Fuel Problem
Thread Starter
Racer
Joined: Jul 2007
Posts: 318
Likes: 0
From: Westport NY
hey Guys; I pulled the fuel pump and it works fine,also I took off the front site screw on the float bowl could not see any fuel. took off the rear screw and the fuel was right to the opening,if I shook the car the fuel would just start to come out,does this help. Could I hook up the external pump along with the internal pump and see how that works or will that hurt somrthing,just grabbing now. Wayne
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
hey Guys; I pulled the fuel pump and it works fine,also I took off the front site screw on the float bowl could not see any fuel. took off the rear screw and the fuel was right to the opening,if I shook the car the fuel would just start to come out,does this help. Could I hook up the external pump along with the internal pump and see how that works or will that hurt somrthing,just grabbing now. Wayne
you can hook up the old one, or both if you know how to do it. sounds like you do.
am guessing -most anaysis is just that, guessing- that new pump is leaking, or lines are clogged with a black beetle or wood wasp. or else, new pump is losing voltage or ground. don't see how it would be so repetitive, does not fit logically.
joe
Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
hey Guys; I pulled the fuel pump and it works fine,also I took off the front site screw on the float bowl could not see any fuel. took off the rear screw and the fuel was right to the opening,if I shook the car the fuel would just start to come out,does this help. Could I hook up the external pump along with the internal pump and see how that works or will that hurt somrthing,just grabbing now. Wayne
Lightly tap the top of the fuel bowl on the front of the Holley carb.
Direct taps with the plastic screwdriver handle on the large straight blade cut screw.
Fuel Inlet Needle & seat direct below.
Try restarting your Corvette.
If it fires,
pick up a new Holley or AED Holley 4160- 4150 rebuild kit with primary & secondary needle & seats, Blue gaskets, floats too.
Go to work cleaning out the carb & rebuild.
Easy to do.
parts cleaned, I can reassemble most any Holley 4- barrel carb in 1 hour.
Another 15 minutes to re-tune without recurving the distributor mechanical advance mechanism or Vertex Magneto.
BR
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Take a small screwdriver with a plastic handle.........
Lightly tap the top of the fuel bowl on the front of the Holley carb.
Direct taps with the plastic screwdriver handle on the large straight blade cut screw.
Fuel Inlet Needle & seat direct below.
Try restarting your Corvette.
If it fires,
pick up a new Holley or AED Holley 4160- 4150 rebuild kit with primary & secondary needle & seats, Blue gaskets, floats too.
Go to work cleaning out the carb & rebuild.
Easy to do.
parts cleaned, I can reassemble most any Holley 4- barrel carb in 1 hour.
Another 15 minutes to re-tune without recurving the distributor mechanical advance mechanism or Vertex Magneto.
BR
Lightly tap the top of the fuel bowl on the front of the Holley carb.
Direct taps with the plastic screwdriver handle on the large straight blade cut screw.
Fuel Inlet Needle & seat direct below.
Try restarting your Corvette.
If it fires,
pick up a new Holley or AED Holley 4160- 4150 rebuild kit with primary & secondary needle & seats, Blue gaskets, floats too.
Go to work cleaning out the carb & rebuild.
Easy to do.
parts cleaned, I can reassemble most any Holley 4- barrel carb in 1 hour.
Another 15 minutes to re-tune without recurving the distributor mechanical advance mechanism or Vertex Magneto.
BR
the one reason I did not consider the carb -yet. it may be the hesitation issue.pecking and twisting are free, though, worth a try.
my $2 says it won't.
Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
He said the fuel pump was fine.
Its real hard reading other peoples mind's at times.
Just like real life auto repair when a customer describes what is wrong with their car or truck.
Out of Blinker turn signal fluid again ??
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
we're all guilty, not being critical.
he said the new/different tank pump was "fine." I assume he meant that it hummed, whatever. and he may be right. but the fuel test he did, in the jug, fuel ran for a short time then shut off while cranking.
maybe you have ideas on that...
if 7 lbs pressure for that engine is ok, I would put the external pump on.
you are too young to remember, but what was the Holly from factory on 396 375hp, Camaro? my memorys says 3310...
Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
yeppir! I just told another post that only the OP ever knows what the history of the problem is. my fav is when they say they turn the key and nothing. then they explain that relays click, a click under the car, etc.
we're all guilty, not being critical.
he said the new/different tank pump was "fine." I assume he meant that it hummed, whatever. and he may be right. but the fuel test he did, in the jug, fuel ran for a short time then shut off while cranking.
maybe you have ideas on that...
if 7 lbs pressure for that engine is ok, I would put the external pump on.
you are too young to remember, but what was the Holly from factory on 396 375hp, Camaro? my memorys says 3310...
we're all guilty, not being critical.
he said the new/different tank pump was "fine." I assume he meant that it hummed, whatever. and he may be right. but the fuel test he did, in the jug, fuel ran for a short time then shut off while cranking.
maybe you have ideas on that...
if 7 lbs pressure for that engine is ok, I would put the external pump on.
you are too young to remember, but what was the Holly from factory on 396 375hp, Camaro? my memorys says 3310...
Never cared to remember that particular Holley 4- barrel carb.
Remembered what was used on the YENKO Camaro's 427 & 1967-1969 L88 Corvette & ZL-1 427 though.
And the 1969 Pontiac Ram Air 5 tunnel port engine.
A buddy of mine back in the early 1990's had a garage full of those BIG Holley 3- barrel carbs ( around 25 of them).
Never would sell me 1 for under $500.00.
He sold the all eventually.
That SOB.
LOL
Thread Starter
Racer
Joined: Jul 2007
Posts: 318
Likes: 0
From: Westport NY
Hi Joe I hooked up the external pump and left the neww system in-place,fired up the car and it kept running,will take it out and see how she does.still only 7lbs. on the gauge,i will get back to you on how she runs. Wayne
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Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
if it was starvation, it would not recover from hesitation.
don't know the story behind that but they work fine from the factory. also, timing too retarded can cause same thing, as can a dozen others.
let us know.
joe
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
I put a 3310 on my '69 350 cu in Camaro. Bad idea. A friend of mine described Holleys as a toilet. Press the handle and it flushes. After I learned how to tune a QuadraJet, I'll never go backwards to a Holley. Anyhow...
It sounds like the ECM is priming the fuel system for 2 seconds at key on, as it should.
When you crank the engine, the oil pressure switch takes over and actuates the fuel pump when it sees oil pressure. It sounds like this part isn't happening. The oil pressure switch is the guy on the back of the engine by the distributor with a two wire connector. Also check out the fuel pump relay (and wiring...).
It sounds like the ECM is priming the fuel system for 2 seconds at key on, as it should.
When you crank the engine, the oil pressure switch takes over and actuates the fuel pump when it sees oil pressure. It sounds like this part isn't happening. The oil pressure switch is the guy on the back of the engine by the distributor with a two wire connector. Also check out the fuel pump relay (and wiring...).
Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
I put a 3310 on my '69 350 cu in Camaro. Bad idea. A friend of mine described Holleys as a toilet. Press the handle and it flushes. After I learned how to tune a QuadraJet, I'll never go backwards to a Holley. Anyhow...
It sounds like the ECM is priming the fuel system for 2 seconds at key on, as it should.
When you crank the engine, the oil pressure switch takes over and actuates the fuel pump when it sees oil pressure. It sounds like this part isn't happening. The oil pressure switch is the guy on the back of the engine by the distributor with a two wire connector. Also check out the fuel pump relay (and wiring...).
It sounds like the ECM is priming the fuel system for 2 seconds at key on, as it should.
When you crank the engine, the oil pressure switch takes over and actuates the fuel pump when it sees oil pressure. It sounds like this part isn't happening. The oil pressure switch is the guy on the back of the engine by the distributor with a two wire connector. Also check out the fuel pump relay (and wiring...).
Have a custom made Holley put together.
Braswell, BLP, Bo- Laws, Brad Urban, ect.
Barry Grant is gone.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
I put a 3310 on my '69 350 cu in Camaro. Bad idea. A friend of mine described Holleys as a toilet. Press the handle and it flushes. After I learned how to tune a QuadraJet, I'll never go backwards to a Holley. Anyhow...
It sounds like the ECM is priming the fuel system for 2 seconds at key on, as it should.
When you crank the engine, the oil pressure switch takes over and actuates the fuel pump when it sees oil pressure. It sounds like this part isn't happening. The oil pressure switch is the guy on the back of the engine by the distributor with a two wire connector. Also check out the fuel pump relay (and wiring...).
