My '98 Ranger has developed an erratic starting problem. Usually it cranks for less than 1 second and starts right up. Sometimes it turns over for much longer and won't start. Often this is accompanied by strong oscillation/vibration of the engine while cranking and no cylinders firing at all. Occasionally, if I just wait for 20 sec or so and then try again, it will start right up. But this doesn't always work. At first it seemed like the "won't start" situation was mostly when the engine was hot; now it seems to happen hot or cold. It has started fine approx 12 times over the past 3 days, hot or cold, and then this evening it wouldn't start, even with multiple cranks.

I have tried spraying starting fluid into the air intake hose and this gets it started every time, although a bit rough at first.

My spark indicator tool shows strong sparking at the coils and along the ignition wires. I installed new wires and 8 new spark plugs 3 years ago. Battery is strong. New starter motor installed 6 months ago. New timing belt about 5 years ago. Air filter is quite clean. I recently cleaned the IAC valve with MAF cleaner and plug connector with contact cleaner. I checked for faults with an OBD scanner and found "NO CODES".

In the searches I've done so far I've seen mention of the inertia switch, but I can't see how this would interfere in such an erratic way; likewise the crankshaft or clutch position switches. I also find it hard to believe that the fuel pump relay could be bad one minute and good the next.

Any suggestions greatly appreciated.

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Steven
1998 2.5L, 5 Sp Manual, 2WD, 2 door reg cab, 183K miles and a blend door that works! (after the "nail fix")

Today I confirmed:
1. I can hear the fuel pump priming with key on/engine off.
2. I removed the inertia switch and checked continuity across both sets of terminal strips (N/O, N/C). Ball rattles when tripped and all goes back to proper operation when re-set.
3. I cleaned the MAF sensor.

Erratic starting problem continues. Any suggestion greatly appreciated.

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Steven
1998 2.5L, 5 Sp Manual, 2WD, 2 door reg cab, 183K miles and a blend door that works! (after the "nail fix")

Perform a fuel pressure test key on, engine off and watch the guage to see if you have a leaking fuel injector. If the guage stays steady but fuel pressure is low, start with changing the fuel filter unless it was just replaced. If the pressure is within specs, key on, engine off and engine running, start looking the ignition system.

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2010 Ranger XL 2.3L 5 Spd 3.73:1 Bone Stock
2013 Scion FR-S 2.0L/H-4, 6spd, 4.11:1 Fast Enough Stock

I measured fuel pressure at the rail with key on/engine off. The pressure jumped to 64 psi immediately. After about 6 minutes it slowly dropped to about 61. Repeated the test several times; all very consistent.

Then, after starting, and with engine at idle it rose to about 67 psi. These readings appear to be right in the middle of the spec. (56-72 psi) so my guess is that I don't have a fuel pump or filter problem.

My Haynes manual says the fuel pressure should drop 3-10 psi when the engine starts up. If it doesn't (as in my case), Haynes suggests applying 10" of vacuum to the pressure regulator. If the fuel pressure drops, it says to "repair the vacuum source". If it doesn't drop it says to replace the regulator.

So now I'm wondering whether to buy a vacuum pump or start looking at ignition issues, or crankcase/camshaft position sensors.

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Steven
1998 2.5L, 5 Sp Manual, 2WD, 2 door reg cab, 183K miles and a blend door that works! (after the "nail fix")

Unplug the regulator's vacuum hose and plug it or better yet install a vacuum guage on it. With the fuel pressure gauge hooked up start the engine, read the gauges. Then hook the vacuum line to the regulator and see if their is a drop. If there is vacuum reading of 18-20 In/mg and a fuel pressure drop then your vacuum source is good and regulator is running a slightly higher pressure then required, if their is no drop in fuel pressure when hooked back up to vacuum, then replace the regulator. Looking at your numbers, the pressure drop was essentially what you were looking for, an injector purge may fix your issue if it is an injector leaking. The slight pressure drop would indicate either the regulator or one of the injectors are leaking slightly.

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2010 Ranger XL 2.3L 5 Spd 3.73:1 Bone Stock
2013 Scion FR-S 2.0L/H-4, 6spd, 4.11:1 Fast Enough Stock

Also, im not sure if your truck has it but once you finish testing your fuel and vacuum. Move to testing your crank position sensor

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Jeremy Block
2003 Ranger 2wd 5 spd. 2.3L, 3 in blocks, 5 in. Camburg spindles, 1 in uniball upper control arms, upgraded coils with Rancho shocks. Buggman LED cluster. Painted 2wd fog bezel, shifter cupholders, door handle surrounds, window lever, and lock lever. 33 in wild countrys.

