1984 2.8 Engine Trouble

[Dirt4x4]

I can't seem to figure out why this engine is not running right. The engine has been rebuilt. The ignition has been changed to duraspark.

Possible problems is the heads where machined but I don't know how much, so the intake could have a vacuum leak internally. There could be another Vacuum leak some where else, but I have every hose capped off to anything going to the intake.

 

[RonD]

Get and hook up a vacuum gauge, $20, best tool in my box

Good read here: http://www.gregsengine.com/using-a-vacuum-gauge.html

 

[Dirt4x4]

Ok I will give that a try. Thanks for the info.

To add to this it only dose that when the temperature gauge gets to normal operating temperature when it's cold it runs fine.

 

[Angie]

is your choke stuck closed?

 

[Dirt4x4]

is your choke stuck closed?

My choke will open gradually as the engine warms up but it never dose go completely open it stops about 10°-20° shy of fully open.

 

[AndyB.]

Before you fixed it, the computer would have sent current to the ceramic heater in the choke thermostat to open the choke; now that you've fixed it, what does that job?

 

[Dirt4x4]

Before you fixed it, the computer would have sent current to the ceramic heater in the choke thermostat to open the choke; now that you've fixed it, what does that job?

I don't know that any thing controls that now.

 

[RonD]

Choke plate will have an adjustment for winter and summer temps, larger plastic cap(black) that can be rotated to set spring control

Did you time the engine with vacuum advance connected or disconnected?

 

[Dirt4x4]

Choke plate will have an adjustment for winter and summer temps, larger plastic cap(black) that can be rotated to set spring control

Did you time the engine with vacuum advance connected or disconnected?

Ahh it was connected I bet I should have disconnected it. On the old distributor you had to disconnect a plug but this would make sense because it was computer controlled where as this is vacuum controlled.

 

[RonD]

The Duraspark can also be converted to HEI down the road, much much simpler and more reliable.
So if it comes up do not spend money on a duraspark module, get HEI instead

 

[AndyB.]

You could really go all out and get a points distributor while you're at it!

I'll never understand a duraspark II conversion.

 

[Dirt4x4]

You could really go all out and get a points distributor while you're at it!

I'll never understand a duraspark II conversion.

So far I like the Duraspark conversion it got rid of all the broken sensors that controlled my old carburetor that was cracked and needed replaced. So while I was replacing those I just switched over to non computer control carburetor, distributor, and coil.

 

[Dirt4x4]

Get and hook up a vacuum gauge, $20, best tool in my box

Good read here: http://www.gregsengine.com/using-a-vacuum-gauge.html

I got a vacuum gauge and tried it and it started out running at 19-20. Once the engine warms up it starts to move plus or minus 1. Then after that the gauge goes all over the place. My guess is that some thing is warping once it gets hot and then I get a vacuum leak.

Here is a Video.