1991 mustang lacks power and has engine ping

also, the engine surges at idle when first starting. near 14 BTDC it doesn't do it as much (2-3 seconds), but as i retard the timing it does it for longer, 12 BTDC 10-20 seconds, unless i play with the throttle.

Have you checked to make sure that your E-Spout plug, and associated wiring does not have a short, or bad connection?...I ask because I had the same problem with my '93 and it drove not only the dealer, but 2 top mechanics crazy!!

are you talking about the plug you disconnect to adjust timing? i remove it to adjust the timing and re-install it after. i can hear an instant change in the engine when re-inserting it. always runs good for about a mile, then back to its old tricks.

Yes, that plug is called the elecronic spout (dont know why)...Try swapping out the ( E-Spout) plug with another one, maybe you have a buddy that has a fox 5.0. and by all means check the wiring for the spout plug. I say this as this is the EXCACT problem that I had way back in '94 with a car that was 1 year old with 3,000 miles on the clock and I was having the same problem as you.....Would run fine after I upped the timing to 15 BTDC for about ten minutes, or 2-3 miles, and then instant problems!..... Mine had a cracked wire about 3 inches from the spout connection that was UNDER the cheap plastic insulation. I was lucky as since this was the only thing that I touched, the third mec. said " It has to be this " and low and behold, after ford going through the whole wiring harness, every sensor,and the A9 EEC-3, it was that crappy piece of braided wire!!!!!.....Check it out.....Sean

(Sorry about the double post, we had a power outage so I did not know if it posted)Yes, that plug is called the E-Spout by Ford. But you should Never replace it after a timing change with the engine on, as this WILL confuse the rather stupid, (Primative) A9 EEC-IV. I suggest that you re-time the motor, then shut down (key in the full off pos.) then replace spout,then restart......If still a problem the I suggest that you swap out the spout with a buddy that has a Stang from '89 to 95 ( or a '88 California ) and see if that's the prob. I would most definitely also check that crappy braided wire going to the spout, as that is where my problem was........Hope this is your prob. as it seems you have run down every other option........Let us know........Sean

i looked at the wires. there are two peach colored ones. the insulation appears to be intact. i didnt see a braided wire in the harness. is there a specific ohm reading for the spout connector? or is it just a connector?

I know that it is a very low impedance 12V connector that when unplugged zeros out both the timing maps, and fuel maps inside of the ECC-IV. I do believe there is indeed a resistor inside the E-spout plug also.......Also do not let those wires fool you into thinking that there might not be a break in one of them under the insulation!! As I believe there was a TSB for the wire, because they had to be replaced on my '91, and when I got my '93 they were now wrapped in black heat shrink tape (but were still faulty) , and by the time I got my '95 the whole E-spout connection was indeed protected with the addition of a nylon wire-loom........Try to find someone with a spout that you can borrow, or try to find one at a junk yard, as I believe the part has long been out of production for replacement, but try Ford also.......I would NOT be such a nag about this if I did not have the SAME problem that drove me and more than a few people absolutely Freekin NUTS :kooky:almostt 20 years ago!!!!!.....And there was no forums back then.......Sean

i'll try to borrow one from my buddy. i've taken my car to a couple of shops too and they all scratched there heads too. the wires going to the spout connector go all the way to the ecm? i should be able to do a resistance test to find out it the wire is bad, right?

Yep! I Was told that those wires for the E-Sout do indeed go all the way to the EEC-IV (By way of the main harness). It has also been said by MANY that the Spout should be much better protected,(Like under the dash!) to keep it out of the elements, heat, ect........I will bet 4 to 1 that this is where your problem is!!!!........Let us know.....Sean

Welcome to AFM!

A BIG THANK YOU kenv !!! . ..........Sean

i have not gotten the spout connector yet, but i forgot to mention that i do have a error code. the code is saying that the reference voltage to the egr sensor is above 5v. i did a volt test and believe it was around 5.13ish... barely over 5v. i guess i need to call my buddy again to get the spout connector to eliminate that as a problem though.

i have taken a couple of videos of the timing marks. one with the spout out and one with the spout in. is there a way to post them on this forum? with the spout out, the timing marks on the balancer still moves around. it moves more with it in. i thought when the spout was pulled the timing marks should remain stationary, unless the distributor is turned.

You are absolutely correct!! With the E-Spout removed the timing is locked out, meaning that the EEC-IV has no control, input.(the E-Spout is the main connection from the base timing to the timing maps in the EEC-IV logic) ....I would definitely replace the spout and go from there.....If all remains unchanged after you replace the spout with another, you should consider replacing your A9-EECIV as this may also be on its way out. They are NOT hard to locate, either online or any junkyard. Just be sure to get one that matches your tranny......But let's try the Sout first......Sean

Also, I doubt very much that the exhaust gas recirc voltage has anything whatsoever to do with your current problem, as that is there to help your cats light offf faster, easier...and with what is listed in your sig. I would be surprised if you still have any:smilie. .......Sean

sorry it took me so long to reply again. i've been chasing vacuum leaks and electrical probs and feel i have them at bay. the brake booster was leaking causing a huge leak. the pollution control hose had a split in it. also, i ohm'd the grounds and found lots of resistance on all of them. after all that, it ran a little better. i took the diablo sport chip out and ran even better, except 75% of the time if have to help it find idle by rev-ing the engine at start up. it still runs sluggish sometimes with valve ping or pre-detonation sometimes (not as loud), sometimes no ping but sluggish, and sometimes boogies out. it used to run primarily bad with the occasional 'haul ass'. now, mostly sluggish to good. just need help with, what i hope to be, is the final step. i just wish the problem would be consistent. its a lot easier to diagnose when it does it all the time...

timing marks with the spout connector are more consistent now too