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Topic: Idle surge...problem still not solved (Read 4992 times) previous topic - next topic

Idle surge...problem still not solved

Ever since I've had this car it's had quite an idle surge...with the old SO motor, it would stall while making k-turns, with the HO motor it would load and unload the suspension at stops and would surge erratically while in park or neutral.

I went to Ford and ordered their "engine idle air kit", apparently there was a TSB for these things and this is the Ford fix.  It is part # F2PZ-9F939-A.  It cost me 43 bucks and change from Holman Ford(which seems to be the MOST expensive Ford dealership around).  I know that Mustangs Unlimited used to carry basically the same thing for like $18.

So, now my car idles almost perfect...in park or neutral, warmed up, it idles around 900rpm(which is higher than I like but proved to be the best adjustment for idle in gear).  While in gear it will idle around 700-750rpm.  After being in gear for a few moments, it will surge around between 600-700 but it doesn't even think about loading the suspension...I still have to set the throttle stop screw according to the directions, so that could further improve the situation. 

I just figured I would post this in case anybody else has the same problem and was looking for a remedy.
Project 3G: Grandpa Grocery Getter-'85 Crown Vic LTD 2-door, 351W with heavily ported/polished GT40 heads, heavily ported/polished Typhoon Power Plus upper & lower intake, Comp Cams 265DEH retarded 1*, FAST EZ-EFI, HD T5, 8.8" 3.73 trac lock with extra clutches, 3G alt. swap, '99 CVPI front brakes, '09 CVPI rear disc brakes, '00 CVPI booster&m/c + wilwood adj prop valve.

Parted & Gone-'88 T-bird Sport, 351W swap, ported GT40 heads

Idle surge...problem still not solved

Reply #1 –
Hate to tell you this but... Cleaning the throttlebody & IAB, setting the idle to 600-700 rpm with the IAB disconnected and finally setting the TPS for .8-.9v would have done the same thing...

If it still surges at that point repl the IAB...

Idle surge...problem still not solved

Reply #2 –
Oh well, I guess I just have another shiny piece under the hood...lol.  It has a new IAC, and the throttle body/throttle plate were just cleaned...I'll probably mess with it some more and see what happens.
Project 3G: Grandpa Grocery Getter-'85 Crown Vic LTD 2-door, 351W with heavily ported/polished GT40 heads, heavily ported/polished Typhoon Power Plus upper & lower intake, Comp Cams 265DEH retarded 1*, FAST EZ-EFI, HD T5, 8.8" 3.73 trac lock with extra clutches, 3G alt. swap, '99 CVPI front brakes, '09 CVPI rear disc brakes, '00 CVPI booster&m/c + wilwood adj prop valve.

Parted & Gone-'88 T-bird Sport, 351W swap, ported GT40 heads

Idle surge...problem still not solved

Reply #3 –
my 86 does the same thing. http://www.foxtbirdcougarforums.com/showthread.php?t=8308

 but what does iac and IAB and tbs and all those others stand for? and where are they
1986 Cougar LS

Idle surge...problem still not solved

Reply #4 –
Hey TC50...I was on mustang-forums.com yesterday and read that when setting the TPS it should be more like .98-.99V...is there any difference in the ECU's(between say a '91 Mark VII and similar year stang) as far as where they like the TPS voltage?  If you say set it to .8-.9V, I will, I was just curious as to the different ranges.

Thanks,
Don
Project 3G: Grandpa Grocery Getter-'85 Crown Vic LTD 2-door, 351W with heavily ported/polished GT40 heads, heavily ported/polished Typhoon Power Plus upper & lower intake, Comp Cams 265DEH retarded 1*, FAST EZ-EFI, HD T5, 8.8" 3.73 trac lock with extra clutches, 3G alt. swap, '99 CVPI front brakes, '09 CVPI rear disc brakes, '00 CVPI booster&m/c + wilwood adj prop valve.

Parted & Gone-'88 T-bird Sport, 351W swap, ported GT40 heads

Idle surge...problem still not solved

Reply #5 –
mustang guys think .98-.99 is for "optimal performance", it makes no difference

get i always say from .90-.99 is good
It's Gumby's fault.

