North American Turbocoupe Organization



88 turbo coupe cooling fan running all the time
Arnold Booth Offline
Junior Member
#1
Dont know where to start....have had this car since 89. Of course its not a daily driver but have gotten rid of 2 cars.....57 Ford and a68 Mustang Fastback and have kicked my tail a thousand times for doing it  so….the T-bird is here to stay,,,,,,UNLESS I cant fix the dang thing,,,,,first off the car sat for a while and I didn't drive it....the ethanol gas went bad which may be my running issues,,,,i had driven the thing to work last week and it ran fine,,,,however it would stumble occasionally.....its to the point know where it will hardly run..fuel filter has been changed,,,,had bout 38 lbs on the rail when I checked it,,so…..dunno ,,maybe the sock in the tank is stopped up?....maybe another fuel filter due to the bad gas has clogged the new one?...….injectors dirty?....but thats not what has me stumped.....the issue now is the rt cooling fan.....the low temp one I guess you say is running as soon as you turn the key on....and this is with the ECT disconnected and the fan controller removed.....I just got a refurbished/rebuilt EEC today …..on initial start when I turned the key on the fan wasn't running,,,,,,had a normal start-up but after bout 10 sec the fan started running.....same condition as old EEC......is something burning up the relay in the EEC?..have I damaged the new EEC?...….lol.....I dunno…….I also noticed and it seems that the fuel pump is running continuously also...but.....the fan.....how in the world is it running?....could the auto temp controller be sending a signal for it to run even if that system is off?.....as I told ya I am a pretty good mech but when it comes to electical stuff I struggle...…I tend to complicate a problem when in many cases its very simple.......plus....I dont have wiring diagrams and again….how is that dang fan running?...lol......and keep in mind it seems that all this just kinda happened at once,,,,,or was the fuel issue there and coincidentally this cooling fan issue came up...…..are the 2 related?.....the cooling fan had been working correctly up to this point...…..lot to throw at ya I know but maybe you can make some sense of it all..... I cant hardly sleep when I cant fix somethin ….lol...maybe you can relate....  plus keep in mind I have a code reader..havent used it years....I tried to read the codes but it seems...….because the cooling fan is running it would not read them?.....make any sense?........…...any help or direction you guys can give will be appreciated...like I said I consider myself to be a pretty good wrench but I sure dont know everything!                                                                                                                                      --Original Message-----
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Jeff K Offline
Administrator
#2
By fan controller I assume you mean the IRCM???? There is NO WAY either cooling fan or the engine or fuel pump can run without the IRCM connected, as the IRCM has both fan relays, the fuel pump and EEC power relays inside it.

Fuel pump and pass side fan running (or both fans running) plus no codes outputted whenever the key is in RUN is usually a damaged PCM, likely due to a fried electrolytic capacitor in the PCM. Fried caps can be changed without too much effort if you know how to solder.

Do you have manual HVAC controls or EATC?

Gas tank can and will rust internally and plug up the sock. BTDT.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Arnold Booth Offline
Junior Member
#3
(09-16-2019, 12:00 PM)Jeff K Wrote: By fan controller I assume you mean the IRCM???? There is NO WAY either cooling fan or the engine or fuel pump can run without the IRCM connected, as the IRCM has both fan relays, the fuel pump and EEC power relays inside it.

Fuel pump and pass side fan running (or both fans running) plus no codes outputted whenever the key is in RUN is usually a damaged PCM, likely due to a fried electrolytic capacitor in the PCM. Fried caps can be changed without too much effort if you know how to solder.

Do you have manual HVAC controls or EATC? 

Gas tank can and will rust internally and plug up the sock. BTDT.
Thanx Jeff....pardon my lack of experience with the T-bird system-IRCM------EEC-----PCM......arent  they the same box?.....Out on the right shock tower?
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Jeff K Offline
Administrator
#4
Not the same. The IRCM is the black relay box on the front of the pass side strut tower. Has 2 fan relays, EEC power relay, AC clutch solid state relay, and fuel pump relay in it along with some timing circuits. PCM is the Powertrain Control Module which controls engine functions and tranny functions in auto trans cars. PCM is located behind the pass side kick panel. PCM is the "modern" term for this.... Back when these cars were made it was known as the EEC (Electronic Engine Control).
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Arnold Booth Offline
Junior Member
#5
(09-17-2019, 11:36 AM)Jeff K Wrote: Not the same. The IRCM is the black relay box on the front of the pass side strut tower. Has 2 fan relays, EEC power relay, AC clutch solid state relay, and fuel pump relay in it along with some timing circuits. PCM is the Powertrain Control Module which controls engine functions and tranny functions in auto trans cars. PCM is located behind the pass side kick panel. PCM is the "modern" term for this.... Back when these cars were made it was known as the EEC (Electronic Engine Control).
 Thanx Jeff for the tutorial on the boxes.....lack of experience and knowledge of all the acronyms have my brain scrambled...…..anyway...….i pulled my PCM out of the car.....turned the key on and the cooling fan ran...….went out and disconnected the IRCM connecter......fan didnt run......so......….shorted wires somewhere ?......somethins tellin the relays to pull in?   and by the way mine does have the electronic climate control box but everything is off......or it says it is......previously I have unplugged all the sensors that feed the computer...I think......one at a time ..water temp,HP AC switch, have i missed one?.....I am lost now....lol
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Jeff K Offline
Administrator
#6
If I remember correctly the main (pass side) fan relay has a "fail safe". If the control signal from the PCM to the IRCM is lost (wire cut, etc) the fan will run all the time as long as the key is in run. Electrically, the PCM grounds the main fan relay trigger circuit to turn the fan off.

