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FS- The electrical troubleshooting manual? I have that, just not too swift at deciphering it....but thank you! Tom

I'm leaning that way, Mr. M! :cheers:

Think it's worthwhile to run all new wires from the relay back, from the sound of it?? :mad:

Hey Pete, Testing the orange (+) and black (-). I'm testing with the key in "on/run" position. When the pump works, I get that momentary "hum" when I turn the key on. When it's not, I get silence. The other (middle) wire of the harness, as you correctly stated, is for the fuel gauge sender. I have to get my volt meter back, but with the key in the on position, I'm getting voltage to the orange (fuel pump +). I'm guessing the pump gets 12V when you turn the key on, then what? Does gas continue in on a siphon effect, or does the pump get voltage continuously after startup, just less??

Well, I thought I'd seen the last of the fuel pump gremlin, so as I was driving to the boneyard to get a turn signal socket today (had the morning off), the fuel pump conks out again. :headpop: I get her going enough to stall out in my driveway, and tear into the fuel tank harness. I'm getting voltage at the harness (my brother has my volt meter, so I'm using a test light). I give 12 volts to the connector to the pump with a jump starter and ....it works. I decide the harness pins aren't making good contact, so I cut the plugs off, strip the wires, and twist them together. NOTHING!! Really frustrating. I have a good ground now. The pump works. I figure if I'm getting a test light on, I'm getting 12 volts (relay is on or off, I figure). Pete what were you referring to BEHIND the tire? Aside from getting behind the taillight to access the ground, which has now been replaced, all my work is in FRONT of the tire. Then again, if I've re-routed the ground, that connector is moot now, I guess. Thanks Tom

I know the left front socket is bad, so I'm going to start there! LOL Pete is right about grounds!! Everything under the hood and really from the grill back is good, since I had it all apart for the engine swap. :cheers:

find another one in a junkyard or online, an OEM/factory piece. Install it yourself or have a glass shop do it. I've seen some very poorly fitting aftermarket rear sliders for Comanche's.

So when I'm driving around all day, turn signals work, brake lights work, all is well. when I have the parking or headlights on, no brakes, no turn signals, no hazards! Bad headlight switch?? I never had these gremlins before I let her sit for 6 months! :cry:

this is why this site is the best, and Pete is a genius. Look what I found behind the driver's taillight (and I took the time to change out all the stripped screws, a bad bulb, and put in new screws with grease on them, so it was a project in a project). The funny thing about this is, I vaguely remember finding a long strand of wire hanging from the car, probably a year ago. I figured "MEH" just some old redneck rigged remains of a trailer harness, and cut it off, never thinking it was my FUEL PUMP GROUND. And the thing ran! When it died, I assumed the 2.5, which leaked/burned/blew by more oil than it used gas, had kicked the bucket, jumped a tooth on the gears, whatever. Well, on the post mortem, the timing marks lined up, and it turns out it was probably my fuel pump, which worked enough to drive it around a bit, and then sometimes not at all. How's that for a kick in the @$$? Oh well, got a fresh engine, bored over with roller rockers! :headpop: It's still slow! EAGLE! Check your grounds!

Good thinking, Pete, all the relays are the same so I did just what you said. Interesting results. The fuel pump relay is the middle of the 3, so standing at the passenger fender, I swapped it with the one to it's right. Got in, turned the key, heard the hum and drove off. Before, I was getting 15-20 mins. before it would stop. Today? 1/4 mile! Boom. No fuel pump. I got under the car, unplugged the harness and put a test light on the orange (+) and black (ground) leads. I had power, but no pump! So I swapped the left relay into the center spot, and put the right one back. Nothing. Put the original fuel pump relay back where it belonged and HUMMMM - drove her the 1/4 mile home. Going to mow the lawn now, so I'll clean up the ground behind the taillight later, but I'm leaning more toward pump problems at this moment. Would you agree? What are the other 2 relays for??? A/C? ? Thanks a lot Tom

Ah, that makes sense. Mine is loud, which I don't mind, because I know when it's working. I'm just stumped if it's a dying pump which fails after a while or a funky relay? Love these trucks! LOL.

Sorry it's an 87 2.5, so I don't have to worry about the fuel rail. Would a bad ballast resistor cause the fuel pump to stop running? OK, did a little reading up on the ballast resistor. Where is it on a 2.5L? The 4.0's were on the drivers' side. Which of the 3 relays is the fuel pump relay on a 2.5? :popcorn:

Sorry it's an 87 2.5, so I don't have to worry about the fuel rail. Would a bad ballast resistor cause the fuel pump to stop running?

