No spark at plug wire ends?

[gon2srf]

Voltage at distributor but no spark at plugs?

Issue: I have a proper voltage reading at the coil and to distributor but am not receiving voltage at plug wire ends.

I have searched and read several threads on this subject and cannot figure out what the issue is. I have just installed a new(er) to me motor. Every single connection has been checked and rechecked.

I have tested voltage at the coil and proper resistance per the FSM. I removed the dist. cap and with the coil wire connected I have voltage under the cap at the spring loaded contact point. The spring is working properly. I have new wires and have exchanged dist. caps and rotors and have the same result. The rotor spins properly as well.

I tighten down the dist. cap and turn over the motor and no spark at end of the plug wire and or the plugs.

I am obviously missing something very simple but i just do not understand how I can have voltage at the distributor yet it won't distribute the current through the plug wires and the spark plugs?
I have also tested the rotors for unusual resistance.


Any input would be appreciated, thanks.

 

[mattafact]

Is the ground strap to your engine hooked up?

 

[gon2srf]

Is the ground strap to your engine hooked up?

Block to firewall
Starter to frame
Battery ground to motor mount
Battery ground to fender well
T-case to frame

All secure sir, I also changed out the magenetic sub assembly in the distributor this morning. Still no spark. WTF

The igniter and coil although they both check out voltage and resistance wise may not be working under load for one reason or another. They are next altohugh I do not beleive they are the cause since the truck started properly a week ago but it's a process of elimination.

 

[bmw635]

I'd check the ignitor ( magnetic thing inside the dist cap) or coil output as it may have 12V but not putting out @ 40kV needed to fire the plug.

 

[gon2srf]

The truck is up and running . The problem was the Air Flow Meter which I damaged when I first removed the air intake weeks ago. I was able to solder the broken leads and she started right up.

 

[bmw635]

Woow, that's quite a curve. I've never seen AFM/ MAF problem causing no spark since the car should have default mixture in DME to run the car in case MAF/ AFM fails like BMW. Of course it'll run like crap but you'll get home.

Wonder if anybody got stranded because of bad AFM/ MAF! Thanks for the update.

 

[gon2srf]

Woow, that's quite a curve. I've never seen AFM/ MAF problem causing no spark since the car should have default mixture in DME to run the car in case MAF/ AFM fails like BMW. Of course it'll run like crap but you'll get home.

Wonder if anybody got stranded because of bad AFM/ MAF! Thanks for the update.

I'll try an post the circuitry, it will make sense then and yes newer models have a limp home override built in.

 

[Brentbba]

Glad you found it Scott.

 

[gon2srf]

Glad you found it Scott.

Pretty darn satisfying, Garrett learned a ton about his truckand gained a lot of confidence. Pulled and installed my first Toyota motor and the truck is purring. I saved about 2g's. Now I have a spare motor I am going to tear down to the crank and rebuild. It should be better than new when done.

 

[Brentbba]

Nice - especially the knowledge Garrett gained during the process!

 

[Newps]

Nice job Scott, you must feel very satisfied with your wrenching skills.

 

[gon2srf]

Nice job Scott, you must feel very satisfied with your wrenching skills.

Appreciate that Tare, coming from a fellow wrencher. I'm bummed I missed you guys up in Big Bear...but I was camping, hiking, cooking and wheeling in Idyllwild while you nerds played with your radios!!! Hahah, just kiddin' of course. The reports on OAUSA arel light on wheeling but afterall it was "Field Day". Maybe some day I'll get the HF bug.

See you soon.

 

[Newps]

I wasn't playing with the radios. Friday was just about relaxing and Sat. we hit the trails.

 

[gon2srf]

I wasn't playing with the radios. Friday was just about relaxing and Sat. we hit the trails.

Cool