Did you try replacing the coil transistor pack found right under the middle of the intake manifold? Those heat up and can fail. Happened on my 2G once before.

The 420a does not have a transistor pack. The coil itself is known good as are the cam and crank sensors. I just can't figure out why I only have power to the coil for a few minutes then it's gone.

So the car runs for 5 minutes then shuts off or it wont start and found that you lose power to the coil after 5 minutes ?

BoostedPhoenix said:

So the car runs for 5 minutes then shuts off or it wont start and found that you lose power to the coil after 5 minutes ?

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The car has yet to be started. I worked on it some more today and basically removed the wiring harness that runs along the back of the motor off and checked it out. Everything was fine.

What I am noticing is that when I check for power to the coil I either have it or not. When I do have power off the yellow wire with a red stripe, I connect it to the coil and turn the motor over. It will then proceed to short or something because I no longer have 12 volts from the same wire.

Try giving your coil pack 12v with a known good voltage source (jumper wire). Turn the key and observe the results. This method would cement your missing voltage diagnosis and rule out your other ignition components (if it starts). It may only be missing a solid ground.

Maverick4g63 said:

Try giving your coil pack 12v with a known good voltage source (jumper wire). Turn the key and observe the results. This method would cement your missing voltage diagnosis and rule out your other ignition components (if it starts). It may only be missing a solid ground.

Click to expand...

Actually I spliced in a 12 volt jumper to the yellow wire with a red stripe I believe it is the left one out of the 3. And it managed to loss power again...this is really getting frustrating.

Are the rest of the car's electronics working properly? Is your black lead grounded to the chassis or the battery negative post during your voltage test.

I have done it 2or ways. The neg lead connected to the middle wire of the coil pack plug(I forget what color that is I want to say black or dark blue). And the neg lead connected to the neg battery terminal.

This is almost exactly what my car did when the ecu fried. Check with a noid light between the center power wire of the coil pack and each of the two outside wires. They should pulse only when the engine is cranking. You know you have a problem if it stays on constantly on one of them as I had, it means one of the coil drivers in the ecu is toast. Make sure to test both of them separately, what happens is that as soon as you plug it into the coil that power has a source to ground and will pull down the voltage enough that the other side won't fire either.

Did you figure it out?

No, I still haven't figured it out. It frustrates me just to think about it. Maybe I will try a new ecu.

Bump.

I have new information. Apparently, the plug that I had plugged into the coil, was really one that was supposed to plug into my transmission. I have since changed that and still have no spark. I tested a bunch of things yesterday and my results are below.

ASD relay good.
Crank Sensor good.
This is getting the 5-0-5-0 signal and has good ground. It however is getting only 1.75 V on the power wire.
Cam Sensor good.
This is getting the 5-0-5-0 signal and also has a good ground. It is NOT getting the full 8v on the power wire.

Upon seeing this I probed the ECU wires and compared with the book on what they should have power wise. All were good except pin 32 had 1.75V instead of 5V and pin 44 had 3. something V rather than 8V.

This leads me to believe that the ECU is bad. Can anyone shed some incite?

Thanks

Anyone?

Anyone able to help?

Here is one for ya.
The issue was that my car would randomly die and wouldn't
start for like 10 minutes.
I had a code on my car,,,checked it once Like a year before at advance auto
just to see what it was, and thought it was the cam sensor.

One day it died on me twice,,,I was pissed.when it started
I went to advance auto,and bought cam sensor,borrowed a 10mm
wrench and put it on in the parking lot. It wouldn't start,mind you
I just drove up in the car. Put my old cam sensor in and it started right up.
So moral of the story is,just because they are new doesn't mean they
aren't bad.
The kicker was the asshats at advance almost wasn't gonna give me
my money back,,,I was like bullshit,ijust bought this and it's junk.
He didn't believe me,,we had to change it out again,To prove to him.
By the way it was my crank sensor that was bad.

I tested both my cam and crank sensors with the voltmeter. They both came up with what the book says that they should.

My main concern is the two wires that plug into the ECU that have a significantly lower voltage than what the book says they should. I am curious as to if that could be caused by something other than the ECU or the ECU itself.

If its intermittent then you can't test it when it,is, working and says its good. Only time you can test it is when it is, acting up. I would change both at, the same time and use dealer parts. Parts store sensors a nothing but junk 4g63 or 420a they are both crap.

When it comes to sensors certain makes really need oem parts.

Sorry, I guess I should have clarified that earlier. It is no longer intermittent. I cannot figure out how to edit the title either. The reason it was intermittent was that I had the wrong plug plugged in. Now I have everything in the correct place, but before I spend over $200 for a new ECU, I would like to know if something else could cause the voltage readings that I am getting.

Get an ECU at the junkyard for $20.

No junkyard around me has one. I have been looking for a while. I actually drove 45 miles to one Sunday to find out the only part that was missing from a 99 was its ECU.

I have one if you need one. Pm me if interested.

P.s. To edit the title you have to edit the original post.

Well I got an ECU from a 99 and installed that Sunday. I now how the pulsing voltage to the two outer wires on the coil pack but do not have the 12V constant in the center. I will have to look at the ASD relay and #4 fuse to see if I blew one of those.

might as well try and replace your wire harness also if your fuses aren't blown..

You don't have your coil plug swapped around with your speed sensor plug do you?