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I had a high idle problem with my 87 (speed density if it matters) and a change of my plug wires fixed it. So I think high idle problems can be traced to a few things maybe.
 

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Discussion Starter #162
Graygoose, I would check out all of your grounds. It sounds to me like you might not have them all hooked up. Keep in mind that a ground to an Aluminum head isn't a good ground. You should be grounding to the block and to the car's chassis.

Keng, I would suggest you take a look at a few things. What is your timing set at? How many miles are on your 02's, plugs and plug wires? Where does your car idle at when you have the IAB disconected?

RagingGrandpa,slantman,
The connectors are not on your cars, at least not the salt and peper shakers. Ford got PO'ed with them and got rid of the design. Any connector could be suspect though. I would probably look at the grounds, IAB valve, and TPS in your case, as well as your MAF if your running a K&N.

Wes
 

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rgr, thx
keng said:
...idles at 1,500 rpm on matter how long i drive it, ...

...when i strat the car...
Ahahaha hawaiians have a language of their own :D
 

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I just dropped a new engine in my stang. Every thing is new. But i just could not get the thing to idle in anykind of stable manner.

I bought the idle plate...it helped a little but far from solved the issue. So I kept doing research. I checked for vacumm leaks...I removed the 10 pin jumpers since I did not need the extra length and cleaned the pins. This did nothing for me. I temporarily installed my MSD 6 AL. (Permanent install will be under the passenger seat later.) No effect. I played with all the idle adjustments. Tried every technique suggested. None of them helped.

Finally...I tried clocking my C&L 76 MM Mass Air. Whoa....it idles stabily and returns to normal idle quickly. Near as I can figure...the sensor tube was in the dead air zone of the intake tube...due to the velocity characteristics of the mandrel bend intake tube. Once I properly got the tube sampling the actual are volume...it made a huge difference.

It is all but solved. It still has a bit of a tendancy to hunt a bit when cold...but after it warms a minute or two...it idles like a stocker. I going to continue to play...but my guess is that I will have to re-program the computer to be totally satisfied with my idle.

For me...the whole reason to have fuel injection is so that you can have consistent and reliable performance in all conditions. If that does not prove to be true...I will put a carberator on it. I know I can get reasonably repeatable performance from those.
 

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Bills said:
...I will put a carberator on it.
vibrat- what? No that can't be it, it started with a c....

Hey honey! WTF is a carblurator?!?

Sheyatt grandma doesn't know either.

:D
 

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Please excuse a newbie for resurrecting this thread, but I need help...Wangstang & others are you out there? I have a stock 87 LX 302 w/ 160K+. Pulled the intake and cleaned throttle body, EGR, etc. Man were they nasty dirty! When I put it back together I started having idle problems. Best I can describe it when I start the car for the first time each day the idle wants to stay at 1300 to 1500 and not drop back no matter how long I drive it, how warm it gets. If I stop and restart it will idle normally at around 800. Have tried the 10 pin fix, checked vacuum lines, plugs etc pretty new, new PCV valve. If I'm checking correctly the TPS is reading .66 at idle and goes to 4.5ish at WOT. Will this cause the problem I have? What else should I be looking for. Thanks for any and all help.
 

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I am having the exact same problem, right down to everysymptom you listed and no one as been able to help solve it.
 

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have you guys reset the idle memory. i had this problem & resetting the idle strategy worked for me & its been more than a year now. its goes something like this:
1. disconnect negative battery cable for 20. min. or so
2. unplug the i.a.b solenoid connector
3. after said time has gone by, reconnect battery cable & start the car. under the T.B. there is a set screw to adjust idle-set it to where you want it [ about 700-850rpm is good]
4. after car is running, let it run for 2-5 min. & shut it off.
5. reconnect the i.a.b solenoid connector & again let run for 2-5 min. & shut it off.
6. restart car & turn ALL accessories on & let run 2-5 min. & turn off.
7. take it for a drive & get back to us. this worked great for me.
FYI - i had to do this a few times to get it right so stick w/ it!
 

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I have tried it three times exactly step by step with the exact same reults, it made no diffrence. It is speed density does taht matter, and there are no vacum leaks. thanks
 

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Here I thought I had a fix then Keng says it doesn't work:( I will try it anyway this afternoon and post results.

btw, don't want to sound dumb but what is speed density? :eek: If the car isn't mass air is it speed density by default?

Thanks for the tip.
 

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speed density applied to the 1986-1988 Mustang 5.0's. There may be some EARLY 89's in existance too with Speed Density.

The Mustang 5.0 was converted over to Mass Air during the 1989 model year with the first cars having it being out in California.

on your air intake tube to the throttle body, if it is just a plain rubber tube with NO sensor near the air box, you have speed density. If you have a sensor there, you have mass air.

If you Mustang is a bone stock 86-88 with NO MODS EVER - it's speed density.
 

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87lxdc- try what i said & let me know. if it didnt work for the other guy hes got other issues w/ the car. i was amazed it worked!
 

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Wes,
I have an 86 mustang. Should I keep the speed density setup or convert? I was thinking of converting to gain more power and better drivability. But with all the problems you guys seem to have with MAF, why should I convert? The 86 5.0L has 5,000 miles, a trickflow street intake, BBK 70MM throttle body, Ultradyne cam roller special speed density profile cam, 1.6 roller rockers, 255LPH fuel pump, MSD6AL ignition, and factory cast iron heads. The idle hangs at 1500 rpm out of gear at a light or cruise, responds fine in between shifting. I plip the gas and idles fine at 850 rpm. Rarely will the idle surge after installing a new IAC motor. Car also has a whistle which drives me nuts. By looking at this post, I guess the whistle is from the BBK aftermarket throttle body. It could be a vac leak, haven't checked because I believe it would effect the idle more.
 

