Lorenfb

Check here ( www.systemsc.com/diagnostic.htm ) for troubleshooting info,
and then here ( www.systemsc.com/waveforms.htm ) for info on the the various signals.

sourcandy

OK i mismarked the car in the previous post... not a C2 just a 89 911 3.2 Carrera. We took the seat out today... took out the ECM/ ECU and opened it up.. it has a performance chip on it from Auto Authority. and has the code version written on it. Is it possible this chip failed causing the car not to start?

However I would think if the chip failed it wouldn't have fuel.
-Ed

Lorenfb

If the engine has fuel, i.e. the injectors are working and fuel is entering the cylinders,
then then:

1. The coil is bad or;
2. The coil has no power or;
3. The distributor cap is bad or;
4. The coil wire is bad or;
5. The DME ECM is bad.

sourcandy

this isn't looking good looks like the DME ECM took a dump on us.
I know the coil is fine, i took a working coil from my car and swapped it in... same problem. The coil wire is easy enough to test... i'll double check it again just to make sure. The cap and rotor are good as far as i can tell... they are both brand new. And i have working old ones that i've swaped in to double check.

Took the speed and reference sensor out the other day to make sure they didn't get nicked up or something on install... adjusted them again. They appear to be operating.... i read somewhere if the tach jumps while cranking then they are doing they're job... and it does bounce while cranking. The relay has power on the lower two plug holes 12.5+ on both. And i can audibly hear it click when it's pluged in hot. There is also something else under the seat that i can seem to identify... it's a goldish color, 2 1/2 or 3" round aprox. and has two wires from the DME relay going into it. The top of this piece is loose and can be turned by hand.... I don't know what it is but i have a feeling it probably shouldn't do that.

-Ed

madmmac

With the ignition turned on do you show battery voltage at the coil?

Lorenfb

Again:

1. The coil is bad or;
2. The coil has no power or;
3. The distributor cap is bad or;
4. The coil wire is bad or;
5. The DME ECM is bad.

sourcandy

Yes Loren... I see your post...

I just dont' like admiting the fact that a 700-1200 part just up and died on me. I think there is still a route cause for the problem. like... why did the DME ECM fail? and not the relay?

-Ed

Lorenfb

"I just dont' like admiting the fact that a 700-1200 part just up and died on me"

$700-$1200????????????

Read here ( www.systemsc.com/problems.htm ) for info about why ECUs fail.

sourcandy

Well from what i read on your link a couple things jump out at me.

We KNOW there is a problem with the electronics system as we had both high beams blow at the same time twice within the same month. Also the lights flucuate... brighter and dimmer while just cruising. We were in the middle of diagnosing this when the car died. We were leaning towards regulator not alternator as we saw 14.4 volts at the headlight connectors. So overcharging could be a cause.. but i would suspect that would be a sudden failure with no warnings.

Water... not an issue... NEVER EVER found water on the interior of the car. I looked at he ECU and the components are corroded either so that illiminates that cause.

Aftermarket chip... yes it was chipped but we had none of theproblems you describe it passed emissions test with below normal numbers so i feel strongly this was not the culprit.

Vibration... this one stuck out.. the car does have a harder suspension on it than stock as well as shock tower bars and a beefier sway bar in back. I'd lean on this one more than anything as it intermittenly worked for a day or so. However... I looked closely for cracked solder joints hopping for an easy fix when we took the ECM out... I didn't see any... so it's still possible a component was damaged or a hairline crack in the board that I can't see.

I just want to fix the problem of why it went out before replacing with a new one. Thank you for giving me some possible areas to look into for diagnosing.

-Ed

glenncof

My 1985 Cabolet would not start. It would have been the FIRST time in 153,000 miles the car would have left me stranded needing a toe. I rolled the fuel pump fuse since the fuse/block setup is less than reliable (intermittent contacts). Finally it started and I got home.

Engine sounded like no fuel so I put voltmeter on the fuel pump fuse after cleaning the fuse and clips with sandpaper. Yep DME relay was intermitant.

My manual said to use jump from fuse 16 to 17 to run pump and that was fine. So I ruled out the fuel pump.

Got a relay from for $30 +$10 shipping. Seems to have fixed the probelm. Note total miles on the car was 170,000 and I had never replaced the relay.