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No sir. The check engine light does not come on at all. I pulled the ECM just to inspected it. The rubber piece that seals the ECM in the firewall is FUBAR.
I did a lil research on the "engine" light and like posted earlier its for the oil pressure and coolant temp. Well I disconnected the oil pressure sender and installed a cheap pressure gauge (gonna install autometer gauges if all goes well) to verify I had oil pressure the day I got the truck. (45 psi on cold start up) because the dummy gauge on the dash was reading below the N. I'm gonna wait on the reader to get here to see if I have any codes. Thanks to you all who responded.
I have heard of 1986 and earlier trucks where the CEL does not work or the bulb is not powered. 1987 and later it should be functional.
Interesting problem.
Randy, going on degraded memory, I researched this before, reviewing the 85-89 EVTMs. I couldn't find my old post on the forum, forum search application is not very good. I'll keep looking. I believe I sent Gary a spare 1987 EVTM, when I get to his house next month, I'll review it. I don't think they made the CEL connection to the ECA until the 1988 MR.
No sir. The check engine light does not come on at all. I pulled the ECM just to inspected it. The rubber piece that seals the ECM in the firewall is FUBAR.
No worries, every thread is a learning experience, all these lads out here love teaching, and occasionally we hear that a truck got fixed…... most everyone out here agrees with your statement to diagnose before throwing parts at it, with the exception of normal tune-up components.
I’m guessing from the photos, that your ECA is not the original one. The good news is that the notorious Capacitors (CAPs) are most likely newer than 1987 in your ECA. They look ok, but the photos are challenging. Hopefully your ECA was replaced with a closely Typed ECA for that year/engine/altitude/etc.
Its good you noticed the condition of the seal, it is important to protect the ECA from moisture the best you can.
You may be able to resolve the “Engine” light illumination with a new oil pressure sending unit. I don’t believe that the ‘Engine’ light is tied to the Coolant Temp gage or sending unit, just the oil, after reviewing Randy’s drawing.
I do recommend you perform a tune-up since you don’t know the history of the plugs, wires, dizzy cap, rotor button, fuel & air filter. These are scheduled maintenance items, not expensive, and the schedule is designed to minimize in-route breakdowns and maintain good performance. The scanner can’t diagnose these items. Stock Spark Plugs are only rated for 30K miles and you can’t always tell if they are fully functional by looking at them.
Check your engine timing.
When you get your scanner;
Engines are easier to diagnose over the internet when all the codes are listed, and in order of test.
KOEO - (O) Self-Test Codes = ?
KOEO - (C) Continuous Codes = ?
KOER - (R) Self-Test Codes = ?
Make sure your A/C, Heat, Radio, etc. are turned off when testing.
The "10" appears during KOEO to indicate the start of Continuous Memory Codes.
The "10" appears during KOER to indicate the start of the WOT test.
Grab a notebook and keep tract of your codes, and eventually your electrical measurements.
Do you have any Non-Stock modifications?
(Air Intake? Smog System? EGR Delete? Exhaust System? Ignition System?)
Eventually, you will want to change the engine oil, Tranny fluid and filters.
Then the differential fluid.
And when you replace your brakes next, take a close look at your wheel and axle bearings.
Listen also for “Clunking” when shifting from forward to reverse and back to forward, a typical noise that comes from failing universal joints.
Grounds are something you want to keep on your radar while trouble shooting, the Battery/Engine/Body and the ECA grounds are important and sometimes get removed or degraded over the years. One very important one is a small black ground wire leading to the Negative Batt terminal from the Engine Computer/ECA, check for that one and clean it.
A maintenance issue to consider is cleaning the Idle Air Control Valve. When these get clogged up they can affect the Idle.
Also, you are going to be asked to check your fuel pressure, so you might think about borrowing or buying a Fuel Pressure gauge. Low pressure will affect your Idle.
When you get the chance, describe your Cold Start Idle characteristics, RPM level, for the first, second, third and fourth 30 seconds.
And welcome to the FTE Forum…….
No worries, every thread is a learning experience, all these lads out here love teaching, and occasionally we hear that a truck got fixed…... most everyone out here agrees with your statement to diagnose before throwing parts at it, with the exception of normal tune-up components.
I’m guessing from the photos, that your ECA is not the original one. The good news is that the notorious Capacitors (CAPs) are most likely newer than 1987 in your ECA. They look ok, but the photos are challenging. Hopefully your ECA was replaced with a closely Typed ECA for that year/engine/altitude/etc.
Its good you noticed the condition of the seal, it is important to protect the ECA from moisture the best you can.
You may be able to resolve the “Engine” light illumination with a new oil pressure sending unit. I don’t believe that the ‘Engine’ light is tied to the Coolant Temp gage or sending unit, just the oil, after reviewing Randy’s drawing.
I do recommend you perform a tune-up since you don’t know the history of the plugs, wires, dizzy cap, rotor button, fuel & air filter. These are scheduled maintenance items, not expensive, and the schedule is designed to minimize in-route breakdowns and maintain good performance. The scanner can’t diagnose these items. Stock Spark Plugs are only rated for 30K miles and you can’t always tell if they are fully functional by looking at them.
Check your engine timing.
