Car starts then dies

[phatford]

1990 fox starts then dies only when cold. When I give it gas it will stay running but then dies until warmed up after about 3-7 minutes holding the gas on about 1100-1700 rpm. I have adjusted the voltage on the tps, it's good, cleaned the mass air, it's clean? I have been fighting this problem for years, hell I had Cincy speed check it out years ago when they dynoed it and they were stumped if I remember right. The car only 40k miles on it when I bought it 9 years ago...in that time I have put 2k miles on it..that's right 2k in 9 years lol
Any help or experience would be greatly appreciated, I would like to start driving it again this year!! After it's warm it idles kinda high which I don't like 1100rpms it runs great when warm! It's kind of em em embarrassing revving it up hahah

Thanks in advance!

[Kevin1989]

Mine does that, it will not idle until it got some heat in it. It never bothered me that much I always thought it had something to do with the o2 sensors and open and close loop,

[phatford]

Do you think your o2 sensors are bad?

[phatford]

Is there a way to check them? I have no check engine light on

[redfirepearlgt]

Does that year have the air idle controller on it? If so try cleaning or replacing it. Does not sound like O2 sensors if it is only at cold startup...and I assume that means first start regardless of outdoor air temps.

O2 sensors have to warm up before a car will go "closed loop". At cold start cars are idling "open loop", (learned about this from Adam@S&M) meaning there is no O2 sensor activity. The sensor must get up to operating temp before it can begin to measure O2 content. If I recall correctly it takes upwards of two minutes for an O2 sensor to reach its operating temperature and begin sensing.

[Rick93coupe]

I'd also be looking at the IAC valve. You can meter them, I know a good working Ford IAC reads somewhere around 7-8 ohms. If it's down closer to 1 it's defective. I went through this last summer, you just get a reading across the 2 pins.

[Adam@S&MMotorsports]

If it is not an IAC or CTS issue, then it needs more or less cold start enrichment or more IAC airflow when cold. Has the car been tuned?

[redfirepearlgt]

Sorry...meant Idle Air Controller (IAC). I also have issues with PVC v. PCV valve. LOL!!!

[phatford]

Car was tuned by Cincy speed years ago. They were stumped on the issue and I did not want to dump anymore money into it at the time.

I have replaced iac twice thinking well maybe the new one could have been defective.
I replaced the tps once and moved it until it read the correct voltage.
Last night I sprayed carb cleaner around everywhere all over the vacuum lines doing a little at a time listening and spraying again with zero changes in idle and no surges so I believe vacuum lines are good.
I'm about to bring it up to you at s&m! My buddy Alex Shadwick recommended y'all.

It also acts the same at any outside temp.

I was reading up on the open and closed loop thing..seems like at start up the MAF sensor controls the air and when warm the o2 sensors do their job. So yes I agree the o2 sensors are ruled out.

If I swap to a 24# maf sensor and injectors do I need to retune?

[Maximus]

Car was tuned by Cincy speed years ago. They were stumped on the issue and I did not want to dump anymore money into it at the time.

I have replaced iac twice thinking well maybe the new one could have been defective.
I replaced the tps once and moved it until it read the correct voltage.
Last night I sprayed carb cleaner around everywhere all over the vacuum lines doing a little at a time listening and spraying again with zero changes in idle and no surges so I believe vacuum lines are good.
I'm about to bring it up to you at s&m! My buddy Alex Shadwick recommended y'all.

It also acts the same at any outside temp.

I was reading up on the open and closed loop thing..seems like at start up the MAF sensor controls the air and when warm the o2 sensors do their job. So yes I agree the o2 sensors are ruled out.

If I swap to a 24# maf sensor and injectors do I need to retune?

Years ago, as In Adam tuned or Tracey tuned it? Did we use an SCT chip or a Quarterhorse chip?
If you do switch to 24s you will need a re-tune.

[phatford]

If I remember right I think it was Adam. As of the chip I have no idea what was used

[Maximus]

If I remember right I think it was Adam. As of the chip I have no idea what was used

Gotcha. Well Adam now is S&M, so Im sure he will get it squared away for ya.:bigthumb

Although Adam is no longer with Cincy Speed, I will try and get you handled if Adam cant. Either way you will be in good hands. :)

[phatford]

Yes sir I appreciate it. Tax returns came.. Time to make some unwise investments!

[Adam@S&MMotorsports]

It won't be a problem. Data logging software has come a long way since then. Let me know when you are ready:bigthumb