backdoc

Recap: The other day after a car wash(touchless), I was at a McDonald's drive-through waiting to place my order over the loudspeaker. I must have been sitting there for about 10 minutes b/c they were having trouble with the intercom. The car stalled and I had to push it into a parking spot. I had it flat-bedded to my house on Friday.
While it is in my garage, I pulled one code: 16705 engine speed sensor implausible signal. I did a continuity test as per the Bentley manual, and I got normal readings. So, could the sensor still be bad?
I checked inside the ECU compartment, and there is no sign of water damage.
I disconnected the high pressure fuel line, and cranked the engine a few seconds, and no fuel came out, but the battery was just about dead from trying to start it.
What are my next steps? Should I get a new sensor and see if that fixes it?
Do I need a new fuel pump? What is the definitive way to check the fuel pump, and where is the fuel pump relay? Just not sure what direction I should be heading, and could use all the help I can get. My battery is charging right now, so I can't tell if cleaning the engine speed sensor worked. Sorry for all the questions, but I just don't want to take it to a mechanic yet, until I have tried everything I could at home. Thanks a lot.
Doug

taga8

Step 1 - Fully charge the battery.
Step 2 - Go to the relay panel in the passanger side footwell, pop the cover off, the relay you are looking for is in the lower right hand corner. Take the casing off of the top of the relay and see how it makes a mechanical connection.
Step 3- disconnect the fuel input line into the engine, take the line and put it into a gas can (something fairly large, the pump will push out about a pint every 5 seconds).
Step 4 - put the relay back in the car with the top still off, force the relay closed (I use a nylon flat blade non-conductive).

This should start the pump pumping and you should hear the fluid start to pump into the can. If this works, your issue is probably just low voltage (possibly alternator). If it doesn't you could have a pump problem or a sender problem.

If you want to check the pump, put at least 5 gallons of fresh gas in the tank (this will easily fill up the internal reservoir), try forcing the relay again, if still nothing, then you need a pump.

backdoc

I will do all that tomorrow. Thanks. A couple of questions. Does the fact that I got an engine speed sensor fault have anything to do with all this? I did check voltage at the relay according to the Bentley manual. I took the relay out, turned the key on, and took readings at where the relay connects, and the relay is getting 12volts. Could the relay be bad?

taga8

The engine speed sensor probably doesn't have anything to do with this, at most I am guessing that you threw that code as the car was dying.

You can test the relay by just leaving it in place, have the fuel line into the gas can and turn the ignition and try to start, you should get fuel as it cranks, but if you don't it could be the relay, pump or sender. If you don't get fuel, try forcing the relay manually, if you get fuel then its a relay

tozoM8

I had engine speed sensor code with a bad ignition switch.

ttuling

They don't go bad too often, but on another car model where they did, they'd be temperature sensitive and work well except for the times when the car didn't run.

Tom

backdoc

Taga8,
I did just like you said. Disconnected the high pressure line, put the end in a coffee can, turned the key to the on postion, and manually activated the relay. Fuel started pumping out into the can like crazy. So I guess I need a new relay? Thanks for all the help.

Doug

PaulW

Sounds like you have fuel. You need to try cranking the engine over with the key. See if fuel is pumping.

Fuel pump relays are inexpensive, but I do have a brand new one that I could mail to you tomorrow.....I think they are $20 or $40 or something at the dealer.

Look at the number at the top of the relay, find another relay with the same number, and use that one as a test. If they have the same number, they are interchangable.

taga8

I agree with paul on this one, make sure you try it with just cranking the engine, that way you know the realy is bad (don't force the relay manually this time).

I had a low battery once and I was getting no fuel, just charged the battery and everything was fine for another 20K miles, so it might be charging the battery that fixed it and not a bad relay.

backdoc

I had the fuel line disconnected yesterday, and cranked the engine after I recharged the battery and no fuel came out of the hose, but when I manually activated the relay today, fuel came out. I went to NAPA, and they wanted $70 for a relay. I'll get one on-line and a fuel filter and oil filter while I'm at it. Might as well do a little tune up while the car is inoperative.