3.2 Carrera - Won't start !! Any ideas

Hi,

drove the car this morning for 5 mins,
parked up for 1/2hr
then got in to go home - no start

All electrics seem to work fine,
when you turn the key I can hear a humming noise - presume the fuel pump running?

no turn over from the engine.
It's got fuel in the tank,
lights and all electrics seem fine - so don't hink it's due to a weak battery;
put in a new DME
checked all fuses, and fuses in engine bay - all seem fine.

confused:

Any help would be great!

Thanks

[DonMo]

If you are not getting a signal from speed sensor, the car won't start. It has to detect the flywheel moving before it will give fuel. Resistance between the middle and outer pin is about 1000 ohms. Location of the connector is left side of engine where three connectors are mounted vertically on a metal piece. The speed sensor is either the middle or bottom one. Both are same sensor so the 1000 number is good. You can also disconnect the connector to the DME and check the corresponding pins for resistance. Actuatually, that is a better check (at least for me), I had a wire come loose inside the connector in the engine bay.

[stlrj]

Solenoid went bad is my guess.

Joe

[midlife]

When the starter solenoid starts to go, it will work cold but not hot.

First you may want to check all the electrical connections.

THanks for info above,

did a search and it seems - ignition switch, or the yellow cablefrom ignition switch to starter are likely culprits.

If I turn on the ignition with headlamps already switched on they will flick on/off as the key is turned - and I understand this is a symptom of a bad ignition switch??


in the meantime I'll try and bump start it

as a complete novice - how do you ( hopefully ) bump start a car!! )

[88911coupe]

I had similar probs and it turned out to be the starter. To bump start mine I just made sure it was pointing down hill and turned key to run, put it in first with clutch depressed, got it moving and realeased clutch. Worked like a charm

[Thrasher]

Mine had exact symptoms as DonMo last Spring, however the car cranked endlessly with no spark. DonMo's analaysis was exactly my issue, except it is not the speed sensor, but rather, its twin, the reference sensor.

I'd replace both while you're doing it. The voltmeter test at the engine compartment connection confirmed this.

Your issue is likely not the sensors, since you have cranking.

[rick-l]

Originally posted by Oxford_Hippo
did a search and it seems - ignition switch, or the yellow cablefrom ignition switch to starter are likely culprits.

If you could put a voltmeter or a test light on the yellow wire at the starter it would exonerate the ignition switch and narrow it down to the starter.

[steve911]

It might simply be a dead battery. I had the same thing happen to me yesterday. Drove car for 2+ hours, parked to stop at a store and then nothing. No crank whatsoever, though the electricals appeared to work fine.

Called AAA and they jump-started the car - car fired up right away. After talking with Tom Ammon of MobileWorks, he suggested making sure the charging system was OK. Checked voltage across the battery when the engine was running and saw 13.6 volts. Battery has been in the car for the 5 1/2+ years I've owned the car - don't have any history as to when it was replaced.

I'm off to buy an Optima tonight

[ianc]

no turn over from the engine.

Just to be a bit more specific, what do you mean by this exactly?

ianc

[detroiter]

If you can determine that there is no spark, try jiggling the harness connection to the Motronic box under the driver seat. If this doesn't work open the box and look for any corrosion, etc.

Good luck!

[Hugh R]

Originally posted by Oxford_Hippo
as a complete novice - how do you ( hopefully ) bump start a car!! )

Put it in second, turn on ignition, have friends push and dump the clutch.

Miracle? it's started.

went out to the car car week ago ( been left sitting outside a friends house accross town ) , to try and check the cables / plugs under the dashboard - behind the ignition switch. - sadly all seemed ok - so no easy fix.

tried the car iginition just in case - but no joy.

1 week later
went out to the car this afternon, with a friend and second car ready to tow it to the garage.

we pushed the car back about 2m to make access easier for the tow rope,

thought I'd try the ignition again - just in case

and - miracle - engine started fine!!!!!!!!!!!11

can anyone explain how the pushing it back a couple of meteres has changed / solved the fault??

