Ok I have a 84 z28 which came out with a 305, but the guy i got it from ripped it out and dropped in a 350, with a 4 bbl carb. It ran when i got it, and by the time i got it home and off the trailer it wouldn't start. Ive replace the timing belt, the distributor, and had the carb redone. Its getting gas, and spark and we are totally stumped. It cranks over just want to go any farther.

 

I do hope you mean timing chain.
Did you verify the distributor was properly timed to the #1 cylinder's compression stroke?

 

yes thats what i ment.....and yes i have

 

If youre getting gas, spark, and crank, the only thing that would keep it from running is timing. Is it backfiring or blowing out of the carb at all?

 

it was then i replaced the timing chain and so far it hasnt dont it again

 

When you replaced the timing chain, you made sure to line up the marks on both sprockets right?

 

yes....my uncle and grandfather did that part, both are good mechanics. Its an older 350, only has the bare minimum of wires and such. I have no idea the year or what it came from so as of yet i cant give to much info on it.

 

Are you 100% sure youre getting spark and fuel?

 

if timing is right, getting gas, getting spark and have compression it will run......I would double check everything.....

 

we took the fuel line from the carb and stuck it in a mason jar and pumped it....it spit out fuel into the jar. we took the plug out and attached the wire to it and tried to turn it over and it was sparking....time had been checked and rechecked so many times. we are thinking its a wire some where any ideas of any wires that must be hook up for anything to happen. its got us stomped.

 

i had a problem where my car wouldnt start and had it towed to the shop. i am not sure but i think they said it was a resistor or transistor hooked up to my tac causing the problem. but i think i could be wrong.

what ever it was all they did was bypass it.

 

I had the same problem when I got mine, the distributor was 180 out. If that doesn't help you, I dunno. All I can suggest is start over again because it should be running as others have said.

 

Youre getting fuel to the carb, but maybe its not spraying any out? Or it could be flooding it out. Are you using a mechanical pump or the in tank electric?

 

Are you sure you have the firing order right?

 

it has a mechanical fuel pump.....i was thinking the same thing about it not spraying in....ill check it out and see what i come up with

 

Did you remove the stock in tank pump when you switched to the mech pump? Or was your car a factory carbed car?

If youre getting spark, and the timing is on, you can spray starting fluid in it. If it starts then you know you have a fuel issue.

 

my 74 k5 has a 350 w/carb. i had a similar issue. had spark. timing dead nuts on. getting gas... the issue seemed to be too much gas. so i put a fuel pressure regulator on it. i had a gauge and it was reading up around 15psi every time the stock mechanical fuel pump would pump fuel. i dialed down around 4-5? i don't recall. runs fine now.

 

ill give that a try then, and it came out with a mechanical 1 on it

 

Thats why I was asking about the pumps. A carb needs 4-7 PSI to work, if you use more pressure than that, the gas blows right through the carb and will flood it out. If you have an intank pump from a TBI or TPI car, you need a return style regulator. The TBI pump puts out 15ish PSI, the TPI pump is more like 30.

The PO put on the mech pump but unless the car was originally a carb car, it will have a pump in the tank. The mech pump will struggle to pull fuel through the dead pump, causing fuel starvation issues. But it will usually pull enough fuel to start, but would run like crap on the streets.

 

well ill see about replacing my pump then, cause in sure its the original 1, and ill get a regulator

 

Id make sure its the problem first. Have someone try and crank it while you look down the carb and see what its doing. If you dont see any fuel spray then thats the problem. If you see lots of fuel even when its not cranking, then you know youre having a flooding issue.

 

ok whats the best way to fix a flooding issue if i have 1....im wanting to cover my bases

 

Flooding could be caused by a few things. Like too much fuel pressure, fuel floats not set right, bad gasket, something broke in the carb.

 

well i just had it rebuilt, so its good there. if i find out its the fuel pressure what would be the best kind of pump to get to replace it, there are so many lol.....when and if i do replace it i plan to add a regulator to it to, any ideas there

 

People make mistakes, it could still be a bad gasket or something wrong with the carb. And you have to adjust the fuel float levels with the carb on the car. Id check to see that youre getting fuel into the cylinders before you go replacing things.

 

not if its an edelbrock or carter the top of carb has to come off to adjust float level.....

 

If this is an 84 Z28 and the 8th digit of the VIN is H or G, then it came stock with a qjet carburetor and mechanical pump. The fuel lines, supply AND return, will run along the pass side fender well to the pump on the block. The stock pump will have two rubber fuel line connections (one is a return) and one hard line supply to the carb.

DO NOT look down into the carb while someone tries to crank it. That's just asking to become a Darwin award recipient.

Find out what the problem actually IS before beginning to dicker with components like float level, etc.