Of course the fan wont run with the IRCM connector disconnected as the high current 12 V feeds to the IRCM (heavy gauge yellow wires) can not power up the IRCM and the circuit from the IRCM to the fan is disconnected.

Have you checked for any PCM codes?
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Arnold Booth Offline
Junior Member
#7
(09-17-2019, 11:46 PM)Jeff K Wrote: If I remember correctly the main (pass side) fan relay has a "fail safe". If the control signal from the PCM to the IRCM is lost (wire cut, etc) the fan will run all the time as long as the key is in run.  Electrically, the PCM grounds the main fan relay trigger circuit to turn the fan off.

Of course the fan wont run with the IRCM connector disconnected as the high current 12 V feeds to the IRCM (heavy gauge yellow wires) can not power up the IRCM and the circuit from the IRCM to the fan is disconnected.

Have you checked for any PCM codes?
Jeff I tried to run the codes when all this started but.....wasn't able to ….havent read them in years and honestly wasn't sure of the flashes.....I thought maybe the fan running constantly was messin the test up,,as I remember from years back as the test progressed the fan would come on momentarily and then go off......gonna put it all back together and try again....can you tell me the wire to look for from the IRCM to the PCM that could be the culprit?.....in ur opinion and experience do you feel the PCM or IRCM is internally bad?....not holdin ya to it just from your experience...I work on airplanes and we run into problems like these all the time and we have have known good hardware/units to keep from chaisin our tails......thank so much for takin the time…….will get back to ya......any advice you can think of is more than appreciated.....I sure dont wanna junk my Bird!
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Jeff K Offline
Administrator
#8
The only IRCM failures I have heard of are a failure of one of the relays inside, but in general failures are rare.

98% of the old EEC IV PCM failures I have seen or heard of are due to aging electrolytic capacitors. Failed caps are generally obvious..... they expel a waxy gooey electrolyte out the bottom. Failed caps can be replaced relatively easily if you have decent soldering skills. I have personally never seen or even heard of failures of any of the ICs or MOSFET switching transistors. There are PCM repair companies out there (google is your friend) that repair the MUCH more complex OBDII PCMs, and may also repair our older PCMs.

You are right about both fans briefly running during the KOEO PCM self test, and the main fan running continuously during the KOER self test.

I have a vague recollection that the main fan control wire from the PCM to the IRCM is brown but dont hold me to that. When I will get some time I will try to remember to have a look at my EVTM (i.e., circuit diagrams) and verify the color.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
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Arnold Booth Offline
Junior Member
#9
(09-18-2019, 12:11 PM)Jeff K Wrote: The only IRCM failures I have heard of are a failure of one of the relays inside, but in general failures are rare.

98% of the old EEC IV PCM failures I have seen or heard of are due to aging electrolytic capacitors. Failed caps are generally obvious..... they expel a waxy gooey electrolyte out the bottom. Failed caps can be replaced relatively easily if you have decent soldering skills. I have personally never seen or even heard of failures of any of the ICs or MOSFET switching transistors. There are PCM repair companies out there (google is your friend) that repair the MUCH more complex OBDII PCMs, and may also repair our older PCMs.

You are right about both fans briefly running during the KOEO PCM self test, and the main fan running continuously during the KOER self test.

