Ok, I've about had it with this

[99FiveOh]

Every single SN95 5.0 I've ever owned has had this one issue and it's driving me crazy. Not only that, but it's really embarrassing when people look at me like I can't drive a stick. Of course what I'm referring to is the damn car stalling after warm starts. Like when I go to the store and the car's been off for a few minutes it will hunt for a second and die.

No, I haven't checked codes because all they're going to tell me is that my EGR, Smog and associated stuff is missing. I've had this issue in cars with no codes before and nothing I have done short of getting it tuned has fixed it.

There has got to be a specific cause and a cure. These cars didn't do this when they were brand new so why do they do it when they get older? What sensor is responsible for information the computer needs to stop this? I'd really like to know.

I have converted to Fox throttle body in hopes of fixing this problem with no effect. It did however fix the hunting/surge issue that would happen out of the blue. It will idle smooth all day long now. I just have to keep giving it gas after warm startups for a minute or two until it settles down.

I never had a Fox do this EVER! If this crap continues I'm going to chunk this T4M0 into a river and put an A9L in there. There's no reason to suffer poor drivability when I don't even have the huge HP numbers to go with it! UGGGG

 

[VibrantRedGT]

There's a FOX in my garage and it does the same exact thing.

 

[99FiveOh]

There's a HIGHLY modified Fox in your garage. My car is about stock so I can't see any reason for this. I do have one of those hyperchip things in the computer, I've always been afraid to remove it.

 

[revhead347]

I had a Fox and it didn't the same thing. My new engine does the same thing. It's annoying.

Kurt

 

[VibrantRedGT]

Its the same reason Harley's leaked for 50 years, it's normal, they are made like this. Mustang's with 5.0's must do this.

 

[Dino Dino Bambino]

Of course what I'm referring to is the damn car stalling after warm starts. Like when I go to the store and the car's been off for a few minutes it will hunt for a second and die.

There has got to be a specific cause and a cure. These cars didn't do this when they were brand new so why do they do it when they get older? What sensor is responsible for information the computer needs to stop this? I'd really like to know.

The component that's causing the problem is obviously sensitive to heat soaking so my money's on the PIP sensor.

 

[revhead347]

The component that's causing the problem is obviously sensitive to heat soaking so my money's on the PIP sensor.

No, it does it with a brand new pip sensor. It's just the way 5.0s are.

Kurt

 

[Last5.0]

I've never experienced this problem you describe, and I've owned 5.0's since '88, but then none of them ever had more than 45k-55k miles on them...lol

 

[99FiveOh]

The component that's causing the problem is obviously sensitive to heat soaking so my money's on the PIP sensor.

Don't even get me started on that I'd be willing to bet my life that my PIP is in good working order now.

I guess I'll wait till I get my turbo in then tune the car, my tuner said he can nip that problem right in the bud for me whenever I'm ready. He's probably one of the best SN5.0 tuners in the country!

 

[Dino Dino Bambino]

I'd be willing to bet my life that my PIP is in good working order now.

I hope you're right but God knows where they're being manufactured these days (Made in China? Hecho en Mexico?) so can you totally rely on a new sensor being good?
A small percentage of new sensors end up being duds so don't take it for granted.

 

[99FiveOh]

Man, I'm the one who brought this to everyone's attention here on the forums. Search and you'll find the threads where people thought their brand new distributors were fine when in fact they weren't... and in the end they all did what I told them and fixed their issue.

My PIP sensor is an expensive unit from NAPA that is made to OEM specs. Trust me, my pip is fine.. and a failing pip will leave you on the side of the road for 30 min or more until it cools down and runs fine. My car is just stalling, it starts right back up and I can keep it running with the pedal. If the PIP fail it will not restart until it has had time to cool.

