Stranded during road trip

Took the 78 vert on a little cross-country trip yesterday (cross-state actually). Its a 78 1600cc fuel injected little beauty that I recently purchased. I guess it hadn't been driven that far in a while, but after about an hour on the road, the rotten egg smell was overwhelming. I figured the voltage regulator was shot and was cooking the battery. Because I'm about 60 miles from home by this time, I figured I'd unhook the battery and try to limp back home on alternator juice alone. Well you guessed it, the VR really was gone and without the battery to absorb the over voltage situation, I made it another coupla miles before she left me stranded.

Now, my question. Since I've checked all of the fuses that I know of, I'm looking for advice on how to troubleshoot the problem. The engine spins, but won't run. I suspect I've fried one of the fuel injection components, but because I really dont know what to check first, I'd really appreciate advice on what to check and in what sequence.

Any advice appreciated!!!!

Thanks jim

Reply to
susanfender
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I would check the points and power to the coil.

Mario Vintage Werks resto

Reply to
Kafertoys

Mario has a good suggestion. With a helper to turn the key, you could even check for spark at the Hi Tension lead.

If there is spark, I would guess there is a good chance that the alternator was putting out high enough voltage to damage the ECU (computer).

Speedy Jim

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Reply to
Speedy Jim

Thanks Mario What should I be looking for on the points? I suspect you mean correct gap and check to see if they are burnt and pitted?

On the coil, I suspect you mean check for 12v on the positive side of the coil right??

Thanks Jim

Reply to
susanfender

Speedy Jim When you write "check for spark at the hi-tension lead" do you mean holding holding the coil lead to the distributor cap a 1/4th inch above the cap and looking for spark as the ignition is bumped? I am not familiar with the term "hi-tension lead"

Thanks jim

Reply to
susanfender

Hold the coil lead near grounded metal (fan shroud) and bump starter. Should give a nice fat blue spark.

Jim

Reply to
Speedy Jim

I don't mean to do too much second-guessing, but it seems to me that it would have been much better to disable the alternator rather than the battery. Just disconnecting the alt warning light would do the trick. I recently did this semi-accidently by driving my bug around while the speedometer was taken apart in the garage. I didn't think about the alternator requiring the voltage signal through the warning light, and went on a fairly long drive around town with the stereo going, stopped and restarted the engine a few times, etc. Took me a minute to figure it out the next day after I put the speedometer back in and found the battery was dead....dumb luck that it got me home and failed there.

Anyway, my point was, you can make it pretty far on battery power alone. At least with a carburated engine...now that I'm thinking about it, the fuel injection would probably suck down the battery much quicker as well as failing before the ignition gave out....

Harry

Reply to
Harry Smith

OK, finaly got hold of some borrowed tools. The car sat overnight so when I caught a ride out to check on it, This is what I found. I have ~12v at the positive site of the coil when the ignition is on. Had my boy bump the starter for me resutlingt in a nice, fat blue spark from the coil wire to the fan shroud. Looks Good! Plug the coil wire back into the dizzy and she starts right up. Woopee!!! Well, almost. It ran for about 30 seconds, started running rough and smoking a lot, then died. If she had a carb on her, I'd say she ran about long enough to run the gas out of the float bowl then died.

So.... What should I check next? Thanks Jim

Reply to
susanfender

Now it gets tough.

I would want to know if the fuel pump runs (should run all the time starter is cranking and continue if engine starts). It's under the fuel tank. You can feel/hear it if you are right up under there.

Alternative is to put a pressure gauge in place of the cold start valve (5th injector).

Next I would want to know if the injectors are firing during cranking. You may be able to see the brief pulses sent to them by connecting an old analog meter to one of the injector plugs. Or, maybe, a tiny 12V bulb. Otherwise, it means pulling an in jector out andd watching \the stream. They are a bitch to remove and hoses will snap, etc.

Smoking could mean that the cyl head temp sensor has gone open. When cold, it should measure about 2500 Ohms. Doesn't seem likely.

You have to get some kind of clues. This is where I would begin. Alternative is to swap parts, starting with the ECU.

t'other Jim

Reply to
Speedy Jim

Ok, dragged her home today and this is what I found so far. As stated before, I have spark. I pulled the air filter out and had my boy use a screw driver to open the air meter gate. Every time he pushed it open, I could hear the fuel pump running. I haven't checked it for pressure, but I could hear it bubbling. I suspect this was from the pump pushing fuel back into the tank through the pressure regulator.

So whats next? I have a multi meter and I need to check the injectors. I suspect I need to check for voltage at each injector? How exactly do I do this? Does each injector have a clip on plug or are they hard wired? Would an over voltage situation (wouldn't if have been an over current situation vice over voltage since I have an alternator???) have blown the injectors or is is more likely that I blew out the ECU?

Thanks JIm

Reply to
susanfender

Yes, sounds like pump is working.

Each injectopr has a plug. Just stick the meter leads in one of the sockets. Remember that this will be just very short pulses.

Injector would not have been damaged by overvoltage; if anything, the ECU would. Overcurrent not possible.

One more test: Behind the tarboard on right side of engine there is a ceramic resistor block. This is the ballast pack. Connect your meter from ground to any terminal on the pack. Measure voltage during cranking. Should have roughly 12V. This will confirm that the ECU is getting power.

Jim

Reply to
Speedy Jim

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