Surging Idle

TorchRed_4.0

Member
Mar 2, 2019
67
2
8
I’ve read the entire surging idle checklist, I’ve metered to make sure they all work, my TPS is brand new, my IAC is brand new, timing is set, injectors new, spark plugs new, ECU has been sent off and repaired, i’ve checked my 10 pin connectors, it’s a brand new motor, everything about it.

-347 Stroker
-GT40 heads
-E303 cam
-Tuned

The car just still runs rough and surges and I’m just out of ideas on what it could be.

It’ll crank then die immediately about 3 times, but when it does stay running, it just sits there and surges.

Here’s my codes:
21 - Coolant sensor out of specified range
24 - Air charge temperature low
85 - Canister purge
41 - Oxygen fuel sensor/Lean fuel mixture
53 - Throttle position sensor input out of specified range

Any advice would be appreciated. Like I said i’ve looked through that checklist, it hasn’t helped.
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Looked through the checklist?
Not sure what that means. You have codes that need to be resolved, like the purge canister, is it hooked up?
Air charge temp low?
Tps out of range?
The list covers some if not all of that.
Have you looked for a vacuum leak?
 

TorchRed_4.0

Member
Mar 2, 2019
67
2
8
Looked through the checklist?
Not sure what that means. You have codes that need to be resolved, like the purge canister, is it hooked up?
Air charge temp low?
Tps out of range?
The list covers some if not all of that.
Have you looked for a vacuum leak?
It means i’ve read through it, and checked everything it says that could be an issue to the idle problem. Purge canister is gone, got rid of it, and yes i’ve looked for a vacuum leak can’t find any using the fogging method.
 

Dan02gt

mazing how much gas smell came from that tiny hole
10 Year Member
Mar 2, 2003
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To me all those codes point to a wiring issue. Either something with the 10 pin salt and pepper connectors or a burned pin 46 trace on the EEC.
 

TorchRed_4.0

Member
Mar 2, 2019
67
2
8
The purge canister delete tells me, ahh, nevermind.
Custom chips don't fix things.
What year is the car?
Did the car run ok before the rebuild?
It’s a 1990, it ran okay, but it needed rings and all sorts of stuff, but It definitely doesn’t run as good as it did before the rebuild. But everything is new and all sensors are getting power. Maybe the timing is STILL off? I’ve redone the timing so many times now I don’t think that could be it. It’s frustrating, might just have to slap a carburetor on it.. LOL
 

7991LXnSHO

wanna catch the space herp
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Sep 1, 2010
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@TorchRed_4.0 Reading the list is not the same as working through the list and fixing the little and not so little things. I do not see anything here that should not be easily fixed by going step by step - and putting the charcoal canister and purge solenoid back on.

(@General karthief is that close enough to what you wanted to say in post #8? I wanted to say it since post #1 and hope it helps.)
 
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Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
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Did you run the engine test with the engine warmed up? Or with it cold?

Code 21 is common if you test a cold engine. Just want to see if it’s a real code, or a false code.

If 21 and 25 are real, those are probably the two main codes to focus on.

Test the sensors following this guide and resistance chart

Test at the sensor, and then down at the ECU connections to see if there is a wiring issue from the sensor down. Coolant would be pin 7 to 46 and air intake charge would be pin 25 to 46.

They both route through the 10-pin connectors at the rear of the intake.
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
23,729
8,771
203
@TorchRed_4.0 Reading the list is not the same as working through the list and fixing the little and not so little things. I do not see anything here that should not be easily fixed by going step by step - and putting the charcoal canister and purge solenoid back on.

(@General karthief is that close enough to what you wanted to say in post #8? I wanted to say it since post #1 and hope it helps.)
Well, I really, nevermind