electronics
#1
11-17-2000, 10:02 AM
#2
11-17-2000, 04:07 PM
electronics
Lugie,
I'm just a shade-tree, but I believe the PCM is your truck's computer/brain whereas the EEC-IV, etc., is the type of software/firmware programmed into the PCM. Your '92 has a PCM and EEC programmed into it. The EEC tells the PCM how the truck should run. Someone correct me if I'm off base here.
How are you confirming no spark and no fuel? For fuel, listen for a whining/whirring after you turn the key but before you engage the starter...this is the fuel pumps running. If no whine/whirr, try tapping the fuel pump relay under the hood...should be in a cluster right behind your windshield/coolant reservoir on driver's side fender...it's plainly marked fuel pump relay. You may have a bad relay.
To confirm spark, pull the coil wire off the distributor cap (top , center wire) and hold it up to the valve cover while someone cranks the engine. If you see spark, you have fire from the coil to the distributor but not out to the plugs...hence a possible distributor problem. If you see no spark, you probably have a coil problem (maybe just a bad coil wire).
PCM death is rare, but not uncommon. You might try running a Key-on, Engine off (KOEO) self test to see what codes the PCM gives you. It's simple to do, you just need a jumper wire, and the codes will read out (flash) through your dash check engine light. Go to this web site and read on:
http://www.dalidesign.com/hbook/eectest.html
One word on codes...a repeated code 11 (system passes/okay) is easily mistaken for a code 22 (map sensor out of range, or failure). Most others are easily distinguishable from each other.
Good luck. Today's trucks aren't as simple as the older ones (such as my sorely missed 68 & 69 F100s), but they're more comfortable as we age, stiffen and gain weight...and they're just as reliable once you figure out how to "read" them.
I'm just a shade-tree, but I believe the PCM is your truck's computer/brain whereas the EEC-IV, etc., is the type of software/firmware programmed into the PCM. Your '92 has a PCM and EEC programmed into it. The EEC tells the PCM how the truck should run. Someone correct me if I'm off base here.
How are you confirming no spark and no fuel? For fuel, listen for a whining/whirring after you turn the key but before you engage the starter...this is the fuel pumps running. If no whine/whirr, try tapping the fuel pump relay under the hood...should be in a cluster right behind your windshield/coolant reservoir on driver's side fender...it's plainly marked fuel pump relay. You may have a bad relay.
To confirm spark, pull the coil wire off the distributor cap (top , center wire) and hold it up to the valve cover while someone cranks the engine. If you see spark, you have fire from the coil to the distributor but not out to the plugs...hence a possible distributor problem. If you see no spark, you probably have a coil problem (maybe just a bad coil wire).
PCM death is rare, but not uncommon. You might try running a Key-on, Engine off (KOEO) self test to see what codes the PCM gives you. It's simple to do, you just need a jumper wire, and the codes will read out (flash) through your dash check engine light. Go to this web site and read on:
http://www.dalidesign.com/hbook/eectest.html
One word on codes...a repeated code 11 (system passes/okay) is easily mistaken for a code 22 (map sensor out of range, or failure). Most others are easily distinguishable from each other.
Good luck. Today's trucks aren't as simple as the older ones (such as my sorely missed 68 & 69 F100s), but they're more comfortable as we age, stiffen and gain weight...and they're just as reliable once you figure out how to "read" them.
#3
11-17-2000, 08:27 PM
electronics
tmcalavy,
thank you for all of the information. I bought a manual for how to read codes, but i have not successfully ran any codes. I am going to read up on that web address that you gave me. I am determining no spark by taking a plug out, grounding it and turnning the motor over and nothing happens. I am determining no fuel because there the plugs are dry when I pull them out of the head and because when I crank the motor for a minute I do not smell any fuel. I dont know if you would smell fuel on a fuel injected motor like you would on a carb. At first signs of this problem I could take a spark plug out and ground it and get the motor to fire, because of this I first though it was just a spark problem so I have replaced plugs, wires, cap, rotor, control module, coil, and distrbutor. I cant go much farther back. Thanx for your time and for any further help.
thank you for all of the information. I bought a manual for how to read codes, but i have not successfully ran any codes. I am going to read up on that web address that you gave me. I am determining no spark by taking a plug out, grounding it and turnning the motor over and nothing happens. I am determining no fuel because there the plugs are dry when I pull them out of the head and because when I crank the motor for a minute I do not smell any fuel. I dont know if you would smell fuel on a fuel injected motor like you would on a carb. At first signs of this problem I could take a spark plug out and ground it and get the motor to fire, because of this I first though it was just a spark problem so I have replaced plugs, wires, cap, rotor, control module, coil, and distrbutor. I cant go much farther back. Thanx for your time and for any further help.
#4
11-18-2000, 07:13 AM
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electronics
There should be 2 relays on your drivers side fenderwell, one is the EEC relay and the other is the fuel pump relay. I had the wires on both these relays corrode and cause no start conditions.
It started out as an intermittant problem then finally stranded me, but at least I could track down the problem then. I have no doubt if I had taken it to the dealer, they would have billed me hundreds of $ and still not located such an intermittant problem.
As it was, I only had to buy the 2 pigtail connectors for the relays which cost me $12 apiece. I am just speaking of past experience with my local Ford dealer here and I am sure not all are as inept as this one.
DannyP
89 F-150 4x4 former EFI I-6 now carbed 351W, Edelbrock heads,cam,intake,carb.
MSD 6A, T-18 but looking for a ZF. 3.55's.
It started out as an intermittant problem then finally stranded me, but at least I could track down the problem then. I have no doubt if I had taken it to the dealer, they would have billed me hundreds of $ and still not located such an intermittant problem.
As it was, I only had to buy the 2 pigtail connectors for the relays which cost me $12 apiece. I am just speaking of past experience with my local Ford dealer here and I am sure not all are as inept as this one.
DannyP
89 F-150 4x4 former EFI I-6 now carbed 351W, Edelbrock heads,cam,intake,carb.
MSD 6A, T-18 but looking for a ZF. 3.55's.
#6
12-11-2000, 12:36 PM
electronics
On the fuel pump relay thing...
I had the same thing happen, the relay went bad. Then at 3000 miles after that, the same thing happened again. Figuring it was just a freak bad unit, I replaced it and again had the same thing happen. I ripped out the relay, tossed it and instead of replacing it again with a crap-made $50 relay, I replaced it with a $3, dash controlled single pole switch to manually switch the fuel pump on and off and by damn, it has not stranded me since.
I had the same thing happen, the relay went bad. Then at 3000 miles after that, the same thing happened again. Figuring it was just a freak bad unit, I replaced it and again had the same thing happen. I ripped out the relay, tossed it and instead of replacing it again with a crap-made $50 relay, I replaced it with a $3, dash controlled single pole switch to manually switch the fuel pump on and off and by damn, it has not stranded me since.
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