Explorer EFI shutting down after starting

[EBGeek]

@Broncobowsher I just tried again, same result after unplugging the MAF...

 

[Viperwolf1]

I have seen one explorer that had the magnet get dislodged from it's place in the cam position sensor. The bushings wear badly on those. It had some weird running issues.

 

[Big Slim]

and your not getting any OBD codes? would think a bad sensor would throw a code.

 

[EBGeek]

@Viperwolf1 any reliable way to test cam sensor? I wondered if I might've blitzed a sensor of some kind with the wash down but I suppose it couldn't hurt to try replacing it...it looks like they're about $50 and it still has the original sensor from when engine was pulled/installed

 

[EBGeek]

Right no codes other than P1409

 

[Viperwolf1]

@Viperwolf1 any reliable way to test cam sensor? I wondered if I might've blitzed a sensor of some kind with the wash down but I suppose it couldn't hurt to try replacing it...it looks like they're about $50 and it still has the original sensor from when engine was pulled/installed

You should probably just take a look at it first. Take the 2 screws out of the top and see if everything is still there and it doesn't look like the rotor has made contact with anything.

 

[EBGeek]

Well, there's not much to the cam sensor after all. I pulled it and the magnet and rotor look great...thanks for the tip to take that out of the equation, Viperwolf...

 

[surfer-b]

I notice you have the c4 tranny, if you could find someone close to you that has a PCM for a c4 setup or a straight shift setup you could swap and see if it runs, the straight shift will have a higher idle but thats about all

 

[EBGeek]

Yep...since I can't find a mechanic to look at it for literally a month, I'm thinking about buying another PCM and pay the local guy to reflash my 'good' config onto the new PCM. It's just nuts since this PCM ran great until I gave her a bath...

 

[EBGeek]

To SurferBs point, if anyone has a spare Explorer PCM lying around that I could test with, I'll be more than happy to pay for shipping/your time/etc. Grasping at straws at this point, but will probably go ahead and order another one just so I have a spare in case that's where my issue lies...

 

[Broncobowsher]

You can try unplugging the cam sensor.

The neat part about EFI is if you remove most sensors the computer will go into a limp mode and run fairly decent using guessed data for the missing sensor.
The hard part is when the sensor still sort of works. The computer is getting a signal and is trying to make it work. Remove the bad information going into the computer and it has a better idea of what to do. I once had an EEC-IV down to nothing more than a crank trigger and it would still run. Not great, horrible throttle response, but still ran.

 

[lars]

To SurferBs point, if anyone has a spare Explorer PCM lying around that I could test with, I'll be more than happy to pay for shipping/your time/etc. Grasping at straws at this point, but will probably go ahead and order another one just so I have a spare in case that's where my issue lies...

Maybe this has been answered already, but where is the PCM mounted? Is there realistically any way water could've gotten into it? I haven't held an Explorer EEC-V PCM for ages, but if it's anything like the EEC-IV Mustang 5.0 PCM's with which I'm familiar, it's pretty easy to open them up and have a look around. Might be able to spot water-induced corrosion on electronic bits if water has actually gotten into it.

 

[Tiko433]

I just sent my ECM to get tested. They tested it , repaired and returned it to me in a week. PM if you want to see who I sent it to.

 

[country_boy_71]

double check the inertia roll over switch. it turns the fuel pump off when trigged

 

[surfer-b]

you may have already posted about the GRND but if you have not be sure and check to make sure the PCM ground is good and not loose

 

[EBGeek]

you may have already posted about the GRND but if you have not be sure and check to make sure the PCM ground is good and not loose

The PCM grounds through the connector and not through the housing right?

I hope that @EFI Guy is still in business, as the local outfit has tried multiple times with putting a chip in the back of my PCM to no avail... But when Garry built my harness/PCM he didn't use a chip... So now I'm thinking that might have something to do with it...

I've determined it will run with the locally programmed chip, but ONLY if the chip is installed while the PCM is plugged in. If you unplug the PCM (which I have to do to install into firewall) it does the 1 sec shutdown. If I reseat the chip while PCM is plugged it, it will run...

This is total madness yall. The local shop is killing me... Since they don't seem to understand my Bronco has ran 40k + miles with the old setup WITHOUT the chip in the back...

 

[EBGeek]

The PCM grounds through the connector and not through the housing right?

I hope that @EFI Guy is still in business, as the local outfit has tried multiple times with putting a chip in the back of my PCM to no avail... But when Garry built my harness/PCM he didn't use a chip... So now I'm thinking that might have something to do with it...

I've determined it will run with the locally programmed chip, but ONLY if the chip is installed while the PCM is plugged in. If you unplug the PCM (which I have to do to install into firewall) it does the 1 sec shutdown. If I reseat the chip while PCM is plugged it, it will run...

This is total madness yall. The local shop is killing me... Since they don't seem to understand my Bronco has ran 40k + miles with the old setup WITHOUT the chip in the back...

I've also verified that if I unplug the chip, it cranks and runs just fine, presumably with the Explorer code which isn't right... But it does at least run...

 

[surfer-b]

Yeah, I never really understood why you were installing the chip, maybe I missed something. Gary doesn't use a chip he just reprograms what is needed and removes unneeded programs, IE the anti-theft, downstream O2 sensors, an whatever else is not needed for your application. I would say the chip they installed is messing with the PCM. I would remove the chip, contact Gary and start from there, he will get it straightened out for you.

 

[67EB_in_619]

I would agree that ignition staying hot in run is suspect.
try disconnecting the crank wire from the starter, hold the key in crank, and manually jump the starter to get it to turn over and see if it stays running in crank.
Id also take a look at the basics like grounds and relays.

 

[EBGeek]

@surfer-b, I think you nailed it...unfortunately I was trusting the local 'professionals' and assuming they knew what they were talking about...I hadn't reached out Garry since it had been 6+ yrs since he built/programmed my setup and I wrongly assumed he wasn't in the game anymore. Anyway, turns out the local idiots had no idea what they were doing and it took me a month of back and forth to come to that conclusion.

I cannot tell you how excited I was when I heard back from Garry. I've sent him my PCM and letting him work his magic on it...

Oh and yes, it absolutely was the stupid chip causing the issue from the get go...at Garry's direction (because my engine/setup is pretty much bone stock explorer) I was able to pull the chip (with a stock PCM bought off of ebay) and it absolutely runs like a champ (though I'm still sending Garry my PCM so I know it's right).

Moral of the story - don't trust your rig to just anybody...just because someone builds hot rods doesn't mean they know Jack diddly about our setups...