#4 plug keeps going bad

[manoa matt]

Without good grounds the ignition system will not work properly. The ignition module must have clean bright metal contact with clean bright metal of the coil heat sink. That in turn should have a good clean bright metal contact with the mounting to the fender, a secondary ground wire from the coil heat sink mounting stud to the ground pod is good insurance. Little known is that each cam tower should have a ground wire from one of the three studs on the rear cam removal plate to the firewall, which will help to ground the head and plugs.

Accel makes a coil for breakerless electronic ignitions that has the same primary and secondary resistances as the original coil. Try Summit racing its around $40. You coul always go with a dry coil to increase the spark output.

[racydave]

Check the wires in the distributor to the pick-up, they flex, and often go bad. Also the connector to the ignition switch, the connections get hot and melt in the connector.

[Tempest455]

Hi all,

I have installed a new magnetic pickup/wire assy and checked the wires from the ecu to the coil. Everything appears to be in order. It was very strange in that the car was running tops for about a half hour then slowly started to degrade in performance until it died and would not start again. Verified that motor is getting fuel (plugs are wet with fuel but not fouled, nice tan color) It is going to be raining here the next few days so i wont be able to monkey with her but I will check grounds and the coil again when the weather clears up. I did notice that there was continuity (a few hundred ohms) between the coil tower and the coil case... This seemed odd to me. Any thoughts or advice on verifying the coil as good/bad?

Thanks a bunch!
BG

[Tempest455]

Still not having any luck getting this thing running again. I read some other posts about shorted tachs causing a no spark problem. I disconnected the tach and tried to start the car. Not only did it not start but the tach zoomed right around to the gauges maximum position and pegged hard. I shut the ignition off and reconnected the wire. Car still did not start but now the tach pegs out as soon as the ignition is turned to run. What in the world is going on with this thing?

Thanks,
BG

[So Cal Mark]

if the plugs are wet, you're not getting ign spark

[Tempest455]

Well the only thing that is not new in the entire fuel and ignition system is the ignition coil. I purchased an Accel breakerless coil from jegs. Hope this fixes the spark problem.

Any idea why the tachometer pegs out full swing past 8K RPM when the ignition is powered on????

[So Cal Mark]

is it converted to elec ign? is the tach connected to the - side?

[Tempest455]

The car is 100% stock and unloved since 1989. The tach was fine until I disconnected it from the (-) side of the coil and tried to start the car (thinking the tach was shorted and shunting my spark to ground). Now whether it is connected to the coil or not, the gauge slams clockwise to the max detente. Granted this isn't a big deal I just hate when things that worked 5 minutes ago stop working due to troubleshooting some other problem. (My GTO never behaves like this)

I reviewed some schematics online and I cant really determine what fault would cause this. Wondering if anyone else has ever seen a tach behave like this.

Thanks for the help!

Brandon

[So Cal Mark]

are the other gauges working normally?

[Tempest455]

right as rain

[Tempest455]

Okay, I replaced everything in the ignition circuit to include the coil, ignition module, magnetic pickup, cap, rotor, wires and plugs, the coil is getting 12VDC but still no spark at the plugs. I have confirmed that ground is not the issue via continuity checks. (I have work on airplanes that had worse wiring than this car and they still flew )

I am wondering if something may have gone wrong with the magnetic pick up in the dizzy. If i understand the theory of operation correctly this device provides a difference of potential via magnet to the ignition control module which, in turn, triggers the coil to fire at the appropriate time. Is there anyway to verify the proper operation of the components from the coil
back to the magnetic pickup? If not I will just continue to keep the foreign car parts business from going under like GM!

Also the tach is still pegged out when the ignition is turned on.

[rlux4]

Have you downloaded the FI diagnostic pages yet? If you've replaced all the ignition components and haven't found the problem you need to go through the FI controls (check inline fuse behind fuse panel, brown wire with white stripe, dual relay, and ECU.) Most of the time when there is a no start condition on our FI cars it will come down to the fuse, grounds, or dual relay. Make sure that the two ground wires are attached on the back 2 bolts of the far left side of the left cam cover.
Ignition and cam timings are correct?
Ron

[So Cal Mark]

if you've replaced all ignition components and you have no spark, it sounds like you have something connected improperly. Have you tested the system with a voltmeter or at least a test light?

[adrians]

I would suggest rechecking the wires going to the coil, I spent three days trying to get the car to start only to discover I had put the wires to the coil around the wrong way, the older wires loose some of their color and it's difficult to work out which is white and/or pink.

Just an idea !

[Tempest455]

Still working this issue. I guess I will start from the beginning and state that the car was running just fine for 15-20 minutes then sputtered out. I have replaced all of the ignition components. I have pictures of the ignition system before I took everything apart. All wires are back in the right spot and good ground to the block and other various ground hubs in the engine compartment are good.

Double relay clicks over and all pre-start bells and indicators cycle properly.
I took the ECU out and opened it up. No burnt components or obvious damage.

I checked spark by holding a plug to the valve covers and cranking the motor. Nothing.
I also removed the coil wire from the coil and cranked the motor. A very faint spark can be seen jumping around the tower in low garage ambient lighting. So I am at least getting some voltage but i question the current levels.

Lately I have had this hunch that perhaps the alternator went bad? I have heard that these cars have exciter wires or circuits that trigger the alternator upon start up? I have read also that without an alternator the car will not start on just a batteries or jump current alone. Let me know if I am onto something with this theory as I can't get the alternator out to test it due to a rusty bolt. I can keep working to get the unit out (WD-40 and breaker bar 1/4 turns until she loosens up) but if this theory seems unlikely I will focus my efforts elsewhere.

Thanks for sticking with me on this!

here are some pictures if anyone is interested.

http://www.flickr.com/photos/tempest455 ... 098412211/

Spring is coming!