Might be the end of the Ranger (Fueling Issues)

[Millster]

OK guys I'm about at my wit's end with this truck so here's the rundown.

TFI died back in 2006. I let it sit for a solid 2 years before I finally diagnosed the TFI as the problem. Since then it will start up and run great for a bit until it's well warmed up and then it starts to surge and stumble and eventually die. Once it cools off again, it runs great... and the process repeats.

What I've done:
New TFI (again).
New HP fuel pump and canister fuel filter
New plugs
New FP relay
New ECM relay (Didn't work out of the box, so in a fit I replaced the relay with a manual switch)

Any and all of those things should have cured it but did not.
So here's where I'm at. The accumulator; mine has the deep one with the filter in it. Are these known to go bad and cause these types of issues? Would it just be replacing the filter or are there other bits I should clean/replace?
Tank switch; clean, replace, bypass?

Would there be any issue (aside from the loss of fuel capacity) if I just bypassed the tank switch and accumulator and ran lines straight from the front tank to the HP pump? By my figuring, as long as I don't let the tank run low, I shouldn't have starvation issues on corning but I could be wrong.

This is kind of my last-ditch effort with this truck. I love it and it's in really good nick other than some surface rust and this little running issue but I can't keep dumping time into it. I only have so much of that.
If I can't get this fixed quickly and easily, it's probably headed for the scrap heap.

 

[Funnyman141]

how is the fuel pressure regulator, whats your engine vacuum at idle, also something else to check is the fuel strainer in the tank rust can build up around the pick up and starve the engine, causing it to die. Hope some of this helps.

 

[Millster]

FP regulator is fine. Fuel pressure is steady at about 37lbs. Perhaps a little on the low side, but it holds there. Until the truck stops running and it drops to zero.

Vacuum is just shy of 20, so again it's not bad.

The strainer, there's one I've been wondering about. That and the pickup tube from the pump to the top of the tank. It would seem that what's happening is the fuel volume is low causing my high pressure pump to eventually overheat and shut down (given that when the truck dies, the fuel pressure drops to 0 and won't come up until it's sat about 10 minutes).

I didn't want to spend more money on this cursed rig, but given that I'll be lifting the gearbox out of my Saab this summer to replace the clutch it might be handy to have a shop crane and load stabilizer around anyway. This would also facilitate easy removal of the bed of the Ranger to check out the fuel system.

My wife's going to kill me for keeping about it, but it's going to eat me alive if I send the Ranger off to the scrappy with any hope of getting it running.

 

[sjr53]

My 88 BII did that. It ended up being a bad MAP sensor. I was getting a Lean code, but no check engine light.

 

[Millster]

My 88 BII did that. It ended up being a bad MAP sensor. I was getting a Lean code, but no check engine light.

Would be worth checking into again, I suppose. They last 10 or 20 times I've checked, there haven't been codes. Yes, I've been at this for a while.
This is the most confounding bloody vehicle I've ever owned. My 1976 Jag was a total basket case but was up and running soundly (on all 12 cylinders) within a weekend, my Maserati BiTurbo was easy to keep running by adding oil every day until the seals on the turbos blew to the point the engine ingested pieces of the compressor and blew nice holes in the pistons. Even my current Saab 9000 has been easy to keep running compared to this silly Ford.
And yet, the Ford is the one vehicle I haven't given up on. The Jag needed a new trans eventually and was too expensive. The Maserati ate itself to bits, still have the Saab and hopefully will continue to. The Ranger, I've been fighting since 2007 and don't plan to give up until it just flat will NOT go.

 

[mdn14]

The Ranger, I've been fighting since 2007 and don't plan to give up until it just flat will NOT go.

That's the spirit!

 

[FordRanger1991]

ya checking fuel system might not be a bad idea. But you dont need any special lift to take the bed off. It is six bolts and then make sure to unplug your break lights in the back. Then you and a friend could easily lift it off. Of course then everything is exposed so checking fuel pump should be really easy.
so after the truck heats up you dont have fuel to engine... is that correct?
if the truck dies and you turn the key of then back on do you hear the fuel pump priming the gas lines again?

