setting idle speed on '88GT
 

I assume there is more to setting the idle speed on an '88GT than adjusting the screw on the TB.
The reason I ask is becuse I turned the screw on my TB to raise the idle speed and after I shut it off, it was back to where it was before.
Do I have to disconnect the IAB first? Will I need to adjust the TPS too then?

Is yours a mass air car?

If so:
1) Disconnect the battery (and the IAB valve) for 20 minutes.
2) Reconnect the battery (but not the IAB valve), start the engine and adjust the idle.
3) wait 2 minutes, connect the IAB valve, turn off all accessories, start the engine, let it idle for two minutes.
4) Shut off engine for two minutes.
5) Turn on all accessories, start the engine, let idle for two minutes.

I don't know if this works for Speed Density cars.... Not sure but I don't think so!
Phil

No, it's speed density

make sure the enigine is fully warm. disconnect IAB motor while the car is running. Set the rpm where you want it. turn the car off, reconnect the IAB and start the car. your done. I never had to do a relearn procedure anytime i adjusted fords minimum air flow.

James

This procedure works for BOTH mass-air and speed density,there's no reason why it wouldn't work

James,
I'm not an EFI expert and only have a basic knowledge of the EEC system but here's why I recommend doing the relearn procedure when changing the idle speed.

Most peple think the EEC "Adaptive Control" system only makes changes to the "Keep Alive" memory tables during closed loop and that open loop uses fixed tables...

In fact, during open loop, the EEC system relies on information stored in the "Keep Alive" memory tables as well as the last values that it was using while in Closed Loop (even after the key is turned off.)

So, even though you've corrected the idle when the engine is fully warmed (closed loop), when it cools and then you start the engine again, the car might still idle low because it's using previous "Keep Alive" memory to make corrections in open loop!

The only way to clear the "Keep Alive" adaptive memory tables is by disconnecting the battery.

I might be wrong, but I doubt it!
Maybe a resident "EEC Guru" (if there is one) might be able to clear this up!
Phil
:confused:

I was under the assumption that because a Speed Density system doesn't have sensors that directly measure engine airflow, all the fuel mapping points must be preprogrammed. (which includes Idle)

Don't any changes have to be reprogrammed? (Including Idle)
Phil

Nope, speed density is just more touchy to modifications is all,and with tuning,they run just as good as mass-air cars do

For setting the idle,it's just setting the idle,it's the same on every fuel injected 5.0 Stang. Think of it this way,my stang was speed density before I installed the blower,once I installed the blower,I converted to mass-air,now why would I set the idle any different,see what I'm saying?

Because a Mass Air flow car uses a "Mass Air Flow Sensor" (MAF) to measure actual airflow into the engine directly at the *THROTTLE BODY*!

A Speed Density car uses a "Manifold Air Pressure Sensor" (MAP) and RPM to *CALCULATE* how much air is entering the engine.

The Speed Density car doesn't know that you opened the butterfly at the throttle body to let more air in, you have to tell it by reprogramming the Electronic Control Module (ECM.)

Since the "Mass Air" car can measure airflow into the engine at the throttle body, it is able to compensate by adding more fuel based on the actual measured increase of intake air!

Get it yet?
Phil

I know the differences between mass air and speed density thank you ;)

You still set the idle the same,no matter what your working with,that doesnt change anything:rolleyes:

I would believe you but you've yet to give me a detailed explaination as to *WHY* and *HOW* that comment is true!

All you've told me so far is:
1) "speed density is just more touchy to modifications"
2) "This procedure works for BOTH mass-air and speed density" (referring to setting the idle)

Then you went on to ask yourself: "I converted to mass-air,now why would I set the idle any different?" And then you asked me: "see what I'm saying?"

Sorry, I don't See What You're Saying!!!!!!
You're asking me to just believe you without any detailed, technical information as to (again) *WHY* and *How* there is no difference.

C'mon, if you're right you should be able to explain *WHY* and *HOW* in a few short paragraphs!
I'd appreciate it!
Thanks,
Phil:p

Phil, I'm not an expert on Ford's ECM but are you trying to say that people with SD cars are not able to adjust idle speed unless they have the technical knowledge to reprogram the ECM and if you have mass air all you need to do is those simple steps you mentioned above?
I don't know but that doesn't make ANY sense to me:confused: :confused:

I'm going to settle this once and for all. I'm going to adjust it the way serv1 said to do it. If that doesn't work then I'll try your way for MAF cars....if that doesn't work then I guess I'll have to find someone with a laptop computer and knowledge of Ford's ECM programing to adjust my idle speed.
I'll post my results here later tonight.

