Hey new here, not sure if this is posted in the right spot but I have a 1994 Ford Ranger 3.0 automatic that cranks but won’t start. I got it on trade and it had a miss, went to put a jumper wire in to check flash codes, now it will crank but won’t start, I’ve checked spark, has fuel pressure at the fuel rail and all fuses are good I checked with a test light I’m at A loss to what it could be any help would be appreciated thanks

 

so do a 50/50 test, use. starting fluid or? spray so in the intake. if it pops or tries to run it has a fuel problem, if nothing its spark issue. id start here first.

 

So I sprayed some carb cleaner in the throttle body it will run for a second idles pretty high then shuts off probably gonna replace fuel pump see if that’s it

 

i think theres a fuel regulator on the fuel rail. it has a vacuum line to it. if the vacuum line smell like fuel it needs to be replaced.

 

You stated it has fuel pressure at the rail. If so, no need to throw money at a fuel pump. How did you determine you have fuel pressure? Do you hear the pump run for two seconds when you turn the key to run (before trying to start)?

I know you can get codes to flash with OBD1 but I‘ve never heard of anyone doing this with OBD2. Do you think your jumper caused a problem, maybe blew a fuse or diode? Does CEL go on when key goes to run and then turn off when you turn key to start?

 

good information

 

Okay, I guess yours is still OBD1. Still, suspicious that it won’t start after checking for codes.

 

I didn’t even think to check the Diode

I checked the inertia switch it isn’t flipped

Suspect it’s fuel Pump because I don’t hear it coming on, it has pressure at the fuel rai but maybe it’s not enough, I pressed the schrader valve and it shot some fuel though that’s why I first thought it was getting enough fuel, but when I sprayed carb cleaner into the intake it will run for few seconds, I don’t have a fuel pressure reader getting one in the next few days, check engine light comes on with key on , when I tried to read flash codes my check engine light never flashed, I’ll check along the fuel rail for a fuel pressure regulator and see if it has a vacuum line on it,

 

looking for fuel problems, id start at the motor and work my way back. i dont really hear my fuel pump when key is turned on. if its poping you know you have spark. there is a gauge you can put on the Schrader valve on the fuel rail.

 

Does your CEL light up even now with it not starting or was that before the no start situation? If it's not, the ECM (computer) isn't booting up. You could not be getting fuel into the cylinders because the ECM isn't firing the injectors. I'm suspecting you had your jumper wrong. That blew the diode to save the ECM and now it's not getting power. That could both cause the injectors to not fire and cause the fuel pump to not run, and it could also result in no flashing codes. You should at least get code "1" "1" (all good). If the light is on at first, does it go off when you crank the engine over? With my engine that means the ECM is getting a spark signal and it will try to start. Yours is probably looking at more signals (crank position, cam position, etc.). You have a distributor or it's distributorless?

You can borrow a fuel pressure tester from the chain auto parts stores (put down a deposit equal to the cost of the tool), but on my '89 the adaptor for the Ford Schrader valve on the brand Autozone and OReilly's loan out (OEM?) doesn't work right. I think it pushes in the pin on the valve so far it closes it off on the other end. So you may have to confirm you're getting fuel pressure by squirt testing. If you bleed off the pressure, crank over the motor for a few seconds and then check if it squirts or dribbles, you'll know if the pump and regulator are building pressure in the rail. It won't take much pressure to at least get it to fire up and idle.

 

So after some more investigating I found a vacuum line off at the air intake tube running to the throttle bottle and noticed my mass air flow sensor didn’t look like it was plugged up all the way, I plugged it back up and it starts but idles really high, when it’s running I can move the mass air flow sensor plug a little and it will idle down but sounds like it’s cammed so suspect it’s a mass air flow sensor, could that cause a no start? And a misfire/ high idle? Or could it be a wiring problem? Check engine light does come on when the truck is running

 

not sure what the problem is now? it starts and runs? ck for flash codes if the CEL is on.

 

Here's a portion of a post from one of our highly regarded members (RonD) that has information you should be considering. This person's problem was likely spark related, but the info here is still relevant for you. The thread is titled "1994" and was from Feb. 2024, if you want to search for it.

"1994 3.0l spark system is autonomous, the TFI module with coil and distributor, does spark for start up and RPM advance no need for PCM input. (snip)
But without the SPOUT/PCM connected to TFI, the engine can start and run fine it will just hesitate on acceleration."
(snip)
Yes, you can pull out the PCM and open it up, there are 3 capacitors that leak/fail after 20+ years and can be easily replaced, but they only effect fuel system, 1994 PCM didn't have much for spark, just load advance, which shouldn't stall an engine."

I agree with docm that if you're getting a CEL when running that you need to know what code that's from. The PCM is too expensive to replace without either first rulling out every sensor or actually seeing you have capacitor leakage. When the capacitors are starting to leak it can cause misfires.

You should be able to check if the TPS is behaving correctly with an ohm meter. Some places say you can back pin the connector but I haven't been able to do that, so I unplug it and check from the pins. There's three wires and one pair (power source and signal return) should smoothly change from high resistance to no resistance as the TB butterfly is opened and closed. I don't think a bad TPS would cause a no start, the computers often can ignore a bad sensor, but if it's sending the PCM the same signal as WOT, this would cause clear flood mode and the injectors won't fire (so no start).

High idle is usually a vacuum leak. More air is getting into the intake than the butterfly would allow and the PCM adds more fuel if the O2 sensors tell it the mixture is lean.

 

hey yall sorry I been busy looked at the ranger again yesterday I ended up buying a mass air flow sensor thinking it would help it plus the other one looked like crap but that didn’t fix it, really starting to believe it’s the throttle position sensor haven’t check it yet with a meter however it will start still on carb cleaner, idle really high but when I unplug the throttle position sensor it will idle Normal after leaving it running for 10 mins or so I can restart it without carb cleaner have to plug back in the throttle sensor it starts under it’s own power it idles high I unplug the throttle sensor again and it idles fine it will also rev it will just hang up for a second if I rev it hard then idles back down also starting to believe I’m gonna have to replace the head gaskets it bubbles and builds pressure in the recovery tank also I’ve watched several videos on YouTube how to check flash codes I tried the jumper wire method and that’s what caused the no start or atleast what I did before the problems started it ran before that