73 620 with matchbox distributor misses at high idle

[Cordova Kustoms]

Hey guys I got a question. I have a miss at high idle and it's not running lean. I think the coil is giving up. I used a small block chevy points coil I have thats new but it runs even worse! Anybody got any clues?

[sebpv]

Many problems with what you're saying:

First, I assume that you actually have a L16 engine with, dual point dizzy?

If so:

-only use engine matching coil, i.e L16

-inspect the condition of the points

-use a feeler gauge and check for correct distance

-check the dizzy cap contacts

-check you spark plugs and make sure they are within spec

-check your ballast resistor for correct resistance

If you actually have the matchbox:

-cant help you but Im sure there are similar checkups you can do

[Cordova Kustoms]

L16 with electronic matchbox distributor from 79 if I remember correctly. Ran it at high idle, sprayed the carb with carb spray and it didn't smooth out so it's not running lean.

[Doctor510]

You have to use a coil that matches the distributor, 280ZX.  Check the resistance across the pos and neg posts, should be <1.0 ohms

[Cordova Kustoms]

Ok I pulled the numbers off the distributor. They are D4K9 120204 and below that is 22100 H9701.

[datzenmike]

What does it do at normal idle speed?

 

High idle... you mean with the choke on???

 

 

Won't be the EI. 

[Cordova Kustoms]

It starts to misfire at like 4000 4500. Like 60 on the freeway. I'm going to put a coil in, in the morning. I have one coming that I ordered for a 79 which is what I think the distributor was from.

[Cordova Kustoms]

At normal idle it purrs like a kitten. It doesn't give me issues unless I got my foot in it or I'm on the freeway.

[datzenmike]

That would be highway speeds.

 

22100-H9701 is for a '78 through '82 Datsun 210 and 310 with A series engines. Probably converted for L series use. No worries all the EI coils are basically the same and the '79 S10 will be fine.

 

I would look on the distributor cap and rotor for cracks and carbon tracking which is a low resistance path to ground where it is arcing. It will look like a fine lightning strike zig zag across the surface. May also be on the coil to the negative terminal. Next, look at each plug wire for signs of arcing. Or just replace if you don't know how old they are. Next the plugs. At higher speeds and heavier throttle it becomes harder to fire the plugs. Use only NGK B6ES for a '73. If you have Champion or Autolite or what ever... get rid of them.

 

Keep in mind that spark ALWAYS looks for the easiest path to ground... ALWAYS. What you need to do is make that so impossible that it has to jump across the spark plug gap.

 

Last think that will cause poor high speed RPM break up is bad valves. Lets leave that for now.

[Cordova Kustoms]

Ok good I ordered the right coil at least. The cap rotor plugs and wires are probably 3 years old. I replaced when I put the matchbox in. I remember it being from a 310 now that you mention it Mike. I'll check everything tomorrow but the coil I've never replaced and it looks like it went down with the titanic. The plugs, now that's interesting. I don't remember what they are but I'll check them out. I'm a hot rod guy and seen and done just about every combination of engine and trans into every kind of car or truck. This goddamn little truck kicks my ass!

[datzenmike]

They're great aren't they!

[Cordova Kustoms]

Its always an adventure I swear! (Little Wreck!) Ill let you know how everything works out. It was a roach when I got it and now it's at least graduated to mouse turds!