 

[Millster]

ya checking fuel system might not be a bad idea. But you dont need any special lift to take the bed off. It is six bolts and then make sure to unplug your break lights in the back. Then you and a friend could easily lift it off. Of course then everything is exposed so checking fuel pump should be really easy.
so after the truck heats up you dont have fuel to engine... is that correct?
if the truck dies and you turn the key of then back on do you hear the fuel pump priming the gas lines again?

I realize I don't NEED it but isn't it handy to have a shop lift around?
Anyway, I keep forgetting that I've got the Ford Motorsport light bar in the bed so that's going to impede a lift no matter what.
Still, I think that's the route I'm going. Probably without buying the extra equipment, though. I'm going to do this on a budget. If I have to spend much money at this point, it's just not worth it.

As far as how it goes with the fueling, after the truck heats up, I have nothing at the engine. Just air. When I turn the key back on, I can occasionally hear one of lift pumps but very weak sounding. The pressure pump stays off. Once everything cools down, everything starts going again. The best guess I've got is that something between the lift pump and the pressure pump is knackered and blocking fuel volume. Once the pressure pump starts to heat up, it shuts down until it cools back off. It's either that or I'm heating a wire up somewhere but I've checked all of that over and over and have replaced the only ones I could find with issues.

 

[87RangerXLTct]

Did you check the inertia switch? my friend had a similar problem with his ranger, ended up needing a new inertia switch..There should be a way to bypass the switch to test it first

 

[Millster]

Did you check the inertia switch? my friend had a similar problem with his ranger, ended up needing a new inertia switch..There should be a way to bypass the switch to test it first

You know, I checked the inertia switch years back when it wouldn't start at all (that turned out to be the TFI, for those who've been following along). I guess I hadn't associated it with warming up and killing the truck, but it does make sense and is even more likely since I had been messing around with it before. Bypassing the switch doesn't take much. Just a jumper wire will do the trick. For all the effort it'll take, I might just give it a go.

I undid my stupidly modified wiring today, taking out the switch I'd put in place for ECM power and restoring the relay having determined that only made things worse. I put the battery on the charger for a couple of hours and it's holding a partial charge. I obviously need to put it on for a full day, but I don't have a secure area with an exterior power outlet and the hoodlums around here can't leave anything that isn't tied down alone. It'll have to wait until I can be around the house to make sure it doesn't sprout legs.

 

[Millster]

OK. Well, got the battery charged enough to get the truck to fire.
Now it seems to have major problems. At first, the idle would drop to about 500 then catch and rev back up and repeat. Eventually that stopped.
Now, the issue is that I've apparently lost a cylinder or two. I did not do a lot of troubleshooting, but it is idling very rough, smells of raw fuel and bogs down horribly when you first press the throttle. It eventually revs, but the flat cylinder or cylinders clatter like a rod is about to come through the block. So they're definitely getting fuel, they're just totally lacking spark and are apparently running on compression. Doesn't act like timing. I had just done the spark plugs when it died again last time, so I'm thinking I've either fouled one or two out or have one that has come loose. Again, I didn't play with it much.

Comically, though, it sat idling on however many cylinders for a good 30 minutes running off the rear tank while I looked it over, got out my air compressor and filled the tires, etc. The only time it died was when I was trying to pull it back around to the front of my house and didn't get into the throttle enough to get it up the curb. That was made more fun by the fact the battery connection had worked loose and wouldn't give the starter enough power. Nothing like hurriedly fixing a loose terminal in the middle of the street.

So anyway, it runs again. I have some work to do, but I'm hopeful for an actual fix this time. I'm going to pull the fuel system apart and check/clean everything, check the timing after I fix the flat cylinder(s) and see what I get. I'm imagining I'll have to pull the cat off as well and see if it's plugged. Hey, if I can get the truck running, I'll have no problems spending a bit to replace a converter.