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DLK
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No power to ignition or fuel pump GTV6

Post by DLK »

A while back I bought a GTV6 that needed a lot of attention. We had to weld in some parts and rebuild most of the drivetrain.

Now the engine is back together and all the suspension has been renewed.

Yesterday we connected a fresh battery to the car (all the welding was done with the battery disconnected) and tried to start the car.

No luck....

The fuel pump does not get 12v. If I switch the two plugs on the double relay near the right front of the engine bay the pump starts but does not switch off.

Also I do not get a spark on the spark plugs. Once I switch on the car there is roughly 6 volts on the ignition coil.

All wiring from and to the ignition switch looks to be OK. Also the wiring to and from the fuse box look OK.

Does anyone know where to look if both fuel system and ignition system are not powered? I suspect it is something simple but i can't seem to find it...

All the help will be much appreciated.
kevin
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Re: No power to ignition or fuel pump GTV6

Post by kevin »

Check your power source to ecu relay . This is separate red wire that runs from rear of car ( battery ) alongside the power cable . It connects to the 6mm stud on bulkhead alongside the battery and starter cable .
DLK
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Re: No power to ignition or fuel pump GTV6

Post by DLK »

Thanks for the tip! I will check that.

Any other tips are more than welcome!!
kevin
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Re: No power to ignition or fuel pump GTV6

Post by kevin »

Have you tried bypassing the ignition incase your ignition barrel has given up the ghost . Could just be coincidental . There three wire to ignition as you will see on the plug connector under steering consul . Worth a try because if their is no power there then you have to go back to bulkhead .
DLK
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Re: No power to ignition or fuel pump GTV6

Post by DLK »

Finally found time to tinker with the car. Once there is vacuum to the amm the fuel pump gets 12v. So that circuit works!

When I measure I get 12v on the resistor for the ignition on two connections and 12v to the coil when disconnected. Once I connect the wire from the resistor to the cool I measure 7volts.

The ignition computer gets 12v, gound on two terminals.

Only thing I can't measure or do not know how to measure is the pulse from the distributor.

The wire from the distributor to the ignition computer is okay.

But still no spark!! What am I missing?!
MR2 Zig
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Re: No power to ignition or fuel pump GTV6

Post by MR2 Zig »

Possibly a bad coil? If you haven't already done so check your grounds. They are a bigger problem than I would have ever thought.
MR1 Zig (I made rate!)
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kostercj
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Re: No power to ignition or fuel pump GTV6

Post by kostercj »

Hello,

I haven't posted in a while, but I want to chime in on this thread. (If you want to skip the long tale of woe & intrigue, jump to the next paragraph.) My 1986 GTV-6 had a version of the electrical gremlin in which occasionally it would either refuse to start or quit while running. At the times it wouldn't run, it would crank but not catch. I lost track of how many times I was towed from somewhere in greater LA to the service garage, and when it arrived, the car would start fine. Sometimes the car would run just fine for a period of months before the gremlin popped up again. This went for a period of a couple YEARS. More than once, while the mechanic was working on it, trying to isolate the potential problem, it would suddenly start fine and behave as if there were no problem at all. The combination relay was replaced, the fuel pump was replaced, among other things, the ignition switch was examined, the fuse box was detailed, the various cold start connections were looked at, the ECU, the AFM, etc., etc. Eventually, through a seemingly endless process of elimination, it became clear that the basic problem was that the fuel pump wasn't getting current.

On Friday morning after Thanskgiving I was again towed out to the garage. I drove over to the garage more than once on Saturday and Sunday, but it still wouldn't start. (At this point, everyone is praying that it WON'T start ...) It stayed dead on Monday, and Onofrio had the chance to finally figure out what was going on. It took 3 days to trace everything down, but in the end it was a wire under the dash around the fuse box that leads to the fuel pump. When that wiring issue was fixed, the car was running fine again -- AND the electric windows run faster AND the headlights seem brighter. A couple weeks ago I drove it to/from the San Francisco Bay Area with no problems.

Perhaps this doesn't all pertain to the specific problem of this thread, but maybe the ruling-out process can be helpful or encouraging to someone.

Regards,

Charlie Koster
San Gabriel, CA
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