It sounds like the ECM is priming the fuel system for 2 seconds at key on, as it should.
When you crank the engine, the oil pressure switch takes over and actuates the fuel pump when it sees oil pressure. It sounds like this part isn't happening. The oil pressure switch is the guy on the back of the engine by the distributor with a two wire connector. Also check out the fuel pump relay (and wiring...).
as for the Holley, even if it was 3310, it worked fine for tens of thousands of stock engines -provided the tuners didn't start "thinking for themselves" and modifying them.
anyway, that's what he has. no need to start throwing money away.
also, according to my fsm, 6e3-c2-3, the oil switch is backup only, to the FP relay. the book says that the ecm enables the relay when it sees dist pulses.
ask why the engineers would employ the switch as full time fp wire, with no backup, unless you further complicate the design by pulling in the relay if ecm senses low oil pressure?
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The emulsion tubes on my 3310 got plugged up. They have little tiny holes in them. I had to replace the metering body.
I have looked at the ECM code and schematics. There is no code to control the fuel pump. It's all done in hardware by the chips in the ECM. The ECM test bench I'm building doesn't have distributor reference pulses going into it yet, so I can't verify that part. Too much going on in my life right now. I probably won't be able to add this until next week at the earliest.
In another thread a guy with a "starts but immediately dies" problem found his oil pressure switch was not connected (as I recall, the engine had been taken out and replaced, so it just didn't get reconnected during the reinstall). I don't know if plugging it in resolved his problem.
I have seen quite a few of these "starts but immediately dies" threads. It would be nice to finally resolve this so we'd have a good answer for these people. Or at least a list of things to check...
I have looked at the ECM code and schematics. There is no code to control the fuel pump. It's all done in hardware by the chips in the ECM. The ECM test bench I'm building doesn't have distributor reference pulses going into it yet, so I can't verify that part. Too much going on in my life right now. I probably won't be able to add this until next week at the earliest.
In another thread a guy with a "starts but immediately dies" problem found his oil pressure switch was not connected (as I recall, the engine had been taken out and replaced, so it just didn't get reconnected during the reinstall). I don't know if plugging it in resolved his problem.
I have seen quite a few of these "starts but immediately dies" threads. It would be nice to finally resolve this so we'd have a good answer for these people. Or at least a list of things to check...
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
The emulsion tubes on my 3310 got plugged up. They have little tiny holes in them. I had to replace the metering body.
I have looked at the ECM code and schematics. There is no code to control the fuel pump. It's all done in hardware by the chips in the ECM. The ECM test bench I'm building doesn't have distributor reference pulses going into it yet, so I can't verify that part. Too much going on in my life right now. I probably won't be able to add this until next week at the earliest.
In another thread a guy with a "starts but immediately dies" problem found his oil pressure switch was not connected (as I recall, the engine had been taken out and replaced, so it just didn't get reconnected during the reinstall). ]I have seen quite a few of these "starts but immediately dies" threads. It would be nice to finally resolve this so we'd have a good answer for these people. Or at least a list of things to check...
I have looked at the ECM code and schematics. There is no code to control the fuel pump. It's all done in hardware by the chips in the ECM. The ECM test bench I'm building doesn't have distributor reference pulses going into it yet, so I can't verify that part. Too much going on in my life right now. I probably won't be able to add this until next week at the earliest.
In another thread a guy with a "starts but immediately dies" problem found his oil pressure switch was not connected (as I recall, the engine had been taken out and replaced, so it just didn't get reconnected during the reinstall). ]I have seen quite a few of these "starts but immediately dies" threads. It would be nice to finally resolve this so we'd have a good answer for these people. Or at least a list of things to check...
My logic says that if my 91 uses FP relay in run mode, and your 86 does not, that is a MAJOR departure from the design. Do you believe that GM would have slipped that in, so that 25 yrs later, we're still confused?
: it probably didn't happen. Another opinion: All c4's use FP relay in run mode, oil switch is full time backup.
"I don't know if plugging it in resolved his problem."
you said it in one sentence: no one knows if even one such problem was resolved by plugging in the switch. few OP's verify fuel pressure, etc, at the time the engine dies. at any rate, none of the recent problems was related to that.
not being that familiar with all c4's, I have to stick with the FSM,and some logic.
saludos, joe
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
I'm pretty sure now the statement I made earlier was wrong. It was based on the other thread I mentioned about the guy with the disconnected oil pressure switch.
