88 2.9L Misfireing/backfireing issue

[Mark_88]

I can appreciate your having reached a level of frustration that quite a few would have taken more drastic actions by this time...as in parked it and bought something else to drive...so I admire your perseverance.

Were you able to test the fuel pressure while driving? I posted a video a few months back showing another Ranger owner connecting a fuel pressure tester to the FPR and running it up over the hood so he could see what was happening under load.

In his case the pressure did not drop so he was able to move onto something else (if I recall correctly)...but it might show you if and when the pressure is dropping so you can focus on that.

My 89 Tempo was doing something very similar but more often than not it would just die and I'd have coast off the road. That turned out to be a wonky fuel pump that I replaced no less than 5 times in 14 years...frustrating but fortunately it was covered by an extended warranty that I just happened to have bought when I purchased it new from the dealership.

If you have already done that and found no drop in fuel pressure then I apologize...it's easy to forget...

So maybe at this point a good exercise would be for you to go over all your posts and write down in the order what was done (replaced part or cleaned etcetera) and maybe post that if you have time and want to resolve this logically.

I think from recent attempts your greatest improvement that seemed miraculous, was from moving the wire harness around...that seemed to result in instant improvement without anything else being done...which is why I keep going back to a wiring issue at this point.

The idea that the TFI was heating up and causing the failure seemed like the most likely idea before as did the wire harness to the TFI...

 

[88 XLT Ranger]

I can appreciate your having reached a level of frustration that quite a few would have taken more drastic actions by this time...as in parked it and bought something else to drive...so I admire your perseverance.

Were you able to test the fuel pressure while driving? I posted a video a few months back showing another Ranger owner connecting a fuel pressure tester to the FPR and running it up over the hood so he could see what was happening under load.

In his case the pressure did not drop so he was able to move onto something else (if I recall correctly)...but it might show you if and when the pressure is dropping so you can focus on that.

My 89 Tempo was doing something very similar but more often than not it would just die and I'd have coast off the road. That turned out to be a wonky fuel pump that I replaced no less than 5 times in 14 years...frustrating but fortunately it was covered by an extended warranty that I just happened to have bought when I purchased it new from the dealership.

If you have already done that and found no drop in fuel pressure then I apologize...it's easy to forget...

So maybe at this point a good exercise would be for you to go over all your posts and write down in the order what was done (replaced part or cleaned etcetera) and maybe post that if you have time and want to resolve this logically.

I think from recent attempts your greatest improvement that seemed miraculous, was from moving the wire harness around...that seemed to result in instant improvement without anything else being done...which is why I keep going back to a wiring issue at this point.

The idea that the TFI was heating up and causing the failure seemed like the most likely idea before as did the wire harness to the TFI...

Mark thanks for hanging in there and helping its very much appreciated. When I hooked the fuel pressure gauge up and started it up it was popping running crappy. The pressure was at 32psi no drop at all I haven't tested it driving down the road. The TFI wire harness I moved it and it killed the engine the reason I didn't have the connector pushed in tight it was moving. The TFI is brand new Motorcraft unit they tested the old one it passed. I took the computer out looked it over no issues I could see

Here is what has been replaced new

Ignition Module
MAP sensor
Dist rotor and cap
Plugs and wires
coil
Fuel filter
High pressure fuel pump
02 sensor used Bosch
5 quarts Lucas & Filter
Fuel pump fuse put old one back in place as no change

It all started from a vacuume line blowing off that black round deal one of the cables from the throttle body goes to. I fixed it drove 1/4 stopped than took off popping sage started. It always had lifter ticking sometimes real bad and bogging but it wouldn't rev up like it does now. Its strange its not like pop pop pop 1/2 second apart its more like 5 seconds apart. Its like when you start running out of fuel you get that backfire popping before it runs out. If it was fuel pressure I would think it wouldn't rev up to 4K in low gear under a load going up hill?

 

[Andy D]

Not up on 2.9s. If this thing has a distributor, check the rotor and shaft for play. That is the trouble with a 30 yr old car. Things break or wear out a lot more than on newer cars

 

[edj]

This embarrassing and since I didn't drive it anyway it spanned a period of over a year. I was determined to get it running again...My 88 2.9 was doing something similar. It seemed to be fuel related as the fuel pressure was low and erratic. It had sat for quite awhile and since the gas had turned bad, I drained and replaced it. Then, replaced high and low pressure pumps with NOS parts, fuel filter. Fuel pressure was now good and steady at 39psi. Sent injectors out to be refurbed, new timing chain and gears, plugs and wires, finally cap and rotor. It ran, but had no power. Apparently at some point, I put the wires on the cap in reverse firing order(CCW instead of CW), corrected that and it fired up and runs great. Now on to the drivetrain, rust repair, etc...

 

[88 XLT Ranger]

I don't know

I tried just about everything I can think of and all of you with your great help. It runs great sometimes than others popping bogging when it pops bogging I give it light throttle it wont pop but still bogging more throttle pop real bad I stuff it to the floor into low gear she revs up we get going bogging but no popping. I did try Red Line fuel system cleaner but it didn't help I was going to try something that removes water in fuel?

I don't know what I can use in the fuel tank that wont harm the Cats? this bunch of shit CA Smog rules. I think if it wasn't for the hills to climb it would not do this as much. Once it stops popping driving around town on flat land its perfect

 

[Mark_88]

Did you try by passing the inertia switch?

I know we went over that but I don't see it listed...it was causing my Tempo to do similar carp...ended up replacing the engine only to find out it was the inertia switch.

Easy to bypass...just put a U shaped wire into the connector when you disconnect it from the switch and test drive...if no popping...replacing the switch is very easy.

 

[88 XLT Ranger]

Did you try by passing the inertia switch?

