Cold starting issue-Throttle response

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Sep 9, 2021 | 08:49 PM

Big-Dawg

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From: Gibsonville,NC

Cold starting issue-Throttle response

Hello all, I have an 86’ xlt lariat, 302, auto w/AOD & it has EFI. I have an idle/throttle response issue at startup. At first crank it idles up to around 2500 rpms then dies. When I re-crank it and give it gas, there is almost no throttle response, the engine starts idling very rough and popping like popcorn. It only does this until it warms up then it runs smooth as silk. It happens after it’s been sitting overnight or for enough time to completely cool the engine. I ran the codes KOEO & got 11, 10(separator code) & 64. The 64 code tells me it’s low voltage to the ACT sensor. The crazy thing is I’ve ran codes after recently replacing the sensor, within the last 2 months & it never threw this code. So what changed? Is this one of the capacitors in the ECU that routinely fails over time? I’ve attached a video of startup after it has sit all day, sorry it’s so dark. Any advice with this would be greatly appreciated.

Last edited by Big-Dawg; Sep 9, 2021 at 10:02 PM. Reason: Attachment didn’t load

Sep 10, 2021 | 06:53 AM

Franklin2

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From: Virginia

Why did you replace the ACT sensor? Do you have the old one? You could put it back in. Check the part numbers, I want to say the coolant temp sensor and the ACT sensor might be the same sensor if you happen to have one of those sitting around.

Sep 10, 2021 | 01:23 PM

Big-Dawg

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From: Gibsonville,NC

Cold start-Throttle response issue

Quote:

Originally Posted by Franklin2

Hi Franklin2, I replaced the ACT sensor trying to fix a surging issue & it corrected that. I do not have the old one as the sensor actually looked like a burnt match, I assume it was the original 35 year old sensor. I’m planning on pulling it this weekend & bench testing it. Might have to replace it & see what happens. Thanks!

Sep 13, 2021 | 02:16 PM

Max Capacity

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From: Tolland, CT

Wasn't there a thread a few weeks back where someone cleaned the Idle Air Control. Could that be your issue ? I know they can get a build up of carbon in them.

Sep 26, 2021 | 02:52 PM

Big-Dawg

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From: Gibsonville,NC

Cold starting issue

Hello again all, I ended up cleaning the IAC valve & it started running as it should for about one week. Now it’s back to its old rough idle at first start again. I actually cleaned the IAC valve a few minutes ago & cranked it to no avail. Does anyone know where I should look next? Thanks.

Sep 26, 2021 | 03:33 PM

Max Capacity

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From: Tolland, CT

So your saying after

"I actually cleaned the IAC valve a few minutes ago & cranked it to no avail."

The engine won't start ?

The engine cranks over, but not fire up and run ?

Sep 26, 2021 | 08:41 PM

Big-Dawg

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From: Gibsonville,NC

Reply

Quote:

Originally Posted by Max Capacity

So your saying after

"I actually cleaned the IAC valve a few minutes ago & cranked it to no avail."

The engine won't start ?

The engine cranks over, but not fire up and run ?

Max Capacity, I cleaned it thinking it would help with the rough idle/throttle response issue & it made no difference. Yes it cranks & runs, just very rough until it’s up to normal engine temp. Thanks