what do you think?

I just installed a new 350 motor in my 51 merc.The motor has an isky cam, ballbearing rocker,high rise edealbrock intake and a 4 barrel edealbrock carburator.It has petronix distributor with an accel coil.Checked timing,checked fuel all looks good. Here is the problem when i drive it a few miles it starts to stumble under load .If i put it in park its fine but if i put it in gear its starts acting up (stumbling).It only does it after the car has been driven for a while.I thought maybe coil but its new.Checked it and its holding 12v but does go up to about 16v under load.Bad ground?bad coil? Maybe thats why it only happens after the car has been driven awhile because it heats up.What do u think.Thanks in adavance u guys

 

I have a coil in my closet that once it gets hot it turns itself into a diode. I kept it because it is the only one I have ever seen do that.

If you suspect the coil maybe you could try a different one just to rule it out. They are cheap in the whole scheme of things. never hurts to own a spare coil.

 

thanks porknbeaner will do. could a bad ground also cause this problem

 

Bad grounds can do anything they want. What about the gas cap. Is it vented are should it be ?

 

The age-old question to answer: is it fuel or ignition?

Got a fuel-pressure gauge you can tee in at the carb inlet?

 

Is it leaning out? You say you put it in park, then I assume it's idling and the bowls getting a chance to refill... just a thought.

 

How big is the cam? If its a automatic you might have to change the converter out to a bigger stall. Some times if the stall isnt enough for your cam when you put it in gear it loads up the motor because there's not enough stall for the cam to work right.

 

When I was 16, I had a '41 Ford Super Deluxe coupe. We put a 305 in it with a quadrajet carb on it. When I first started driving it, we had cleaned out the fuel tank and filled it up, and added a quality inline fuel filter. However, I could drive the thing for about 5 miles and the little filter at the fuel inlet would clog completely and stall out and die.

Sounds like a fuel delivery issue. Fuel pump - weak? Fuel filter - primary blocked, secondary blocked?

When you put it in park and let it idle, what happens when if you nail the throttle? Does it continue to run okay or does it stumble?

 

its holding at 6lb of pressure for fuel.It is automatic (turbo 400)But it will drive fine for a while then it just starts acting up like it wants to die.oh gas cap is vented as recommended.Thanks for all the responses can always count on u guys to come threw

 

checked coil and its pretty hott reading 17v what could cause this

 

Try running a hot wire from the batt to the petronix and see if it fixes the problem.Had this happen on my dads comet and there was not enough voltage getting to it.The old wireing didnt have enough ohm's for the petronix to work right espicaly after it warmed up the engine heat made it worse.

 

did you check the float setting ?? it may be too low ,,,, and you are running out of fuel ..

 

probably just the Merc trying to regurgitate the chevy

 

updated wiring harness? coil mounted on engine or elsewhere? which Pertronix unit are you running? you might want to contact them for ideas. there are a few threads on setting up Pertronix properly, maybe need their coil. stock used torque converter?
type of fuel pump/gas tank?

 

<HR style="BACKGROUND-COLOR: #e5e5e5; COLOR: #e5e5e5" SIZE=1> <!-- / icon and title --><!-- message -->probably just the Merc trying to regurgitate the chevy

this was too funny made me spit my drink all over my desk

<TABLE id=post6625052 class=tborder border=0 cellSpacing=0 cellPadding=6 width="100%" align=center><TBODY><TR vAlign=top><TD style="BORDER-BOTTOM: #e5e5e5 0px solid; BORDER-LEFT: #e5e5e5 1px solid; BORDER-TOP: #e5e5e5 0px solid; BORDER-RIGHT: #e5e5e5 1px solid" class=alt2 width=175>

Join Date: May 2006
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</TD><TD style="BORDER-RIGHT: #e5e5e5 1px solid" id=td_post_6625052 class=alt1><!-- icon and title --> Re: what do you think?
<HR style="BACKGROUND-COLOR: #e5e5e5; COLOR: #e5e5e5" SIZE=1><!-- / icon and title --><!-- message -->probably just the Merc trying to regurgitate the chevy
</TD></TR></TBODY></TABLE><TABLE id=post6625052 class=tborder border=0 cellSpacing=0 cellPadding=6 width="100%" align=center><TBODY><TR vAlign=top><TD style="BORDER-BOTTOM: #e5e5e5 0px solid; BORDER-LEFT: #e5e5e5 1px solid; BORDER-TOP: #e5e5e5 0px solid; BORDER-RIGHT: #e5e5e5 1px solid" class=alt2 width=175>

Join Date: May 2006
Location: Waco,Texas
Posts: 248


</TD><TD style="BORDER-RIGHT: #e5e5e5 1px solid" id=td_post_6625052 class=alt1><!-- icon and title --> Re: what do you think?
<HR style="BACKGROUND-COLOR: #e5e5e5; COLOR: #e5e5e5" SIZE=1><!-- / icon and title --><!-- message -->probably just the Merc trying to regurgitate the chevy
</TD></TR></TBODY></TABLE>

 

The car runs good but from lets say ontario ca to pomona ca it starts idealing bad like it wants to die

 

Don't most Pertronix require reduced voltage to the coil? Check their site....

 

Thanks
Jagman<SCRIPT type=text/javascript> vbmenu_register("postmenu_6625144", true); </SCRIPT> will look into it

 

something else to check. The Edelbrock carbs are known to boil the gas in the float bowl. A thick carb gasket can help the carb from becoming a heat sink. This will especially be a concern in warm climates and high under hood conditions.

 

You have 17 volts comming out of the negative post on the coil?

I would need to ask GMC Bubba to be sure but 17V to the petronix sounds like way too much, you are running a resistor before the coil? Maybe the control mod is getting hot.

 

You HAVE to make sure the primary resistance (ohms) is within spec of the Pertronix, and it will vary depending on which Pertronix you have. I used the kit to convert the old points style dist. to theirs and after the pertronix coil dropped dead I bought the Accel super stock. The pertronix wants 1.5 ohm and the Accel is ( I think) 1.2 but after calling pertronix they told me that 1.2 would be fine but no lower.

 

thanks guys for the response

 

Have any vacuum lines in the system ? If so check for a leak.

 

Yup...It's CRS for sure. Chevy Rejection Syndrome

 

Damn...Beat me to it!

 

I have noticed over the years that Ford/Mercs have an allergic reaction when exposed to too much GM engineering.

I have fried a petronics before. I never did figure out if it was due to a bad ground or if it was wrong resistance.

On one of my vehicles I changed the inards of the holly style distributor to a GM pickup and reluctor. It used the ignition control out of a late 80's pickup and all the parts inside the distributor.

http://www.binderplanet.com/forums/showthread.php?t=47254

Check out the distributor section on the link above. Quite a few options available. Some of them will still maintain a non- computer type look to.

 

Some more good reading. Give a little more detail.

http://www.binderplanet.com/forums/showthread.php?t=48159


http://www.binderplanet.com/forums/showthread.php?t=48435


I guess it doesnt matter if it's not ignition realated.