1992 Explorer 4.0 No Spark No Fuel
Thread Starter
|
Freshman User
Joined: Aug 2010
Posts: 29
Likes: 0
1992 Explorer 4.0 No Spark No Fuel
VEHICLE: 1992 Ford Explorer, 4.0, 4wd Automatic, CALIFORNIA EMISSIONS w/ 59,000 Miles...
PROBLEM: Engine rolls over great, BUT No Spark, No Fuel
Here are the tests I've done:
- Each and every relay √
- Each and every fuse √
- Ensure inertia switch hadn't popped √
- Directly connect 12 volts to pump & pump came on √
- By-pass inertia switch √
- Replace PCM √
Any other ideas? I'm thinking it's time to start checking grounds and chasing wires
PROBLEM: Engine rolls over great, BUT No Spark, No Fuel
Here are the tests I've done:
- Each and every relay √
- Each and every fuse √
- Ensure inertia switch hadn't popped √
- Directly connect 12 volts to pump & pump came on √
- By-pass inertia switch √
- Replace PCM √
Any other ideas? I'm thinking it's time to start checking grounds and chasing wires
Postmaster
Joined: Dec 2001
Posts: 3,742
Likes: 2
From: UT
Time to look at the wiring. In particular, I would carefully check the PCM power circuit. PCM power feeds the fuel pump relay, the ICM (which controls spark), and the PCM, which commands the fuel pump relay to close and controls the timing advance. A no start due to lack of fuel and spark is often related to that power circuit.
Thread Starter
|
Freshman User
Joined: Aug 2010
Posts: 29
Likes: 0
Time to look at the wiring. In particular, I would carefully check the PCM power circuit. PCM power feeds the fuel pump relay, the ICM (which controls spark), and the PCM, which commands the fuel pump relay to close and controls the timing advance. A no start due to lack of fuel and spark is often related to that power circuit.
Logistics Pro
Joined: Jun 2009
Posts: 4,808
Likes: 83
From: Cedar Rapids, IA
Does the 1992 Explorer use a Crankshaft Position (CKP) sensor? If so, a bad CKP sensor or one with too large a gap could explain the lack of spark and injector pulse width. Do you have fuel pressure just no injector pulse, or no fuel pressure? If no fuel pressure, does the bulb test work when the key is turned to "Run", particularly the "Check Engine" light? Have you tried connecting a Ford EEC scan tool to the truck to see if there are any KOEO codes?
-Rod
-Rod
Cargo Master
Joined: Aug 2003
Posts: 3,263
Likes: 92
From: BC Canada
Its been a loooong time since I was under the hood of a 92, but if I recall correctly there were several wires (large/small) connected to the battery. One of the smaller ones powers the PCM,,, the green monster creeps inside the wire casing and devours the copper..... Philip
Post Fiend
Joined: Nov 2007
Posts: 9,944
Likes: 4
From: Somewhere In FTE Land
Trending Topics
Thread Starter
|
Freshman User
Joined: Aug 2010
Posts: 29
Likes: 0
When I turn the key on the check engine light doesn't even illuminate and I get no reading when I connect the scanner to the PCM; however I did try a re manufactured PCM from autozone and still have got no spark or fuel (the low pressure pump doesn't even come on)
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Ford Super Duty: 5 Things Owners LOVE, 5 Things They LOATHE!
Joe Kucinski
Every 2026 Ford Truck Engine RANKED from WORST to FIRST!
Michael S. Palmer
The Best F-150 Deal of Every Trim Level (XL through Raptor)
Joe Kucinski
Postmaster
Joined: Dec 2001
Posts: 3,742
Likes: 2
From: UT
KOEO, the CEL is supposed to come on to indicate that the PCM is getting power and is ready. The CEL staying off is further evidence to me that you need to check the PCM power circuit.
on edit: Up to this point, I have assumed that you've included the EEC relay and the EEC fuse when you say that you've tested each and every relay and fuse. I'm going to drop that assumption and ask if you've verified these two components. It seems that the most common failure spot in the PCM power circuit is the relay. At this point, if you can't state with absolute certainty that there is power to that relay, that the relay is closing (KOEO), and that there is power coming out of that relay, then that is where I would suggest you start.
on edit: Up to this point, I have assumed that you've included the EEC relay and the EEC fuse when you say that you've tested each and every relay and fuse. I'm going to drop that assumption and ask if you've verified these two components. It seems that the most common failure spot in the PCM power circuit is the relay. At this point, if you can't state with absolute certainty that there is power to that relay, that the relay is closing (KOEO), and that there is power coming out of that relay, then that is where I would suggest you start.
Thread Starter
|
Freshman User
Joined: Aug 2010
Posts: 29
Likes: 0
Check the wire coming from the EEC relay going to the ECU it's self & coming from the power distribution box to the EEC relay? Sounds plausible I'll take a look
Thread Starter
|
Freshman User
Joined: Aug 2010
Posts: 29
Likes: 0
KOEO, the CEL is supposed to come on to indicate that the PCM is getting power and is ready. The CEL staying off is further evidence to me that you need to check the PCM power circuit.
on edit: Up to this point, I have assumed that you've included the EEC relay and the EEC fuse when you say that you've tested each and every relay and fuse. I'm going to drop that assumption and ask if you've verified these two components. It seems that the most common failure spot in the PCM power circuit is the relay. At this point, if you can't state with absolute certainty that there is power to that relay, that the relay is closing (KOEO), and that there is power coming out of that relay, then that is where I would suggest you start.
on edit: Up to this point, I have assumed that you've included the EEC relay and the EEC fuse when you say that you've tested each and every relay and fuse. I'm going to drop that assumption and ask if you've verified these two components. It seems that the most common failure spot in the PCM power circuit is the relay. At this point, if you can't state with absolute certainty that there is power to that relay, that the relay is closing (KOEO), and that there is power coming out of that relay, then that is where I would suggest you start.
Thread Starter
|
Freshman User
Joined: Aug 2010
Posts: 29
Likes: 0
Alright so I've got power going to the yellow wire where it comes into the connector next to the battery (later leads to the ECU), but do not have power at the EEC relay... this means I have to dig into the harness to find the troubles? damn the bad luck
Postmaster
Joined: Dec 2001
Posts: 3,742
Likes: 2
From: UT
Yellow wire should be hot at all times, so it's good that you have power there. None of the other leads has power? The red/lt green lead coming from the ignition switch should have power with the key on. If you don't have power there, I'd probably go back to the ignition switch and make sure it is closing right.
Thread Starter
|
Freshman User
Joined: Aug 2010
Posts: 29
Likes: 0
Yellow wire should be hot at all times, so it's good that you have power there. None of the other leads has power? The red/lt green lead coming from the ignition switch should have power with the key on. If you don't have power there, I'd probably go back to the ignition switch and make sure it is closing right.
Thread Starter
|
Freshman User
Joined: Aug 2010
Posts: 29
Likes: 0
Yellow wire should be hot at all times, so it's good that you have power there. None of the other leads has power? The red/lt green lead coming from the ignition switch should have power with the key on. If you don't have power there, I'd probably go back to the ignition switch and make sure it is closing right.
Last edited by FSeriesGuy04; Oct 5, 2011 at 12:49 PM. Reason: Typo