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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Hello all!
I have a 1983 Z28 with the 305 HO and I am stumped on a fuel issue.
I started with a new intake manifold due to an oil leak off the back of the motor. I had a Carter mechanical I purchased previously and thought this would be good time to replace that too.
Now I can only get the car to run on fuel in the carb only.
I used the hack saw blade trick to install the pump the first time. It appeared the push was hitting the very end of the fuel pump arm and therefore was not moving enough fuel.
I took it out and used a bolt through the block to hold the push rod in place and reinstalled the pump. I am still have the same issue. It has a new pump and 3/4 tank of gas (I put almost 5 gallons in the tank before this so it has gas and spark.
Hello all!
I have a 1983 Z28 with the 305 HO and I am stumped on a fuel issue.
I started with a new intake manifold due to an oil leak off the back of the motor. I had a Carter mechanical I purchased previously and thought this would be good time to replace that too.
Now I can only get the car to run on fuel in the carb only.
I used the hack saw blade trick to install the pump the first time. It appeared the push was hitting the very end of the fuel pump arm and therefore was not moving enough fuel.
I took it out and used a bolt through the block to hold the push rod in place and reinstalled the pump. I am still have the same issue. It has a new pump and 3/4 tank of gas (I put almost 5 gallons in the tank before this so it has gas and spark.
Well you know what they say about "NEW." Never Ever Worked! Can you disconnect the fuel line between carb and pump, place loose end in a catch can and crank engine to see if any fuel is coming out the line.
Comparing old to new...pump lever identical?
I don't know how hard it is to make this mistake but is the input and output lines connected correctly? I've only heard of this happening with aftermarket style pumps that require npt fittings/barbs to install.
...I took it out and used a bolt through the block to hold the push rod in place and reinstalled the pump....
Of course, you removed the longer bolt from the front of the block and installed a shorter one when finished, right?
Someone had to ask.
You can also gently blow back through the fuel line to the tank with the filler cap removed to insure the line and filter/sock in the tank are clear. It is also fair game to rig a fuel line to a temporary tank/bottle to the inlet side of the pump and crank the engine to wet down the check valves and diaphragm in the pump, just in case they are stuck to their seats from long storage.
My 83 HO didn't have an electric in-tank pump from the factory, and it was built near the end of the production run, so I'd guess none of the 83 HOs had one. The in-tank pump was a service order addition installed by the dealer later on.
I don't remember exactly when it became a thing, but the dealer installed mine sometime in, I'm thinking, 1984, maybe, so Scott's 83 may or may not have one. It would depend upon whether or not that particular car was taken to a dealer for the "fix." If his car was mine, lol, then it has one. Mine never got the little fan "fix" though, whenever that came out.
Understood that '83s might not have one but... That's an interesting thought on the in tank fuel pump considering the work that was done on the vehicle. IDK, I'm just asking. How's it wired and is it possible that the wiring was accidentally disconnected during the intake swap.
Last edited by stew'86MCSS396; 10-15-2022 at 03:46 PM.
Dont the H.O engines also use an in tank (electric) fuel pump. Is that working?
Not all L69s received an in-tank pump. It was installed on some vehicles per a TSB that was issued. They also received a carb heat shield, and an electric fan mounted between the passenger side fenderwell and fender, with a duct that ran up to the inlet of the carb.
Not sure why the factory didn't just use something like this cantonracingproducts.com/canton-85-000-phenolic-insulator-for-small-block-chevy-fuel-pumps/ since The Real Problem is heat getting into the fuel via the pump's intimate metallic connection to the block.
For that matter, just putting in 2 of the super-thin gaskets between the plate and the block, and 2 gaskets between the pump and the plate, makes a YYYYYYUUUUUUUUUJJJJJJJJJJE improvement in the whole fuel-boiling behavior that these cars suffer from. That's what I did for years.
Butt, to Scott's issue though; the stock pump is entirely adequate for at least 400 HP worth of fuel. Makes no sense to mess with it. Best fix for the "pump not working" scenario is to simply put the/a stock one back on it.
True; but the car was absolutely identical in every way to a 84, in that particular system. After the "fix" came out people would go to the stealership and buy that goofy crap and put it on their 83 cars back then, for why I can't begin to imagine. And their techs would do it as well and charge the customer since 83 wasn't covered by the TSB. Blatant rip-off. Both the pump and the fan were very inelegant attempts at a solution that tried to cover up The Symptom instead of actually fixing The Problem.
True; but the car was absolutely identical in every way to a 84, in that particular system. After the "fix" came out people would go to the stealership and buy that goofy crap and put it on their 83 cars back then, for why I can't begin to imagine. And their techs would do it as well and charge the customer since 83 wasn't covered by the TSB. Blatant rip-off. Both the pump and the fan were very inelegant attempts at a solution that tried to cover up The Symptom instead of actually fixing The Problem.
Oh I agree 100%. GM has never been great at actually fixing the problem, especially in that era. Look at the lawsuits from all of the problems with the Citation. I’ve had many 84 L69 cars over the years, and quite a few had the TSB “fixes” don’t, yet they didn’t fix anything.
Didn't cost me anything. The dealer covered it under warranty. And it never misbehaved again.
Not sure where the car is today. May 9, 1986, 5:30 am, "a day that will live in infamy." Beautiful morning, opened the blinds, looked out the window, GONE. It was like being in The Twilight Zone.
Of course, you removed the longer bolt from the front of the block and installed a shorter one when finished, right?
Someone had to ask.
You can also gently blow back through the fuel line to the tank with the filler cap removed to insure the line and filter/sock in the tank are clear. It is also fair game to rig a fuel line to a temporary tank/bottle to the inlet side of the pump and crank the engine to wet down the check valves and diaphragm in the pump, just in case they are stuck to their seats from long storage.
After getting more than a little pissed I decided to double check everything. I used the original bolt after reinstalling the fuel pump. The easiest thing to screw up is fuel filter. I installed backwards. Runs fine when you have it in correctly!!
No electric fuel pump or that band aid fix for fuel boiling on my car. I have a 180 degree fan switch and a new radiator in my car and I have never had any issues with fuel boiling.
10-09-2022, 08:18 PM
