Hard to start, won't idle

[mtipton]

Hey guys,
First time posting on this site, figured you guys could help me out here


Okay the deal is i recently decided it was time to give the old 2.9 a new life. I pulled it cleaned it all up and sent it to a local machine shop to do all the work.
They cleaned up the block, bored it .30 over and put a torque profile on the cam. I had them re-assemble the bottom end of it seeing as they already had it and i built the top.

Now since i have this thing back in the truck and everything hooked up for the life of me i cant get this stupid thing to run....it cranks and cranks to no avail, if you unplug the fuel pump relay, then connect it it will barely start but die unless you have the throttle pinned.

I have swapped the distributor, throttle sensor, plugs wires cap, MAP sensor, coil and TPS. Fuel pressure is a steady 38-40 psi, i have plenty of spark. the one thing that throws up a flag is i only have 100-105 for compression on the cylinders, i know its a new engine and the rings most likely havent seated yet but i still see that as low.


So if anyone has any ideas... they would be appreciated because i am stumped!

 

[Elchai]

Since it dies if you don't floor it, i would think it might be a problem with your IAC valve, since the fuel pressure is good, ( i've had 2.9's run on 20 lbs), there is spark, and there is no backfiring (since you didn't mention any), that rules out valves and some sensors.,

 

[disciplerocks]

It will still idle with or with the IAC working. It would just idle poorly or fluctuate. Sounds like an electrical problem to me. I am not familiar with the the way the air is regulated yet on the 2.9, but thats one place I'd check and the TPS.....can't think of anything else right now off the top of my head.

Edit: Are you sure the timing is set correctly? If its 180 degrees off it may cause similar problems.

 

[Big Jim M]

How did you test the compression? Should take all the plugs out and hold the throttle wide open before starting the testing. If you did this and that 100 lbs is the true compression... my guess would have something to do with the camshaft or the timing markers are a cog off...
The fact that it WILL START means it ain't 180* out.
Big JIm

 

[mtipton]

Thanks for the tips guys, I'm going to pull an IAC valve from a wrecker and see what happens, the timing I believe to have bang on, going to
play around with it some more and see what I can find

 

[mtipton]

Found the problem, just so happens the machine shop didn't align the cam with the crank and the timing was at 30 degrees ahead. Also they made a mess of the thing. Didn't have the keyways lined up for the crank and was sitting out of place, tooth was cracked on thr sprocket as well, going to be talking to them get a new timing kit and see what happens

 

[disciplerocks]

Ah yes the timing. I thought that may have been the culprit. Although I was wrong about it being 180 degrees off. I had to set the timing on a friends car once without a timing light and I got it 180 off and it did the same, at least until fire came out of the throttle body lol.

 

[Big Jim M]

Oh boy!

Ah yes the timing. I thought that may have been the culprit. Although I was wrong about it being 180 degrees off. I had to set the timing on a friends car once without a timing light and I got it 180 off and it did the same, at least until fire came out of the throttle body lol.

I think I would question ALL the work they did! If they cannot get that part right what would make me think they could get ANYTHING correctly done?
I would go all the way with these guys. Pull the heads and look at the rings and also the bore job.. You could have a real lemon on your hands here..
Big JIm

 

[Elchai]

I'm with Big Jim on this one, since they couldn't get a simple timing setting done right, and that's with the engine off!!!, Imagine something more complex like rings and such.