[SOLVED] 1997 ranger no spark no fuel

[Shepherd]

Hi guys, sorry to make this my first post. I'm Shepherd! I created and account here because I ran into a problem with my Ranger that I haven't been able to solve.

This ranger has 478,000 miles on it. A few months ago I did a full tune-up (all plugs, filters, etc) along with the timing belt and fuel pump.

So today I noticed the signals weren't working, which was odd, so I popped open the fuse boxes in the engine bay and cabin and checked everything, I only found two blown 10A ( one in the engine box and one in the passenger box ). They weren't significant things so not worth mentioning.

Anyway, I pulled everything initially one by one - the relays, the diodes, fuses, etc. When I went to turn on the car, it wouldn't start. I replaced all the big relays too.

I don't hear the wine from the fuel pump anymore. When I press the shrader valve to check for any fuel nothing comes out. I took some plugs off the ignition packs to check for any spark when turning over and saw nothing. I also sprayed starter fluid in the intake and it doesn't even sputter, so I guess it for sure also has no spark now too. I have no idea what I could have possibly done, or how to even troubleshoot this.

Also, when I turn the key to electrical on I noticed the CEL doesn't appear at all. Which I can't remember perfectly but I feel like it used to pop up before turning the vehicle on.

Someone elsewhere suggested that my computer may have shorted out. If I grab another one out of a 93 - 97 2.3 std is it a simple swap? Mines a 97.

To avoid another post. I pulled the PCM and opened it up hoping to find evidence of burnout. No odd smells and it looks perfect inside. I jumped the relay for the FPR and the pump turns on. Tested for voltage at the PCM relay and it has 12. Also on the FPR relay slot, if I jump the pin next to the FP on pin, it clicks the PCM relay.

Sorry for the long post, thank you all for reading and chiming in with any suggestions!
Shep

 

[Shepherd]

 

[MikeG]

PCM fuse went out in my truck earlier this month, near identical symptoms as yours. I'd check it with a multi-meter for continuity even if it looks good. 30A.

Good luck.

 

[Shepherd]

Just to be safe I swapped that one out already .

 

[Shepherd]

Update: I got one of those Autozone code readers and it just says ERROR. Nothing more. I don't know what that means, but I'm sure it isn't something too good. Could it be that the computer is bad or not getting power?

 

[Shepherd]

Another update: bypassing the relay next to the fuel pump relay (guessing pcm?) allows the fuel pump to prime with key on, everytime the fuel rail pressurizes. I also hear little noises coming from the computer. Still no spark though. Did I post in the wrong section or is this problem too random/wild / weird?

 

[RonD]

Yes, the CEL should come on with key ON, that means computer(PCM) is powered up
Then CEL will go OFF while cranking engine, that means computer is seeing Crank Signal from crank sensor

There is no connection between starter motor activation and computer, computer only know you want to start the engine when it sees Crank sensor pulse(crank sensor rarely fail, so NOT your problem)

From your description the computer is not powering up(also explains ERROR on OBD reader)
That's the PCM relay, it also provides 12volt to the fuel injectors and fuel pump relay(not fuel pump) along with the computer when it closes

And if fuel pump relay also actives when you jump PCM relay slots, that means computer DID boot up, it controls the fuel pump relay by grounding it for 2 seconds when its booting up

So doesn't read like a computer issue, reads like Key ON is not activating the PCM relay

And if you also have a no crank issue that could point to an ignition switch issue
Ignition switch is under the steering column, above brake pedal, the key slides a rod when its turned to put ignition switch into its 4 positions, ACC, OFF, RUN, START

Do the other dash light work with Key ON?

Is CEL on when you jump PCM relay?

 

[Shepherd]

Hi Ron,

Thanks for the information, I was suspecting some of it but I'm not a professional so it helps a lot to get confirmations. ( and I was hoping the crank sensor is ok because I did the timing belt already several months ago it was a pain... I read replacing that sensor involves the same dismantling procedure )

To answer your questions -

The engine does crank with no problems at all.

I also did pull the ignition switch just for giggles and to inspect it, without knowing it is a non-serviceable unit. I didn't want to break it so I reinstalled it. It seemed to move around pretty well, but I don't know more other than it appears to work the same it always has with its different positions.

I attached a picture of the dash. Looks like I've got ABS, Brake, Airbag and battery. ABS and airbag go away after a few seconds. (Airbag light has always been on since I got the truck five years ago).

The CEL doesn't come on when I jump the PCM relay.

 

[RonD]

Because its easy to check, try testing any fuel injectors Red wire with key on or PCM relay jumped, you can use a 12v test light or a volt meter
You can uses a sewing needle to pierce any wire to test voltage, or OHMS, doesn't hurt the wire insulation and can make testing easier, just an FYI

If no 12v then problem may be on the underside of engine fuse box, corrode RED wire on PCM relay slot

CEL does have a fuse, in 1997 its fuse #11 in cab fuse box, 7.5amp, long shot
PCM Grounds the CEL bulb when it boots up
If you have a meter then test fuse 11 for 12v with key on, one leg will have 12v(key on) the other won't with fuse removed

While in the cab fuse box, check Fuse #19, 25amp, should have 12v with key on, it powers the Coil Pack, but also powers(turns on) the PCM relay via a plug-in Diode in the engine fuse box, a diode is directional so needs to be plugged back in the same way it came out, so NOT the same as a fuse

Its more likely that 12volt power to the PCM is the issue not the PCM itself
If the fuel injectors have 12volts then you will probably need to pull off the 104 pin plug on the PCM, upper center of firewall, unhook battery first, then when its off you can hook battery back up to test 12volt wires/pins

 

[Shepherd]

Sorry I didn't reply earlier!

Seems bad luck was a big factor on this one, because I had a faulty multimeter that caused me to think the issue was something else.

The issue did happen to be the fuse #19 SLOT. the fuse was fine, but the little metal sheating / slot that the fuse connects into had somehow pushed back, so the fuse wasnt blown but there wasn't any contact being made.

To make matters better, my multimeter somehow was reading 12, always. I guess it got burnt onto its LCD.. I have no idea how. I threw it away after it robbed me of two days of my life.

Thanks so much everyone for helping me troubleshoot this. It was a simple problem but a very obscure one for me... and I learned a lot about how to troubleshoot important systems in my truck with these tips too.

During everything, even after the problem was fixed, my CEL still never comes on and the OBD2 still just comes up with error. None of that matters to me now though, as the truck started right up after fixing the little fuse slot.

 

[RonD]

Good work

Boy, a bad volt meter, real bad luck on that one