I installed a brand new 350ci/290hp crate motor about a year ago. It didn't
run great with the old Quadrajet, so I put on a new Edelbrock
600cfm/electric choke/vacuum advance carb. I used an adapter plate to mount
it. The EGR valve is gone, and blocked off with a plate. The emissions
control stuff (minus the Cat) has been taken out of the equation ;-)
Basically, I start the truck, and it idles as it normally does when started
cold after sitting a while.
Regardless of whether I take off immediately, or let it warm up a bit, it'll
die after about 30 seconds, more and more frequently. When it dies, it's a
real struggle to get it running again. When I do start it, there a 50/50
chance that all the fancy footwork in the world on the accelerator won't
keep it running. Even if I do manage that, there's no way I can put it in
gear....it'll die immediately. Sometimes after 2 or 3 minutes, it'll start
and run as normal, today when I was attempting to leave work, I was stranded
for 15 minutes.
Here's some additional info: When I was at the doctor's office about 3
weeks ago, I started it, backed out of the parking space, and then the truck
died. I managed to start it, but had to be tricky with the gas pedal to
keep it running. Again, putting it in gear was out of the question. I
finally found a comfortable spot to keep my foot rested on the pedal, and I
sat there giving it gas to keep it idling for about 15 minutes. After that,
the idle speed suddenly surged up, and I took my foot off the gas. It ran
fine at that point.
It seems to be getting fuel just fine. The filter is a clear glass one,
mounted right up in front of the carb. It's full of gas, and when I try
(sometimes in vain) to start the truck after it dies, I can smell the gas
coming from the tailpipe. It seems to be getting plenty of spark and air.
The choke seems to be ok (as far as I can tell).
The only explanation I can come up with is that something, somewhere is
getting stuck...hence the 15 minutes of running like crap followed by
everything suddenly being just peachy.
I will add that "running just fine" for this truck isn't exactly great.
It's run EXTREMELY rich since I got the new motor and carb. The timing is
advanced to (don't laugh) like 14 degrees BTDC at idle (really!). I have
never managed to lean out the mix. I think the rich running condition and
the weird startup problem may be related. The startup problem occured like
twice in the 2 months leading up to this past month. Lately it's occured
every 3-4 days, and getting more frequent...
I know this was a long post, but I figured I'd provide the best description
of the problem I could.
I'd appreciate any suggestions as to what may be the cause of this.
Jon R. Pickens / jonrpick at yahoo dot com
Catch me on Yahoo or AOL Instant Messenger, screen name "jonrpick" on both.