I have a vague recollection that the main fan control wire from the PCM to the IRCM is brown but dont hold me to that. When I will get some time I will try to remember to have a look at my EVTM (i.e., circuit diagrams) and verify the color.
Hi Jeff K,,,,,,,Arnold Booth  AGAIN,,,,,,,lol.....Jeff my original problems have come back,,,,,,if you remember i was having a problem with my fuel pump and primary cooling fan running with the key on only.......and i had a general poor running issue which has been fixed,,,,,was just plain bad /dirty fuel.........  dang ethanol gas.....not sure if you keep any correspondence but our initial e-mails were back last Sept...... i have been driving the car since Sept,,,,,,running just fine with no issues......well 2 weeks ago i drove the car,,,,,,ran like a sewing machine,,,,,came home shut it down......didnt drive/run the car for 4 or 5 days......went to drive it and turn the key on,,,,,,,,the cooling fan and fuel pump started running continuously,,,,,tried to start and engine turned over fine but would not start,,,,,,like the ignition had been inhibited/blocked or something,,,,,,i disconnected the IRCM and turned the key on and no fan or fuel pump operated....correct me if i am wrong but,,,,,#1 the cooling fan should not be running.....#2 think the fuel pump is timed in that it just runs momentarily to charge the fuel rail and shuts off until the engine is started and running......so......i am ready to put a stick of dynamite inside and blow the car up....lol...J/K...but my frustration level is up a bit just because of the lack of knowledge and education on all the electroinc systems and how they intermingle......i do not understand how it could be running so good,,,,,,i drive in and shut it off,,,,,sits for a few days and then wont even start,,,,,,,,the no start issue has never happened.......... it has always ran even though it was crappie until i got the fuel issue solved.........does any of this make any sense to you? Is something inhibiting the ignition?  Is the ignition tied too the fan fuel pump running issue or is it totally separateIt seems in all my reading and researching i had seen bad ignition switches causing problems like this  or am i just grasping at straws?....Any advice/help would be more than appreciated ...............88 Turbo coupe                                                                                               
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JT Offline
Posting Freak
#10
(05-06-2020, 11:28 AM)Arnold Booth Wrote:
(09-18-2019, 12:11 PM)Jeff K Wrote: The only IRCM failures I have heard of are a failure of one of the relays inside, but in general failures are rare.

98% of the old EEC IV PCM failures I have seen or heard of are due to aging electrolytic capacitors. Failed caps are generally obvious..... they expel a waxy gooey electrolyte out the bottom. Failed caps can be replaced relatively easily if you have decent soldering skills. I have personally never seen or even heard of failures of any of the ICs or MOSFET switching transistors. There are PCM repair companies out there (google is your friend) that repair the MUCH more complex OBDII PCMs, and may also repair our older PCMs.

You are right about both fans briefly running during the KOEO PCM self test, and the main fan running continuously during the KOER self test.

I have a vague recollection that the main fan control wire from the PCM to the IRCM is brown but dont hold me to that. When I will get some time I will try to remember to have a look at my EVTM (i.e., circuit diagrams) and verify the color.
Hi Jeff K,,,,,,,Arnold Booth  AGAIN,,,,,,,lol.....Jeff my original problems have come back,,,,,,if you remember i was having a problem with my fuel pump and primary cooling fan running with the key on only.......and i had a general poor running issue which has been fixed,,,,,was just plain bad /dirty fuel.........  dang ethanol gas.....not sure if you keep any correspondence but our initial e-mails were back last Sept...... i have been driving the car since Sept,,,,,,running just fine with no issues......well 2 weeks ago i drove the car,,,,,,ran like a sewing machine,,,,,came home shut it down......didnt drive/run the car for 4 or 5 days......went to drive it and turn the key on,,,,,,,,the cooling fan and fuel pump started running continuously,,,,,tried to start and engine turned over fine but would not start,,,,,,like the ignition had been inhibited/blocked or something,,,,,,i disconnected the IRCM and turned the key on and no fan or fuel pump operated....correct me if i am wrong but,,,,,#1 the cooling fan should not be running.....#2 think the fuel pump is timed in that it just runs momentarily to charge the fuel rail and shuts off until the engine is started and running......so......i am ready to put a stick of dynamite inside and blow the car up....lol...J/K...but my frustration level is up a bit just because of the lack of knowledge and education on all the electroinc systems and how they intermingle......i do not understand how it could be running so good,,,,,,i drive in and shut it off,,,,,sits for a few days and then wont even start,,,,,,,,the no start issue has never happened.......... it has always ran even though it was crappie until i got the fuel issue solved.........does any of this make any sense to you? Is something inhibiting the ignition?  Is the ignition tied too the fan fuel pump running issue or is it totally separateIt seems in all my reading and researching i had seen bad ignition switches causing problems like this  or am i just grasping at straws?....Any advice/help would be more than appreciated ...............88 Turbo coupe                                                                                           

It's most likely not starting, when the fuel pump and cooling fan runs constantly, due to lack of fuel injector pulse from the EEC. This ignition system does not need the EEC as the ignition is fired from the PIP/TFI module (base timing) and the EEC just adjusts that timing.

Fuel pump and cooling fan running constantly while engine is off is a good indication of a failed EEC.
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