Need help troubleshooting a possible EEC startup problem

manicmechanic007

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Sep 26, 2017
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Sure or basically yes
Much easier with the schrader valve though
We (I) used to either block off the return line to the tank or run less than 30 lbs to clean with
You do not want any of that cleaner getting back to the fuel tank!
Try OTC or Rotunda for the hose adapter
Drill and tap for the schrader valve first
 
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JohnW63

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My Dad bought a section of the fuel line that comes with the Shrader valve that is supposed to attach to the fuel rail he already has. I just have to figure how to move his flexible section of fuel line to a place where it will connect to the new section of fuel rail.
 
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JohnW63

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I got the book that was mentioned above. It's got some cool sections in it. You can put the car in " Test each injector " mode? That would be interesting. The section on testing each of the valves or solenoids or sensors was what I like so far.
 

JohnW63

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I removed the MAS and the throttle body to inspect and clean them, with the appropriate cleaners. I found a small section of the screen in the MAS was pulled loose from the edge. I can post a picture, if needed. I would estimate 1/2" of it. Is that going to through things off. If so, what years have the same MAS so I can try to find another one.

When I removed the throttle body the butterfly valve seemed to stick in the fully closed position. It took more force to get open than I thought it should. After lots of spray, tooth brushing the edges of the butterfly and the rest of the area that it rests on when closed, it has a little resistance when closed still.

I also checked out the air bypass module. I cleaned that as much as I could with spray and twisted shop towels. As I mentioned before, this unit has a plate between it and the throttle body with small recessed Allen screws to adjust the idle speed, I have been told. They are pretty far adjusted in. Looking inside the screws go all the way across the air channel that they are threaded in. Air can get past them, because the passage is larger than the screw but it easily blocks half the passage. You'd have to back these out a ways for the air flow to change, I think.

I didn't have time to install the fuel line, as we were working on another old car. Building a wooden dash took longer than expected.

By the way, if I took a quick video of the car starting, so you could hear it, would that be helpful?
 

JohnW63

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While I was taking the video of the car starting from cold. I got another look at the Mass Air Flow. The area pulled loose is larger than I estimated. I don't know if once a section pulls loose it keeps going under air pressure or I didn't look close enough when cleaning it. Can the housing be purchased somewhere?
 

7991LXnSHO

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The screen in the MAF is there to help straighten airflow a bit. Pulling it IIRC was common before bigger ones were available. I doubt you’ll miss it, and you do not want it getting sucked in the engine.
 
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JohnW63

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I removed the screen, to be sure.

I have the fuel line hooked up, but forgot to bring one of the adapters to fit this Shrader valve. I'll try again tomorrow. I did test the Engine Coolent Temp sensor. It measured out at 59.9K ohms, which I think is high. I read somewhere here that it should top out at 58,7K. I did get a code 21 " Coolent Temp out of range" code during engine run test. I think I'll replace it. It might be contributing to the cold start issue that goes away after a minute.
 
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7991LXnSHO

wanna catch the space herp
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If you are running tests before it is warmed up, it will give you that code.
Have you found the write ups here about pulling codes, the no-start checklist and the surging idle checklist?
Besides lots of step by step tech help, the Surging idle checklist has the specs to see if your air and water temp sensors are in spec.
 
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JohnW63

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7791,

"If you are running tests before it is warmed up, it will give you that code.'

I think we let the engine warm up before the last test and error codes. I have no trouble doing it again.

The Temp Sensor has a chart of ohm reading based on the temp. From 57.6K ohms at 60 deg F on up. The reason I need to test this is because once the car is warm, it runs fine. I can't get it to temp and then look for errors then, because the error situation will be gone. In a nutshell, the car acts like the " choke " isn't working correctly. At dead cold it will fire up, run for 10 seconds and shut off. On restart it will run, but, you can not give it gas or it will stumble, sputter, and try to die. If you just let it run for a minute or so, you can rev the engine and it all seems well.

This makes me believe the issue is within the window referred to as " Cold Start " I think both the Engine Coolent Temp sensor and the Air Temp sensor values determine this. Since our setup only has a ECT sensor and no Air Temp sensor, only the ECT is in play.
 

manicmechanic007

Mustang Master
Sep 26, 2017
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John,
There are several things that will cause your concern dies after cold start
You will still need to perform the self tests properly or you will be chasing your tail
Once you have no codes outputted Then you can proceed with the real? problem Likely to be a vacuum leak or faulty injectors incorrect MAF
Rash of bad maf connectors in 1994. You'll need to test that pid
Your post 65 has me concerned. Have you sprayed the intake down with carb foam yet to see if the rpm picks up or stumbles?
The upper intake gasket has a tendency to crack. Orange injectors right?
 

