88 2.9L Misfireing/backfireing issue

[88 XLT Ranger]

Unless you have a lot of water in your fuel I would say it is probably not the problem. I started putting a locking gas cap on my Ranger because I was certain someone was messing with my fuel...not that I piss off a lot of people but it only takes one and my last neighbor was that guy. Among other things he would toss a pile of cigarette butts on the ground around my truck...the houses were very close together and he wasn't allowed to smoke in the house so he came outside...I said something to him and he suddenly became my worst enemy...lol

When I locked my gas cap he became even more of an a-hole and finally I told his Dad what he was doing and his Dad chewed the kid out so bad...but I didn't have any more butts on the ground.

So if you've made any enemies recently you might consider someone messing with the truck...I heard that a ping pong ball in the tank can frustrate the heck out of somone trying to troubleshoot them...but the pickup on these trucks would not allow that to happen...so one good thing.

I doubt that it is your computer...I did read where that caused the problem on the other vehicle but I think they are more like an on/off switch...they either work...or they don't...but, then again, the Inertia switch was supposed to be like that too but I found out they can be wonky due to moving parts inside...the PCM does not have moving parts...just he input from sensors that would tell it how to respond...

Or a bad ground...I know you've looked at that and added a ground strap...

Mark

No one messes with anything around here where out in no mans land miles from town. I seam to get the best work done when I get pissed off at this thing. One of my Big Block Ford friends told me to start it up and remove one spark plug wire at a time on the Dist cap. If I notice a big change its fireing Ohhhhhhhhhhh ok. I started it up removed number one cylinder on the Dist cap and got a good Zaaaaap. It was fireing I put back on removed number 3 cylinder wire on the Dist cap nothing but the misfire tick went away. I did notice a good spark from cap to wire on number 3. I pulled the plug its black wet fouled its a Denso I put a new Motorcraft in AP 105 and put an old wire on that looks good. I fired it up popping missing again I shut it off. I removed the plug black wet fouled I disconnected the coil wire turned it over to clear out the cylinder. I put a new AP 105 in fired it up smooth as a kittin let it run at 2K for a few min. I removed the plug white clean dry looked good. I went and changed all plugs back to Autolite platinum AP 105's


I may have to step up the heat range on that one plug but I see no chart on Autolite plugs as far as heat range. If I step it up two heat ranges it might not do this on and off popping deal. It must have been fouling out and picking back up again? what is two steps hotter than AP 105?

 

[Mark_88]

I have no idea about the heat ranges on plugs for that engine and wouldn't know where to start looking. I could search just as easily as you but I'm more familiar with the 2.3 plugs and what works best (carbureted at that).

If the plug is fouling sporadically that just tells you what we suspected all along...and not necessarily the plug type or range will affect that because it is somewhere in the source of the spark (most likely) that is causing it to foul (fuel smell). When the spark is shut off to that cylinder (#3) then you need to work backward from there if that makes sense.

So, yes, you made a bit of progress in determining that it is the plug on one cylinder that is not firing and causing the popping. Now you need to figure out what is affecting cylinder #3 to the point that it is firing sporadically...could be a bad ground on the coil...could be the harness...

It almost rules out computer because the distributor fires the plugs...they are not that complicated...someone said distributor but I can't personally see the distributor being sporadically skipping one cylinder...doesn't make sense.

 

[Spott]

Maybe you have a spark problem in cylinder #3, that is, it's not igniting the fuel. Or maybe you have a fuel problem in #3, such that the spark cannot ignite it.

Getting a hotter spark plug is not solving the problem, it's just addressing one symptom. Find the cause of the problem and fix that instead.

If you possibly have a bad injector that's dripping fuel in, instead of spraying it, that would cause a misfire. Liquid gasoline is much harder to ignite than gasoline vapor.

If you can, I'd grab a couple of fuel injectors from 2.9s in the salvage yard, from different engines if possible. Try swapping them into cylinder #3, or cleaning them (search online for articles about soaking fuel injectors to clean them) and then swapping them in. You can even get a kit with new plastic spray caps and O-rings for a few bucks and "rebuild" your fuel injectors as part of the cleaning process.

When you did a compression test, was #3 low?

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[88 XLT Ranger]

Maybe you have a spark problem in cylinder #3, that is, it's not igniting the fuel. Or maybe you have a fuel problem in #3, such that the spark cannot ignite it.

Getting a hotter spark plug is not solving the problem, it's just addressing one symptom. Find the cause of the problem and fix that instead.

