Motor won't start

[Tim Kay]

Ok, time to bring in my pinch hitters. I’m at the bottom of the ninth with 2 strikes, actually more strikes than I care to think. So here we go, hope you guys can help.

No spark at the plugs thus no fire, not even a short fire, nothing.
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com

Components: AEM ecu, MSD 6A with blaster coil, Accel electronic distributor, TWM 8 stack fuel injection.
<o></o>
So far:
1. Fuel pressure is normal
2. Injectors seem to be working
a. Plugs get damp with gas
3. New set of plugs
4. Emptied gas tank and filled with fresh fuel
5. Plug wires are good quality
a. Less than two years old
6. Tested MSD
a. per MSD’s trouble shooting instruction I get a real healthy spark at the coil wire (end that
pops on to the distributor cap)
7. Rotor appears fine
8. Distributor cap appears fine
9. Sent AEM ecu in for diagnostics, apparently, fine.
10. Remove and ground spark plug, turn over the motor and no spark.

<o></o>
Circumstance: Driving normal for many miles, stopped for gas and one mile later the motor died (no popping or missing, just died like fuel pump shut off). Would fire and run smoothly but no more than 30 seconds. I thought the gas may have been bad, see #4. Repeated attempts to fire would reduce to no fire at all (again, no popping or missing). Next day or two I could start the car in the morning with same result, fire for 30 seconds then not at all. Now it simply will not even fire.

Suggestions...

 

[Aaron L.]

maybe the fuel pump?

 

[Gregg]

Tim, you state your getting spark into the distributor but not out, so I would re-check the cap & rotor. How clean are the contact points and gap between end of rotor and cap as well as anode inside cap which rides on top of rotor?

 

[Tim Kay]

Due to normal fuel pressure, fuel pumps (both) are good.

 

[Tim Kay]

Gregg,

This is where my focus is now, I don't know how to check the 'gap' between the rotor and cap. The cap node appears to be making contact with the rotor, the rotor contacts are a bit rough like they're making contact...

 

[Randy V]

I've had rotors burn through right under the tab and the spark goes from the coil tower through the top of the rotor to the distributor shaft..

 

[Tim Kay]

I've had rotors burn through right under the tab and the spark goes from the coil tower through the top of the rotor to the distributor shaft..<!-- google_ad_section_end -->

Randy,

when this happens, are there obvious signs when looking at the rotor?

 

[Gregg]

Tim, I would replace cap and rotor. Quick check, clean up/sand the top and edge of the rotor, inside of the cap at wire pickup points. Pull the center anode down a little inside of the cap to make sure it is making contact with top of the rotor (usually on a spring) and try and clean the tip if you can. See if that works.

 

[Tim Kay]

Gregg,

You and Randy are making perfect sense. The signs are pointing to the distributor. I will take your suggestion and clean up the rotor, cap and adjust the node.

Are there any test I can do with the distributor installed that can indicate whether the rotor and cap are working properly?

 

[Al Jones]

Tim, don't bother checking the gap,Randy and Gregg are correct - if the node is touching and it's still bad, just replace the cap and rotor.

 

[Wally]

HI Tim As far as seeing anything on the rotor it may just look like a heat mark, Check around the rivit holding the arm on . I'm assuming you have the standard size cap & rotor as most of these cars don't have room for the HEI size ones. By the way this got worse over time I think Randy nailed it. The carbon track has now established it's self and will not allow it to even start.

 

[Ian Anderson]

Dizzy drive gear worn and jumping teeth

Occasionally things will line up then they won't

Ian

 

[Dave Bilyk]

Tim,
think simple too - loose wire - broken wire, check wiring for continuity.

Dave

 

[David Morton]

Cracked Cap.

 

[Randy V]

Randy,

when this happens, are there obvious signs when looking at the rotor?

It depends on the style of rotor you have.. If the rotor has a fixed tab rather than one with a spring-steel tab for contact to the coil wire button in the cap - it's darned near impossible to tell.. You have to look up through the inside of the rotor and you "might" find a small burned spot. I have had some luck (at the track) with putting a dab of RTV up inside there and then pushing the rotor down (but not all the way) on the distributor shaft. I might stop maybe .030" shy of having the rotor seated all the way down on the shaft when I do this.
-edit- You might be able to accomplish basically the same thing by putting a single piece of electrical tape folded over on top of the dist shaft before pushing the rotor down on top of it..

 

[Randy V]

Dizzy drive gear worn and jumping teeth

Occasionally things will line up then they won't

Ian

This also has merit... If you have incompatible distributor/cam gears or are running a high volume pump - that will aggravate the problem...

Try turning the distributor shaft by the rotor - it should only move as much as the advance mechanism in the distributor allows...

 

[RichardH]

possibly loose earth connection to engine?

 

[Bill Kearley]

An off chance but do you have any radio interferance (capacitors) They can ground your ignition if defective. when they get hot
Bill

 

[Bill Kearley]

Do the quick easy thing first. cap and rotor.
Bill

 

[Tim Kay]

Guys, thanks for the suggestions. Most suggest the cap and rotor which I started down this road early on with a visual inpection. Now I'm just going to replace for new parts, hoping it's not the distributor. With any luck I will find one local without having to order one. I will let you all know this afternoon.

Tim, don't bother checking the gap,Randy and Gregg are correct - if the node is touching and it's still bad, just replace the cap and rotor.

AJ
This is where I will start

The carbon track has now established it's self and will not allow it to even start.

Wally,
Did not notice this in my visual inspection of rotor and cap, but honestly wasn't looking for it.

Dizzy drive gear worn and jumping teeth

Ian,
I checked the gear when I had the cap off. I tried manually to turn the distributor shaft and it only moved a slight bit (seemed normal). Then I turned the motor over enough times to watch the rotor\shaft turn a full rotation.

think simple too - loose wire - broken wire, check wiring for continuity.

Wolodymyr,
I did simple checks but if I have to get into the wiring harness I'm lost...

Cracked Cap

David,
Checked that when I took the cap off. BTW, if the cap was cracked wouldn't the motor still fire but pop a bunch (like "shoot'n ducks)?

It depends on the style of rotor you have.. If the rotor has a fixed tab rather than one with a spring-steel tab for contact to the coil wire button in the cap - it's darned near impossible to tell..

Big Foot,
Spring tab

possibly loose earth connection to engine?

RichardH,
I checked that, I have a short strap connected to the motor and chassis

An off chance but do you have any radio interferance (capacitors) They can ground your ignition if defective. when they get hot

Bill Kearley
I certainly hope there is no radio interferance, I have no clue where to start if that's the case.

Do the quick easy thing first. cap and rotor.

Bill Kearley,
Amen, I like easy. The least path of resistance, this is where I'll start. I love it when I get permission to do the easy thing.