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Does this ten pin connector remedy work on 2.3 cars? My 88 2.3 convertible runs great but with it in drive the idle will jump to 2k to 3k and stick there for various lengths of time( I notice it happening most at stop lights) If i shut the car off and restart it most of the time it will return the idle to normal. Thanks for any help with this guys.
 

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My 351, which I just got running is having serious idle issues. when cold, it wont idle high, and once its warm, the idle fluctuates, it will idle a 800 or so for a few seconds, then go up to 3,000 or so and stay for about 30 seconds, then back to idle...back and forth. I cleaned out the IAB but other than that I dont know what to do. I know the fuel pressure is too high, i havent been able to get a guage on it because I cant find a fitting to put it on the stock fuel rail. Could this have something to do with it?my alternator doesnt work either, so this is happening with the car on jumper cables...

this thread is very helpful, I tried cleaning the IAB, need to do the 10 pin fix next.

bowlcut86-dont know if you got any answers yet, but you need to convert to speed density with all those mods.

also i ran the code reader, only code i got that wasnt smog related was TPS out of range(can't remember the code number)
but I cant set the tps because i have to keep changing the idle around. what should I do? thanks!! hopefully some of the original people are still subscribed!
 

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here's a new one for idle surge that i ran across the other day at work and figured i should share it here.

symptom,
idle hunting/surging/hanging high

cause,
leaking intake gaskets sucking from the lifter valley

test,
plug off the PCV valve and it's port at the back of the intake mainfold, connect a vacuum guage to the fresh air inlet on the oil fill pipe and make sure no other air can ENTER the engine. at idle there shouldn't be any vaccum showing on the guage.

fix,
replace intake gaskets, inspect for oil discoloration along the lower width of the gaskets usually at cylinders 7 and 8.
 

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After reading what you said I tried it. And I've tried just about everything. And that was the problem the upper intake gasket was leaking thanks so much for your help.:joy:
 

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Ok guys this is hands down the most informative thread I have found on the idle subject. I have spent the last two days reading and trying some of the 2years worth of solutions that are posted. Nothing worked yet.

Here it goes , My first post BTW, 92 5.0 auto indicates 98k maybe 198k I do not know. First thing in the morning it starts fine and idles around 850, then after 2-5 mins it goes to 1300. Temp sensor changed Bypass changed, TP changed, comp changed, cap and rotor. I did the 10 pin last night twice, reset the idle 3 times and adjusted the tp from .54 to .97. When I adj the tp the idle went to 2400and came down slowly. I am driving it with the bypass unplugged it seems to responed better. If the car is running and I unplug or plug the bypass in there is no change.

I can introduce air by cracking the boot at the throttle body and the idle will come down. This is air that the MAF does not see. When I introduce air by operating the bypass manually with my finger the idle goes up, this is air the the MAF sees.

I was headed out today to buy a new MAF sensor mine does not have a gasket between the mounting and the MAF body, should it?
Yesterday I was convinced it was the 10pin. I bent all the females twice but did not clean and regrease because I did not have the dielectric grease. Could I have missed it? I did not think so thats why I did it a second time after no results the first time.
 

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Greygoose, check the PIP in your distributor. you can get it from Ford for 80 dollars. Next check the TFI module. I said many times before that there is many lawsuits against Ford because of this. The TFI gets so hot it causes the car to die out . After that, check your IAC and TPS and adjust them if you replace them. Its better to replace with OEM parts to be safe.Then check your wires, rotor and cap and then your coil. I had the same problem as you, I replaced all of these and the problem is gone. But Im pretty sure it has to do with the PIP or TFI. If all of these check out, go to your fuel system and check the fuel pump, regulator, filter, relay and any signs of vapor lock. If these seem fine, I dont know what else to tell you. Hope this helps.
 

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STR1 said:
Ok guys this is hands down the most informative thread I have found on the idle subject. I have spent the last two days reading and trying some of the 2years worth of solutions that are posted. Nothing worked yet.

Here it goes , My first post BTW, 92 5.0 auto indicates 98k maybe 198k I do not know. First thing in the morning it starts fine and idles around 850, then after 2-5 mins it goes to 1300. Temp sensor changed Bypass changed, TP changed, comp changed, cap and rotor. I did the 10 pin last night twice, reset the idle 3 times and adjusted the tp from .54 to .97. When I adj the tp the idle went to 2400and came down slowly. I am driving it with the bypass unplugged it seems to responed better. If the car is running and I unplug or plug the bypass in there is no change.

I can introduce air by cracking the boot at the throttle body and the idle will come down. This is air that the MAF does not see. When I introduce air by operating the bypass manually with my finger the idle goes up, this is air the the MAF sees.

I was headed out today to buy a new MAF sensor mine does not have a gasket between the mounting and the MAF body, should it?
Yesterday I was convinced it was the 10pin. I bent all the females twice but did not clean and regrease because I did not have the dielectric grease. Could I have missed it? I did not think so thats why I did it a second time after no results the first time.
Come on guys please respond to the above. The next morning the idle started out at 1300 and now its at 3200 warm. And my lightning blew a plug and they will not fix it
 
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