Engine IAC adjust spacer plate factory settings

emba129 · Jan 20, 2022

Hi all. I had idle issues on my 93 Cobra. I found it to be associated with the IAC adjustment plate. Bad gaskets I believe. Idles pretty good without it installed.

I removed it, gave it a thorough cleaning. Bought new gaskets and now I need to put it back to factory settings. The installation instructions from Ford say that it comes from Ford preset at maximum airflow for engine applications of 5.0L displacement or smaller.

The plate required a good cleaning. I removed the two set screws fully and cleaned everything thoroughly. I see that both set screws had blue Loctite indicating to me that they were factory set.

I’m going to reinstall it. Does anyone know what the initial settings are for the 2 set screws for a factory 5.0? I want to get back to baseline so I can tweak to get the best idle with the plate. The car has a mild aftermarket cam so I want to reinstall to get the optimal idle

Thanks all

General karthief · Jan 20, 2022

If it idles good without it leave it off, that plate was a 'fix' for a TSB for idle issues on some 5.0-5.8 efi trucks and cars. The factory did use them.

dgollem · Jan 20, 2022

Not sure about factory settings but I added one to my car years ago because I could not tame the surging idle issues. The plate helped out a lot but required some tweaking. If it idles ok without it that's the factory and the way to go. The idle plate is a work around. If you put it back on just tweak the screws until it idles where you want it, not that hard but patience is the key because it does not negate the IAC it just allows extra air to enter to increase idle. Adjust then wait a few minute or two and see how the idle reacts, repeat until satisfied.

Mustang5L5 · Jan 21, 2022

I would make every effort to not use that plate. It’s a band-aid solution and if you idle is good without it, then you don’t need it.

emba129 · Jan 21, 2022

Turns out it DOES need the plate. This Cobra has an aftermarket, relatively mild, CAM (not sure of the specs on it) Without it I had slight surging idle (800-1000). I put it back on with new gaskets. Started out with the screws all the way closed. Backed the inboard out 2 turns and the top one 1.5 turns. Idle smoothed out perfectly. Did a Base Idle Reset and it runs like new

Thanks all

7991LXnSHO · Jan 21, 2022

In theory, this is doing the same as opening the throttle a little more at idle, but without having to slot the TPS to get it back into range with a big cam.
The base idle reset steps works fine for my current combo. But I have one of these in my parts box in case it does not with my next engine and I do not want to learn how to tune a new computer system.

emba129 · Jan 21, 2022

I tried to increase the idle the same way with the idle screw and to get it to smooth out the idle was at 1200. The fine tuning of the plate allows me to get it to around 900-1000 for a smooth idle. Also, I’d doesn’t hang between shifts, which is good.

dgollem · Jan 22, 2022

Glad it worked out for you. Sounds like the same solution I arrived at, I could always get the idle better with the plate than without. Mine has been in use for more that 20 years now.

emba129 · Jan 24, 2022

I need to tweak it a little with the car is first started cold.. I get some low RPM surging.

manicmechanic007 · Jan 25, 2022

Working for Ford I installed many a plate
Took off almost as many
I agree very few stock engines can benefit
The Lightning was one
They came about for the 85 fuelie Tempo surge

Willybill32 · Jan 25, 2022

manicmechanic007 said:
Working for Ford I installed many a plate
Took off almost as many
I agree very few stock engines can benefit
The Lightning was one
They came about for the 85 fuelie Tempo surge

@manicmechanic007, my ‘86 (5.0, E303 cam, TFS TW heads, shorty headers, 24lb injectors, MAF, etc.) bucks a lot below about 1,200 RPM, making it difficult to drive in parking lots, etc. My tuner says it’s all happening before the TPS says the throttle plate is open. Would one of these plates maybe help with reduce the bucking?

Bill

manicmechanic007 · Jan 25, 2022

It sure might WillyBill32
You should try one if you can still find one
I have one somewhere

Willybill32 · Jan 25, 2022

manicmechanic007 said:
It sure might WillyBill32
You should try one if you can still find one
I have one somewhere

LMR.com shows one. If you have one handy, I’d be glad to buy it, but otherwise I can get it from LMR.

manicmechanic007 · Jan 25, 2022

If I can find mine I would just give it to you
I will try to look this afternoon evening

Willybill32 · Jan 25, 2022

manicmechanic007 said:
If I can find mine I would just give it to you
I will try to look this afternoon evening

Thank you!

