I got bored today so I scrounged around the shop and ran across an old MSD 6A box....

just the basic spark box...took be all of about 30 minutes to install it...this is with adding wire to the Positive side that goes to the battery and screwing it to the drivers side fender wall just under the hood spring...

Didnt do anything with starting but it does seem to accelerate easier and it looks like it is a little easier on gas...

Just for giggles I found an old Tach I had from back when I was a teen and had a 78 Gutless...Put that tach in the truck and hooked it all up and it worked...well for about 1 mile and then it died...

So quest for a new tach...maybe someday...lol

Spark box works good...

Now if I can just fix that ultra high idle when I fire it up cold...shoots to 3,000rpm for 2 seconds before it comes back to normal...I am thinking the Temp sensor is going south...cleaned the AIC and it was fine...

 

it should do that its fast idle warm up as long as it drops back down to under 800rpm then its fine other wise you have a vac leak

 

it's not suposed to be that high....

when you start it cold it should start at 1,500rpm and work its way down...

a couple times I have started it has went up to 4000rpm...no vacuum leaks...it idles at 600rpm with ease...and very steady

 

Will be interesting to hear what is causing the high spiking RPM's. We know the PCM controls idle speeds thru the IAC. What input or inputs could be informing the PCM to set such a high value?

 

The two wire temp switch next to the Thermostat hosing....this does 2 things...tell the engine when it is cold or not and set the AIR pump to bypass mode...

going to replace it this week sometime...

Funny thing is the Auto parts place say my truck does not have a Knock Sensor....but sure as day it is right there beside teh coil....