Fast idle after intake mod

Topic: Fast idle after intake mod (Read 10663 times) previous topic - next topic

Fast idle after intake mod

Reply #30 – February 06, 2014, 09:50:18 PM

Quote from: jcassity;428532

i wish i had never thrown my old dwell meter away,, it was buttstuffog.. i thought it was only good for carbs and such.
had adaptors for checking and setting points and such,, to be honest i didnt know how to use the darn thing... now i think i could figure it out and make it useful for something.

Should have saved it

. A tach/dwell meter is useful for setting the base idle on any EEC-IV cars with a distributor, including our 5.0 powered cars.

Fast idle after intake mod

Reply #31 – February 06, 2014, 09:54:56 PM

So just what is base idle if not setting the throttle body to give a idle speed of 50-100 RPM LESS than where the PCM will set it????????????(IAC is disconnected for this adjustment)

If it's already in the ball park so to speak, there is less chance of a hunting idle due to IAC swings...

I've ALWAYS set the base idle on my 5.0 & 2.3, and usually improve idle quality... Throttle bodies on high mileage applications can almost always be tweaked for some improvement... After base idle is set then it's time to tweak TPS and adj if necessary...

Fast idle after intake mod

Reply #32 – February 06, 2014, 09:58:07 PM

Quote from: TOM Renzo;428516

That MIN idle screw is not a base idle screw technically speaking,, often the two get confussed and each have major differnces. I did a a thread on this a few years back but basically no modern EFI engine controls base idle with a set screw. Actually the IAC uses Step counts. And i am if correct in saying Fail safe does not control IDLE speed to any great lengths in an OBD1 Engine management system> The link you posted is not totally correct to set base idle in my records from ford.

Also your IAC just simply might be bad. Also the diameter of the throttle plate hole and bypass screw on some TB units also has to be adjusted. I included this procedure to tune the IAC MOTOR in the old thread, I need to dig that up have it ready for posts like this. Throttle plate hole is also critical as it also bypassed air past the throttle plate.

ahh,, fixed it for you tom,,, slap me later :)

Fast idle after intake mod

Reply #33 – February 07, 2014, 12:12:16 AM

Great info guys. Thanks for all of that. Want to hear a real bone head thing that I did this afternoon? I was looking for an easy access vacuum line to hook my gauge up to and the EGR plate was right there with two hoses going to it. I thought that when I removed the old intake I saw some fluid coming out of it but it didn't really register. So I pulled the hose off and stuck my vacuum gauge in it and started up the car. Is everyone laughing now? That's learning the hard way.

Fast idle after intake mod

Reply #34 – February 07, 2014, 01:04:14 AM

you lost me but.. if its running great, thats all that matters

Fast idle after intake mod

Reply #35 – February 07, 2014, 10:18:55 AM

Quote from: jcassity;428552

you lost me but.. if its running great, thats all that matters

I didn't realize the EGR plate is liquid cooled, i thought those hoses would be vacuum. It surprised me when I unhooked one hose, hooked up the vacuum gauge and started the car and coolant started pouring all over the place out of my EGR spacer. I hope that's what it's supposed to do otherwise I have a serious problem.

Fast idle after intake mod

Reply #36 – February 07, 2014, 10:37:29 AM

I will admit, I did have a minor laugh at your expense, but I'm over it now.

Fast idle after intake mod

Reply #37 – February 07, 2014, 10:41:02 AM

Quote from: marianadeeps;428570

I didn't realize the EGR plate is liquid cooled, i thought those hoses would be vacuum. It surprised me when I unhooked one hose, hooked up the vacuum gauge and started the car and coolant started pouring all over the place out of my EGR spacer. I hope that's what it's supposed to do otherwise I have a serious problem.

Yep that's normal. If you followed the line you would have noticed that it went back to the heater core pipe. Probably should have done that before hooking up the vacuum gauge lol

Fast idle after intake mod

Reply #38 – February 07, 2014, 02:22:55 PM

ok,, so you didnt lose me after all becaue thats all i could think of but ,,,, for some reason ,,, i couldnt think it was possible.
I am still laughing at your expense!,, yet i to am not the brightest crayon in the box so i should stop now before carma finds a convient corner of my world to lurk in.

Fast idle after intake mod

Reply #39 – February 07, 2014, 02:23:58 PM

you may want to check your brake booster interior vac operated hvac controls, all things vac related........... humm,, now its starting to sound kinda serious.

Fast idle after intake mod

Reply #40 – February 07, 2014, 05:11:46 PM

Quote from: jcassity;428585

ok,, so you didnt lose me after all becaue thats all i could think of but ,,,, for some reason ,,, i couldnt think it was possible.
I am still laughing at your expense!,, yet i to am not the brightest crayon in the box so i should stop now before carma finds a convient corner of my world to lurk in.

yeah, I thought you guys would like that. It won't be the last. I sit a desk all day shuffling papers going to meetings and writing software. This is the first car I've ever torn apart -- what the f*** do I know?

I'm going to be spending some serious time in you DIY pages -- half of those things listed I need to do. It's fantastic.

Also Tom R, if you're reading this, I don't care if you yell a me or think I'm an idiot, just keep answering my questions -- my rear disc brakes are working because of you.

Fast idle after intake mod

Reply #41 – February 08, 2014, 01:54:21 PM

No one is yelling at anyone. Just passing on good info between us as usual. Have a great day!!!

Fast idle after intake mod

Reply #42 – February 11, 2014, 12:39:21 AM

The computer controls idle with the iac. if it doesn't stall with the iac unplugged, you have a vac leak and the ecu pulls timing to try to lower your idle. this is what I believe causes the surge.

No need for a tach or anything. I did this yesterday, and my car pulled 675rpm on my emissions paperwork.

Fast idle after intake mod

Reply #43 – February 11, 2014, 04:30:32 PM

ok. so here's an update. I started the car, pulled the plug on the IAC, no change to the idle -- it usually behaves (idles properly) when it's cold. I let it idle for 5 minutes, then took off the air filter from the end of my cold air intake. I then placed my hand over the intake and the car, sucking like mad, stalled after I had sealed the opening. If I had a vacuum leak, it would have kept running, wouldn't it? I can get the car to idle any speed I want by varying the degree by which I seal that intake with my hand. So.. does that mean my TB is not closing correctly when the engine is warm?

I've not tested the TPS yet and that is my next to do.

Fast idle after intake mod

Reply #44 – February 11, 2014, 04:50:25 PM

You should be able to kill it by covering the tb opening

Check you tps. do a sweep with the key on, engine off. make sure it has no dead spots and gradually increases thoughout the sweep. it should read 2.5v's or higher then idle, and idle should be .5-1.1v's as tom mentioned.

You should be able to lower the idle screw until the car starts lugging without the iac plugged in. if you plug the iac back in and it doesn't raise idle, then the iac is most likely bad. I've done this exact thing on my cars, and they all have idled flawlessly.