start but wont idle after transmission install

[lunchboxlust]

Yes moose it ran fine before the trans swap. I borrowed a scan tool from one of the guys from work. The service engine light is on but still no codes. When doing the transmission I only disconnected the maf and the other one that is behind it. I think it is a temp sensor. As far as the transmission removal I only disconnected 2 O2 sensors after the cats, two speed sensors on the trans. One on the front and one on the back. The transfer case plug, the large transmission plug on the pass side and the neutral safety switch. I think that is all. I have a 300 amp alt and did the big 4 and I was thinking I should remove the grounds and clean them. I knew I had one exhaust stud broken before the job but when it was cold yesterday when I was trying to get it running I noticed that I have a major exhaust leak now right at the header. I know an exhaust leak will cause it to run bad but to not run at all? I'm looking for my test light at the moment so I can test fuses without removing them. I also talked to a old school ford mech. about the IAC and he said from what he can recall the plunger in the IAC should return shut after I open it with a pick. He wasn't 100% but I didn't know if anyone one her could confirm this.
Going to test fuses. Ill be back later tonight

I would like to thank all of you for helping me. This site has helped me many times and even given me many hours of enjoyment reading and looking at other expeditions.

 

[lunchboxlust]

If fuses are bad then circuits don't work - as in doesn't do anything. Doesn't hurt to check them though.

Fuel pressure is within spec to run, that leak down isn't enough to worry about for this problem. A fast leak down would be of concern.

Next up would be exploritory inspection of the intake system for blockage, injector harness for critter damage, egr valve vacuum test, damaged vacuum hoses.

If everything checks out the next step will risk the cats, crank up and hold at whatever rpms will keep it running long enough to throw codes. While running you can "shoot" each manifold exhaust port with an ir temp gun. Any cylinders that aren't firing will be a lower temp than the cylinders that are. Dump too much raw gas in the cats and they are toast.

I didn't see this post. I will have to do this on Friday afternoon when I can get a hand. I don't have many friends I can call on for free and my brother sleeps in the afternoons so revving the hell out of my truck with no exhaust when he is sleeping would be funny for me but he would not be impressed. But I do have an ir temp gun.

 

[stamp11127]

Might want to check that the ground strap is still connected between the engine and chassis. Inspect the transmission wiring harness where it runs by the exhaust manifold. There have been issues in the past where the wires have been burned from poor routing.

 

[1955moose]

An idle air control motor, or iac would cause it to not want to idle, but it still should run. Our company Dodge 150 pickup from our Harley shop had a bad Iac motor, it ran fine, but wouldn't idle. From the items you disconnected, a malfunctioning maf sensor or the o2 sensors not getting a reading from the computer, could cause havoc. Or the failure of one of the sensors, definitely cause your symptoms. I would look at the wires and plugs coming from those items, to be sure you don't have a break in the wire, or pin. Maybe Stamp or bedrk, can supply you with some wiring, and diagnostic for the items in question. You also might want to try a different code reader, it's hard to believe your not throwing some kind of code, the way it's running. One last thing, make sure the air box where the maf sensor goes isn't cracked. It's easy to crack, if old and not careful.


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[lunchboxlust]

Well I went back out and I realized that the service engine light only comes on after it dies. If i keep starting it it without removing the key will stay on but as soon as I remove the key and put it back in it is off until it dies again. So I think I got excited when I noticed it the other night and didn't realize it wasn't really on. I started to remove the grounds under the hood to clean them and the hood came down and I smashed my face on the batt so after throwing my 1/4" ratchet I decided to be done for the night.

 

[docraymund]

Next time be careful, jam a wooden mop handle under the hood. If all things fail, what you can do is disconnect all sensors that are not necessary for the engine to run. Just leave the essential: tps, maf, coolant temp, crank and cam sensor, etc. I think it will run because sometimes if the pcm detects a bad sensor it will inhibit the engine from running to prevent further damage to the engine. Just figure out what are the truly essential sensors needed for an engine to run.

And also maybe you could borrow or rent a smoke machine to locate leaks. You may have overlooked a pulled vacuum line.

 

[tcwaltz]

out of curiousity (even though I had mine apart I don't recall how easy this would be to do). When you were putting the tranny back in and turning the motor to align the torque converter bolts, did you by chance turn the engine backwards and jump timing? I'm not sure that is even possible with these since they are chain but they do have tensioners.

 

[lunchboxlust]

It was a job to turn the engine but i only had a 19" breaker bar. I had my brother turn it while I put the nuts on the converter so It wasn't me turning it but he did say one way was much harder to turn than the other. I do know that if you don't have the converter all the way seated the studs will bind on the flex plate so before you have the transmission mounted you have to make cretin the converter is all the way seated, it goes on you hear a clunk then turn it and push it on farther till it clinks again. I guess if you don't seat it all the way you can destroy the transmission pump..

So for an update I got it running. I feel really stupid but I have a spectra cold air intake and the place where the MAF is the same on both ends and I installed it backwards. I don't know what made me want to check for that but I'm glad I did. After flipping it, it fired right up. A huge thank you to everyone that has read my thread and contributed to any idea of things to try. I didn't want to leave this question open ended like so many other ones so I swallowed my pride and yes I'm stupid and the issue was an oversight on my end. I'm just glad that part is over. Now I have to drill and tap the exhaust studs from the heads. Do I have to remove them or do you think I can do them by removing the fender plastics?

 

[Bedrck47]

Thank you for the update And no your not stupid I would say your a better man for admitting your mistake. \

There are some good videos on youtube on replacing the studs Suggest you look at them If you decide to drill them Then get a good angle drill and take your time

 

[docraymund]

Glad you fixed it!