Running Rich (Still)

[79F1504X400]

Last night I searched the threads here about 2.9L's running rich and basically I went away thinking coolant temp sensor, MAP sensor or FPR. All of which are new now, and its still running rich. So much that the exhaust stinks. I can drive it. Seems to have the same amount of power, doesnt stumble or hesitate, just sounds funny in the exhaust. It wont start after letting it sit over night, I have to use some ether to get it started, once its warm its no problem. The injectors even sound different, which is hard to explain. I have replaced the ECM, still not 100% sure I got the right one. So does anyone have some ideers/suggestions? Im starting to think maybe I have a couple injectors that could be plugged. And since I found some broken wires on the FP circuit...the pumps run as soon as you turn the key on....no 2-3sec prime. The fuel pump relay is new....like about 2 weeks old.

 

[holyford86]

I'd go through and check the wiring to the fuel pump. Also check that the orange ground wire to the back of the passenger side head is intact.

 

[79F1504X400]

When I had the bed off last week I checked all those wires going to the tank. All checked good. Got good ground on the orange wire just like schematic says it should, assuming thats the wire you're referring to. The wires I repaired was actually the plug there on the frame rail going to the high press. pump. It had a loose connection somewhere in the plug so I removed the plug all together and spliced the wires. I was laying under the truck with pumps running/engine off wiggling the wires listening to them cutting in and out. Problem solved. Now they just run continuous...which is what was happening before I found the loose wires.
Now Im convinced this thing is possessed. After all what I posted last night...went out 5am this morning and it started right up. No strange sound in the exhaust...no strong gas smell either. Purred like a kitten in the 30 deg. weather. Thought about driving it to work....a whopping 4 miles....but thought better of it based on my lack of trust at this point.

 

[Big Jim M]

Sounds like you got her... As a hint...drive it around and around the block.. Never getting too far to push it home. put that 4 miles on it like that.
Big JIm

 

[79F1504X400]

Thanks Jim. Thats my game plan. I did drive it around the block once yesterday. When I get home after work the first thing Im going to do is start it up. Im crossing my fingers.

 

[79F1504X400]

Its Baaaack

Started fine this afternoon. Let it warm up, idled like a dream. Decided I'd go get some gas which is maybe a mile away. Filled it up and when I started it the rough idle and super rich exhaust was back. Wont idle very well either, it lopes, almost dies, catches itself and keeps trying to idle. Also noticed when its in this mode the fuel pumps dont prime....they just keep running. I dont think I've seen anything like this posted on here. Theres not much else to replace on this beast as far as sensors and the like. The vacuum thing on the pass. side fender with the green and red lines and the sensor on the pass.side of the lower intake and the TPS have not been replaced. Now what?? This is so weird.

 

[79F1504X400]

Update

No good news...I have a bad feeling Im going down the wrong road with this but hell its only money right?? Went to O'Reilly's and ordered another ECM, except this one is a BWD part and not a Cardone whatever thing for about the same price.....we'll see here in a week if it works. So does anyone have a known good spare ECM for an 86 with a 2.9?? I probably should have asked this a week ago but.....

 

[RustedRanger]

One problem mine had that I didn't find until a friend who does mobile diagnostics put on his diagnostic computer was a bad plug-in for the coil. Mine was running until I started cleaning plug-ins and then it wouldn't start. He could move plug-in around and it would change the idle,the coil was also weak. Just a thought since it ran good then all the sudden didn't.

 

[79F1504X400]

Thanks

I'll remember to check that when and if I get it running. The coil is new,bought it last spring, but one never knows when an electronic part decides it doesn't want to work anymore. In the past I've done the wiggle the wires thing when its running, but that was mostly over on the pass. side to make sure the FP relay and EEC relay were making good contact.

 

[sjr53]

My 86 Bronco II had some unfilled factory holes in the inner fender splash guard that let water get on the coil & corrode the primary coil wiring. That gave me trouble may years ago. I've heard that having a misfiring ignition will put O2 into the exhaust & then the ECM ritchens up the fuel mixture. I just remember it barely ran as I was pulling off the highway. I made it to the airport parking lot & lifted the hood to find the coil slightly wet & the red wire contact was corroded. Cleaned it later & plugged several holes in the splash guard with small bolts & nuts.

And after saying all that, Your problem with the pumps seems unrelated.

 

[79F1504X400]

SUCCESS!!!!! I hope....

I say that with some reservation. Got the new BWD ECM yesterday, got it installed following the instructions and VIOLA...it runs. I've put about 25 miles on it since last night and haven't had a problem. So....I'm going to say that original problem here about a month ago was bad wires on the plug going to the high press. FP on the frame. I got on the wrong track fooling around with the ECM, as I believe the original was good. The first ECM I bought (Cardone) definitely caused some problems. I did check the coil wires and the one going to the distr. was not fully seated, I heard a click when I pushed on it. That could have been my misfire problem with the rich exhaust and eff'd up idle. Thanks Gents for your input.

 

[79F1504X400]

Still Starts

Just went out and started it again. Its a thing of beauty