daviddeep

iTrader: (4)

I'd love anybody's advice on my current electrical problem (I'll try to keep it brief):

1. Drove my '90 GTU to work last week. When I went to go home, it wouldn't start. Headlights were bright but starter motor was turning very slowly. Mazda reman starter is about 1 year old. Got a jump from fiancee's '01 Integra GS-R (ugh) and car started right up.

2. On the 5 mile drive home, car went into limp mode, i.e., wouldn't rev above 2000, some backfiring, etc. Also voltmeter never got above 11 volts or so. Check engine light came on.

3. Read error codes using jumper wire and got only one code: a single fast flash = code 01, "trailing coil/igniter." I don't have a multimeter or an igniter checker, so I visually inspected all connections, and they're good. I've read in various posts that the trailing coil/igniter rarely fails.

4. Removed alternator and battery. Alternator pulled a steady 14 v on the Pep Boys tester; they recharged the battery (it is 1.5 years old) for free. All belts are new and properly tightened.

5. Main 100A fuse was intact, but looked brownish, not bright copper like the other fuses. I replaced it, but this had no effect.

6. Now car will not start with a jump, and my one brief attempt to crank it with a freshly charged battery caused the volts to drop very suddenly, as if there is a huge short somewhere. Also, after removing and replacing the battery, I now get no error codes at all, but when I turn the key to "on", the check engine light illuminates for a few seconds then goes out.

I feel pretty helpless in the world of electrical problems. Does anyone have any suggestions? If I go out and purchase a multimeter for testing, can I get a cheap one someplace? Will I be able to figure out how to use it if I follow the instructions in the Haynes and FSM, or is it time to tow it the 10 miles to "DCP Motorsports", the local rotary expert?

Thanks for reading.

SureShot

Your best clue - the voltage drop when you turn the key to start.
Either the battery or it's connections are weak, or the starter is shorted.

Check for the simple/cheap thing first.
Try to crank it, then feel for hot spots at the battery cable connections (including the starter end).

Wankel7

Or you have a bad battery cable (Positive or ground). Maybe the power cable from the battery to the alt.

James

daviddeep

iTrader: (4)

Thanks for the suggestions. I'll take a closer look at the battery cables this evening after work.

Would a short/hot spot in the battery cable or problem with the battery itself produce an 01 error code (which FSM says is "trailing coils/igniter")?

Wankel7

One way to check for bad positve cables is this.

With the car idling check the voltage at the alt. Then the battery and see what the voltage drop is.

And for the starter while cranking the car see what voltage is at the starter. Then compare that to the voltage at the battery during cranking.

If there are large drops there is a prob in that cable or the ground

James

daviddeep

iTrader: (4)

SureShot, you guessed right. The short was at the starter end. Last year my car was in a minor flood and the starter being submerged somehow shorted and fried the starter and the positive lead wire, according to the mechanic who allegedly "fixed" it. He installed a new wire from the positive battery cable directly to the starter. What I didn't know until I got under the car today is that he just bolted the new wire on top of the old fried wire on the starter end. He essentially "piggybacked" the new cable along the outside of the harness and zip tied the whole thing together.

This sorry "fix" lasted for over a year. Maybe the progressive corrosion of the old lead underneath the new one had something to do with why it worked for a while before dying.

I cut off the corroded starter positive wire and capped it with a Dryconn filled waterproof cap, electrical tape, and tied it off and away from the starter. Now the car fires right up and runs normally.

Two lingering issues:

1. Why would this electrical short have thrown engine error code 01 "trailing coil/igniter"?

2. Aside from the check engine light (which is fine), my idiot lights aren't lighting now when I start the car. Where would I begin to look for this problem? I have an extra idiot light cluster that I will swap in tomorrow as an experiment.

Thanks everyone for helping.