Bill

Dan02gt · Jan 25, 2022

Willybill32 said:
@manicmechanic007, my ‘86 (5.0, E303 cam, TFS TW heads, shorty headers, 24lb injectors, MAF, etc.) bucks a lot below about 1,200 RPM, making it difficult to drive in parking lots, etc. My tuner says it’s all happening before the TPS says the throttle plate is open. Would one of these plates maybe help with reduce the bucking?

Bill

I doubt it will help much at all. E cams are known for low speed drivability issues.

General karthief · Jan 25, 2022

I agree, ask me how I know.

90sickfox · Jan 25, 2022

I drove an E cam for years. In a 302...a 306...and a 347. I didn't have any drivability issues with it and it always baffles me when I hear people say it. I ran it EFI and carbureted. The same exact camshaft. Something I did do was clock the throttle body so the IAC was on top and the linkage was at the front. I don't have any pictures ( I don't think ). This was an old trick for surging idles back in the day. It was like that when I bought the car so I kept it that way. I still have the bracket that the gas cable bolted to somewhere.

I loved that camshaft in my 347. It was mild for it but pulled hills with no problem. It also pulled the car north of 160mph. ( something I'd never do again in a fox )

Dan02gt · Jan 25, 2022

90sickfox said:
I drove an E cam for years. In a 302...a 306...and a 347. I didn't have any drivability issues with it and it always baffles me when I hear people say it. I ran it EFI and carbureted. The same exact camshaft. Something I did do was clock the throttle body so the IAC was on top and the linkage was at the front. I don't have any pictures ( I don't think ). This was an old trick for surging idles back in the day. It was like that when I bought the car so I kept it that way. I still have the bracket that the gas cable bolted to somewhere.

I loved that camshaft in my 347. It was mild for it but pulled hills with no problem. It also pulled the car north of 160mph. ( something I'd never do again in a fox )

My dad had a E cam in a 90 GT with a GT40 top end and it ran great. A buddy had one in a 93 with Edelbrock aluminum heads and Trick Flow intake. It had all the issues people talk about with E cams. We fought with it for about a year trying to deal with the idle issues and low speed bucking. He finally got feed up, ripped it out, and installed a Steeda #18. Just like that all his issues went away. It seems like issues with them are really hit and miss. With so many good cams on the market for reasonable prices, I don’t see the point of fighting with one.

90sickfox · Jan 25, 2022

Dan02gt said:
My dad had a E cam in a 90 GT with a GT40 top end and it ran great. A buddy had one in a 93 with Edelbrock aluminum heads and Trick Flow intake. It had all the issues people talk about with E cams. We fought with it for about a year trying to deal with the idle issues and low speed bucking. He finally got feed up, ripped it out, and installed a Steeda #18. Just like that all his issues went away. It seems like issues with them are really hit and miss. With so many good cams on the market for reasonable prices, I don’t see the point of fighting with one.

I agree with you 100%. Aftermarket cams have come so far over the years. I wouldn't run an E cam again unless it was given to me. All the alphabet camshafts are a bit archaic. I have a comp cam xe282hr now and like it. It's a low vacuum at idle type of grind which could cause bucking and such at lower rpms but I don't have that issue with this cam either. My next one will be custom made. If I had a cookie cutter build I'd use a cookie cutter camshaft. There are proven dyno numbers for most basic builds with off the shelf camshafts. My comp cam isn't the best for what I'm doing and my engine is a special POS. Next time it'll be an aftermarket block and custom camshaft.

Engine IAC adjust spacer plate factory settings

emba129

Member

General karthief

wonder how much it would cost to ship you a pair

dgollem

Mustang5L5

That is…until I whipped out my Bissell

emba129

Member

7991LXnSHO

wanna catch the space herp

emba129

Member

dgollem

Attachments

emba129

Member

manicmechanic007

Willybill32

But at least it's tight!

manicmechanic007

Willybill32

But at least it's tight!

manicmechanic007

Willybill32

But at least it's tight!

Dan02gt

mazing how much gas smell came from that tiny hole

General karthief

wonder how much it would cost to ship you a pair

90sickfox

Wasn't a pretty sight...and I've got big hands

Dan02gt

mazing how much gas smell came from that tiny hole

90sickfox

Wasn't a pretty sight...and I've got big hands

Similar threads

Engine IAC adjust spacer plate factory settings

Member

wonder how much it would cost to ship you a pair

That is…until I whipped out my Bissell

Member

wanna catch the space herp

Member

Attachments

Member

But at least it's tight!

But at least it's tight!

But at least it's tight!

mazing how much gas smell came from that tiny hole

wonder how much it would cost to ship you a pair

Wasn't a pretty sight...and I've got big hands

mazing how much gas smell came from that tiny hole

Wasn't a pretty sight...and I've got big hands

Similar threads

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