I know we went over that but I don't see it listed...it was causing my Tempo to do similar carp...ended up replacing the engine only to find out it was the inertia switch.

Easy to bypass...just put a U shaped wire into the connector when you disconnect it from the switch and test drive...if no popping...replacing the switch is very easy.

Mark

Thanks for helping out again is the inertia switch the fuel shut off switch? I never looked into that. I went to the auto store this evening got Lucas Fuel System cleaner added it with a full tank of Cheveron Super Unleaded. It ran great until the same place off the highway popping now after 4 hours cooling off I fired it up popping like on Nitro real loud I gave it a few stabs of the throttle it cleared up runs fine again

 

[Mark_88]

Yes, the inertia switch is under the dash on the passenger side and I remember asking you about it but couldn't recall if you tried bypassing it.

Worth a shot...but if you put in fuel injector cleaner and it is working better then maybe it is the injectors getting fouled by something...like a deteriorating line or something...

But to bypass the inertia switch you just need a small section of copper wire (12 or 14 gauge like the wires on the switch will work) and make a U shape out of it and plug it into the two wires...this will simply make it work all the time (complete the circuit so the switch won't shut off the fuel pump).

takes five minutes and might solve the problem...because that switch can act intermittently...as I found out myself.

 

[88 XLT Ranger]

Yes, the inertia switch is under the dash on the passenger side and I remember asking you about it but couldn't recall if you tried bypassing it.

Worth a shot...but if you put in fuel injector cleaner and it is working better then maybe it is the injectors getting fouled by something...like a deteriorating line or something...

But to bypass the inertia switch you just need a small section of copper wire (12 or 14 gauge like the wires on the switch will work) and make a U shape out of it and plug it into the two wires...this will simply make it work all the time (complete the circuit so the switch won't shut off the fuel pump).

takes five minutes and might solve the problem...because that switch can act intermittently...as I found out myself.

Thanks Mark

I will give that a try this afternoon the fuel system cleaner after adding it still pops the same but much louder. That Lucas must have some kick to it I used Red Line before that didn't change anything

 

[bronco2fan]

Not to sound stupid, but have you checked the cats? Does it smell like rotten eggs out the tailpipe? No rust issues on them? I still think it's a wiring issue somewhere around the distributor too. And I'm thinking your best bet may be to do the Duraspark conversion and eliminate the computer and electronics all together if you really want to save her. Just throwing that out there. Good luck.

 

[wildbill23c]

Not to sound stupid, but have you checked the cats? Does it smell like rotten eggs out the tailpipe? No rust issues on them? I still think it's a wiring issue somewhere around the distributor too. And I'm thinking your best bet may be to do the Duraspark conversion and eliminate the computer and electronics all together if you really want to save her. Just throwing that out there. Good luck.

Duraspark on a 2.9L V6 I don't think is gonna work LOL.

 

[88 XLT Ranger]

Yes, the inertia switch is under the dash on the passenger side and I remember asking you about it but couldn't recall if you tried bypassing it.

Worth a shot...but if you put in fuel injector cleaner and it is working better then maybe it is the injectors getting fouled by something...like a deteriorating line or something...

But to bypass the inertia switch you just need a small section of copper wire (12 or 14 gauge like the wires on the switch will work) and make a U shape out of it and plug it into the two wires...this will simply make it work all the time (complete the circuit so the switch won't shut off the fuel pump).

takes five minutes and might solve the problem...because that switch can act intermittently...as I found out myself.

Mark

I bypass the inertia switch same results no change it sounds like a tick tick tick at idle once I give it some throttle its pop pop pop. If I pull the vacuume line off on the plenum you can hear it a loud pop inside the plenum. I checked the firing order over and over all correct. The Lucas fuel system cleaner is not doing anything still same issues. It was ticking popping I moved wires no change at all. It must be an intake lifter the dam thing sounds like it cross wired when it does this

 

[88 XLT Ranger]

This sure sounds like at TFI issue

Failure
The modules will fail once they have absorbed too much heat or cause other problems. When this happens the vehicle will stall and take a period of time for a successful restart, after the heat has dissipated. It can also cause a bad miss on an erratic basis.


The bad miss erratic basis? It was missing popping I let it cool a few hours fired it up no popping. My original Motorcraft TFI and the new Acccel TFI and this new Motorcraft TFI that is on it now all do the same thing same issues. You think one of the new ones would work for a while not fail right off the bat. I have no starting issue or dieing issues at all now sometimes it pops misses when ice cold as well

I had all three TFI's tested at Oreilly Auto Store all pass even the original old Motorcraft one. I don't know but I am getting to the point of beating the shit out of this Ranger nightmare

 

[Mark_88]

The idea with the TFI whether new or old is to get it away from the heat. Once they heat up they are no good and you may have to move it off the distributor to fix the issue if heat related...a good heat sink and hanging it off the rad are the recommended fixes. Just need to extend the wire harness a bit.

 

[88 XLT Ranger]

The idea with the TFI whether new or old is to get it away from the heat. Once they heat up they are no good and you may have to move it off the distributor to fix the issue if heat related...a good heat sink and hanging it off the rad are the recommended fixes. Just need to extend the wire harness a bit.

Mark

The last time I had TFI issues I bought a new one from a Ford dealership it lasted 14 years until now. I buy two auto store TFI one Motorcraft and the other Accel no go on those. I see this on remote mounting but where do you get the heat sink they show? do they make a kit for change over?
http://www.therangerstation.com/tech_library/remote_tfi.shtml

Another question why can't one just use like a thermo wrap like header wrap a thin pice between the TFI and Dist? there has to be something els than that grease stuff to use. Maybe its wishful thinking I was thinking of using my original Motorcraft TFI with this new clear grease stuff