Prologue: A couple of weeks before the problem happened I had the battery replaced

The problem:
The check engine light came on and when I checked the code P0705 (with my hand held code reader) it told me that there was a fault with the transmission range sensor. The car seemed to be running ok and so I did nothing (mistake!), although I ordered a new sensor.

(I should point out that I live in a small place called Dukhan in Qatar and getting to a repair shop is quite difficult, in my defence).

Then one day a week or two later the car started to shift out of gear when it reached OD and rev really high. I switched OD off and I was able to reach home (some of the shifting was a little erratic on the way).

I tried the car the following day to try to further diagnose the problem and it seemed back to normal. I used it for short journeys for a few more days until the shifting out of gear happened again like before.

I got the car home and tried the following day and this time after I started the car I swear I put it into reverse and it started to creep forwards! I switched off the engine and went to work in our other car.

When I got back I tried to start the car and the next thing happened which now has me stumped. I turned the key and it made a sound like the engine was about to turn over for a fraction of a second and then stopped and all power from the car appeared to be switched off. No instruments, lights, nothing. The red anti theft lamp was pulsing gently (not flashing on and off just getting a little brighter and dimmer) and there was a faint ticking like from a relay coming from the fuse box.

No amount of removing and reconnecting the battery made any difference. I checked the fuses and relays and I could not find a problem and so I convinced myself that it could be something to do with the relays soldered on to the fuse box circuit board.

Gritting my teeth I removed the fuse box and dismantled it. Apart from one fuse that was blown (39 – Console power points, which seemed unrelated) all the fuses were intact. I had already tried switching the user serviceable relays around to see if that made any difference to no avail.

I ordered some of the small soldered relays from eBay and decided to replace the most likely of the them (R303 fuel pump), just in case (although I thought if this was gone the car would turn over by not start).

Anyhow I reassembled the fuse box – put it in the car and connected everything up. The interior lights came on (because the door was open) and I thought I was in business. Holding my breath I turned the key and…same as before tiny attempt to turn the engine over which stopped after a fraction of a second and then all electrics gone again. (In the interim I had put my (new) battery on charge just in case).

Sigh.

The transmission range sensor arrived and I replaced it, but still no change – all electrics (apart from the gently pulsating anti theft light).

Update – I pressed the fuel cut off switch in the trunk just in case and I reconnected the battery today just to see and this time the fuse box started ticking again like before. I pulled all the relays and it is clearly one of the soldered ones. By feeling with my finger I think the one vibrating the most with the ticking is the middle one (fuel pump) again. The anti theft light is now going on and off in time with the ticking and the rest of the car is powered down.

I’m British and I’ve done a bit of work on cars at home before, but most of our cars are manual and so autos are a bit of a mystery to me. Can anyone help?

Can a fuel pump relay (or the fuel pump) cause the rest of the car to power down?

The transmission selector lever moves easily – can the transmission be jammed in gear preventing starting? Would that ‘trip out’ all the electrical systems?

With everything dead, how can I start diagnosing the fault?

How on earth is the transmission, fuel system and electrical system interfering with each other?

(I know I probably brought this on myself by ignoring the warnings the car was giving me – believe me I feel like an idiot now.)

Thanks in advance to anyone offering advice.

 

It could simply be a bad ignition switch.

 

I think you are trying to solve all the issues with one fix. Your gonna have to go at this logically.
First thing is you need to determine is if you have a fully charged battery and good battery cables. If you have a DMM, what voltage does the battery show?

If you don't have a DMM, turn the headlights on and watch them while someone attempts to crank the engine. If the headlight go out when attempting to crank, more than likely the battery isn't fully charged or you have poor connections to the battery or defective battery cable(s).


Let us know what you find. If you have an adequate battery and cables, then we'll move on to alloro's point.

 

Nope.

Your current symptoms are, as Jim mentioned, of a discharged battery or a bad battery cable or connection. You'll need to use a voltmeter and do some voltage drop tests when trying the crank in order to find the problem. Here's a decent enough article on how to do it: http://www.aa1car.com/library/voltage_drop_testing.htm

 

Dear all,

Many thanks for your replies. Short answer: the connection on the positive battery terminal was dirty and as a result was giving intermittent contact. I cleaned the terminals and now the car starts.

I feel like such as fool as I have done exactly what I tell my students they should not do (I am a computer science teacher) and that is believe in the error. If you don't believe the error is there you won't be able to find it. Typically they say things like 'sir I have done everything right but it still doesn't work - the computer is broken'.

So thank you all for forcing me to get my DMM out and run a few tests - found the problem in about two minutes.

I took the car out for a drive and now I am back to my original transmission problem. Clutch appears to be slipping a bit and when it reached OD it shifts out of gear. Car continues to drive with 'slipping clutch' with overdrive switched off. I have previously changed out the transmission range sensor based on a check engine light fault. I have also just checked the transmission fluid with the dip stick and it appears clean and full (I have not had the car that long and so I don't know the age of the fluid).

Any ideas or can you direct me to a more relevant thread?

Thanks,
Steve

 

How many miles on it?

 

150K - I know - it's loads!

 

Check for a broken or dislodged O/D servo clip.

You'll have to drop the pan and valve body to do so. The clip that breaks is inexpensive, Ford part # f2vy7384b

 

Then it could be worn clutch packs or a blown seal.