backfiring and sputtering

pat julian · May 4, 2015

i'll be brief..93 ranger 2.3 five speed.220K..running perfecdt this morning but died with a sputter suddenly after driving about 90 miles..bad fuel pump..replaced pump and filter..starts fine idles fine..but when you try to drive..sputters, pops,,backfires..running rich...my son is a certified tech across ford, gm, and cummings to name a few..and he's stumped...thinking possibly plugs as they have 70 K on them..wires are less than a year old, timing belt at about 60K..no reason we can think of it should act this way..has a cat about a year old..beofre it died tis morning ran perfectly..i drive 300 miles per day in it delivering parts..and it's never given me any priblems til today..any thoughts anyone ??? thanks...

RonD · May 4, 2015

sputters, pops,backfires reads like bad gas, water in the gas
But smooth idle would be odd, but not unreasonable with bad gas.

'93 has fuel pressure regulator(FPR) on fuel rail, it has the fuel return line and a vacuum hose, remove the vacuum hose and check it for fuel or fuel smell, if FPR leaks fuel is sucked into intake.
But I would expect idle to be bad since it has high vacuum.

How do you know it is running rich?

MAF sensor reads the air coming in
computer uses that data to set 14:1 air:fuel mix

O2 sensor reads Oxygen level in exhaust, too much oxygen is lean, too little rich
computer uses that data to fine tune the original 14:1 calculation by adjusting injector open time.

If computer's 14:1 calculation is too far off of what the O2 sensor data is saying then CEL(check engine light) will come on with a Lean or Rich code, engine is not running lean or rich, the computer is just telling driver something is wrong because "numbers don't add up"

pat julian · May 4, 2015

thanks for the reply...no cel..running rich because i can smell it...so can my son...not black exhaust however..just unburnt fuel...hard to think so much could go wrong at once...we did suspect bad gas...i fill up very afternoon at the same place..but...with a full tank this morning..if it were bad gas..i don't think it would have run almost a hundred miles with no problems until the fuel pump died..

alwaysFlOoReD · May 4, 2015

check injectors?

pat julian · May 5, 2015

no...but we will..by the time we got the pump in..it was dark..and my son had to go...thanks...

tomw · May 5, 2015

Wrong fuel pump delivering too much pressure? If it were powerful enough, it could overcome the FPR and deliver more fuel than commanded. I would check the regulated and 'un-regulated' fuel pressure readings.
All else is unchanged. The thing that changed causes the new problem. At least I'd hope so as otherwise would make trouble shooting much more difficult.
tom

Mikel89us · May 5, 2015

I really doubt its too big a fuel pump.. I have a 225lph pump ( thrice the size of stock) on my stock system and it runs fine.

pat julian · May 5, 2015

this is actually the second fuel pump we installed yesterday the first came from my company..we sell ac delco, motorctarft etc i got an aftermarket pump as i couldn't afford the 400.00 motorcraft..and it made a noise and did not pump much at all..off to o'rielly's two blocks away and put theirs in..fired right up..but just has a sputter problem when trying to move the truck..it's sitting right now at 3;46 pm and idleing just fine...once you ease the pedal past the sputter point..it revs fine..wondering if there is trash in the throttle body ??
just hard to believe it was running perfect then BAMM!! sputtered to a stop..the old fuel pump did not click or hum when you turned the key on...sure sign it had died...thanks for the help and info..my son will be here later this afternoon to run some tests and see what it is...

pat julian · May 5, 2015

after several tests..my son has determined the fuel pressure regulater is the problem..crazy design ford has the screws that remove it underneath...has anyone replaced this part on a 93 or similar ranger?? and if so..any tricks..looks to be a tight fit to remove those allan heads olding it on..or perhaps you have to remove the entire fuel rail ?? any help appreciated on this...and while i'm asking...do you suggest the 20.00 regulator form oreilly's or another store..or go with the motorcraft at 100.00 ?? thanks again for everyone's time ...

Mikel89us · May 5, 2015

Remove the upper intake, remove the fuel rail from the intake, flip it over and do it that way. Best way I have found except taking it completely off, but the fuel lines are a pain to get off.

XLTsplash · May 5, 2015

I've replaced a lot of them on different Ford engines because Ford had a recall on them. I used a 4mm 1/4" drive socket, the cut a piece off of a 4mm allen wrench and glued the allen into the socket. Then grind the allen down so that it only sticks out of the socket about 1/8". I would use a short handle flex head ratchet. Some of the screws you could get to with just the ratchet and allen socket set up. Others I would use a long extension with a u/joint swivel. I always found a way to get to the screws without taking anything else apart. Because the recalls didn't pay much.

pat julian · May 10, 2015

update....used an obd-1 scanner to find problem..it was throwing a code..we couldn't see it..because the bulb in the dash for the cel was shot...used a scanner with a beeper...showed it was the ICM module....only one of them in town...so we go get it...wouldn't you know it..it was dead !!! not fire to the coils at all..the old ICM would at least start the truck and idle..rev up once you eased it past the misfire point...the new ICM would not start the truck at all...hopefully tomorrow will be a better day..I work for an AC/DELCO/MOTORCRAFT supply house...surely we have one in stock that works...

pat julian · May 11, 2015

sputter problem solved..

It was the ICM..I noticed in the archives many had the same problem and the part mounting with three bolts..and no hole drilled for the fourth one to ground the ICM..Pronto part number 4176 has changed the mounting holes just a bit on the part they make..and the upper right hand bolt now also acts as the ground...put on in this afternoon..and WHAM BAM..she fired right up and smooth as before..have to return the same part from Advance..as it was DOA out of the box...hope this helps someone else with the same problem... :beer:

alwaysFlOoReD · May 12, 2015

Thanks for the update.

Sent from my XT1032

backfiring and sputtering

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