Hey all, I jsut got thru rebuilding the motor. Everything is back together but I cannot get it to run right. There are a number of issues and I am trying to get a couple of them right so I can tackle the others. I am having idle issues, it won't start withtout opening the throttle, and it seems to run really rich.
Setting idle;
On the mustang boards I have read this routine for setting idle, is it the same for our V8's? Disconnect IAC, start motor, set Min idle for ~900rpm using the idle air screw on TB. Shut down, reconnect IAC, start motor and let it idle for 2-3min, then shut down. Restart, run accy's (AC, etc) for 2-3min. The vehicle should now have learned it's idle.
What about clearing the ECU? is it the ssame, just disconnect it for 15min?
She seems to be pulling a good bit of air in at idle, even with the TB closed 100% and IAC disconnected, which makes me wonder if the IAC is bad or dirty. I am going to try and put a full gasket under the IAC to seal it off and rule that out.
Any other ideas!??
I figure once I have the idle set I can easy adjust FP to lean her back out.
If I stand correct, the idle screw on a 97 cannot be adjusted, its capped off. All I can think of is to disconnect the battery for at least 10 min. This should reset all the parameters in the ecu and relearn everything. Hope this helps.
BTW.....I just re-read your post and if you dont have a gasket under the IAC then it WILL leak and more than likely you might have a bad IAC....spray some carb cleaner into the IAC and let it set for about 2-3 min to dissolve any build up it might have then dry it off pretty good...note, it will run pretty bad for a few sec to get the remaining cleaner out of there......
Last edited by 98txexplorer : 02-04-2004 at 09:49 AM.
I have a different TB on the motor. I took the IAC to work today and when I looked at it, it was sitting 1/8" open, and could easily be moved with my pinky. So it is toast. I even tried it again here at home and all it did was buzz when I turned the ignition on. SO I am replacing that. Fo now I put a mustang one in, just to close the bypass, and I was able to set the idle to 900rpm. was a bit weratic so I put timing light on #1. it was not sparking until I played with the wire at the coil pack, swapped coil packs and plug wires out and same issue. I am hoping it is just becaue the ECU cannot see the IAC and it in limp mode. I will know more tomorrow when I connect a good IAC to it. it WAS sparking fine yesterday with the bad IAC connected....
I plugged the bad IAC back in and no change?? What is wierd is that if I pull the wires at the coil pack they start arcing acrost to thier contact and the motor smooths out? why would they fire when they have to arc at the coil and not when plugged in??
i think that you have a vaccum leak. disconnecting the coil pack will thwor a cel causing the engine to run in open loop mode which is an extremely rich setting partially compensating for the vaccum leak. also 60,000 volts can easily jump a small gap
Well I HAD a bad IAC which has been replaced, but it still ran rough.
Well that is the problem, I have found that #1 & 6 are not firing at all. I verified this with a timing light and they show not spark, I can also pull both plug wires at the plugs and it does not affect idle at all. The ONLY time I can get them to fire is if I pull thier plugs out of the coil pack most of the way, then they arc and the engine smooths out!?!?!? This is driving me crazy!! I have swapped in another coil pack and also swapped out both plug wires.
I was thinking maybe grounded plug wire, or maybe short in the harness, but why would it start working when I pull the plug wires partially out of the coil??
ANYONE have any ideas?? I am really close to yanking it and using an entirely different ECU and harness I have in the garage. will be allot of time modifying the harness, but I KNOW that it will work with the distributor system..