Check for Air: If the choke plate is completely closed try opening it up some. Ensure that the throttle cable is connected properly and opening the throttle butterflys in the carb. Don't discount this, I've seen broken linkage waste all kinds of time when a simple visual check should have been done.

Check for no fuel: pour a couple tablespoons of fuel into the carb throat and try to crank. If it fires, makes a significant attempt to start or runs for a second or two: you can begin to make a logical connection.

Check for spark: If the above doesn't produce results pull a spark plug out, observe it's appearance (wet/black, clean, etc.) and test for spark while having it connected and grounded, using insulation between you and the components. You should observe a bright spark. You can rent a spark tester at most of the chain stores.

If the above doesn't help you, go back over everything you did when replacing the timing chain and distributor and make sure it's right.

 

i have done what you said with the spark plug and it is getting fire. so that much i do know is going on. when i had the carb redone, i was told that the floats were right where they were supposed to be according to that the paper said. ive been running threw everything and it all appears to be dead on. is there any way to test a fuel pump at all.

and its not the original engine in it. the 84 z28 came out with a 305 this has a 350 in it now.

 

I use a low pressure fuel/ vacuum gauge T'd into the fuel line to the carb. The mason jar test you already did shows that the pump is prob working well enough to start the car. Im curious about other issues though. I would suggest starting at the beginning. Check compression, check spark on more than one wire just in case of a bad cap/rotor. One post mentioned starting fluid. Try that once youve verified compression and spark on multiple cylinders. If it starts on starting fluid and has fuel pressure to the carb. You will need to look at the carb itself. One point on installing timing gear in a small chev. The dimple marks point to each other with the motor at #6 TDC not at #1. This can be confusing to some. Thats why I say to check compression. You may have the cam 180 out.

 

If, in fact, you've done everything I've said then why are you still chasing down the fuel pump? It didn't start when you poured a little fuel into the carb throat (like I outlined above) so why STILL suspect a bad fuel pump?

I didn't assume it was the original engine, simply provided some info that would help you determine whether or not it had a carbed or FI fuel system originally. Didn't want you chasing down an assumed high pressure fuel pump when you likely don't have one.

AND if I relied on everything I was told was RIGHT on vehicles I've worked on instead of checking everything out MYSELF there would be a dozen or more broke down cars still in my driveway...

 

im saying it was the fuel pump and the reason i havent checked the carb was because i have faith in the guy who did it and right now i dont have the time to tear it apart and look at it. i know it had benn carbed because both 305s that where placed in the 84 camaro were carbed, with the mechanical fuel pump. i was going to check the entire fuel system and i said if i need to i was asking what type was the best to replace it with....i have also removed several plugs and check for fire, its firing on all that ive checked. before i found the timing chain needed to be replaced, i would add gass to the carb and it would start then once the gas was used up from that it would die. i ive narrowed it down to most likely its either the carb or something blocking it in the intake or it could be the pressure leading into the carb. it could be to much and just be going every where or to little and not getting enough in

 

When they installed the timing chain & sprockets, did they leave them dot-to-dot? And then the distributor was installed? Or, was the distributor not disturbed since the engine last ran?

I'm suspecting you have the distributor in 180 degrees off. When the timing sprockets are lined up dot-to-dot, the engine is in the #6 firing position, not the #1 firing position. If you will note from the illustration posted by ymenic, #1 and #6 are opposite to each other on the distributor cap. The engine turns over twice for every revolution of the distributor, so when the mark on the front damper is lined up with timing tab, you can't know from that alone whether the engine is in the #1 or #6 firing position.

 

Second that, although it appears the OP has already diagnosed his issue as the fuel pump. I find myself, more and more, gaining empathy with Sofakingdom's tone in his later posts before he left this forum....I'll work harder.

 

i never said it was the fuel pump....ive said we have checked the timing and its all in order....every time we go out to work on it we recheck the timeing and the firing....but ill run threw it all again to make absolutely sure.

 

Easiest way to check the timing is to pull the #1 plug, stick a finger over the plug hole, and have someone bump the starter. When you feel your finger getting pushed off the plug hole, youre on the compression stroke. Bump the starter until you dont feel it building any more pressure, then pull the distributor cap off and see where the rotor is pointing. If its not close to the #1 terminal then your timing is way off. If its off, move it so the rotor points to #1 terminal. That method will get the timing close enough to start and put a timing light on it.

 

You're killing me

 

As much as I hate making assumptions, I'll assume timing alignment is correct.
I would do the following:
Disable fuel pump by disconnecting fuel supply line (from the gas tank) to the pump.
Remove the spark plugs.
Crank the engine for at least 30 seconds.
Let it sit for a half-hour.
Install a new set of cheap spark plugs, preferrably pre80s that can be gapped for .035". If you've bought high dollar plugs save those for when the egine is running again.
Spray starter fluid in to carb hold throttle wide open and crank.