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Topic: Odd question (Read 4838 times) previous topic - next topic

Odd question

SUP; guys, got a question, ever since i added my gt 40 intake, bumped timing to 12, car idles better and has more power w/o the iac hooked up,ive tried a diff iac and didnt make a diff, i even replaced wiring harness. dont have any codes accept for the one for egr delete, no vacumm leaks all lines are new. car also has headers and 2 chamber lers.brand new gear drive, msd coil and cap and wires. im thinking its prob not getting enough fuel , so when i unhook the iac it bumps the mixture up?

Odd question

Reply #1 –
Did you ever hook the o2 sensors back up?
Quote from: jcassity
I honestly dont think you could exceed the cost of a new car buy installing new *stock* parts everywhere in your coug our tbird. Its just plain impossible. You could revamp the entire drivetrain/engine/suspenstion and still come out ahead.
Hooligans! 
1988 Crown Vic wagon. 120K California car. Wifes grocery getter. (junked)
1987 Ford Thunderbird LX. 5.0. s.o., sn-95 t-5 and an f-150 clutch. Driven daily and going strong.
1986 cougar.
lilsammywasapunkrocker@yahoo.com

Odd question

Reply #2 –
Yes everything is hooked up except egr delete.

Odd question

Reply #3 –
Can I assume that we are working on your 88 Cat? Stock fuel pump? Size injectors?

83 351W TKO'd T-Bird on the bottle


93 331 Mustang Coupe - 368 rwhp

Odd question

Reply #5 –
Base idle reset was done each time ive changed the iac, fuel pump is stock and injectors are factory psi. idle is ok most of the time but sometimes when cold it will surge for a few seconds, im just wondering why it would idle better and have more power with iac unplugged, im thinking it makes fuel mix richer. or because of my mods injectors are now to small and might have to go to stang injectors.

Odd question

Reply #6 –
The IAC just controls idle. Nothing more. Removing it should not increase power.

What size injectors are you running? If it's the stock computer you have to run 14lb injectors.
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

Odd question

Reply #7 –
yea they are the stock injectors 14lbs, im been thinking about changing cam and using a lsc computer and stang 19 lbs injectors.

Odd question

Reply #8 –
With a gt40, and assuming HO cam and firing, you really ought to have MAF (calibrated) and 24's  14's aren't even almost close to enough fuel for that.  Don't do any WOT pulls if you're fond of your pistons.

Odd question

Reply #9 –
No; its a non ho motor, cougars dont come with ho motor. its a so motor with a gt40 intake 65mm tb headers flowmaster, msd ign, air intake kit.

Odd question

Reply #10 –
The reason it idles better with the IAC unplugged is because with exhaust, GT40 intake,65mm TB,cold air intake you have exceeded the limits of what the speed density ecm can handle as far as fueling since you have made the engine flow more air in and out with your mods. The ecm is hunting for an idle because its most likely on the lean side. With the IAC unplugged your just taking away the ECM's ability to try and change the idle to stabilize it and its just idling off what ever amount the throttle blade is open on the set screw. Its still running lean with it unplugged and Id be careful with making to many full throttle pulls like this.

Step up to the LSC ecm and 19s at the very least and it should run a lot closer to normal again.
Brian R.
88 2.3t Ranger
83 TC  gt40p motor,Vortech,TFS1 cam,long tubes,MS PnP,T5,8.8,17x9 Cobra 17s

Odd question

Reply #11 –
thanx i was figuring it was starving for fuel, im used to carbs lol...i noticed the plugs where more white than tan like usual.

Odd question

Reply #12 –
None of ours did, but I'm laying out a common configuration that a lot of guys shoot for.  You can't just throw a gt40 and headers on a 150hp SO motor and expect it to be happy, it's speed density for Christ's sake, It operates on a wide set of assumptions.  There's a reason guys who mod go for a certain set of parts, it's because they play well together and make good power.
Get yourself some GT40 heads (steer away from P's) for $300, somebody here will probably GIVE you an HO cam if you ask nice and pay shipping.  You shouldn't just throw a GT40 on top of E6's and an SO cam. It's not ever going to be happy.  You'd have been better off with headers and an HO upper.  I've probably still got my 19's in a box somewhere, and with a SD HO EEC, that would probably run pretty happy making around 275, if a little lean at the very top (GT40 heads, HO cam, 19# and HO EEC, GT40 upper and lower).  The setup you have now will have slowed your port velocity, and is probably screwing up your MAP reading, skewing it one way or the other, and owing to the greatly increased plenum volume, introduced a nice delay into it's ability to give fast and accurate readings of manifold vacuum.  We're only talking milliseconds, but when it's trying to calculate load, a dozen or so ms is enough that it might not ever catch up.  It'll just bounce back and forth as it tries to react to and correct for an inaccurate load.  If I could guess, your idle is probably happier when you've disabled spark advance, right?  With TFI, this would be done by removing the SpOUT connector, I don't know how it's done with your MSD.  Spark advance is determined by that load calculation that can't be happy.

Odd question

Reply #13 –
thanks for the help sir!!! i figured it was running kinda lean, but im getting no spark knock. im gonna change to h/o cam if i can find one. use the lsc ecm and some 19 lb injectors and go from there, im used to carb cars, im old school...lol if i change to gt40 heads also i will probably have to switch to mass air ive been told.

Odd question

Reply #14 –
I found a good deal on a h/o firing order cam its a 270hr cam, for 80.00 never ran. would that work? or is it to agressive for the speed density set up?