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I recently acquired a 1986 Elky with a 305. It has the original smog equipment, but I had to plug off the vacuum line going to the air management valve and to the efe tvs to keep it from stalling at idle. I also need to keep the idle at 700 rpm in drive or it surges and occasionally stalls. The truck drives ok, but the “service engine soon” light is always on. When I jump the a and b connections of the aldl, and turn the ignition switch on, I can hear a fan start, but I do not go into the diagnostic mode, the “service engine soon” light just stays on. I also turned the ignition on first and connected the a to b and this also caused the fan noise, but no diagnostic mode. So, I cannot retrieve fault codes. I disconnected the battery to clear codes, but “service engine soon” light comes right on when I turn on the ignition.
I am considering replacing the ECM.
I looked at the CARDONE 77-7169 ECM from several sources. Some say “programming required”, others say “The PROM(s)/CALPACK must be transferred from the original module to the replacement module.” Then another says “ Additional Relearns (Theft, Crankshaft, Idle, Etc) May be Required”.
If I install the prom, does this satisfy the programming requirement, and if I take the truck for a ride, will this initiate the relearn?
I would appreciate any suggestions.
 

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welcome Harry
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are you on the right A&B,, top 2 right hand terminals,, [no offence, but had to ask]
heres a pic/codes
https://www.elcaminocentral.com/showthread.php?t=27196
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the CEL should allways come on with the key on/engine off.. that's normal..
start the engine and it should go off,
or start blinking in diagnostic mode..
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“The PROM(s)/CALPACK must be transferred from the original module to the replacement module.”
should be all you need to do on those,, and yes it will relearn on its own..
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I don't know man??
check the grounds
ground terminal B to a known good ground.. that's all the A terminal does..
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which Fan Noise are you hearing?? is it the blower motor/HVAC ??
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:texas:
 

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Discussion Starter #3
Sorry, the sound I hear when I turn on the ignition is not a fan, it is a fast clicking noise coming from the carburetor, maybe the stepper for the metering rods or mixture control solenoid. I ran a ground wire right from the engine to the aldl a/b connection and it did not help me get into the diagnostic mode. I ordered a OTC 2000 scanner. It will be interesting to see if it communicates with the ECM.
 

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ok, yea the ticking noise is the MCS, that is normal,
means the MCS working and the ECM is at least doing something..
it runs about 30sec when you turn on the key..
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check all the connections on the ECM??
its inside the passenger side front kick panel..
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check the fuse connection/power to the ECM..
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could be the CEL light driver module above/behind the glove box??
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Darbysan will be a-long, he's purty sharp, see what he has to say too..
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Sorry, the sound I hear when I turn on the ignition is not a fan, it is a fast clicking noise coming from the carburetor, maybe the stepper for the metering rods or mixture control solenoid. I ran a ground wire right from the engine to the aldl a/b connection and it did not help me get into the diagnostic mode. I ordered a OTC 2000 scanner. It will be interesting to see if it communicates with the ECM.

I have the OTC2000 it won't scan unless all the sensors/ECM are hooked up . It's a great real time scanner and easy to read. Check the plugs and pins at the ECM and the board they connect to for a loose connection just one wire not making contact will cause hell. Ground wires also make big problems if there not clean underneath metal to metal.
 

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Discussion Starter #7
I really appreciate the help I am getting. I went thru the procedure for “won’t flash code 12”. I got 12.26 volts at terminal C. When I grounded terminal c, the lamp went off. I grounded Terminal 5; I did not get the code 12, but I did get the clicking in the carburetor. I tested terminals A and U and both had good grounds . Terminals C and R both had over 12 volts. I cleaned the connector contacts. I did not do the last step to see if code 51 flashes, it won’t. It looks like the problem is in the ECM. I am going to wait and see what the OTC 2000 does. If it pulls codes maybe and I can get a good idle, I can live with this ECM. I have the idle at 700 rpm now and the truck runs great. I also ordered a EGR valve. Maybe I am getting some exhaust leaking into the intake manifold.
 

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Harry, since this is an issue related to the ECM, I suggest posting your question along with symptoms on the gearhead-efi.com site. That site is dedicated to tuning but the folks who contribute are all very knowledgeable in whatever goes on with the ECM. I'm certain someone would be able to advise you on whether your situation requires replacing the ECM. Also, when you post your question there, be sure to give them the service number--7 or 8 digits that is printed somewhere on the outside of the ECM. Good luck!
 