I've been having intermittent stalling. When I started the new engine for the first time, it ran great for 20 mins then stalled. We noticed the fuel pump wasn't humming, so I unplugged the harness at the gas tank, cleaned the contacts, and we were back in business. Since then, I can drive the truck for a bit, and then it dies, and the pump doesn't hum. Let her sit for 20-30 mins (about the time it took for the AAA guy to come! :eek:) and the pump hums and it starts again. Is this typical of a dying pump, or should I consider the relay? If I do replace the pump, I guess I should replace the strainer while I'm in there, and definitely the lock ring, right? Thanks! Tom

We're getting hit with heavy rain from Hanna, so I ran outside and checked and actually the floor is dry! That adhesive is pretty strong so I may just leave it, if there's no leak. Thanks for the advice. You'd think the thing would just come the right length! :mad:

Hey guys, I got a new hood cowl seal (thanks, Brent). It's a much better design than the original, worn out seal -- thicker, sticks on great with adhesive backing. One question, it isn't as long as the old one. It was about an inch shorter, so I centered it, so there's 1/2" of lip exposed on each end. Is that ok? Should I have stretched it to meet the ends? I know some on here have replaced it -- thoughts? Thanks Tom

I forgot about that valve! My other trucks had it, and it used to stick. Maybe the PO took it off. I'll look when I get home -- thanks! For those that have the valve, what color are the lines going to/from it? Tom

Had this problem for a long time, now that I've been through the whole engine and put in new AC parts, maybe I'll figure it out. There is a pink vacuum line that, on my truck, comes out where the heater hoses and evaporator are (HVAC "box") and goes no where. Where does this connect on the 87 2.5L? I don't have a good vacuum line diagram. There's also a blue vacuum line in the neighborhood that's got tape on it and traces back to the intake area, goes nowhere. Truck runs fine. ..I'm not convinced my defroster problem is from the vacuum "football." Tom

That's what I usually do. I have a tool for doing it on GM's which didn't fit. The guy helping me out is a Ford certified mechanic, and he said we could cold crank it first for pre-lube without doing damage or causing binding. So I took his word for it, he knows his stuff. It didn't bind, the fuel pump harness was acting flaky. thanks

LOL. I have an update. Cranked, no start; poured gas down the TBI, no start; good spark. Rotated the distributor 180*, poured gas in the TBI, starts and runs for 15-16 mins at 2500rpm. STOPS. Won't start again, needs jump. Still won't start. Starts with fuel in TBI, runs for 5 mins, STOPS. We noticed the fuel pump wasn't humming, had power at the harness. Cleaned the contacts -- it HUMS ! And starts. Seems the motor was running on a siphon effect - for awhile! So it runs. Didn't drive it, still have to fab the clutch hydraulics. But progress. :brows:

I think you get them thru the dealer. Originally posted by TAZ: The Patch Kit (part #4443965) shows to be used through 1990. There are still plenty available with a retail price at $65 - $70 depending on dealership used. I would contact TAZ if you want one. here's the TSB with how to instructions: http://www.greatlakesxj.com/tech/cps.pdf Not trying to hijack this thread, but the TSB is for 4.0L trucks. Is there the same problem with the 2.5?

It actually says "timing not adjustable." Where'd you get 8 degrees from??

If it were one of my GM's, I'd guess ignition module. That's where I'd start. Where did you get the CPS bypass harness, Eagle??

OK, if anyone's been following along, my 87 MJ stopped running one day for no reason. I changed the CPS, just for kicks, and it didn't start (was getting spark and fuel). I decided, at 190K on the weak 2.5 to get a core rebuilt and install it, with a 2001 AX-5. ANYWAYS, I put ALL new sensors in, got it bolted up, dropped in the distributor at TDC (unknown if at compression or exhaust stroke), and primed her up. She didn't start, and I didn't have a helper to check for fuel and exhaust (though I could smell fuel at the TBI). If there's spark, we're flipping the distributor 180 degrees. My fear is that after doing that it STILL won't start, and I don't want to cold crank a new motor to any great extent. Where would be the place to start doing detective work if that's the case? THANKS!!! Tom

So I wired up my PermaCool fan to this Imperial (by Hayden) fan control. Has a wire to battery, ground, fan(+) - with fan (-) to ground, backup power wire (for ignition off fan operation), and a wire to a/c. The way to test this before finding out it doesn't work and cooking your motor is to turn on the a/c and see if it kicks on the fan. I didn't splice it into the a/c (+) wire yet, but did give it 12 volts, and the fan didn't come on. Tested the grounds and they are good. I hooked the backup power wire to the fusebox with a female butt connector to one of the "Batt" spade terminals. Should the backup power go somewhere else? Does the a/c(+) give 12 volts? I always like to assume the part works out of the box, but I suppose that could be the problem too. Anyone?? :mad: