new to me 1996 explorer from grandma ignition issues , many parts changed | Page 3 | Ford Explorer Forums - Serious Explorations

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new to me 1996 explorer from grandma ignition issues , many parts changed

update, checked long term fuel trims at recommended rpms, still getting awful mileage like 6 mpg. idle long ft1 max 11.7 min 8.6, longft2 max 10.9 min 7.8 at 868 to 744 rpm, 1500 rpm test longft1 max 2.3, min 2.3, long ft2 max 0.8, min 0.8, 2500 rpm test longft1 max 1.6, min 1.6, long ft2 max min both 0.00. i really need to read up on understanding these trims im getting frusterated lol note. as for replaced egr solenoid i could draw air with my mouth through the new part and the old part (unplugged in my hand), so i assumed was fine. if i take green vac hose off egr valve i can feel a little bit of vac palpitating but not crazy suction or anything. unplugging it does not seem to affect anything.
Tiny bit of vacuum is ok. It is not going to lift the pintle. Those fuel trims are ok, so it eliminated a major vac leak. 8-10 is about the edge of normal (ideally zero) so there is some compensation. Ideally things should be zero, but those are good numbers.
 



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progress, think i found the culprit. finally done messing with fords dumb 1/16" npt fuel rail port so i unscrewed it and put a better adapter in so i can get on the fuel rail. key on, fuel pump primes and i get not even 1 psi of gas, just barely trickling/pissing out real slow. but it keeps coming like its being held back. had the old lady fire it up and once engine fires fuel psi came up to 28 psi. same results multple trys. im hoping its the regulator not allowing gas in to fire it off, seems like once motor runs and vac pulls on reg it opens a little more. worth a shot looks pretty easy to get to right on top by intake manifold and fuel psi port. wish i checked fuel first like everyone else said lol
So the higher fuel trim at idle could be compensation for this, at least it can run.
 






changed fuel regulator today. took for a test drive and was like man this thing runs like ****. heard arcing under the hood at beer distributor and sw my new autozone spark plug wire dangling arcing to ground on the motor. the crimp from factory was faulty and fell off the plug boot. fell off the spark ignition when i unplugged the other end. drove it to the zone on 5 cylinders since i was close. they gave me new wires. still having ignition issues. im trying to eliminate all electrical component before i think about the fuel pump. not sure how bad that is to do. with key on i get 28 psi at rail, running sometimes its 28 psi and sometimes its 38 psi, it varys. fuel seems very bubbly or airy when i use the purge tube into a bottle off the guage. if i jump the relay with a needlenose i get about 27 psi but it seems to struggle to do it. is air in the fuel normal? i got jackstands and a big garage im just not sure how to do pump if thats what i need. thanks guys
 






^ You'd just (drain first if possible, which can be done easier with the filler tube disconnected, going in that way with the drain hose) drop the tank (you'll want a floor jack and piece of plywood over the jack saddle to distribute the weight), disconnect the lines (using Ford connector release tool), and electrical plugs, hammer 'n punch (rotate free) the fuel sender retaining ring (aka tank lock ring) off the tank, pull the sending unit out.

Many people would replace the whole sending unit with the pump at this age of vehicle, if all of it is factory original. Many people would replace the fuel filter at this point too, maybe even before doing the pump to see if the filter was the problem. It also needs the Ford fuel line disconnect tool.

Some people instead cut a hole in their floor pan under the 2nd row seats so they don't have to drop the tank. It's not the route I'd choose but if you would rather do that, there are forum topic(s) here with pictures of doing it that way.

As far as air in the lines, if your pressure gauge is not making a tight connection (has a leak) that might throw off your fuel pressure reading, but if your pressure regulator is bad and the fuel line empties, then you may have air in the lines when the pump is first energized.
 






There are pros and cons to the hole in the floor method, however if you craft a nice trap door to cover your new hole, it make the next fuel pump change easier. Some do this for future provision. If you are dead on a trail, or on a long trip, you don't want to have to drop the fuel tank.
 






If im getting fuel pressure my pump is still working? Hard to tell if its intermittent. What tells the relay to close? The computer? Pulling my hair out lol
 






Once the engine is running the fuel pump should run continuously. Yes, the PCM controls the fuel pump.
Things I can think of which could cause fuel pressure to fluctuate

A weak relay, or bad socket connection
bad electrical connection in fuel pump circuit ( could even be loose wiring at the fuel pump cut off switch)
Weak fuel pump.
vacuum leak
 






Does it have a check valve inline? Could it possibly be sucking air at the inlet? Like i said it seems like alot of vapor is coming out the test port. Ive heard speak of a evaporative canister on the tank i cant find the location. My gas tank has been in a vacuum before when i went to fill at idle almost empty. Just looking for pieces of the puzzle.
 






changed fuel regulator today. took for a test drive and was like man this thing runs like ****. heard arcing under the hood at beer distributor and sw my new autozone spark plug wire dangling arcing to ground on the motor. the crimp from factory was faulty and fell off the plug boot. fell off the spark ignition when i unplugged the other end. drove it to the zone on 5 cylinders since i was close. they gave me new wires. still having ignition issues. im trying to eliminate all electrical component before i think about the fuel pump. not sure how bad that is to do. with key on i get 28 psi at rail, running sometimes its 28 psi and sometimes its 38 psi, it varys. fuel seems very bubbly or airy when i use the purge tube into a bottle off the guage. if i jump the relay with a needlenose i get about 27 psi but it seems to struggle to do it. is air in the fuel normal? i got jackstands and a big garage im just not sure how to do pump if thats what i need. thanks guys
In the old days you would get flamed for not using Motorcraft ignition parts. Maybe aftermarket quality improved, maybe not. Plugs should be Motorcraft, maybe Autolite in a pinch. I tried Denso Iridium TTs (not saying to use those, they go in every Lexus and cost a fortune and I got them free) but they work amazing, but motorcraft finewire is similar.

28 is probably at very low end of the spec, this is taken from my Ford service DVD

KOEO, HOT IDLE, 30MPH, 55MPH
FUEL PRES 29-32 30-32 30-32 32-35 PSI

H43 CHECK FUEL PRESSURE

  • VTA~us~en~file=ani_caut.gif~gen~ref.gif
    WARNING: THE FUEL SYSTEM IS PRESSURIZED WHEN THE ENGINE IS NOT RUNNING. TO PREVENT INJURY OR FIRE, USE CAUTION WHEN WORKING ON THE FUEL SYSTEM.

  • Key off.
  • Install fuel pressure gauge.
  • Verify vacuum source to fuel pressure regulator.
  • If engine will start:
  • Start engine and idle. Record fuel pressure.
  • Increase engine speed to 2500 rpm and maintain for one minute. Record fuel pressure.
  • No Start:
  • Cycle key on and off several times. Record fuel pressure.
Is the fuel pressure between 30-45 psi (210-310 kPa)?
Yes No
Fuel system is capable of required fuel pressure. GO to H44 . Fuel pressure out of specification. GO to Pinpoint Test HC .



IF YOUR SCAN TOOL CAN DO AN OUTPUT TEST (like Forscan) then try this, but jumpering the relay should have the same result. Your readings may be a bit low.

HC2 CHECK FUEL PRESSURE


  • VTA~us~en~file=ani_caut.gif~gen~ref.gif
    WARNING: BEFORE SERVICING OR REPLACING ANY COMPONENTS IN THE FUEL SYSTEM, REDUCE THE POSSIBILITY OF INJURY OR FIRE BY FOLLOWING DIRECTIONS IN FUEL SYSTEM CAUTION, HANDLING AND WARNING AT THE BEGINNING OF THIS PINPOINT TEST.

  • Key off.
  • Release the fuel pressure.
  • Install fuel pressure tester.
  • Scan Tool connected.
  • Key on, engine off.
  • Enter Output Test Mode (refer to Section 2A ) and run the fuel pump to obtain maximum fuel pressure.
Is fuel pressure between 35 and 40 psi (240-280 kPa)?
Yes No
GO to HC3 . GO to HC9 .
 






fuel pressure has been pretty consistent at key on enginine off 28 to 30 and running 38 psi. been watching 02 sensor bank 1 sensor 2 i believe and at cold start it has decent varying output, after about 5 mins or so motor warms up and signal drops to zero. 0.000v. i watched it happen. gonna try swapping it tomorrow, looks not too bad to get to as behind cats right on bottom. pb blaster on it now. wires looked fine and connection looked tight. also for ***** and giggles i bought a pcu on ebay for 24.99 free ship on a 96 explorer (needs flashed) i put the thing on anyhow without flashing it and the machine runs exactly the same. kinda rolling the dice but at least i can eliminate that variable. unhooked battery for this procedure.
 






