Cam sensor, Crank sensor, or Fuel pump. Help

[Hybred]

UPDATE:
My problem was the PCM.
symptoms = Quickly Flashing Check Engine Light w/ Key On, Engine off; clicking fuel pump relay, clicking Idle Air Bypass solenoid, no start condition, unable to pull codes. IF it did start, truck would intermittenly shut off & restart, loss of power, missing, poor fuel mileage


Hello everyone.
'97 Eddie Bauer w/ 5.0L
I have an issue with my truck shutting off, stumbling, low power, bad fuel mileage, failing to start. I am fairly certain that the problem is one of the above mentioned.

A few days ago while sitting in traffic, it just shut off. Started right back up. Drove a few miles, and it shut off again while coasting to a stop light, & then restarted on its own. It did this again about 20 seconds later. I pulled into an Advance and asked them to pull the codes, , no codes. When I got home it shut off as I pulled into my driveway and would not restart. The fuel pump relay was clicking very rapidly. Turned the switch off & back on & then it started up fine, although while I let it idle for a few mins it stumbled & nearly shut off twice.

The next day I chanced it, (bravery or stupidity), and it stumbled / missed pretty bad going up a hill but then cleared up and ran fine all the way to work (11 miles). Leaving work it shut off on me 3 times but restarted right away, & then lost alot of power and began stumbling pretty bad so I pulled over and got a ride. The CEL was flashing very rapidly. After I shut it off, it wouldn't restart, the fuel pump relay was clicking rapidly again.

I came back the next day with a code reader and it gave me P1121 which I have read means the TPS & MAF aren't in "synch". The truck did start however & I drove it the 3 miles home, it ran like crap.

I believe that code popped up because of a lack of fuel, wether the pump is bad, or one of those sensors is telling the EEC to turn the pump off/on. I tried swapping the relay with the other 2 and regardless of which one I put in the spot for the fuel pump, it clicked rapidly.

Is there any way to test the Crank position sensor? Can a bad one produce intermitten problems or is it one of those that either works or it doesn't?

I have read conflicting data on the Camshaft sensor. So I don't know if it provides a PIP signal to the EEC or not. Some threads I have read say that it is only used for starting, and others claim it is used to provide the EEC w/ a PIP signal & injector timing. I un-plugged it when the fuel pump relay was clicking & it had no effect on the relay.

Would a bad / failing fuel pump cause the relay to cycle like that?

I can't afford to just throw parts at my truck, plus it is like 18° outside.

Thanks for any insight,
-Rock

 

[Turdle]

Hmm, I suspect the relay first. They do start doing this kind of thing when they go bad.

Also, check the connections in the power distribution box, where the pcm relay and fuel pump relay connect in to. Look for evidence of overheated connection. There is a yellow plasic shield preventing view, but if you disconnect the battery, and take your time the power distribution box will unsnap apart and snap back together.

For a "free " quick check, swap the fuel pump relay with another in the box. If you slightly twist the little connector tabs on the relay, it will help it to "bite in" to the socket better.

My 98 Mountaineer did just this same thing. I noticed, with the key turned to on, if I "jiggled" the relays I would hear things turning on and off. It was actually a bad connection in the pcm power relay causing the fuel pump relay to cycle--


Hope this helps. If not, well, we haven;t spent any money yet, and have eliminated a few possibilities. Please post your findings.


If the cam sensor was bad, I would expect a specific cam sensor code. However it might not hurt to take the cap off ( 5.5mm bolt) and clean out the inside.
However, a flaky connection might just cause the type of code you reported.

 

[Hybred]

Thanks Turdle!! I will pull the power distribution box apart and see if there is anything going on in there. I already tried moving the relays around, but regardless the one in the fuel pump relay spot would click rapidly.

I have read that a rapidly flashing CEL was a sign of an ignition problem. Would this happen if there was a fuel delivery problem? This flashing CEL symptom is the main reason why I am considering the Crank and Camshaft sensors.

I have another set of coil packs I will throw on tomorrow after looking at the Cam sensor, and maybe a set of wires too. I wouldn't think that a set of Taylor's would fail, but I can't rule it out at this point. I plan to monitor the fuel pressure and wait for a stumble or shut off to rule out the fuel pump if pressure stays constant.

I truly appreciate your insight & ideas. Thanks

 

[96eb96]

Clean your maf too!

 

[Turdle]

Weak battery, or, poor battery connection resulting in low voltage will cause relays to go nuts also.

 

[budwich]

flashing cel usually indicates a "miss detection". Anyways, you might be able to readily eliminate your "guess" of the fuel pump, just run a jumper from the battery to "just past" inertia switch TEMPORARILY to see if things change. IF they do, you can focus on things in front of that point.

 

[Hybred]

Clean your maf too!

I'm working on that one. Someone filled one of the Security Torx bit screws with epoxy. Factory maybe to prevent tampering? IDK. I got most of it out so far.

 

[Hybred]

-MAF is fine
-Fuel pressure is steady at 40psi & I can hear it running.

Truck won't start at the moment, flashing CEL, Fuel pump relay is clicking, and the Idle Air Control valve is clicking.
I guess my next move is to start un-plugging things until that stops.

Power Distribution box is fine also, I took it apart and don't see any bad signs.

 

[Turdle]

http://www.explorerforum.com/forums/showthread.php?t=264205&highlight=start

Try this. Without touching anything else, disconnect the Crankshaft position sensor. Tap it lightly with something, and plug it back in. Then try starting the truck.

 

[Hybred]

http://www.explorerforum.com/forums/showthread.php?t=264205&highlight=start

Try this. Without touching anything else, disconnect the Crankshaft position sensor. Tap it lightly with something, and plug it back in. Then try starting the truck.

I don't think I ever said so many GDMF'ers before as when I was trying to unplug that Cranshaft position senosr. What a pain to get to. Finally just took the tensioner assembly off in order to get to it. No change.

I think the problem is the PCM. I have disconnected almost every input/ output/ sensor that connects to the PCM and still had the flashing MIL and clicking relays & solenoids. I Checked the volts at the TPS (5v), fuses, relays, all the grounds. I spent ALOT of time diagnosing this because I really didn't think the problem could be the PCM.

So I went to the local pick 'n save and was able to find 1 PCM from a V8 Explorer, but it has a different code then mine. I plugged it in to my truck and the flashing MIL & clicking relay's / solenoids quit. All seems normal. I have to finish installing all the other stuff I dissassembled before I can test and see if the truck will start with this different PCM. Any thoughts on that? If there was a PATS system on the donor (2000) will it affect me? I don't have the PATS on mine.('97)

UPDATE - PATS from ('00) PCM will not allow my truck to start. Makes sense now that I think about it, it is looking for a signal and not getting it. Only out $25 though ...:exp:

 

[Hybred]

My problem was indeed the PCM.

Installed another one today. I made sure to get one with the same part number this time and the truck started right up. No problems now.

 

[wisconsin5.0]

Im having the same issue!
just posted this after noon. Not sure why this one didn't pop up when i was searching earlier in august. Any way to the bone yard tomorrow to find one. If this works I will post for the clicking relay issue. I thought i was all alone in this one! Can I link this post to mine? in case some one is replying id like to send them this way.