Idle surge...problem still not solved

Reply #6 –
Thanks, well, I'm looking for "optimum idling" lol  Before I installed that idle adjustment plate...the idle speed would not increase when running the a/c or defrost(a/c clutch engaged) and it would just kinda bog...since I put the plate on it will bump the idle up a little bit when I'm in gear and at a stop.  Which is what I thought it should do, but never did. lol  Once the weather breaks here( nor' easter)I'll go ahead and check all that out and post my results...

Thanks Again,
Don
Project 3G: Grandpa Grocery Getter-'85 Crown Vic LTD 2-door, 351W with heavily ported/polished GT40 heads, heavily ported/polished Typhoon Power Plus upper & lower intake, Comp Cams 265DEH retarded 1*, FAST EZ-EFI, HD T5, 8.8" 3.73 trac lock with extra clutches, 3G alt. swap, '99 CVPI front brakes, '09 CVPI rear disc brakes, '00 CVPI booster&m/c + wilwood adj prop valve.

Parted & Gone-'88 T-bird Sport, 351W swap, ported GT40 heads

Idle surge...problem still not solved

Reply #7 –
My anderson standalone won't even say the ecm is in it's idle table until .96v and wot at 4.60v,kinda hard to get it perfect,and the idle screw has to be set first or it's impossible to get both.

Idle surge...problem still not solved

Reply #8 –
how do you adjust the TPS?
87 T-bird two tone diarrhea color. 5.0 converted with AOD.  GONE BUT NOT FORGOTTEN
 
94 Lincoln Towncar, Dark Metallic Green, 4.6L AOD
SOLD!!!!
 
99 Mercury Cougar. V6 MTX75 Trans. CURRENT PROJECT DAILY DRIVER.

Idle surge...problem still not solved

Reply #9 –
Okay, well I set the idle screw as recommended by Ford...withing .002" of the throttle lever, then 1/2 turn...it was idling at about 525rpm with the IAC disconnected.  I checked the TPS voltage and was only getting .68V at best...I adjusted the TPS, and got as far as .74V in the stock sotted holes.  I took off the TPS, elongated the holes slightly bolted it back on and set the idle screw until it was at approximately 650rpm and .92V.  The car has a mind of it's own...at first it didn't surge but idled at 800rpm in gear and closer to 1200rpm in park or neutral....after shutting the car off and restarting it, it idles at 850rpm in park/neutral and about 700rpm in gear...and surging again.

I still have the "idle air kit" on the car but both air bleed screws are cranked down tight so it's as good as not even being there.

Apparently, it also turns out that my throttle body is of the "sludge tolerant" design, according to Ford...don't know if that makes a difference.
Project 3G: Grandpa Grocery Getter-'85 Crown Vic LTD 2-door, 351W with heavily ported/polished GT40 heads, heavily ported/polished Typhoon Power Plus upper & lower intake, Comp Cams 265DEH retarded 1*, FAST EZ-EFI, HD T5, 8.8" 3.73 trac lock with extra clutches, 3G alt. swap, '99 CVPI front brakes, '09 CVPI rear disc brakes, '00 CVPI booster&m/c + wilwood adj prop valve.

Parted & Gone-'88 T-bird Sport, 351W swap, ported GT40 heads

Idle surge...problem still not solved

Reply #10 –
Quote from: Sick88Tbird
Hey TC50...I was on mustang-forums.com yesterday and read that when setting the TPS it should be more like .98-.99V...is there any difference in the ECU's(between say a '91 Mark VII and similar year stang) as far as where they like the TPS voltage?  If you say set it to .8-.9V, I will, I was just curious as to the different ranges.

Thanks,
Don


The program in a stock computer assigns(if that is the correct term), TPS voltages of below 1 volt as idle... It then "learns" this voltage and adjusts A/F ratio to 14.7 to 1(assuming the o2 sensors are functioning)(it takes a while after an adjustment is made, but basically the EEC compensates for whatever you do). IF the voltage is over 1v the EEC goes into accelerate mode and opens the IAC/IAB(whichever you want to call it), to increase engine speed so if you suddenly back off the throttle it doesn't die... The reasoning for setting the voltage at .99 is there is less travel of the throttle to go from idle to acceleration(yea you can really tell the difference that .005-.010 less pedal travel makes when you mash the gas...NOT...) Setting it at .8 is ok as is .95, just as long as it is below 1 volt with throttle closed(Ford specs say it should be between .6-.8).