I think your fuel pressure looks pretty much spot-on for a '96. Maybe a trifle low, but not low enough to cause issues.
 






fuel pressure has been pretty consistent at key on enginine off 28 to 30 and running 38 psi. been watching 02 sensor bank 1 sensor 2 i believe and at cold start it has decent varying output, after about 5 mins or so motor warms up and signal drops to zero. 0.000v. i watched it happen. gonna try swapping it tomorrow, looks not too bad to get to as behind cats right on bottom. pb blaster on it now. wires looked fine and connection looked tight. also for ***** and giggles i bought a pcu on ebay for 24.99 free ship on a 96 explorer (needs flashed) i put the thing on anyhow without flashing it and the machine runs exactly the same. kinda rolling the dice but at least i can eliminate that variable. unhooked battery for this procedure.
Post cat sensor? I wouldn't bother unless you like changing parts. Sounds normal to have flat line, means the converter is working right.
 






First thing when i got truck was engine light for o2 sensor bank one sensor one, which i replaced. I read that you should replace upstream and downstream sensor together as the new one will read faster and the older one will be slower confusing the pcu. I whined it out today trying to clean injectors as my works ford fleet mechanic told me he has had issues with low mileage engines he swapped for blown high mileage van and bucket truck engines. He said low mileage older engines injectors had to be swapped as they were that nasty from sitting idling etc. Said the old ones from blown motors actually worked in the replacement engines. He said get oem parts as the cheaper replacements are a few ohms off. My boss is bj baldwin a country multi millionaire. Good old boys fixing ****, said you pay higher price for electronic parts because we actually fix **** here and dont risk the small variances. After i tried cleaning efi tonight in garage my cat was screaming and sounding like boiling liquid in cat after i shut her down. No wonder 6 mpg im sure tons of unburnt fuel in her. Im gonna try other 02 sensors maybe calcs are off **** its a 1996 computer. Lol
 






First thing when i got truck was engine light for o2 sensor bank one sensor one, which i replaced. I read that you should replace upstream and downstream sensor together as the new one will read faster and the older one will be slower confusing the pcu. I whined it out today trying to clean injectors as my works ford fleet mechanic told me he has had issues with low mileage engines he swapped for blown high mileage van and bucket truck engines. He said low mileage older engines injectors had to be swapped as they were that nasty from sitting idling etc. Said the old ones from blown motors actually worked in the replacement engines. He said get oem parts as the cheaper replacements are a few ohms off. My boss is bj baldwin a country multi millionaire. Good old boys fixing ****, said you pay higher price for electronic parts because we actually fix **** here and dont risk the small variances. After i tried cleaning efi tonight in garage my cat was screaming and sounding like boiling liquid in cat after i shut her down. No wonder 6 mpg im sure tons of unburnt fuel in her. Im gonna try other 02 sensors maybe calcs are off **** its a 1996 computer. Lol
Check injector leakdown. How long does it hold pressure when you turn the key off?
 






Fired her off, 38 psi after shutdown. 2 hours later 30 psi. Had to trash autozone chinese guage as it blew gas slowly through face of dial leaking through the guts. Threw my old yellow jacket suction hvac one on reading nice now just cant throw it back on refrigerant systems now lol
 






Ran it hard again, shut off at 38 psi, hour later 40 psi. Could be ambient temp increase or reg bleedthrough, either way i smile at any pressure test that rises. Be it with nitrogen on a gas line or refrigerant line. So injectors arent leaking? Ive been working on an 1999 waste oil burner thats been trying me all week at a commercial garage . Damn clean burn oil burners made in lanc county suck when they aint maintained
 






0 psi this am before work
 






You might as well pull the valve cover and have a look at this point, but using a bore-scope would be easier.
 






Can your scan tool see misfires? Some scan tools can show misfire counts well before a code is set. These engines crack heads, but yours are way under the mileage to do so. Does your temp gauge move around? Any coolant loss?
 



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I have a ancel ad410 it says in im readiness (whatever that means) misfire monitor ok. However i just reconnected battery. I dont notice any coolant loss. I maybe added a little to rad since reservoir wont draw in. Temp is very consistent from idling through warmup. I do have a small drip on one fitting on rear of rad. Temp needle may move a little on revving kinda jerky like. I did bump the boot off the sender ( i think) i put it back on it just kinda sits on it? Will have updated results tomorrow im gonna mess with it.
 






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