First of all, Thank you all for being here to help us out. My family was full of greasemonkeys but I never started working on vehicles till I got our first van. An 83 Econoline e150 with a straight six.

So far so good on that one now.


Last night we got an 84 e250 with a 460 and a brand new edelbrock carb.

The first thing we had an issue with was the radiator totally overheating and spraying when we idle.
When we are moving its fine but we idle for 10 minutes and its like a Yellowstone geiser.

The second issue is the backfiring. We made it about 80 miles with some small intermittent backfiring and then 2 major backfires with huge sparks. Low torque and it eventually died. Currently it has no air filter unit.

Hard as hell to start even with a big 14 volt battery but we noticed that the alternator belt is loose.

I have learned to replace and diagnose some things but fuel systems are new so far. I would love to learn how to fix it myself.

Thank you.

 

HI and welcome..

Will the engine start after it sits and cools down? Did the van sit for a long time before you bought it? Do you know any history of the van? Who installed the new carb and was it running good after that?
I am not experienced with the big blocks but the one of the first things I would do is (if it will run) Check the timing with a timing light.
Pull all the plugs out and look look at them and while you have the plugs out, do a compression test. Check the cap and rotor. While you have the cap off and the plugs out, set the engine to TDC and make sure the rotor is pointing directly at #1 on the distributor cap. While set at TDC I would check for slack in the timing chain. Here's a video for that

NExt I would do combustion block leak test.(if it will run) IT will help determine if you have a bad head gasket. You can get the loaner tool at most any parts store.
Check all the vacuum lines make sure they are in good shape and hooked up properly.

 

Overheating at idle sounds like a loose belt. Tighten that and rerun it. If it was overheating while driving, that can cause the backfire problems, low power, pinging, etc. Does the dash temp gauge work?

Get it to idle first, then start on the rest of the symptoms.

 

starters fail with heat. if it's only hard to start when hot, then you've solved that one.
(It'll also be a mother****** to start if the timing is too far advanced, it will kind of gallop, eg. Whomp, whomp, instead of crankcrankcrank)
if you're getting backfires, I'm assuming through the intake (exhaust is not technaically a backfire), that means you have fuel pooling then igniting. if it was the timing, you notice it very frequently.

on mine, it's been cause by a few diffrent things over the years.
lets use the KISS method.
-Cap and rotor corrosion
-loose spark plug wire
-loose coil wire
-melted vaccum advance hose
-Too rich of a fuel mixture
-blown powervalve
-Bad DSII module (Happened twice to me within 5 years).

Does it backfire on accelleration or decelleration? If so, only from a stop, or if you stomp on her?
How about when it shifts?

Hows your fuel pressue?

Mechanical pump or electric?

Hopefully we can get to the bottom of this.
-Devin.