Oh Brother - suddenly B4000/V6 won't fire up after running the day before!

[sd359]

First find out if it is fuel or spark related. What superunknown98 said is the best way, you can use starting fluid or throttle body cleaner directly in intake if it cranks it is fuel if not more than likely spark. Just don't get crazy and spray to much about a 1 sec burst into the front of the intake. Also is this a 4.0l OHV or 4.0l overhead cam? If it is the fuel pump it is alot easier to take the bed off than trying to drop the tank. 6 bolts, tail light wiring harness and fuel fill tube. It's only about 10 bolts if my memory serves me correctly. I've had to replace fuel filler tube twice and fuel pump once and I wouldn't go about it any other way.

 

[cobrajocky]

First find out if it is fuel or spark related. What superunknown98 said is the best way, you can use starting fluid or throttle body cleaner directly in intake if it cranks it is fuel if not more than likely spark. Just don't get crazy and spray to much about a 1 sec burst into the front of the intake. Also is this a 4.0l OHV or 4.0l overhead cam? If it is the fuel pump it is alot easier to take the bed off than trying to drop the tank. 6 bolts, tail light wiring harness and fuel fill tube. It's only about 10 bolts if my memory serves me correctly. I've had to replace fuel filler tube twice and fuel pump once and I wouldn't go about it any other way.

This B-4000 4.0L V6 is a 1997, the last year for the OHV engine. I believe the OHC came out in 1998 or 99. If I remember correctly this 97 OHV engine has a Timing Chain too, not a belt.

I've had a few people say getting to the Fuel Pump in the tank is a "Biotch" it get at and lifting the bed is the best access. HOWEVER, I have a full Lear Shell on this truck and that SOB is hard to remove and heavy! There's also a factory bedliner. Would a fuel pimp with only 99,998.4 miles on it suddenly die the day after working fine all day the day before? How about the FP relay?

Anyone know if these late 90's V6 B-4000's/Ranger had a "High Pressure" external fuel pump (not in the tank) along with the low pressure fuel pump that is in the tank? The older 80's and I think the early Rangers' had that setup - 2 fuel pumps.

The morning it wouldn't start I tried the Carb Cleaner Spray trick, learned that back in the early 70's when I raced British cars (Triump's and Austin Healey's.) Not a sputter, burp or vague attempt to "Fire up". I sprayed into the plastic intake assemble where it connects to the Air Cleaner housing. It was the easiest place to open up. I tried 3 or 4 times, nothing.

*Considering the type of ignition system these B-4000/Rangers V6's had and that it's impossible to get to the spark plugs, what is the easiest why to determine that it does have spark??

A thought - This truck has had on again , off again problems with the Crankshaft Positioning Sensor, which is stupidly mounted at the bottom front of the engine so it's connector easily gets fouled from road dust/grime/moisture. Could this effect it's not starting if it's not reporting to the computer where the crank position is?

I really appreciate all the advice from you guys on diagnosing this problem. I'm about to turn 73 and on a SSI fixed income with money being tight, so I really need to figure this out as cheaply as possible.

Best wishes.

 

[MikeG]

I'm pretty sure my 97 doesn't have an external pump. At least not that I've ever seen or noticed.

A fuel pressure gage might be a worthwhile investment.

 

[sgtsandman]

If a tank drop is necessary, a transmission jack will work well if lifting the bed is not an option. It has a wide enough saddle to handle a fuel tank with no problem.

 

[cobrajocky]

Gentlemen, thanks for all the help.

After it warmed up from a chilly morning yesterday I got out my test lights and DMM to dive into the fuel pump circuit starting at the fuse box. I read a 1990's Ranger XLT owner had loose wire connectors in the fuse box for the FP relay. Also checked the 30A fuse. Fuse was good, relay was good, so were the connectors. But there was no voltage to the FP! This morning after studying the circuit diagram for an Ranger XLT I went back out to trace the whole wire run as far as I could get to the tank.

In the circuit I noticed that there is this Fuel Pump Inertia {collision} switch mounted on the passenger side of the cabin inside the firewall, right at your feet when sitting. I didn't even know these was one of these switches in the circuit. No power going through it. The circular reset button is kinda hidden in a "well", which I also didn't know it could be reset. So I pushed down the button (no much travel, but you can faintly hear a "click") to reset. Moved to the driver seat, turned on the key, heard the FP, waited a couple seconds and cranked it ...... Immediately started. WAHOO! That was a F'ing Relief, no Fuel Pump problem and would be a hellacious job of either pulling the Lear Shell and then the bed / or dropping the tank! (If I ever get to design a Pickup Truck I'm putting an access panel in the bed to get to the fuel pump!)

Now, I need to find what is causing that sudden unpredictable and inconsistent (it comes and goes) engine stall from a dead stop (cold or hot), or when a sharp turn from a stopped condition like in a parking lot. I may have to start a new thread on that one.

Thanks very very very much guys!