If you possibly have a bad injector that's dripping fuel in, instead of spraying it, that would cause a misfire. Liquid gasoline is much harder to ignite than gasoline vapor.

If you can, I'd grab a couple of fuel injectors from 2.9s in the salvage yard, from different engines if possible. Try swapping them into cylinder #3, or cleaning them (search online for articles about soaking fuel injectors to clean them) and then swapping them in. You can even get a kit with new plastic spray caps and O-rings for a few bucks and "rebuild" your fuel injectors as part of the cleaning process.

When you did a compression test, was #3 low?

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Spott & Mark

I went to auto store got an E3 spark plug put in number 3 cylinder it ran great good power until going up the grade putting a load on the engine. It popped took it home pulled the plug looks to be burning ok. I pulled the wire from the dist cap nothing no change. I put the new wire back on I hear a change road test ran fine until same place. I got back pulled the plug nice and dry pulled the wire no change I can see the arch from wire to cap it seamed kinda weak. I took an MSD wire boot no wire plugged the end put it on the Dist cap fired it up I herd snapping noise. I turned the lights off pitch dark the coil was arching in between the coil and magnet around it. I put the wire back on still popping but coil was dark no arching. I tuned it off fired it back its running fine again

This is the new Napa coil I replaced when this issue started months ago. I don't know if the coil will do that with one cylinder disconnected? The truck runs great when its firing 65 mph no problem

 

[Mark_88]

I forget the exact numbers on a coil, but I recall it was in the range of 30,000 volts or more...so it would make a bit of noise if arching out...

http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

This document poppped up on my search for coil voltages...I know you said you looked at the wire harness and all but the first thing that stood out was the part about the SPOUT connector wire and hitting a bump to kill the coil trigger...

Sounds very familiar...

Is there a bump on the road where this starts acting up? You say it runs fine until a specific section of the road and then the popping starts...

I am aware that you can experience this from just starting the engine...but it was happening before you got to where you had to start the engine again...and mysteriously clears up at some point...maybe another bump...or whatever.

Another stretch would be hydro lines or other EMFs that are wonking out your ECU PCM...

but check the SPOUT connector wire if you haven't do so already...pull back the shielding and check for sparks with lights out again...or visually inspect if you have good light...

 

[88 XLT Ranger]

I forget the exact numbers on a coil, but I recall it was in the range of 30,000 volts or more...so it would make a bit of noise if arching out...

http://www.therangerstation.com/tech_library/TFI_Diagnostic.shtml

This document poppped up on my search for coil voltages...I know you said you looked at the wire harness and all but the first thing that stood out was the part about the SPOUT connector wire and hitting a bump to kill the coil trigger...

Sounds very familiar...

Is there a bump on the road where this starts acting up? You say it runs fine until a specific section of the road and then the popping starts...

I am aware that you can experience this from just starting the engine...but it was happening before you got to where you had to start the engine again...and mysteriously clears up at some point...maybe another bump...or whatever.

Another stretch would be hydro lines or other EMFs that are wonking out your ECU PCM...

but check the SPOUT connector wire if you haven't do so already...pull back the shielding and check for sparks with lights out again...or visually inspect if you have good light...

Mark

The spout connector is the one little plug in front of the Dist with yellow wire? I took it on the back dirt road it starts off real rough bouncing up and down. I had no issues once I go up the road steep for 4 miles just before I got to top popping and its smooth paved just like the highway. It seam to do it when the engine lugs down to 45 mph on the highway. Now the dirt road I only go 35 trying not to rev the engine to much. I was going to run it with the plug wire off cap the dist post. With it off it don't pop just boggs but the coil archs real good

 

[Spott]

If you take off a plug wire, the coil is still trying to send voltage out, and it's an amount of voltage that's normally able to arc across an air gap (like the one in a spark plug). So it certainly may arc to the nearest ground if the wire is removed.

To see an arc when the wire is missing is more-or-less expected, and does not indicate a problem. If you see arcs anywhere (except inside the plugs) when the wires are connected, then there's a problem of some kind.

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[88 XLT Ranger]

If you take off a plug wire, the coil is still trying to send voltage out, and it's an amount of voltage that's normally able to arc across an air gap (like the one in a spark plug). So it certainly may arc to the nearest ground if the wire is removed.

To see an arc when the wire is missing is more-or-less expected, and does not indicate a problem. If you see arcs anywhere (except inside the plugs) when the wires are connected, then there's a problem of some kind.