Thanks

[88911coupe]

OK just to add to the daily "3.2 no start" my car is doing the same thing. It's got a relatively new battery AND starter. I tapped the DME relay and no help and I can also feel the DME relay click when I turn the starter on but there are two connections IIRC in the relay so I guess it could be bad.
I assume the engine has to be out to replace the sensors?
Just to add to the issue I checked the battery and it shows 12.6 volts with the key out of the ignition. Is this sufficient? It's 5 month old battery for what that's worth.
Just to clarify, when I turn the ignition on the other electronics fire up fine, radio, fans, etc but I get nothing from the starter, not even a click, although as I said, when I turn the key I can feel something click or energize in the DME relay itself.
Not sure if this is related but when I was driving the car prior to parking it the a/c seemed to just stop working and I turned it off. After a few minutes it was working fine.

TIA

[Thrasher]

No, the engine does not need to come out to test or replace the eith er of the 2 flywheel sensors.

You can search this topic for pix, but basically just locate the three sensor bus on the left side of your 3.2 (top is white: cyl head temp, next two below are black and identical, one is speed sensor, other is position ref sensor)

position ref sensor is the one that will tell the DME where TDC is while the starter is cranking. If DME doesn't receive the signal, it will never spark.

You can check for spark first, and if none is there, try pulling the position ref sensor at the bus. An Ohm meter reading will tell you good/bad. It's all in Bentley, or in the archives.

Good luck!

[88911coupe]

Thrasher, I think we were posting at the same instant. THis may be a dumb question but when you mean spark are you referring to the engine firing up or turning over? As I said in when I updated my post a minute ago the engine does not turn over when the ignition is turned to the start position.

[Zeke]

Originally posted by 88911coupe
I had similar probs and it turned out to be the starter. To bump start mine I just made sure it was pointing down hill and turned key to run, put it in first with clutch depressed, got it moving and realeased clutch. Worked like a charm

Not first. Second is OK, 3rd actually will do it with less stain on everything. Never first. There may come a time when you might have to use reverse, which would be the worst of all gears to use. But. if you're on a hill and can't get it turned around safely, slip the clutch a lot to get the revs started. Don't dump the clutch.

[rick-l]

Originally posted by 88911coupe
, etc but I get nothing from the starter, not even a click, although as I said, when I turn the key I can feel something click or energize in the DME relay itself.TIA

That would be the current following the blue path (coming from the yellow wire of the ignition switch) that turns on the darlington that in turn energizes the fuel portion of the DME relay. Note the red path (diode OR) that comes from the microcontroller.

Courtesey of JR Wilk

Sounds like ignition switch is good. Starter Solenoid?

[Aerkuld]

Originally posted by Thrasher
No, the engine does not need to come out to test or replace the eith er of the 2 flywheel sensors.

You can search this topic for pix, but basically just locate the three sensor bus on the left side of your 3.2 (top is white: cyl head temp, next two below are black and identical, one is speed sensor, other is position ref sensor)

position ref sensor is the one that will tell the DME where TDC is while the starter is cranking. If DME doesn't receive the signal, it will never spark.

You can check for spark first, and if none is there, try pulling the position ref sensor at the bus. An Ohm meter reading will tell you good/bad. It's all in Bentley, or in the archives.

Good luck!

I don't think that the reference sensors are the problem. Hippo seems to be suggestion the the motor doesn't even turn over. I can see the reference sensor preventing a spark if it isn't generating a signal, but not stopping the motor spinning over in the first place.
I'd do as others have suggested and check the starter motor solenoid and ground connections.

Hippo, as far as bump starting is concerned sit in the car with it in a high gear - 3rd would probably do. Turn on the ignition to it's normal run position, then push the clutch down to the floor. Get a guilable assistant or two to give you a good push up to speed, then briefly let the clutch up. You will want to press it straight back down again when the motor fires. If it doesn't fire repeat the process, a little throttle might help, if its not firing straight off.
Once it starts, buy your assistants a beer.
Don't rely on this as a solution - find the problem and fix it as it gets really inconvenient having to take two people with you everywhere to help you push the car, not to mention the beer!

Good luck!

[defcon65]

This has happened to me twice - won't start (turn over) and then for no reason, it will start again. Other Pelicans have suggested that the starter or solenoid is going bad, the starter won't work when it gets hot, the connections and grounds may be loose or corroded or the ignition switch is bad. I think I'll start with the connections, clean the ignition switch contacts then proceed to looking at the starter or solenoid. A somewhat common problem with 911s, I'm led to believe. Park on hills if possible.