Great!
I'm not trying to be a smart *** but I remember what my friend went through with his brand new 1988 speed density Mustang!

All he did (when it was less than a week old) was remove the air silencer, install a K&N air filter and add a set of equal length headers. He couldn't get it to idle until he had the ECM remapped!

In your case, if it's bone stock, you might be able to correct the idle but otherwise I think you'll discover that I'm right!

Actually, I hope I'm wrong for your sake. I don't have a problem eating my words if I'm wrong!

We'll see, let us know how it turns out!
Phil

Philossifer

You obviously haven't worked on many 5.0 mustangs judging by your lack of knowing how many people use this method of setting the idle on 5.0 mustangs. This isn't something I made up,you can do a search on the net and you will find the EXACT same thing I said here that setting the idle on a 86-93 5.0 mustang involves the same steps.You will find the same procedure listed in a chiltons manual.

The only thing that has to be done after the idle is set,is drive the car,allowing the computer to re-learn the new settings.

Instead of reading books,you need to go out and actually work on some cars to get a understanding of how things work.

Mustanguy,
I have (and still do) work on cars..... If you had read my last post, you would have seen that I mentioned my friends experience with setting the idle on his mildly modded '88 Speed Density car!

I asked you to exlain *WHY* and *HOW* there is no difference in setting the idle on Speed Density vs Mass Air cars and the best you could do is mention a Chiltons manual and my lack of knowledge as to how many people use this method of setting the idle on 5.0 Mustangs! (STILL NO HOW OR WHY!)

Would it be possible for you to scan the page(s) in your Chilton manual that spell out the procedure for setting the idle on a Speed Density car? My Chilton's manual only goes back to 1989 so it deals only with Mass Air cars. I don't mind being wrong, but I'd like to have some proof!

Anyway, I'm still waiting to hear from the guy who asked the question in the first place. He said he was going to post his results (here) about setting the idle on his Speed Density Mustang! He was supposed to work on his car and post his results last night but didn't! (I wonder why?)

We'll See?
Phil

Because I didn't get a chance to do it last night(sorry).
This is getting out of hand. I'll tell you what...I'm going to go do it right now....I'll be back!!!

Phil, if you want a technical answer as to HOW AND WHY ask PKRWUD...I'll guarantee you that he knows the answer.
Now excuse me...I have an idle speed to adjust.

Well, here is what I did:

Got engine up to operating temp
Disconnected IAB
Adjusted idle screw
Turned off engine for 2 min.
Reconnected IAB and started the car.

I believe it worked the way serv1 said to do it.
It's a little high and I'm going to lower it later after supper.

I'm not scaning anything,the fact is you set the idle the same on both mass-air and speed density 5.0's

Think about it,dont be so bull-headed,if you had common sense,you'd know there's not one procedure to follow for speed-density and another procedure to follow if your going to set the idle on a mass-air equiped car, it's the same method you have alot to learn about working on Mustangs,I can see that.

Mustanguy,
I know you're not (scanning anything) because you don't have anything to scan!

You see, I know for a fact that the procedure for setting the idle on a Speed Density car is different than a Mass Air car and as soon as I get the documentation, I *WILL* scan it and post it here!

Furthermore, it was suggested (by 82GT) that I contact PKRWUD as he would know for sure! As a matter of fact, I did email him and he emailed me back with the correct procedure for setting the idle on a Speed Density Mustang.

I'm not going to paste his whole response but this is how he started his response to my question about setting the idle on a Speed Density car:
"It's a major pain in the ***, but it can be changed with different plugs that go into a hole in the throttle plate. This is the proceedure for setting the idle in a SD Mustang....."

So, NOW WHO's BEING BULL HEADED?
Phil

I would be interesting to read PRRWUD'S entire response.
Any chance of you posting the whole thing or getting him to join this thread?
I'm not being a smart ***, but I'm curious to see what he has to say?
Another thing, why was I able to set my idle by SERV1'S method?
Can someone explain that?
Maybe MUSTANGGUY is right after all.
I'll post this on another message board just to see what othe rpeople say too.
The fact still remains though......I've set my idle without reprogramming the ECM.