Help me create the "Surging Idle Checklist"

whitey92lx

New Member
@whitey92lx
What did you get when you dumped the codes?

30 PSI for fuel pressure? How did you do the test?

Check fuel pressure:
The local auto parts store may rent or loan a fuel pressure test gauge if you don't have one.
Disconnect the vacuum line from the fuel pressure regulator. Check it for evidence of fuel present in the line by removing it and blowing air through it. If you find fuel, the fuel pressure regulator has failed. Reinstall the line; leave the fuel pressure regulator end of the vacuum line disconnected. Then cap or plug the open end of the vacuum line and stow it out of the way.
Connect the fuel pressure test gauge to the Schrader port located just behind the alternator.
Turn the ignition switch on & start the engine. Observe the pressure: you should see 38-41 PSI at idle.
Turn the ignition off; reconnect the vacuum line to the fuel pressure regulator. Then disconnect the fuel pressure test gauge. Watch out for squirting gas when you do this.

Fuel pump pressure test
Disconnect the larger of the two fuel lines up by the Schrader valve. It is the return line and does not have the Schrader valve on it. Find a piece of rubber fuel hose and clamp it on the return line coming from the regulator. Stick a bolt in the other end of the hose and make sure that all your connections are tight and leak proof as possible. When this powers up, you don't want fuel squirting everywhere. Hook up the fuel pressure test gauge. Turn the ignition switch on and watch for leaks. You may want to use a helper inside the car to cut the switch off quickly if you have a leak. To trick the fuel pump into running, find the ECC test connector and jump the connector in the Upper RH corner to ground.



Caution!!! You have blocked the return line for the fuel pump! Pressure will rise very quickly past safe levels with a good pump
If the pressure goes up past 55 PSI, the pump is good and the fuel pressure regulator is bad. If the fuel pressure does not hit 55 PSI or more in a few seconds, the pump is bad or you have electrical problems.

I checked the codes via KOEO only, so far. I have them on a logbook in my garage. Looked them up and seemed like all small stuff, but will respond with the exact codes later on. Only 4 codes, ... I'll check later

I have 2 fuel psi gauges, one on the BBK regulator and one on the fuel rail.
 
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jrichker

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I checked the codes via KOEO only, so far. I have them on a logbook in my garage. Looked them up and seemed like all small stuff, but will respond with the exact codes later on. Only 4 codes, ... I'll check later

I have 2 fuel psi gauges, one on the BBK regulator and one on the fuel rail.
Did you disconnect the vacuum line from the fuel pressure regulator when you did the test? That's the only way to get accurate results.
 

whitey92lx

New Member
A quick update: I believe I solved my issue.
I located a vacuum leak under the upper intake manifold where a block off nipple had become dry rotted and no longer fit snug onto the nipple barb. Also just out of curiosity, I pulled the EEC again and checked the repair job I did a few years ago to the signal return trace and although it seemed to be fine, one end that I soldered came off when I tugged on it. I cleaned it up and re did the solder and reinstalled. After do the base idle reset again and taking it out last night for a 1 hour cruise, I believe all drivebility issues have been resolved. No more idle issues at all and it runs perfect.
 
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jrichker

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A quick update: I believe I solved my issue.
I located a vacuum leak under the upper intake manifold where a block off nipple had become dry rotted and no longer fit snug onto the nipple barb. Also just out of curiosity, I pulled the EEC again and checked the repair job I did a few years ago to the signal return trace and although it seemed to be fine, one end that I soldered came off when I tugged on it. I cleaned it up and re did the solder and reinstalled. After do the base idle reset again and taking it out last night for a 1 hour cruise, I believe all drivebility issues have been resolved. No more idle issues at all and it runs perfect.
I am glad to hear that you solved your problem, enjoy your Stang!
 

7991LXnSHO

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Sep 1, 2010
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@jrichker
How esoteric and hard to gather was the info you have put together for our benefit? Should Ford dealership mechanics still have similar diagnostic info on hand?

My dealings with the Ford dealership where the younger service manager and mechanic were very frustrating, especially since the KAM or CM told me what system was misbehaving, as did my spidey sense. One of the guys even owns a Fox body Mustang, But they apparently did not know how to pull codes because the code reader was old and worn out, and they told me there were No Codes. Their “full diagnostic mode” was going to be replace all performance parts, one at a time, until it ran right. It did not matter that it ran fine with the parts before it needed the harmonic balancer and missing smog pump parts replaced. It is not a cow bound, little dealership!
 

General karthief

wonder how much it would cost to ship you a pair
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I have found that most mechanics don't know how or can't remember how to work on these obd1 cars, I've had discussions with my friend at the shop and had to show him things like when his scanner would not communicate with my computer he said his scanner could not read obd1, I found that my computer was bad and now the scanner will communicate just fine. I have helped him several times with a customer car.
There was a mechanic that worked at a local ford dealer here and has a fox, he put a carb on it because it was 'faster' with a carb. :bang:
 

jrichker

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@jrichker
How esoteric and hard to gather was the info you have put together for our benefit? Should Ford dealership mechanics still have similar diagnostic info on hand?

