EFI idling Q's, MAF related..

[Broncrick]

Stumped! been through the Probst book, searched all over online, nada. The rig will run (but rough) but not idle. If you take the MAF conn off it idles and runs better (limp mode). Engine is a 5.0 (non HO) take out. All the parts were untouched from the donor short of Ryans harness. Vacuum is good, timing is on, codes are the usual for a non-smog engine. Ideas?
Rick-

[jvanderveen22]

whats your fuel pressure like? does it rev off idle and act normal or just get worse?

[Delta 4 Wheel]

Hook up every sensor, MAF, etc, and unhook your Idle Air Bypass (on the throttle body) Turn the idle way up before you start it just to get it wunning. After it is running and if it will idle, set it to 650-700 rpms. Then kill the motor, and then plug the IAB back in. Re start- Your idle should not change that much after you plug it back it and run it. Let me know if this helps.

[highlander]

Are you running the non-HO ECU. What was the donor car?

Did you time it with the spout connector disconnected?

[welndmn]

Carl is right, try and reset base idle.
http://www.muscularmustangs.com/idlereset.php

Don't forget after screwing with it to recheck your TPS voltage.

[Broncrick]

whats your fuel pressure like? does it rev off idle and act normal or just get worse?

Press is ~38psi dosent want to idle, like a carb when idle is low, feather it...

Hook up every sensor, MAF, etc, and unhook your Idle Air Bypass (on the throttle body) Turn the idle way up before you start it just to get it wunning. After it is running and if it will idle, set it to 650-700 rpms. Then kill the motor, and then plug the IAB back in. Re start- Your idle should not change that much after you plug it back it and run it. Let me know if this helps.

Will do now

Are you running the non-HO ECU. What was the donor car?
Did you time it with the spout connector disconnected?

A9P, and yes

Carl is right, try and reset base idle.
http://www.muscularmustangs.com/idlereset.php
Don't forget after screwing with it to recheck your TPS voltage.

Great site Mark! I will do the work and report back soon

[Broncrick]

Testing completed. Could not get the idle to stabilize, even with the adj screw all the way in. TPS is at 1.34v, and that is after some 'work' to enlongate the adj hole. Now thinking out loud here, I took the whole EGR plate chit off the intake and have the TB (have Ryan's plate here but am running BC's cable) bolted right to the intake, issues? dangit!

Who has an extra MAF I could borrow for five minutes?

[Lars]

Testing completed. Could not get the idle to stabilize, even with the adj screw all the way in. TPS is at 1.34v, and that is after some 'work' to enlongate the adj hole. Now thinking out loud here, I took the whole EGR plate chit off the intake and have the TB (have Ryan's plate here but am running BC's cable) bolted right to the intake, issues? dangit!

Who has an extra MAF I could borrow for five minutes?

Rick, I don't have a spare meter but I have a couple of MAF electronic modules. You are welcome to try them, just not sure how to get them to you. Currently home with a bad back, not in any shape to drive anywhere. As for that TPS voltage, it's high because the idle screw is cranked in so far. Normal "ballpark" setting is more like unscrewing it till it doesn't contact the bellcrank, then screwing it in until it just touches then one full turn. At that point the TPS voltage will likely be ok, though from the sound of it you won't have an idle (yet).

It's been a long time since I looked at a Mustang or non-HO intake (mine is Explorer). You say you removed the EGR stuff but have the throttle body bolted straight to the upper intake with no block-off plate in between. Is it possible that there's an EGR port in the upper intake that's bleeding exhaust gas into the intake stream due to no block-off plate?

[Broncrick]

Lars, sorry about your back, you need a softer suspension when driving so fast for so long (from SOB), or slow down

My thoughts too, the TPS will come in line once I get it to idle, and I will throw this 'EGR eliminator' plate on for grins and giggles to see if it has an effect. Heck I have time I guess after being down for so long, just getting antsy... back to the garage...
Thanks,
Rick-

[welndmn]

If you turn your idle screw back up, and unplug your Idle Air motor, will it idle? (maybe need your foot to open the blades if they screw is turned in to far when cranking.

[Broncrick]

If you turn your idle screw back up, and unplug your Idle Air motor, will it idle? (maybe need your foot to open the blades if they screw is turned in to far when cranking.

Back up? you mean down right (or out)? I'll try...

It'll start when I crank at first, but die befoe I can run around to the acc cable to keep it going. Putting in the plate now as we 'speak' didnt see any tracking as far as gasses getting past the TB, but wtf

[highlander]

You have an A9P ECU which is for HO motors on a non HO motor, did you switch to 19# injectors if you have the 14# injectors it will run terrible and probably wouldn't idle.

[Lars]

You have an A9P ECU which is for HO motors on a non HO motor, did you switch to 19# injectors if you have the 14# injectors it will run terrible and probably wouldn't idle.

Ooh, good point. I don't remember the color for 14 lb. injectors, but 19 lb. are yellow top. Very important.

[Broncrick]

Yep running the 14lb'ers, kinda beige color. I have a 19lb set here I will try after work, Thanks, didnt even think of that!
Rick-

[Broncrick]

You have an A9P ECU which is for HO motors on a non HO motor, did you switch to 19# injectors if you have the 14# injectors it will run terrible and probably wouldn't idle.

Ok, been a thinking exactly why would the injectors make a difference? they are mechanical, the size is based off engine performance percieved load. The 'puter dosent know a 24# from a 14#, they just dump fuel in when told so. If the engine runs in 'limp' mode fine, the injectors are firing fine, the wires are fine, and the timing is fine. So then 'engine' and its basics are fine.. I am back to a sensor, when introduced into the loop (when the MAF is plugged in) gives me an awful idle/run condition, working on that.

Educate me if I am incorrect here. By the way the 19# injectors are soaking, and I'll get new O-rings Fri just to check out the theory

..and it almost will idle now (but rougher then heck), TPS @ .883v @~650 rpm..

Tnx
Rick-