If you haven't already, disconnect the battery cable for 15-20 minutes so the EEC can start fresh in learning your new settings...

If you are continuing to have idle problems, possibly you have other issues... Has it been scanned for codes???

What exactly is your setup???

Idle surge...problem still not solved

Reply #11 –
I haven't disconnected the battery yet, but that was my next plan...no codes in koeo or koer.  As for not noticing a small difference in the tps voltage...my car "sounds" more crisp through the exhaust.

I have a stock '91 HO from an LSC w/EEC from same vehicle.  I have Flowtech full-length headers, off-road H-pipe, dynomax super turbo's dumped, MSD coil and Super Conductor wireset, Accel cap and rotor, K&N panel filter, and a shade over 14* advance.

I had a problem where I was running Autolite AR133's last summer(two ranges colder) and kept them in until winter...car ran so rich, it totally gummed up my EGR valve and fouled the O2 sensor in bank 2.  I replaced the O2 sensor, egr valve, egr pos. sensor, and egr vacuum control solenoid.  I also replaced the IAC about a week after all that...car ran a little better...continued to break up at about 4,000rpm...new wires/coil didn't help...MSD blaster coil/wireset cured it....oh yeah, and I did put the right plugs back in Autolite 25's gapped at .054"

Thanks,
Don
Project 3G: Grandpa Grocery Getter-'85 Crown Vic LTD 2-door, 351W with heavily ported/polished GT40 heads, heavily ported/polished Typhoon Power Plus upper & lower intake, Comp Cams 265DEH retarded 1*, FAST EZ-EFI, HD T5, 8.8" 3.73 trac lock with extra clutches, 3G alt. swap, '99 CVPI front brakes, '09 CVPI rear disc brakes, '00 CVPI booster&m/c + wilwood adj prop valve.

Parted & Gone-'88 T-bird Sport, 351W swap, ported GT40 heads

Idle surge...problem still not solved

Reply #12 –
Well keep us posted on what finally fixes it I seem to be having a similar idle problem at the moment. Mine seems to idle fine when cold and starts messing up as it warms up. then it speeds up and drops really far on its own. We could possibly have some of  the same things messed up
87 T-bird two tone diarrhea color. 5.0 converted with AOD.  GONE BUT NOT FORGOTTEN
 
94 Lincoln Towncar, Dark Metallic Green, 4.6L AOD
SOLD!!!!
 
99 Mercury Cougar. V6 MTX75 Trans. CURRENT PROJECT DAILY DRIVER.

Idle surge...problem still not solved

Reply #13 –
Quote from: Sick88Tbird
I haven't disconnected the battery yet, but that was my next plan...no codes in koeo or koer.  As for not noticing a small difference in the tps voltage...my car "sounds" more crisp through the exhaust.



Just run it a few days, the EEC will relearn the TPS and it will sound like it's old self again... :D

I got tired of the EEC undoing my changes... I pulled the memory wire for the EEC a couple of years ago... Now every time I restart it has to start the learn cycle all over again(assuming it's set for more than 10-15 minutes)... I mentioned the idea to a buddy and he said Hell of a idea!!! Then immedeatly disconnected his...

Idle surge...problem still not solved

Reply #14 –
I will give it a few days and post back on monday evening.  I'll probably be disconnecting the battery tomorrow morning while I do some things around the house, then I'll drive the wheels off of it all weekend and see what happens.

thanks
Don
Project 3G: Grandpa Grocery Getter-'85 Crown Vic LTD 2-door, 351W with heavily ported/polished GT40 heads, heavily ported/polished Typhoon Power Plus upper & lower intake, Comp Cams 265DEH retarded 1*, FAST EZ-EFI, HD T5, 8.8" 3.73 trac lock with extra clutches, 3G alt. swap, '99 CVPI front brakes, '09 CVPI rear disc brakes, '00 CVPI booster&m/c + wilwood adj prop valve.

Parted & Gone-'88 T-bird Sport, 351W swap, ported GT40 heads