wont stay running

[BukuBandits]

i recently purchased an 84 crew cab that had a 454 in it. the guy i got the truck from wanted to keep the 454 and give me an 86 350. so i put the motor in hooked everything up and the motor will start if i pump the pedal a few time before turning over. then it shuts off after about three seconds of running.then i pump pedal and its starts right back up for another three seconds. has a quadrajet carb and hei dizzy

[leegrady]

Sounds like it is not a fuel problem because the accelerator pump is working. Ya know it sounds like the module in the hei is shot. That is a classic symptom for these modules, and they fail often. I keep an extra one in my glove compartment.

[BukuBandits]

are you talking about the coil or the wires under the cap because i have a new coil and cap on it would the timing have anything to do with it or no

[BukuBandits]

so you keep a spare capacitor

[James McClure]

Lets start with, seperate the possible cause, fuel or ignition. That said, have someone start the truck, and you stand out front with a can of carb spray. Try to keep her running with the spray as fuel. If this works, carb is at fault. If not, ign is. As stated above,, try a module because it's the easiest to change. While your doing that check the wires on the pick-up coil (white and green). Give them a little pull. If either is bad it will break. You'll have to pull the distributor to replace it. Not a real common failure, but it happens often enough to rate mention. Lastly, make sure the grounding tab made it's way into the new cap and also make sure of the B+ supply on the pink or red wire from the ign switch. Hope this helps, jim

[leegrady]

No, I'm talking about the module. it's a transistorized switch. (Capacitors store electricity.) It's in the distributor screwed into the plate just above the centrifugal advance. The module is an electronic "breaker points" (switch) that opens the circuit to the coil so that the coil fires it's spark. A magnetic field is built up in the coil windings when the coil is energized, and when the pickup tells the module to switch, it cuts power to the coil, the magnetic field collapses, and when this magnetic field moves across the conductor as it collapses, electricity is induced into the core of the coil, and is discharged out, and eventually reaches ground at the spark plugs. Modules are small and cheap. Make sure to smear die-electric grease on the bottom of them before instillation. Heat causes them all to eventually fail.

McClure gave some good information about those coil wires, and I must caution those who spray or pour combustibles down or into a running engine. One backfire, and it could be all over: there's no tomorrow. You've got fuel in the bowl. Granted the carb could be in need of an overhaul, but you'd be able to keep pumping the pedal, and it run just on the accelerator pump squirting gas over and over again. Just like spraying carb cleaner or whatever down the air horn.

[BukuBandits]

can anyone post a picture of the module

[PhilaTruck]

This was the first I found through a "HEI module" google.

From a stang, but that's what they look like.

[leegrady]

That's the one!

[BukuBandits]

ok so its not the module.i got the truck running on its own now but it doesnt rev up like normal and it still pops through carb at higher rpms and shuts off.but it will start right back up and idle ruff but run on its own.

[69BBsuburban]

Timing.....timing.....timing....
That or the engine he "graciously" gave you has issues....may wanna do a compression test, and put a vacuum gauge on it.

[BukuBandits]

as for timing i look on the front of the motor and do not see the mark or gauge/marker on the block

[Kenbo-Slice]

Is your vacuume advance working? Maybe the diaphragm is shot. I just had a problem with mine and the motor was running like trash. Put on a new vacuume advance and it purrs like a kitten.

[billnorman]

Popping thru the carb is usually caused by a lean mixture, although a crossed firing order, or sticking intake valve or exhaust valve not opening will also cause it. Could be a clogged main jet or bad metering rod or vacuum leak. Could be timing, but if it was too far advanced it should kick back when cranking. Make sure intake manifold not leaking (spray carb cleaner around seal areas at idle) check plug wires, distributor cap for cracks, compression, and if necessary, watch valves at idle for evidence of a wiped cam or bad lifter or rocker arm.

[billnorman]

O dear did I forget timing chain?

[BukuBandits]

again for timing what do i do if there is no timing mark bolted to the motor

[BukuBandits]

i believe i just read that the motor the guy gave me 1986 the carb is computer contolled now can i just put a non computer controlled carb on that motor.

[raws67]

Do you have to pass emissions? 86 I believe you have a computer controlled HEI also. Im pretty sure your timing tab should be around 12 oclock on that year of 350. Check your #1 TDC and see where you are lining up. If you dont have emissions there you can get a non computer controlled HEI, and I believe in 84 you can completely bypass the computer and run a non computer quadrajet. Also 4 degrees BTDC is almost dead center between the top two timing cover bolts. I had a 350 that ran really crappy like that and I put a vacum gauge in the intake and the vacum fluttered really bad. Found three broken pistons.

[BukuBandits]

do the computer controlled hei and non look the same or are there differences

[daxx]

computer controlled will have a weatherpac 4 wire i believe coming out the back bottom of dizzy..usually right next to the trans fill tube..
if it has one get rid of it and use a reg hei
also chuck the computer controlled carb as far as you can if you don't do emissions in your state..

pull number 1 plug out and have somone crank motor in short busts till you feel compression..you can stick a small screw driver in and roll over by hand to find top dead..DON'T CRANK MOTOR BY THE KEY WITH A SCREWDRIVER IN THERE..you'll feel piston top out then fall
then check balancer for mark and timing tab coresponding
then check cap for #1
pull cap and make shure rotor is pointing at #1 spot
if your timing is way off.. it won't rev or it will pop
try advancing the distrib after you verify top dead and # 1 in dizzy

[daxx]

also if i remember correctly.. been a while..you need to bypass computr to set timing
someone can chime in
either you disconnected the 4 wire or you put a paper clip in adl to bypass dizzy
i think it was the 4 wire for gm

[BukuBandits]

well my dizzy does not have to sets of wires its only has one set that plugs into the cap so my dizzy doesnt need to change just my carb

[Don SC]

BukuBandits, this link might help you understand the computer/non computer controlled carb and ignition - since the ecm controls your timing, it may be the problem.

http://www.crankshaftcoalition.com/w...EI_distributor

[BukuBandits]

thinks for the link DON and it assured me that i deff do not have a computer controlled dizzy just carb. and i am buyin and non controlled qjet today so i will post back tonight the outcome.

[BukuBandits]

ok thanks all who chimed in put new carb on truck runs great