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Discussion Starter #1
89 A-trim 30lb injs... Well, I had a 75mm Pro-M Bullet with wiring problems, my stang started bucking, trying to cut off, and when I gave it some gas the RPM would do a quick dip before revving up, like it was choking. So I bought another 75mm Pro-M bullet, except this one is a supercharged calibration. I bought it used. Now that I got it on, the idle on my stang shoots up to 2k RPM immediately upon startup and stays there forever basically. The check engine light stays on, and occasionaly goes away, but will come back on as soon as you give it a little gas. I've messed with the idle control screw and got no response at all, and tried reading the IAC voltage, but couldn't get a reading (had ignition in on position). All while it's idling at 2k RPM theres a HEAVY aroma of fuel, so it's apparently running really rich. I don't know what to do next. The meter is correctly calibrated to 30lb injs, and I've made sure the meter is flowing air the correct way.

1. Can anyone offer up advice?
2. Can anyone explain to me how to read the TPS voltage, and what it should be set at for my setup?
3. What is the difference with the supercharged calibrated Pro-M MAFs?

Thanks a million.
 

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ShadowStang50 said:
89 A-trim 30lb injs... Well, I had a 75mm Pro-M Bullet with wiring problems, my stang started bucking, trying to cut off, and when I gave it some gas the RPM would do a quick dip before revving up, like it was choking. So I bought another 75mm Pro-M bullet, except this one is a supercharged calibration. I bought it used. Now that I got it on, the idle on my stang shoots up to 2k RPM immediately upon startup and stays there forever basically. The check engine light stays on, and occasionaly goes away, but will come back on as soon as you give it a little gas. I've messed with the idle control screw and got no response at all, and tried reading the IAC voltage, but couldn't get a reading (had ignition in on position). All while it's idling at 2k RPM theres a HEAVY aroma of fuel, so it's apparently running really rich. I don't know what to do next. The meter is correctly calibrated to 30lb injs, and I've made sure the meter is flowing air the correct way.

1. Can anyone offer up advice?
2. Can anyone explain to me how to read the TPS voltage, and what it should be set at for my setup?
3. What is the difference with the supercharged calibrated Pro-M MAFs?

Thanks a million.
Sounds like your MAF calibration is still off. Is the new one cal'd for your 30lb injectors? Pro-m took 3 times to get mine right. are you running with a chip, or is it a stock computer still?

TPS voltage can be adjusted on your car - do a search and there are detailed explanations on this - it should be .94-.98 at idle, key on.

The supercharged cal'd Pro-M MAF's have a richer curve in them to give you the needed fuel. With a stock computer, and a properly cal'd MAF - your car should run pretty darn perfect.

Of course, you could go and get a custom chip burned and a good tuner would be able to get you going by simply applying the transfer function into your EEC.

peace
 

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Discussion Starter #4
Re: Re: Idle staying around 2k, help please?

Tat98Cobra said:
Sounds like your MAF calibration is still off. Is the new one cal'd for your 30lb injectors? Pro-m took 3 times to get mine right. are you running with a chip, or is it a stock computer still?
Yeah, I'm running the stock computer and the MAF is calibrated to 30s. I'm gonna check the TPS voltage and make sure it's good. I cleaned the MAS also, but that didn't make a difference. With the SC calibration, would it make any difference to mess with the fuel pressure? Thanks.
 

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Re: Re: Re: Idle staying around 2k, help please?

ShadowStang50 said:
Yeah, I'm running the stock computer and the MAF is calibrated to 30s. I'm gonna check the TPS voltage and make sure it's good. I cleaned the MAS also, but that didn't make a difference. With the SC calibration, would it make any difference to mess with the fuel pressure? Thanks.
You could turn down the pressure a little bit - it would bring the overall a/f curve up a bit, least it did on mine. Dont expect any miracles though from messing with FP. The computer compensates for pretty much anything we try to manually tweak. Check your IAB too - if it sticks or stops working, it can give you an idle hang. Also, there's 2 10-pin connectors near the firewall that get gunked up and can give you grief. There's a link to a thread somewhere on the Corral that details how to clean them.

peace
 

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"I've messed with the idle control screw and got no response at all..."

Make sure that you first clear the EEC by disconnecting the battery and also disconnect the idle air bypass solonoid before adjusting the throttle stop screw - you should be able to pull the idle down - then reconnnect the IAB.

The advice on cleaning the 10 pins and the IAB from TAT98 is good too, I would try that first.
 

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Discussion Starter #7
I got the idle problem fixed, it's back to normal. I took off the IAB, looked inside it, made sure the solenoid worked, put it back on, and it idles like normal now. While driving though, it still studders under very little throttle (crusing) like it did with the old mass air meter. I'm gonna pull all my plugs tommorow and see if maybe one is messed up. Under WOT in 2nd gear it studder a couple times, but every other gear was fine for the most part. Seems a tad down on power.

I ran a code scanner on it, it threw a MAF code out, something about the voltage. Code 66 I believe it was.
 

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Mine loves to be at 1.01. Idle is rock solid at about 750-800rpm.
 
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