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Well guy's I don't know

I looked at it pitch dark searched no arching no nothing but popping. I drove to town with the E3 plug as soon as I hit the highway great power up to 65mph hit the grade I get 5 miles down to 45 mph and popping. I get to town popping and all the way home popping. I pulled the plug wire at the spark plug plugged the end got in drove it and it had a little more power no popping but bogging. It started surging I pulled over put the wire back on popping got home pulled the plug. The plug was wet around the edges dark looking I put the Autolite back in popped once running fine again

I have had it would it hurt the engine to run it with that one wire disconnected and plugged? the only other thing is once I get to town change plugs the dirty bastard seams to do it once it gets to 45 mph going up the grade under a load or any hill. I know if I was on flatland and had no hills to climb it wouldn't do this as much. If its a dead cylinder I don't think it would run perfect off and on like it is?

 

[Spott]

See above, re: bad fuel injector

 

[Mark_88]

See above, re: bad fuel injector

Yes...you can try something to test this...just swap #3 with #1 and see if he fouling follows that one injector....or simply get a replacement from a junkyard or new and see if it clears it up

 

[88 XLT Ranger]

Yes...you can try something to test this...just swap #3 with #1 and see if he fouling follows that one injector....or simply get a replacement from a junkyard or new and see if it clears it up

Thanks Mark & Spott

I will try switching number 3 cylinder and number 1 cylinder see what happens in the morning. I have a set used injectors from a 1990 3.8V6 Super Coupe red and black in color. Will the one of these injectors work? can I get the fuel rail up enough to change it without removing the plenum?

 

[Mark_88]

I've tried to find a video or even step by step instructions on removing the Fuel injectors on this engine but came up dry so far...

It is fairly easy on a 2.3 so I didn't see that as being a problem...and what a complicated mess those engines are to someone who has been blessed with working only on 4 bangers...lol.

I guess someone with more experience needs to chime in at this point...even the on0line manual didn't have anything on it...maybe my Haynes manual has some steps but that is sitting in a bin outside with several other bins and I'd have to go out and shovel everything off...not happening right away but if you have a Haynes manual check the steps in there...they usually have a few pics also...

 

[88 XLT Ranger]

I've tried to find a video or even step by step instructions on removing the Fuel injectors on this engine but came up dry so far...

It is fairly easy on a 2.3 so I didn't see that as being a problem...and what a complicated mess those engines are to someone who has been blessed with working only on 4 bangers...lol.

I guess someone with more experience needs to chime in at this point...even the on0line manual didn't have anything on it...maybe my Haynes manual has some steps but that is sitting in a bin outside with several other bins and I'd have to go out and shovel everything off...not happening right away but if you have a Haynes manual check the steps in there...they usually have a few pics also...

Mark

I got a Haynes manual the plenum has to be removed I ordered a plenum gasket from Napa and will get there fuel injector O-ring kit. I think my 3.8V6 fuel injector will work ok. I looked the auto store replacement fuel injector BWD for the 2.9L they also fit many fords and the 3.8V6 T-Bird was one of them. Thank god those are not cheap $60+ each

 

[Mark_88]

OK...good to know you have an idea what's in store and that the injectors will work from the 3.8. It's a PITA to tear something down and not have what you need to put it together..especially if that's your only ride.

I was about to change the injectors on my 2.3 with the set I was given for the 2.5 (same engine, essentially) but they were rated higher than the 2.3 was listed at and I didn't want to take a chance on messing things up.


Back then i was new to the fuel injected engine and instead of keeping them I tossed them out...if I only knew how much they were worth...but I had too many things going and had to dump a whole truck...got scrap metal prices for it and that was better than nothing.

Hopefully this is the moment you've been waiting for...

 

[88 XLT Ranger]

OK...good to know you have an idea what's in store and that the injectors will work from the 3.8. It's a PITA to tear something down and not have what you need to put it together..especially if that's your only ride.

I was about to change the injectors on my 2.3 with the set I was given for the 2.5 (same engine, essentially) but they were rated higher than the 2.3 was listed at and I didn't want to take a chance on messing things up.


Back then i was new to the fuel injected engine and instead of keeping them I tossed them out...if I only knew how much they were worth...but I had too many things going and had to dump a whole truck...got scrap metal prices for it and that was better than nothing.

Hopefully this is the moment you've been waiting for...

Thanks Mark

I hope this will take care of the popping issue it must be to much fuel fouling the plug on and off. Napa will have the gasket and O-rings tomarrow the only bad thing its 32% out freezing. I am glad I had the set of injectors from my old 3.8V6 Super Coupe. I will update good or bad

Crossing my fingers hope it works