383 Issues

[MOPARJ]

I have been having a bit of issues with my 383 in one of my cars. You can give it a few shots of gas, it will fire up, but after running for about 10 seconds or so, it will suddenly slow down and gradually quit. It does not suddenly die, as if it were an electrical issue, but a gradual sputtering loss of engine speed over 5 seconds or so. As soon as it dies, I can give it a few shots of gas again, and repeat the cycle, only to happen again. I have swapped the fuel filter and checked pump flow, which seems decent enough, Fuel pressure seems to be 5-7 psi, depending on gauge accuracy. The fuel pump is about 4 months old. It seems to me that the problem may be in the carb.

The carb is a 650 cfm zinc plated Holley Double Pumper Street Avenger with manual choke (yes I did make sure the choke was functioning properly). It is about a year old and to be honest, has been the crappiest Holley that I have ever used. It has had a periodic issue with flooding, due to the floats getting hung up in the rear bowls. Despite constant adjustment, the pump shot in the rear is too fat and drowns the motor with too much fuel, although I have got the handle on that now. I thought maybe this issue I am having now may have been the floats acting up again, but after tapping on the bowls to free anything stuck up, I cant see that being the issue, plus it doesnt seem to be flooding, as it fires back up after I give it some more fuel. I do not need to clean it out, or hold the peddle down, as if it were flooded. It seems to be running itself out of fuel.

Any suggestions or ideas to this issue?

 

[ramcharger]

Got rust in the tank?

 

[MOPARJ]

Got rust in the tank?

There shouldnt be...the tank was dropped and cleaned a few months ago. This problem just surfaced.

I cant see rust sporadically getting sucked into the pump without completely clogging it up. Fuel is getting to the carb.

 

[mullinax95]

This might have nothing to do with your problem but just went through the same thing except mine would have to get hot.... but look it over you might the problem... fuel line routing was my problem!

http://www.forabodiesonly.com/mopar/showthread.php?t=59704

 

[MOPARJ]

This might have nothing to do with your problem but just went through the same thing except mine would have to get hot.... but look it over you might the problem... fuel line routing was my problem!

http://www.forabodiesonly.com/mopar/showthread.php?t=59704

I was thinking something heat soak related, but this will also happen when the motor is stone cold as well.

 

[capnz]

been a few years since i messed with my bb's and holleys
but if memory serves me
you have an issue with the front half of the carb
floats too low
needle stuck shut
dirt in metering block circuits(specifically idle air circuits)
or even the idle circuits in the front of the body
hit every opening in the metering block/body with carb cleaner and make sure all of them have the same flow
i've seen small pieces of debris/dirt actually stuck in the block and affect the air portion of the idle circuits

 

[demon seed]

Put a timing light on it and see if the spark is cutting out (missing) causing the engine to slow down and quit. Years ago I had a faulty reluctor in the distributor, engine would fire up fine then quit about 20 seconds later. To prove that its a carb issue, as the engine is slowing down give her a shot of gas directly into the carb and see if it comes back to life. You also need to varify your fuel pressure and anything over 7 psi install a regulator and set for 6-6.5 psi.

Terry

 

[dodgetkboy78]

Ah yes...........

The Holley Files..........

Movin on.......

LOL


Sounds like the idle circuit or bowl inlet is pluggo'd.

 

[MOPARJ]

Put a timing light on it and see if the spark is cutting out (missing) causing the engine to slow down and quit. Years ago I had a faulty reluctor in the distributor, engine would fire up fine then quit about 20 seconds later. To prove that its a carb issue, as the engine is slowing down give her a shot of gas directly into the carb and see if it comes back to life. You also need to varify your fuel pressure and anything over 7 psi install a regulator and set for 6-6.5 psi.

Terry

Definately not ignition, as spark is good, decent fuel pressure to the carb, averaging around 6 psi, and when it begins to die, I can sometimes peddle it back to life. Fuel has been dumped in it; it runs for a bit, then eventually quits.

 

[swedefish]

I had that kind of symptom in my 383 earlier.
Showed to be dirt in the carb, the fuel filter did fail and there were a lot of dirt from the gas tank in the carb. Had it disassembled cleaned and a new filter then it was ready to go.

 

[moper]

Repeated issues with secondary flooding means an issue with the filter. What filter is on it? Also, if there is crap in the back, there is/was crap in the front. It sounds like there are tuning issues too. What camshaft? What compression? What is your timing setup and curve, and what idle rpm? Where are the mixture screws? I've never had an issue with any new Holley. That is saying a lot. They are not always perfect out of the box. but they are very good general carbs.

 

[MOPARJ]

Repeated issues with secondary flooding means an issue with the filter. What filter is on it? Also, if there is crap in the back, there is/was crap in the front. It sounds like there are tuning issues too. What camshaft? What compression? What is your timing setup and curve, and what idle rpm? Where are the mixture screws? I've never had an issue with any new Holley. That is saying a lot. They are not always perfect out of the box. but they are very good general carbs.

Near stock cam and compression, Hooker Headers. Timing is set right and when carb/fuel is operating correctly, it runs well. The idle and mixture screws are set on par. The secondary flooding issue is mainly to do with the float getting stuck in that bowl and is preexisting from when I had the carb on another motor. It is sporadic and requires constant adjustment of the float level, however, for whatever reason, it never holds the adjustment for long. Compression on all cylinders is great.

I have outlawed everything, with the exception of the fuel starvation scenarion at the carb. I am going to pull it apart today, inspect it, and clean it and go from there. I have already put a new clear filter on it. The filter fully fills and fuel is being pulled up to the carb, more than even psi and volume to feed the motor. The carb just isnt distributing it from there.

 

[moper]

Most Holleys require a rebuild every couple of years just as regular maintenance. I do mine yearly. But a one year carb should be fine. Find out why the loat sticks... that's weird. Also, a double pump carb is a lot for a stock 383. So you may find going with smaller pump cams might help too. Not sure what you mean by "par" Are they out 1 turn, or 3? 4 corner idle? I cant remember... What is the timing settings?