No, this problem is something widespread among these cars and I have a feeling it's due to the very picky factory tune that Ford programmed in. I've owned plenty of Fox's in my life and NOT ONE of them, in stock form, ever gave me any idling issues unless the IAC was bad. Simple fix and it was back to normal.. usually on a Fox if the IAC goes bad the idle will hang real high as it gets stuck in the open position. Ford made the 94/95 just too picky and as everything ages the computer just can't get what it needs to make the car run properly. Poor design but not game breaking.

Anyway, I know a tune will fix it because my old 95 S trimmed car did the same thing until I got it tuned after putting the blower on. Although, converting to Fox throttle body on that car cleared it up a lot, took out the random hunting that it would do just like it did with this car.

 

[revhead347]

Mine still does it with a tune.

Kurt

 

[99FiveOh]

Then you need a new tuner I suppose. You're in GA, so make the trip to Jacksonville FL and see Tony Gonyon at Tuner's Inc / HP Performance. HP Performance - Contact

If this guy can't make your car run right, it won't ever run right!

 

[Adam95GT]

Ive worked on quite a few and never seen this issue.


Is it possible that it has something to do with the 02 warm up min number of switches... I know i fiddled with that in my tune.

 

[Last5.0]

It could very well be something in the tuning. Like I said above, I've never experienced the problem but I had a SpeedBrain EEC in my '95 since about '99 or '00 which I could tune with a laptop. Got rid of it a few years ago but have a twEECer Rt now. I mostly had a problem with the idle dropping and killing the car when turning on the A/C if I didn't blip the throttle. The SpeedBrain had no support for the Idle Speed Control rpm adder when the A/C is switched on, or any support for EGR function.

 

[legalize420]

i think its a problem with the fuel settings. most of the time if you hold the gas for about a minute or just start to drive you can get past the surge and die. then it runs and idles fine until you go to restart. when you first start the car you are in open loop and that seems to be when the problem happens. once you get to closed loop it will idle and stay running. after getting my fuel settings dialed in my car will start up fine every time now.

 

[BlackVert]

it's definately in the tune. mine did that, but i was able to fix it. damned it i can remember exactly what it was off the top of my head thougn.

i think it has to do with the way it is programmed to be rich on startup. when warm, it does not need to be as rich. iirc, there is a tuning parameter to set how long that time is based on the temp, or something like that.

it goes away after about 30 seconds or so or if you start driving it, right?

 

[legalize420]

it's definately in the tune. mine did that, but i was able to fix it. damned it i can remember exactly what it was off the top of my head thougn.

i think it has to do with the way it is programmed to be rich on startup. when warm, it does not need to be as rich. iirc, there is a tuning parameter to set how long that time is based on the temp, or something like that.

it goes away after about 30 seconds or so or if you start driving it, right?

when i first started messing with my tune i zeroed out the start up table and it did help. since then i have started over with my tune a few times and now run the stock table with no problem.

 

[99FiveOh]

Yes, 30 seconds or so it's good.. but if the car does stall, the time starts over again. It's hard to come to an incline stop, keep the engine running, hold the brake and work the clutch. It really takes the fun away from driving this car. I almost wish I'd have gone with a 2 valve PI motor instead of this 5.0! Would have taken me half the time to do the swap and I would have had perfect street manners.

My car isn't tuned, it's just running off the computer. So if there's a problem with that tune, it was Ford who fubar'd it to begin with.

 

[Zero Signal]

I've always been able to fix that with a new IAC and/or opening the TB set screw a bit more. On my wife's 93 GT, it was a new IAC. On my 95, the 347 idles just fine after it starts warm or cold, but only after I put another turn or so on the TB set screw. It will hunt very slightly, but only because I've been too cheap to replace the IAC. I may just do it this week and be done with it. Nevertheless, it seems like a trivial fix

You are correct in that the tune shouldn't have anything to do with it. Your mods are mild and shouldn't affect the idle at startup unless you have a major vacuum leak. Rule out the O2 sensors since they aren't used for a minute or so (if I remember correctly) after startup anyway.