Help me create the "Surging Idle Checklist"

HISSIN50 · Jun 28, 2005

crenth5 said:
My engine doesn't surge, but if you get it over ~2000 RPM's it comes down to 16-1700 and just sticks until you come to a stop. I cleaned the IAC and did't help. I tried turning the IAC upside down and it was worse. I cleaned the MAF tube and that didn't make a difference. Haven't cleaned the element in the MAF yet. I have the idle set at 7-800 and the TPS is somewhere around .95, not over 1. I DO have an E-cam, but it doesn't have a rough idle, it just sticks. I lloked for the 10 pin connectors and couldn't find them. Anyone else have this similar problem?

The VSS and computer will keep the rolling idle at ~1100-1500 RPM to keep the motor from stalling. This is normal (otherwise, when you cranked the wheel, hit the brakes, etc, it could try to stall).

super302 · Jun 28, 2005

crenth5 said:
My engine doesn't surge, but if you get it over ~2000 RPM's it comes down to 16-1700 and just sticks until you come to a stop. I cleaned the IAC and did't help. I tried turning the IAC upside down and it was worse. I cleaned the MAF tube and that didn't make a difference. Haven't cleaned the element in the MAF yet. I have the idle set at 7-800 and the TPS is somewhere around .95, not over 1. I DO have an E-cam, but it doesn't have a rough idle, it just sticks. I lloked for the 10 pin connectors and couldn't find them. Anyone else have this similar problem?

The 10 pin connectors are kinda behind teh intake manifold, sorta hard to find

crenth5 · Jun 29, 2005

What is the VSS? Also, no power steering on my car. My car didn't do this all the time when I got it, but it would do it occassionally. Now it does it all the time. Is the grommet and wire mesh part of the pcv valve?

jrod92 · Jul 4, 2005

Sticking idle

I have tried everything on the checklist checking all sensors, cleaning all electrical connections ect. andn my idle still has a problem. when i push the clutch in while coming to a stop or shifting it revs up to about 2500 rpm and sticks until i let off. when driving it also sticks feeling like i am in cruise control all of the time.

jrichker · Jul 4, 2005

jrod92 said:
I have tried everything on the checklist checking all sensors, cleaning all electrical connections ect. andn my idle still has a problem. when i push the clutch in while coming to a stop or shifting it revs up to about 2500 rpm and sticks until i let off. when driving it also sticks feeling like i am in cruise control all of the time.

An idle that sticks high and won't come down unless you turn the key off & restart the engine is a sign of a bad TPS

The 10 pin connectors are seen in this photo. Photo courtsey of Tmoss & Stang&2birds...

See http://www.veryuseful.com/mustang/tech/engine/ for lots of good inflo

crenth5 · Jul 4, 2005

Where can you buy a new throttle position sensor?

HISSIN50 · Jul 5, 2005

crenth5 said:
Where can you buy a new throttle position sensor?

Any auto parts store should sell them, as well as the dealer, as well as resto houses.

Good luck.

jrod92 · Jul 5, 2005

TPS test

jrichker said:
An idle that sticks high and won't come down unless you turn the key off & restart the engine is a sign of a bad TPS

The 10 pin connectors are seen in this photo. Photo courtsey of Tmoss & Stang&2birds...

See http://www.veryuseful.com/mustang/tech/engine/ for lots of good inflo

Could the TPS still have a problem even if i had it tested at the auto parts store? I also had them test a new one to check for any differences. This problem is getting very annoying.

jrichker · Jul 5, 2005

jrod92 said:
Could the TPS still have a problem even if i had it tested at the auto parts store? I also had them test a new one to check for any differences. This problem is getting very annoying.

Yes. It may have some of the carbon from the resistor piling up by the slider. A TPS is nothing more than a variable resistor, just like the volume control on a radio. How many old radios have you seen that are scratchy and hard to get the volume set on?

jrod92 · Jul 6, 2005

still sticking

I just replaced my tps and the throttle is still revving and sticking at 2500 everytime i push the clutch in. Does it take the computer time to adjust for the new sensor? If not what other suggestions can you offer???

willys1 · Jul 7, 2005

I finally put a new IAB in and no dice,it still happens.I think my egr switch/valve is bad!! Im trying new ones tommorow,I'LL let you know how I make out!!

crenth5 · Jul 8, 2005

I replaced my TPS and it works a lot better now.

willys1 · Jul 8, 2005

Fixed it!! It was a bad vaccum on the lower intake

jrod92 · Jul 12, 2005

willys1 said:
Fixed it!! It was a bad vaccum on the lower intake

where exactly was it on the lower intake?

ArtMan · Jul 13, 2005

Supercharger

One other cause of a surging idle that may have already been addressed (I didn't read every post of the past 5 pages) is one that afflicts supercharger owners.

After installing your Vortech you may find that the engine won't idle correctly. If you are able to rule out the other causes noted above, you should verify the crankcase is vented properly. This doesn't effect all sc owners the same, but be assured its an annoying problem.

The nipple at the oil filler can suck in air at idle. If this happens air is ingested into the combustion chamber that is not metered by the MAF. An erratic or sticky high idle results. When Vortech first sold their kits they had you run a hose to the filter "area". Now they include bosses so you may run a hose from that nipple to the intake elbow that fastens to the compressor. Since I own an older kit I had to order the updated elbow special.

But it cured my surging idle instantaneously and the car runs like silk (even with my cam)

Hope this helps.

rip-cord · Jul 14, 2005

I was reading the posts and I just wanted to know what does clock the MAF mean and how do you go about cleaning it.

The stang was fine before I installed the CAI but now on a cold start it stalled this morning and I started it up and it would jump from 1,500 right down to 400 to 500 and almost stall again. When warm it worked fine no problems.

The only thing that changed was the CAI so what should I be looking at?

Thanks

jrichker · Jul 14, 2005

Clocking the MAF means turning the MAF housing to a different position. This changes the airflow through the MAF and may help some idle problems.

Some theory & background info is helpful now...

There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.

The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

The MAF output varies with RPM which causes the airflow to increase or decease. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow.

rip-cord · Jul 14, 2005

Thanks, I will give that a try tonight. I figured it had to be related to the MAF since I didn't have the problem before the CAI and the MAF is the only thing that I would have touched.

I will let you know how it goes.

1redprix · Jul 14, 2005

Stalling

I Put Afr 165cc Street Heads On My Car This Past Winter...guess What ...it Idled Low And When I Came To A Stop It Stalled...so I Checked Everything On This List...it Was A No Win Situation , And I Was Mad !!! I Put A Idle Adjuster Plate Between The Throttle Body And Iac And Guess What ...with A Few Turns Out And 1 Turn Back In....idles Like A Charm And No More Stalling...thanks Stangnet Members..

rip-cord · Jul 18, 2005

I just wanted to let you know that I cleaned the MAF and while I was at it I gave the throttle body a cleaning as well.

Worked like a charm, idles better then before.

Thanks for the help.

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