year model. The computer programming is specific to the style used as they are mechanically different. A mismatch will result in noticeable driving problems.
The old style had a bypass spacer, you could purchase, and helped with idle issues, member here said, you can get them for the fox body, and fit, mine has the vent.
link-->How to Clean and Test your IAC - Ford Bronco Forum
09-25-2022, 03:30 PM
