Phantom "Hood" Sensor Problem

[SeiGGy]

ok...this one has me and everyone I know stumped...my car runs fairly well for a 93 with almost 200k miles on it now...I drive 100 miles a day on the highway and have no issues...but I only drive the car 3 days a week, and its just straight to work, and straight home (50 mile trip both ways)

so anyhow, the other week I stop by the girlfriend's work to take her lunch on my way home from work, and I get back in the car to drive home, and the car wont start...I pop the hood, check my DIS ground (gave me some issues a couple months back) along with my wires, etc, etc...anyhow, hop back in the car, and it starts...close hood, drive home, all ok...

next day, drive to work ok, starts at work ok, stop to get gas on the way home, get in car to drive home from gas station, car doesnt start again...so once again, I pop the hood and this time I notice something (I left the ignition key in "on" position this time) the CEL went from a dim to a bright light...I thought...weird...

so I turn the key, and it starts...well I thought it was just a fluke, so I close the hood and drive home...well now it seems that if I drive the car for more than 15 mins, and I stop and cut the car off, it does this...

car doesn't start, CEL is dim, pop the hood, CEL goes bright, car starts....

CEL stays off while I'm driving...(need to go run codes tommorrow for a few other small problems)


Also. When I drive home from work, engine runs on the low side of the M-A in the NORMAL guage...within 2 mins of sitting at the stoplight on the exit ramp into town, it goes up to the N-O (closer to the O) area before it goes back down to about the R-M area...I'm wondering if maybe the Temp Sending unit is bad? Radiator was flushed, cleaned and new fluid back in august, along with new Thermostat...

 

[frosho]

do the clamps for your battery cables rise much higher than the battery posts? i'm not sure but i think that when my sho was my brother's he had some problems arise because one or both of his cables the clamps stuck up through the hood insulator and contacted the metal hood. i'm not sure what the problems were but i know he replaced them with different wires after he found out the cause. another thing to check would be the hood ground at the back left of the engine bay.

 

[Racer X]

Check to make sure all of your grounds are tight. If they are, then check your harnesses for shorts or breaks. While someone is sitting in the car, tug and wiggle the harnesses while they watch the light. If you tug and there's a change, you now know where to start.

Good luck.

 

[projectSHO89]

A dim CEL indicates one thing: A faulty electrical connection that supplies either the ground or power to the EEC.

Pay particular attention to the small ground wire that goes from the battery negative terminal to the ground point on the fenderwell, then continues back towards the firewall. I'd suspect a problem with this wire or it's inline connector.

Steve

 

[SeiGGy]

well I've checked all those connections, and they all seem ok...my battery posts are the same as the stock ones...nothing is protruding...the only thing I can think off is that weird metal band thats attached to the hood, its kinda rusty colored so it could be getting a bad connection (but I thought that was just to the hood light) its odd...it just kinda started outa the blue too, I hadn't done any work to it lately, so I know I didnt mess anything up...unless there's a wire being shorted out somewhere inside the car that is shorted near the hood latch (only thing I havent checked)

I'll post more as I figure things out

 

[SeiGGy]

Guys I'm still having this problem. I've replaced the fuel pump...even checked every single ground in the engine bay, nothing wrong there...I did find a leaky fuel line, which I'm about to replace in about 30 mins...but i dont think that would cause the problems...the problem has gotten worse lately...to the point where it will cut off as many as 5 times in the 50 mile drive to work, where before it wouldn't start at random times, now it cuts off randomly while driving. same symtoms...dim CEL, engine cuts off, pop the hood CEL goes bright, car starts back up...ran the codes, and it posts 1-1-1 for both stored and running, so all codes are clean...

 

[Ishodu]

Did you also check the connections at the starter?

 

[SeiGGy]

yeah...well after replacing the fuel line it seems to be better...I'll know in a few days...I drove it about 20 miles down the highway and back to check and it didnt cut off this time...and usually thats where it cuts off...after long drives...so we'll see...

 

[thecrew2999]

i learned that with dirty cables that go on the stock connectors for the battery will cause it to act weird.. i got new ones nice ones might i add and i never had a problems..

 

[shoteen95]

How are the conditions of the battery cables. I believe they can corode through the whole wire, not just the clamps. I know the stock battery cables are kind of lame, I just changed mine out this summer cause they had coroded so bad, the clamps broke to peices in my hand. They were causing a no start situation, and also causing a sort of brownout when the key was turned to start.

 

[93rev2sev]

This sounds like a "water pump leaking on the crank sensor" problem to me.

Check your coolant level. If its low, thats why it heats up. Get some windspeed and it cools off...thats low coolant.

Change your water pump and maybe you can save your crank sensor. Right now its just getting shorted out when the pump stops and the pressure is high enough to spit a little coolant on it. Soon it will start to stall when you get off the freeway. It might start right back up, it might not.

When enough coolant gets baked onto the sensor, the sensor stops working.

A drop of coolant can fill the gap on the sensor, causing the short and no start condition. Trying to start it usually shakes the water off (but the computer is thinking there is a bad CPS). Then when you get out to check things out under the hood, you remove the key and reset the computer...get back in and it starts.

Perhaps the hood sensor resets the computer too? dunno.
Perhaps slamming the hood shook the drop of water off and the computer switched the ignition on.
Perhaps The time it took to get the hood open was long enough to evap the drop of coolant from the vanes of the CPS and the computer switched on the ignition.


Sound about right?

 

[SeiGGy]

ok wow...I found the problem...and its none of the above...

the little black box that sits atop the radiator underneath that black plastic cover on the right hand side (Auto Zone called it a Multi-Function Relay Box) apparently is the cause of the issue.

One night when it stalled out I just started bangin on stuff with a friend watching the CEL...and when I smacked that it cut back on...so we know thats the problem. Bad thing is Ford doesnt make them anymore, and noone carries them...

So now I've been junkyard shopping, and there's not a SHO with anything inside the engine bay within 20 miles so far...for now the car works, I just have to smack the shit outa that box sometimes.

The same box is on the normal Taurus, but the part number is 1 digit off at the end, the SHO model is BA, and the normal is AA...I'm wondering if it would work...there's a junkyard that would sell me one for 20$ and i'm tempted to go grab it...any thoughts?

 

[Green Sho]

I always thought that was the body control module....but yes it should work I took one off of a regular taurus and I've put 10K on it since and no problems.

 

[SeiGGy]

yeah, I had 3 people call it 3 different things today...one said it was the VAS module, one said it was the Body Control Module, and the other said it was the Multi-Function Relay Box...lmao

 

[projectSHO89]

yeah, I had 3 people call it 3 different things today...one said it was the VAS module, one said it was the Body Control Module, and the other said it was the Multi-Function Relay Box...lmao

...and all of them are incorrect. IRCM for pre-92, CCRM (Constant Control Relay Module) for 93-on.

A dim CEL indicates one thing: A faulty electrical connection that supplies either the ground or power to the EEC.

That box, among other things, has the PCM power relay in it. Sounds like either there is an intermittent connection or relay inside.

Steve

 

[hawkeye18]

The only important thing to note when replacing CCRMs is to match the big letter on top. Mine is "J". As long that letter is the same you're good to go. BTW, I have a spare "J" CCRM from a junkyard that I'd be happy to sell you