Rough running 2.9 in closed loop mode.

[BRONCMAN]

I know there are a ton of these threads, but rather than to discuss this in one of the other threads I figured I would post my own. So here it is. 1986 2.9 v6, 5 speed. Recently replaced plugs, wires, cap, rotor, MSD coil, o2 sensor, fuel pressure regulator, & fuel filter. When the truck is first started it runs excellent. As soon as it warms up & the idle drops (closed loop), it idles rough & acts as though it wants to die, but never does. When driving it does fine sometimes, then when I'm just cruising at light throttle it will all of a sudden run like crap & sputtered, acting like its missing. If I punch it when it starts doing that (WOT) it clears right up. Would the IAC do this? I'm thinking possibly egr as well? Just hoping to get some more insight from you guys. Thanks

 

[stegomon]

i forget what it is called...but the plug that is on the back of the dizzy...kind of acts like a cam shaft sensor can act up and do that

 

[sblake01]

i forget what it is called...but the plug that is on the back of the dizzy...kind of acts like a cam shaft sensor can act up and do that

TFI module.

 

[jhammel85]

Have you checked it for codes?

http://fordfuelinjection.com/?p=13

That site will show step by step on how to do it.

Are all the grounds and ground straps in good shape?

Also, see the table near the bottom of this page. Maybe it'll help you find out what's going on during closed or open loop.

http://fordfuelinjection.com/?p=3

 

[BRONCMAN]

Thanks. I checked it awhile back for codes & there were none. I'll check it again tomorrow.

 

[BRONCMAN]

I got codes 24 & 66.

24- air charge temp (ACT) out of self-test range.

66- MAF circuit below minimum voltage.

So I assume I need a new map sensor.

 

[BRONCMAN]

Earlier when I checked the codes, I tapped on the map sensor a little. Well I just got done driving it over to my folks place & back, which is about 10 miles away. It ran great & even idled great after warm up. Nobody in town has a map sensor for it, so ill probably get a new one Monday when I head down through sandpoint.

 

[a31ford]

Did you every get this problem fixed ?

I have the same issue from Time to time, and since the muffler fell off 3 days ago, I noticed that when it runs like crap, it's literally cross firing above 2500 rpm, unless I back off on the throttle, then ever so slowly speed up again,

new plugs, new wires, new cap & rotor, coil checks on the VOM fine

 

[BRONCMAN]

Seems to have been fixed. I ended up replacing the map sensor & the truck ran great for about 50 miles then started doing it again. I then replaces the tfi module as I thought maybe it was heating up & then acting up. This time it ran good after that for about 200 miles. I then figured out everytime the battery was disconnected it would run fine for about 50 miles. I then figured it was a ECU issue & figured I'd replace it but since I had to replace it that it would be a good idea to get rid of the egr & have one less thing to worry about. So I went to the salvage yard & found a 90 ranger with the 2.9. I grabbed the ECU & egr block off plate off it for $30 & installed them in my ranger. Been running great since.... Knock on wood. Sorry for not posting these results earlier.

 

[a31ford]

Thanks for the reply.

Your Conclusion is the same as where I was going on the ECM, and the 50 miles thing is also the same.

Thanks again.

Greg