JohnW63

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"Once you have no codes outputted "

That will never happen. There are things not installed on the car that it will be trying to test.

"Your post 65 has me concerned. Have you sprayed the intake down with carb foam yet to see if the rpm picks up or stumbles?"

Why would reporting the screen in the Mass AIr Flow housing was coming loose concern you? No, I have not sprayed anything down with "carb foam". I don't know what that even is. I get the concept, but I didn't know there was a specific product for the job. Were around the intake would you suggest I spray it? Around the base where it bolts to the engine? Around the throttle body?
 

manicmechanic007

Mustang Master
Sep 26, 2017
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Carb foam is carb cleaner
You can spray it with just about anything to try and diagnose a leaking intake gasket
Chlorinated (non flammable ) Brakleen The engine will stumble
Nom Chlorinated (flammable) brakleen The engine will speed up
I thought you mentioned the hose being loose and not just the screen cracked
Either way spray it all down to test
 

manicmechanic007

Mustang Master
Sep 26, 2017
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Yes
No codes outputted
if the processor sees a rash of codes it will slip into limp mode
So for instance if you have a truck that was a 4 speed and you put an automatic in it the processor will set a clutch switch code
You need to then install a clutch switch into the wiring for that circuit and activate it during the test to get rid of that code
Same as yours for all the chit you're missing. You are most likely fighting a few problems. You need to start somewhere
What was the fuel pressure?
 

JohnW63

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I re-ran the codes after letting the car idle for at least 15 minutes. The car runs really cool. I didn't get hotter than 130 with a laser temp gun on the back of the thermostat housing. The gauge in the car showed 150.

The temp out of range code went away. The rest remained as I listed them above.

Engine off:
81, 82, 84, 85

Engine on:
12, 33, 44, 94

Fuel pressure is 40psi when primed, but drops to 32 right away and is 32 when running. That lower than spec. Fuel pressure regulator?
 

General karthief

wonder how much it would cost to ship you a pair
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You need to go through the surging idle checklist, start at the top and do it step by step, multiple issues require systematic diagnostic steps, jumping around will not get you fixed.
I think fuel pressure is close to specs.
most of those codes are emissaries related, do the list.
 

manicmechanic007

Mustang Master
Sep 26, 2017
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That fuel pressure is fine at 32
The 33 will do it (make it run like chit)
Does it have an EGR valve and a evp sensor?
Put a 195* thermostat in it so it actually gets to temp
Might want to run pinpoint tests on code 12 Idle speed incorrect
It may be trying to relearn idle speed still or it has a problem maintaining base idle
What happened when you sprayed the intake down all over?
All the 80's codes you have are for the thermactor (air pump and diverter valves)
I would find a diverter valve and tab and tad solenoids maybe a egr solenoid or whatever else the car needs and plug them in
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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It's in a 65 stang, don't need all that emissions stuff, it may run a little lean at part throttle cruise without a purge valve and canister but not a big deal,
work on checking the idle control valve, clean or replace, a thermostat change would be a good idea too 180* or 195* will work. Then do a base idle reset, that's in the list.
Did you say it does not have an air temp sensor in the intake?
 

7991LXnSHO

wanna catch the space herp
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Did you pull and block the vac line while checking fuel pressure?
Please follow the steps like General k said.
 

JohnW63

Member
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General,

The harness on this car has a plug that is the same shape and pin count as the ECT that has the wire colors of the Air Temp sensor. The thing is, that plug is only going to reach a few inches away from the temp sensor. The diagrams I've found in the above mentioned book indicate that on a 5.0 the air temp sensor is near the back on the driver's side. Some say " air cleaner ", which doesn't fit the fuel injection system at all. The coolent sensor is close to the thermostat. I haven't crawled on the engine to see if there is another sensor at the back.

"You need to go through the surging idle checklist, start at the top and do it step by step,"

Where would I find this list? I don't have a service manual for what ever car they pulled all this stuff out of, to bolt on a 302 in a old Mustang. I think the small plate in between the air bypass and the throttle body was supposed to help set the idle with one or two allen screws. I know it gets worse if I take the cone air filter off.


7991,

No, I did not. Do you mean the vacuum line on the regulator? It was not required on the car I tested before, except to determine if the valve was working.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
22,755
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polk county florida
The surging idle checklist
The air temp sensor is located on the drivers side lower intake #5 cylinder intake tract behind the injector.
There is also a
ECT sensor that monitors coolant temp, that is on the passenger side lower intake behind the thermostat, you should have both of these installed because they send info to the computer. Without them the computer has a hard time deciding what to do.
Google those sensor locations if confused.
We're gonna get this thing running good soon.