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I really appreciate the help I am getting. I went thru the procedure for “won’t flash code 12”. I got 12.26 volts at terminal C. When I grounded terminal c, the lamp went off. I grounded Terminal 5; I did not get the code 12, but I did get the clicking in the carburetor. I tested terminals A and U and both had good grounds . Terminals C and R both had over 12 volts. I cleaned the connector contacts. I did not do the last step to see if code 51 flashes, it won’t. It looks like the problem is in the ECM. I am going to wait and see what the OTC 2000 does. If it pulls codes maybe and I can get a good idle, I can live with this ECM. I have the idle at 700 rpm now and the truck runs great. I also ordered a EGR valve. Maybe I am getting some exhaust leaking into the intake manifold.
I have an 87 305 ECM you can have the service number is 1228079 I'm pretty sure it's fine.:cali:
 

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I really appreciate the help I am getting. I went thru the procedure for “won’t flash code 12”. I got 12.26 volts at terminal C. When I grounded terminal c, the lamp went off. I grounded Terminal 5; I did not get the code 12, but I did get the clicking in the carburetor. I tested terminals A and U and both had good grounds . Terminals C and R both had over 12 volts. I cleaned the connector contacts. I did not do the last step to see if code 51 flashes, it won’t. It looks like the problem is in the ECM. I am going to wait and see what the OTC 2000 does. If it pulls codes maybe and I can get a good idle, I can live with this ECM. I have the idle at 700 rpm now and the truck runs great. I also ordered a EGR valve. Maybe I am getting some exhaust leaking into the intake manifold.
The OTC 2000 doesn't give codes it reads voltage.
 

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If the Elky is running poorly, and you can't get the A-B jump to work, I suspect it is the ECM. It will go into "limp Home" mode, which basically tries to run everything off of a pack of resistors to simulate the ECM working. The light driver is working, based on your diagnostics. Getting the first code to flash, code 12, is an indication that the ECM is functioning properly. Not getting that code is another indicator that the ECM may not be working. Check all of the pins going into the ECM, as they tend to get loose over time. Check all of your fuses too.
Unplugging the EFE or the AIR system will not trigger any codes, so should not be causing any issues ( as long as the wires are not grounding out somewhere).
 

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wow, a scan tool that wont read codes?? very usefull..
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x2 if the EGR is leaking by, its like a big vacuum leak, nothing will act right..
see if you can pry the valve closed?? or a block-off plate works..
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have you checked the 4pin ECM connector from the distributor??
check the EST module 4-5pin connection,
its usually by the EGR or on the pass finder well, its a 3"x4" box 1/2" thick..
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let us know what you find Harry..
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:texas:
 

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wow, a scan tool that wont read codes?? very usefull..
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x2 if the EGR is leaking by, its like a big vacuum leak, nothing will act right..
see if you can pry the valve closed?? or a block-off plate works..
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have you checked the 4pin ECM connector from the distributor??
check the EST module 4-5pin connection,
its usually by the EGR or on the pass finder well, its a 3"x4" box 1/2" thick..
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let us know what you find Harry..
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:texas:

Yea real mechanics use real diagnostic equipment not a paperclip. You get your truck unlocked yet it's almost flood season again?
:whaasup:
 

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If the Elky is running poorly, and you can't get the A-B jump to work, I suspect it is the ECM. It will go into "limp Home" mode, which basically tries to run everything off of a pack of resistors to simulate the ECM working. The light driver is working, based on your diagnostics. Getting the first code to flash, code 12, is an indication that the ECM is functioning properly. Not getting that code is another indicator that the ECM may not be working. Check all of the pins going into the ECM, as they tend to get loose over time. Check all of your fuses too.
Unplugging the EFE or the AIR system will not trigger any codes, so should not be causing any issues ( as long as the wires are not grounding out somewhere).
Mike always has good advise he's helped me A lot over the years with my 87. I just forwarded a 87 MC SS ECM that he gave me when I was having problems and now it's in Texas helping another member with problems.

Like I said before I have another 87 305 ECM your welcome to if you need it.
 

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Hi everyone! I’ve been a victim of a bad ECM on my 86 Elc. I got a reman from BWD and have not had a problem since I put it in about 8 years ago. You might want to check into BWD. I didn’t have to have a flash done on it.
 
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