Your regulator is in the tank so that method you are describing is NA. I agree most likely not a relay issue but for $5 or else swap it with fan blower. If the truck always start with starter fluid you have a fuel problem. Check for pending codes randomly.

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All these trucks have a crank sensor. Most likely not the issue since it will fire up on SF. These engines got cam sensors when they went to obd-2 in 94/95

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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).

Oh ok. But ckp controls fuel and spark I believe and ive seen a few ranger and more dodge trucks have the exact same same issue with an intermittent crank fault

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Jeremy Block
2003 Ranger 2wd 5 spd. 2.3L, 3 in blocks, 5 in. Camburg spindles, 1 in uniball upper control arms, upgraded coils with Rancho shocks. Buggman LED cluster. Painted 2wd fog bezel, shifter cupholders, door handle surrounds, window lever, and lock lever. 33 in wild countrys.

Today I measured the vacuum level at the fuel pressure regulator; 20 in/Hg. When I pulled the vacuum hose off the regulator it had no effect on fuel pressure at the rail; it held a constant 67psi. I also replaced the fuel filter.

So if I go with Maritime Storm's advice the next thing to do is replace the regulator. My local PartsSource doesn't have a listing for it, but I just now realized that I may have been asking for the wrong part. The Ford shop manual calls it a "Fuel Pulse Damper". Will have to call them back tomorrow.

And just to clarify (per Modelageek's reply)...Yes, the *main* fuel pressure regulator is in the gas tank with the pump, however there is this "pulse damper" attached to the fuel rail as well. The Ford manual says its function is to "reduce pressure pulsations in the injector manifold". This is where I measured the vacuum.

Looks like the pulse damper can be replaced without removing the intake manifold; at least I'm hoping so.

One thing which might indicate the pulse damper isn't working properly...I noticed the needle on my fuel pressure gauge fluctuated rapidly from about 65-68 psi when the engine was running.

One other issue, possibly unrelated to the "won't start problem"...While looking at how to replace the pulse damper I discovered that my PCV valve was out of its socket. Still connected to it's hose but just lying loose on the engine! Could this be related to the hard starting problem? I've re-installed it, but it seems so loose I wonder if the rubber seal is keeping an air-tight connection?

And, yes, the intermittent "cranks, but won't start problem" continues.

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Steven
1998 2.5L, 5 Sp Manual, 2WD, 2 door reg cab, 183K miles and a blend door that works! (after the "nail fix")

I was thinking Crank sensor myself as well when starting to read. What about a faulty fuel cutoff switch if equipped?

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Doug
2003 2.3L DOHC XLT 2WD Automatic Single Cab Step Side

I've already checked the fuel cut-off (inertia) switch and it seems to be OK.

The fuel pulse damper is not available from my local parts store.

I had a look at the crankshaft position sensor. Looks like it mounts with only one bolt, but it's really buried deep. Suspect I would need to remove, at a minimum, the lower rad hose, the alternator and the serpentine belt tensioner. A lot of work to replace something I don't even know is defective.

I'm about ready to give up on fixing this myself. Unless someone has any other suggestions, I think I'm off to the dealer.

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Steven
1998 2.5L, 5 Sp Manual, 2WD, 2 door reg cab, 183K miles and a blend door that works! (after the "nail fix")

If you had a scanner that would be one thing but without it the Dealer sounds like a logical idea.

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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).

As previously mentioned...my OBD II Scanner showed "NO CODES".

One very interesting post I just found indicates the problem may be with the fuel pump's check valve. This prevents back flow into the tank, but if it's not working occassionally that would explain the problem. The thing which tends to support this is that if I turn the key to on, then off, then on again, then to START, the engine will start. Sort of like priming the rail twice.

Scroll to the bottom of the page and see the Senior Ford Mechanic's explination here:
http://tinyurl.com/c2v389w

I will see if my dealer agrees with this diagnosis and get an estimate for replacing the fuel pump (check valve not replacable).

The alternative is to just live with the "double key on" trick.

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Steven
1998 2.5L, 5 Sp Manual, 2WD, 2 door reg cab, 183K miles and a blend door that works! (after the "nail fix")

Please respond to my post #7.

How many times have you randomly checked for codes?

Per your post #4 your check valve appears fine.

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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).

For a potential check valve issue add a bottle of Techron to the tank.

__________________
2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).