My dealings with the Ford dealership where the younger service manager and mechanic were very frustrating, especially since the KAM or CM told me what system was misbehaving, as did my spidey sense. One of the guys even owns a Fox body Mustang, But they apparently did not know how to pull codes because the code reader was old and worn out, and they told me there were No Codes. Their “full diagnostic mode” was going to be replace all performance parts, one at a time, until it ran right. It did not matter that it ran fine with the parts before it needed the harmonic balancer and missing smog pump parts replaced. It is not a cow bound, little dealership!
I have been driving and fixing Fox body 5.0 mustangs since 1992 and have been a member here at Stangnet since March 2000. That exposure and effort has given me a lot of opportunity to learn and work on some interesting problems. I am thankful that God has blessed me with a memory and understanding of all sorts of mechanical and electronic things.
 

Noobz347

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I have been driving and fixing Fox body 5.0 mustangs since 1992 and have been a member here at Stangnet since March 2000. That exposure and effort has given me a lot of opportunity to learn and work on some interesting problems. I am thankful that God has blessed me with a memory and understanding of all sorts of mechanical and electronic things.

Amen! I was a knuckle dragging Crew Chief for my career in the AirForce. I did [not] wish to retire from that and return to pounding the flight-line Like so many others have. I went back to school for computers. Being an aircraft mechanic was my job but computer systems are my hobby.

Who knew that mixture was worth something? Mechanic intimately familiar with what makes aircraft fly and how they work and operate mixed with a computer junky hell bent on making X do Y whether the *^[email protected]#% thing wants to or not. :chin

I hadn't even graduated school before I was snapped up by a company that builds flight simulators. I still pinch myself some days to make sure it's real. My service record and mixture of degrees is all they looked at. I showed for an interview ready for war. All I needed was a pen. :shrug:

I firmly believe that Jack-of-all-tradesman [highly] underestimate the value of their own worth. My father is also such a person. Jrichker goes one step further an documents those experiences for the rest of us. You can add 'meticulous' to his list of virtues. :)

Seriously @jrichker : You have probably accumulated more than enough documentation to write a book. I would prefer to have mine signed if it's not too much trouble. :hail:
 
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jrichker

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Amen! I was a knuckle dragging Crew Chief for my career in the AirForce. I did [not] wish to retire from that and return to pounding the flight-line Like so many others have. I went back to school for computers. Being an aircraft mechanic was my job but computer systems are my hobby.

Who knew that mixture was worth something? Mechanic intimately familiar with what makes aircraft fly and how they work and operate mixed with a computer junky hell bent on making X do Y whether the *^[email protected]#% thing wants to or not. :chin

I hadn't even graduated school before I was snapped up by a company that builds flight simulators. I still pinch myself some days to make sure it's real. My service record and mixture of degrees is all they looked at. I showed for an interview ready for war. All I needed was a pen. :shrug:

I firmly believe that Jack-of-all-tradesman [highly] underestimate the value of their own worth. My father is also such a person. Jrichker goes one step further an documents those experiences for the rest of us. You can add 'meticulous' to his list of virtues. :)

Seriously @jrichker : You have probably accumulated more than enough documentation to write a book. I would prefer to have mine signed if it's not too much trouble. :hail:
Thank you for the vote of confidence. If I indeed write a book on fixing 5.0 Fox Mustangs, I will be sure to send you an autographed copy. :)

It seems that you and I have a similar background: I served 8 years in the Air Force as a crew chief - 43171A. piston engine aircraft I Got my FAA Airframe and Powerplant while I was in the Air Force and spent 4 more years in General aviation fixing small and medium size aircraft. It wasn't long before I figured out that fixing airplanes wasn't going to cut it in the pay department. Back to night classes at college I went to get a 2 year degree in Electronics. That's what got me entry into the computer world; 40 years later, here I am...
 
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Blucifer99

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Jul 15, 2018
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My engine doesn't surge, but if you get it over ~2000 RPM's it comes down to 16-1700 and just sticks until you come to a stop. I cleaned the IAC and did't help. I tried turning the IAC upside down and it was worse. I cleaned the MAF tube and that didn't make a difference. Haven't cleaned the element in the MAF yet. I have the idle set at 7-800 and the TPS is somewhere around .95, not over 1. I DO have an E-cam, but it doesn't have a rough idle, it just sticks. I lloked for the 10 pin connectors and couldn't find them. Anyone else have this similar problem?
Old thread but couldnt resist lol. Vehicle speed sensor keeps idle up while moving to stop stalling. Idle will stay up abit till u stop then fall.
 

ThinBlue502

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May 7, 2019
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Long time lurker here. Joined just to say thank you jricjker. Went through the checklist, new TPS and new IAC valve and my car has a smooth idle and doesn’t die at stoplights anymore. Yes!
@jrichker
 
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General karthief

wonder how much it would cost to ship you a pair
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On what page is this checklist?
 
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