BUILT SN95 STILL ACTING UP AFTER MONTHS OF RESEARCH AND REPAIRS!

[tbk1981]

Ok, this is my first post on this site. I have researched for a good 2 months. I've tried everything mentioned on this site and many more! Made numerous repairs which have turned out not being the issue and costing me a good 2500.00. Below is a build list for the car. I know the original owners name is Dwight from Louisiana and that's about it. I have replaced the IAT, TPS, MAF, ECT sensor, Distributor cap and rotor button, plenum gaskets, valve cover gaskets, alternator, reset the timing and put to 14*, new plugs and wires.. IM LOST AND CANT FIGURE IT OUT. It will not idle correctly, either surges/backfires through intake or through exhaust. I have tried to set base timing with the jumper out, and still nothing. No over heating, it just happened one day at a car wash. Drove the car there just fine and when I went to leave I had to trailer it home!

Trick Flow heat intake
Trick Flow twisted wedge heads
Trick Flow valve covers
Forged pistons
Lightened and balanced crank
Brand new alternator
Custom ground crane cam
Comp cam 1.6 rockers
BBK 75mm throttle body
Pro Flow MAF
Custom C&L short ram intake
Crane HI-6S ignition
Crane PS-91 coil
BBK fuel pressure regulator
Underdrive pulleys
BBK long tube headers
BBK H-pipe with dual cut outs (no cats)
FlowMaster exhaust
Steeda firewall adjuster
Modified stock clutch cable
Steeda clutch quadrant
King Cobra clutch
Steeda Tri-Ax shifter
Ford Racing lightweight aluminum drive shaft
Mushimoto 3" core radiator with aluminum lower radiator pipe
MSD distributor cap
Ford Racing 8mm plug wires
3.73 gears
Autometer Phantom oil pressure gauge
Autometer Phantom water temp
Autometer Phantom volt meter
Autometer Phantom A/F R wideband
Fresh header and valve cover gaskets as of 7/14/2014

 

[96blak54]

You didnt mention TFI module

 

[tbk1981]

I honestly haven't tried that, and I don't know where it is located in this car either. I had the top end pretty much off yesterday.. again... and didn't see anything that looked like a TFI module. The only thing I can find is the jumper plug to set base timing. I will have to crawl up under the car and look around some more, or behind the fenders I guess...

 

[ElrodKTPQ_89]

The TFI module will be on the passenger side of your car under the air box. Next to the SPOUT (the jumper you mentioned).

 

[5litrarag]

Drove in fine and wouldnt start when you got ready to leave? or did it do something weird as you were trying to leave?

Does it have a stock Ford or a MightSuddenlyDie distributor in it?

not enough info here.

 

[toyman]

Didn't see any mention of the IAC (Idle Air Control) valve. It's sole purpose to to control and maintain the idle when the throttle is closed.

 

[GregT94SCC]

The hall effect sensor in the dizzy can do this if its on the way out. I've had this happen to me after a large puddle. Also if your CD box starts to get flaky or the TFI module is on the way out you could experience those symptoms. You need to throw it on a scope and see what the signal going to your coil looks like. Oh and check the primary and secondary resistance on your aftermarket coil. Is it still in the stock location?

 

[tbk1981]

@ toyman - In the original post I put IAT, I meant to put IAC. Sorry for the incorrect information.

@ 5litrarag - I had been driving it on and off for about 2 months with no issues. On the way to meet my buddy it drove just fine. It wasn't until I was trying to crank the car and leave when it started acting up. Any kind of acceleration kills the car. The longer it runs, the worse it gets. I have begged local Mustang guys to help me out but a lot of them don't really care for me because I have a fully built Neon SRT4 which is more hated than Hondas.

Once I start the car, it has a hard time holding at idle. Doesn't matter if the jumper plug is out and base timing is dead on at 14 degree or if the jumper is in and the computer is trying to control the idle. At operating temperature, if ANY KIND of throttle is used, it backfires through the intake. Now, if I adjust the timing, I can get a halfway decent idle. Again though, if I rotate the distributor to the right it will backfire through the exhaust. There is literally no medium as to where it wont backfire at all. It stinks to hell and back of gas too. No codes are being thrown at all so there is no way to get any hints on the root cause. Like I said too, I have EVERY VAC LINE tied or clamped, and has all 100% new trickflow gaskets. No overheating. Oh and I don't know if its just because the car seems like its going to die but the volts on battery drop occasionally. The red LED on the Crane ignition controller blinks intermittently...

Its been an ongoing battle so some things I may forget. Please question what I am saying because I am FAR from an expert on these cars as it is my first v8 ive ever built!

 

[tbk1981]

@ gregt94scc - im not exactly sure what the CD box is, but yes the crane coil is in the same place as the stock one was.

 

[tbk1981]

I tried to edit but it wouldn't let me....

It has an MSD cap and rotor button. Unknown distributor brand though. I have been looking for a good priced used distributor for the car but I cant afford what most people are asking.

Oh one more thing. The IAC sensor... The one in my car originally was a different part number than the one I have in it now. The original one part number was F2SF-9B989-CA annnnndddddd.... NO ONE had one anywhere! So I put in the F1SF-9B989-CA and had to drill out the holes to get it to .94 on the voltmeter. Which was a ***** to do by the way... im trying to remember everything I have ran across!

 

[96blak54]

Them tfi modules are junk and known to fail regarless of brand or how new it is. Check into it and youll find alot more than your head can handle.

 

[tbk1981]

Any recommended brand that I should look for? Or style?

 

[toyman]

I tried to edit but it wouldn't let me....

It has an MSD cap and rotor button. Unknown distributor brand though. I have been looking for a good priced used distributor for the car but I cant afford what most people are asking.

Oh one more thing. The IAC sensor... The one in my car originally was a different part number than the one I have in it now. The original one part number was F2SF-9B989-CA annnnndddddd.... NO ONE had one anywhere! So I put in the F1SF-9B989-CA and had to drill out the holes to get it to .94 on the voltmeter. Which was a ***** to do by the way... im trying to remember everything I have ran across!

You are confusing the parts. The part you are calling the IAC is the TPS. The TPS on the sn's do not need to be adjusted as the ECU will recognize the idle position with the volts between .6v - 1.25v. The IAC valve (not a sensor) is an open or closed solenoid that pulses to maintain idle quality when the throttle in the closed position. Because you keep mixing up the parts it's not clear to me that you did in fact replace the IAC valve. The IAT sensor is located in the air intake tube and measures the air temperature which the ECU uses to calculate the air density.

 

[tbk1981]

So I can go get another TPS and just bolt it in without adjusting it at all? I replaced the MAF sensor at the intake filter, the sensor in the intake tube and the 2 sensors/valves on the BBK throttle body.

 

[CC'S95GT]

So I can go get another TPS and just bolt it in without adjusting it at all? .

Yes The TPS on SN's is non adjustable (unlike the foxes).

 

[Magic]

Any recommended brand that I should look for? Or style?

Always replace TFI modules with another Motorcraft TFI module(if that is the problem).

Your issue does sound ignition related. See if you can find another stock 94/95 distributor to try and see if the problem goes away.