When you get your scanner;
Engines are easier to diagnose over the internet when all the codes are listed, and in order of test.
KOEO - (O) Self-Test Codes = ?
KOEO - (C) Continuous Codes = ?
KOER - (R) Self-Test Codes = ?
Cylinder Balance Test = ?
Make sure your A/C, Heat, Radio, etc. are turned off when testing.
The "10" appears during KOEO to indicate the start of Continuous Memory Codes.
The "10" appears during KOER to indicate the start of the WOT test.
Grab a notebook and keep tract of your codes, and eventually your electrical measurements.
Do you have any Non-Stock modifications?
(Air Intake? Smog System? EGR Delete? Exhaust System? Ignition System?)
Eventually, you will want to change the engine oil, Tranny fluid and filters.
Then the differential fluid.
And when you replace your brakes next, take a close look at your wheel and axle bearings.
Listen also for “Clunking” when shifting from forward to reverse and back to forward, a typical noise that comes from failing universal joints.
Grounds are something you want to keep on your radar while trouble shooting, the Battery/Engine/Body and the ECA grounds are important and sometimes get removed or degraded over the years. One very important one is a small black ground wire leading to the Negative Batt terminal from the Engine Computer/ECA, check for that one and clean it.
A maintenance issue to consider is cleaning the Idle Air Control Valve. When these get clogged up they can affect the Idle.
Also, you are going to be asked to check your fuel pressure, so you might think about borrowing or buying a Fuel Pressure gauge. Low pressure will affect your Idle.
When you get the chance, describe you Cold Start Idle characteristics, RPM level, for the first, second, third and fourth 30 seconds.
And welcome to the FTE Forum…….
Ill go ahead and do the tune up ASAP. Iv already changed the oil, air filter and crankcase filter before I started trying to diagnose. There are no mods that I can tell everything looks stock. Smog system and egr still in place, no intake. Once I get it running right i plan on going through changing all the fluids and inspecting bearings. Ill check the grounds next chance I get. Iv removed and cleaned the IAC valve and throttle body with no change. I went to the ford dealer to see about getting The rubber boot that seals the ECM but they could not find it in there system nor could I find it at any local parts store or online. Do you have any idea where I could get one or some type of substitute.
" I went to the ford dealer to see about getting The rubber boot that seals the ECM but they could not find it in there system nor could I find it at any local parts store or online. Do you have any idea where I could get one or some type of substitute."
I think the 97-03 computer dimensions are slightly larger, maybe someone can confirm this.
You could use this and modify it to fit; https://www.ebay.com/i/253802812288?chn=ps
Or, you can use the large weatherproofing materials @ Home Depot/Lowes and make one and seal with RTV or liquid/spray electrical tape.
The real old windshield grommets would work nice for this as well, maybe an old auto glass shop might have some around or you could get a piece out of a junk yard.
Last edited by vjsimone; Aug 28, 2018 at 08:48 PM.
Reason: Adding text
I think everyone has moved past this point, but to confirm what was discussed earlier, the check engine light was not wired on my '87 either. The socket in the instrument panel is shown as "not used" in the factory service manual. It's interesting to note that the red "engine" light is also shown as "not used" but is wired and functional on my truck. The cluster is printed with "check engine" and the printed circuit on the back of the cluster is present, just no wire in the harness or bulb and socket for that circuit.
When you get the chance, describe you Cold Start Idle characteristics, RPM level, for the first, second, third and fourth 30 seconds.
And welcome to the FTE Forum…….[/QUOTE]
Ok I currently have the ECM out until I figure out how to fix the seal issue. a lil history on the truck. The guy I bought it from, he bought it 3 years ago ran great no issues until about 8 months ago.
Alternator went out then the battery followed by the starter all in about 3 month span. Then 4 months ago it started idling rough and shutting off at random times like driving down the road sitting a a light idling in a parking lot. He would have it towed and later it would fire right up. He put it in the shop and had both in tank fuel pumps replaced. Still would shut off. It always shut off after it was at operating temp. For the last couple months it sat in his driveway cause he did want to spend anymore money on it .This is were I come in. Went to look at it fired right up had a rough idle at first smoothed out after a few secs. took it up the road ran fine. I was aware of issues stated above. Sold $200 drove it home. Now that I have it at home it shuts off when i pull in the yard. Next day it starts right up idle surges up to 12-1400 rpm then drops and almost cuts off down at the 200-400 rpm but then surges back high. If I let it keep doing that it will cut off after about the 4th to 6th time. But if I play with the throttle it will smooth out and idle at about 800 rpm. If I lightly press the throttle it will start to bog down. I can press it harder and it will rev up. But after about 15 to 20 min of idling it will start missing and shut off and will not start back until later. The first time it shut off it seamed like the battery was dead and would hardly turn over. The last 2 times it would turn over fine just sounded like it had no fire. At that point I started trying to reads codes which lead me to the original post.
In your spare time, look around your engine, maybe on the valve cover.
You’re looking for a Calibration Code, on a sticker, something like this; 7-51E-R00
Also, check your driver’s door jam, they may be a sticker with a build date/MFR Date, Location.
Photo these two stickers if you have them.
What Transmission do you have? Manual? Automatic – AOD? C6? Most likely a C6.
I’m assuming 2-wheel Drive?