Today I hooked up an LED to my ALDL connector from terminal A to terminal G. If the fuel pump relay is NOT energized, and the oil pressure switch is ON, then I should see 12V on terminal G. The LED never came on, so we can conclude that the ECM does in fact operate the fuel pump relay if it sees ignition pulses (or I didn't get a good connection... :-).
Despedidas de parte de Cliff
Today I hooked up an LED to my ALDL connector from terminal A to terminal G. If the fuel pump relay is NOT energized, and the oil pressure switch is ON, then I should see 12V on terminal G. The LED never came on, so we can conclude that the ECM does in fact operate the fuel pump relay if it sees ignition pulses (or I didn't get a good connection... :-).
Despedidas de parte de Cliff
Melting Slicks
Joined: Nov 2008
Posts: 2,765
Likes: 5
I'm pretty sure now the statement I made earlier was wrong. It was based on the other thread I mentioned about the guy with the disconnected oil pressure switch.
Today I hooked up an LED to my ALDL connector from terminal A to terminal G. If the fuel pump relay is NOT energized, and the oil pressure switch is ON, then I should see 12V on terminal G. The LED never came on, so we can conclude that the ECM does in fact operate the fuel pump relay if it sees ignition pulses (or I didn't get a good connection... :-).
Despedidas de parte de Cliff
Today I hooked up an LED to my ALDL connector from terminal A to terminal G. If the fuel pump relay is NOT energized, and the oil pressure switch is ON, then I should see 12V on terminal G. The LED never came on, so we can conclude that the ECM does in fact operate the fuel pump relay if it sees ignition pulses (or I didn't get a good connection... :-).
Despedidas de parte de Cliff
A SPST - single pole single throw toggle switch solves many wiring issues also.
Easy way out of diagnosing. LOL
Its what drag racers do that get lazy.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
I'm pretty sure now the statement I made earlier was wrong. It was based on the other thread I mentioned about the guy with the disconnected oil pressure switch.Today I hooked up an LED to my ALDL connector from terminal A to terminal G. If the fuel pump relay is NOT energized, and the oil pressure switch is ON, then I should see 12V on terminal G. The LED never came on, so we can conclude that the ECM does in fact operate the fuel pump relay if it sees ignition pulses (or I didn't get a good connection... :-).
Despedidas de parte de Cliff
Despedidas de parte de Cliff
whether he believed it or no, the FP relay was priming his fuel rails -not the oil switch. "If it works, it doesn't matter how, until it fails."
anyway, this loves to hunt guy has FP, two in fact. not sure if his original problem is still there but suspect so.
joe
Thread Starter
Racer
Joined: Jul 2007
Posts: 318
Likes: 0
From: Westport NY
Hey Joe; This is Wayne,I hooked up my external fp and kept the internal fp hooked up also,started her up and she kept running,took it for maybe a 50 mile ride,everything went well,just a slight hesitation when I come on to it,I think the carb is just getting old and worn out,or maybe tweeked alittle dont know but want to thank all you guys for your help and cooperation,you should be proud for the knowledge you have,ill be 60 in Nov. and I still need to brush up on things,weather is changing here in upstate Ny so will be putting the old girl up for the winter,again thanks so much for all your help. Wayne
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Hey Joe; This is Wayne,I hooked up my external fp and kept the internal fp hooked up also,started her up and she kept running,took it for maybe a 50 mile ride,everything went well,just a slight hesitation when I come on to it,I think the carb is just getting old and worn out,or maybe tweeked alittle dont know but want to thank all you guys for your help and cooperation,you should be proud for the knowledge you have,ill be 60 in Nov. and I still need to brush up on things,weather is changing here in upstate Ny so will be putting the old girl up for the winter,again thanks so much for all your help. Wayne
as for the carb, it is
not worn out!maybe someday remove sight plugs, warm idling, be sure the fuel just runs out. or have a trusted source look at it, as in tune it. be sure secondaries are not opening too soon. some tuners lighten up on them to open sooner. big mistake.
also check timing if you have not done so. ecm controls it, but has no knowledge of what base timing is, so if it is off, retarded, the total equation is off. keep in touch.
my guess is the carb.
saludos (regards) joe
