| FAQ |
| Members List |
| Social Groups |
| Calendar |
| Search |
| Today's Posts |
|
#1
06-02-2002, 11:18 PM
|
|||
|
|||
I have a 72 Lemans with a 350 engine.
I recently installed a edelbrock performer plus cam, 600 carb and intake to match. All new tune up, new fuel filter and everything else that I can think of. Here's my problem. The car is timed and running, it seems to lack power and backfires through the exhaust when opened up. If I am driving it easy, it runs fine. When I get on it a little it starts spitting and sputtering at me. Anyone have any ideas? I need a little help with this one. |
|
#2
06-02-2002, 11:18 PM
|
|||
|
|||
|
I have a 72 Lemans with a 350 engine.
I recently installed a edelbrock performer plus cam, 600 carb and intake to match. All new tune up, new fuel filter and everything else that I can think of. Here's my problem. The car is timed and running, it seems to lack power and backfires through the exhaust when opened up. If I am driving it easy, it runs fine. When I get on it a little it starts spitting and sputtering at me. Anyone have any ideas? I need a little help with this one. |
|
#3
06-02-2002, 11:29 PM
|
|||
|
|||
|
to much or not enough advance???
__________________
some times when you race with squirrels you get your nuts cracked! |
|
#4
06-02-2002, 11:37 PM
|
||||
|
||||
|
This is a long shot but I had the same problem on an engine with a Pertronix electronic conversion from points. The cause was voltage dropping too low at 4500 rpm. Took a while to figure that one out but now it runs fine.
|
|
#5
06-02-2002, 11:37 PM
|
|||
|
|||
|
I have moved the timing around and it doesn't seem to make much of a difference.
Do I need to replace the distributor springs maybe? Would I use stronger or weaker springs? Thanks |
|
#6
06-02-2002, 11:41 PM
|
|||
|
|||
|
I am running points in mine, could it still have a low voltage at high RPM problem?
What do I need to do try in order to correct this? Thanks |
|
#7
06-03-2002, 07:09 PM
|
||||
|
||||
|
Cam timing is not correct or the distributor is worn out.
__________________
Less said,,,,,,,, Less mended. |
|
#8
06-03-2002, 09:07 PM
|
||||
|
||||
|
Pete:
I don't know if there is a minimum voltage for points but it would make sense there has to be one. But if you want to check, here's what the Pertronix tech told me to do to load test the coil. First, make sure the ignition is turned off. Then run a good ground wire from the coil negative post to a suitable ground. Get a voltmeter ready to read the voltage from the positive coil post to ground. Turn the key to ON and read the voltage. Anything less than 7 volts will not work for the Pertronix. My test came up at 5.1 VDC. I wouldn't recommend leaving the coil powered and grounded for too long. I ran a temporary hot lead with 12 gauge wire to the coil positive terminal and went for a test. The engine pulled to 6k without a miss so I pulled the test lead (engine wouldn't shut down  )and rewired the coil positive supply.To point out how weird this was, I checked the voltage at idle and got 12 volts. The problem only showed up at 4500 at WOT. 4500 on part throttle would not produce the miss. I kept looking at the carb for the problem but it was an iffy wire. TinInjun has a couple of good ideas. I've seen problems on new engines where to old distributor was used and they caused problems. I imagine a worn distributor could cause all sorts of problems with points. Good luck with it, Dave |
|
#9
06-03-2002, 10:48 PM
|
||||
|
||||
|
pete, you said nothing of the condition of the engine?,( heads rebuilt ect...) sometimes a leaking valve wil cause this too, what is the condition of the motor( rebuilt ect...)?
|
| Reply |
|
|
The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.
Linear Mode
