Ignition problem
01-18-2002, 10:51 AM
#1
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Thread Starter
Join Date: Jan 2002
Posts: 181
i have a 1st gen wit a 13b from an 87 with a mikuni 44 and a racing beat manifold, msd 6a ign box and stock coils. i recently put in a new rotor, cap, wires, and plugs. in third gear when i get to about 4k rpm my ignition seems to cut off not misfire but shut down completely if i release the gas pedal and throw it in to neutral it comes back on but if i drop it in 3rd gear again it does the same thing again. it also does it in 4th and 5th but never in 1st or 2nd if anyone can help please respond
01-18-2002, 02:24 PM
#2
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Join Date: Oct 2001
Posts: 1,370
good thing u gettin the new msd coils today...hopefully its that, but anyone know anything?
****
Yesterday afternoon (1/18) he passed by my crib and we installed the new MSD coils. The ****** POS is still dieing like he explained in the original message. If anyone has any ideas to what this could be, let us know, atleast 13b1stgen.
ohh yea..GET THEM OIL LEAKS FIXED FOO
:tounge:
****
Yesterday afternoon (1/18) he passed by my crib and we installed the new MSD coils. The ****** POS is still dieing like he explained in the original message. If anyone has any ideas to what this could be, let us know, atleast 13b1stgen.
ohh yea..GET THEM OIL LEAKS FIXED FOO
01-22-2002, 09:25 AM
#3
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Join Date: Oct 2001
Location: Westminster, MD
Posts: 368
It doesn't sound like it is ignition related. Do you have a O2 sensor with gauge to monitor the mixture? I bet it is way lean over 4k rpm causing the motor to cut.
The first place I'd start is to check for vac leaks in the intake system. Check by spraying carb cleaner around the gaskets one at a time while the motor is idleing. If the rpms change when you spray in a certian area, you found the leak.
It could also be a problem with the carb, like a weak acell pump or a cloged jet. In teh first two gears, you will blow past the problem areas in the power curve, but the higher gears will strech out the curve in respect to time and make the problem more apparent.
Good luck
BTW - just to be sure, was it doing this before you changed the wires/cap rotor / plugs ? If it was OK before, start swaping in the old stuff one at a time till it works - problem solved!
The first place I'd start is to check for vac leaks in the intake system. Check by spraying carb cleaner around the gaskets one at a time while the motor is idleing. If the rpms change when you spray in a certian area, you found the leak.
It could also be a problem with the carb, like a weak acell pump or a cloged jet. In teh first two gears, you will blow past the problem areas in the power curve, but the higher gears will strech out the curve in respect to time and make the problem more apparent.
Good luck
BTW - just to be sure, was it doing this before you changed the wires/cap rotor / plugs ? If it was OK before, start swaping in the old stuff one at a time till it works - problem solved!
01-24-2002, 07:29 AM
#4
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Join Date: Jan 2002
Posts: 181
thanks for suggestions RX-Midget but i went ahead and converted my cars ignition system from electronic distributor to a direct coil system. its running even better than before now with more power through out the power band. i wish i would of done this sooner.
01-24-2002, 08:42 AM
#5
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Join Date: Oct 2001
Location: Westminster, MD
Posts: 368
So your problem is gone?
Are you running an MSD?
If you are still having the flat spot, I bet you are running lean, cause the MSD will burn more fuel. This gives you more power but forces you to richen up a little.
What set up are you running? 3 std coils, or a GM DIS coil and 1 std coil? I like my GM style Accel DIS coil firing both leading plugs
Are you running an MSD?
If you are still having the flat spot, I bet you are running lean, cause the MSD will burn more fuel. This gives you more power but forces you to richen up a little.
What set up are you running? 3 std coils, or a GM DIS coil and 1 std coil? I like my GM style Accel DIS coil firing both leading plugs
01-24-2002, 02:09 PM
#6
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Join Date: Jan 2002
Posts: 181
im usin an msd 6al with 3 msd coils, 2 of which are firing the lead plugs and the other firing normally through the distributor. as far as fuel enrichment goes i raised the fuel pressure with the adjustable regulator i have on it and it seems to be running good but im gonna install an egt guage to keep a tab on my air/fuel mixture.
01-24-2002, 10:25 PM
#7
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Join Date: Oct 2001
Posts: 58
This may be a stupid question, but your not running a stock fuel pump are you? If so, you'd easily run out of gas in a full sprint through the gears. Infact, when I first got my Mikuni, I'd run out of gas in a full acceration session with stock pump going into second at when I got near 4000rpm. So even in upper gears, I'd never be able to go past half throttle above 4000rpm at any time or it would nearly die from fuel starvation.
01-24-2002, 10:34 PM
#8
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Join Date: Oct 2001
Posts: 58
opps, almost forgot, even if you do upgrade your fuel pump if you have any resrictions in the fuel line going to the carb, your going to get fuel starvation in full throttle above 4k for sustained times possibly. Also if you are not sure about the correct setup for the fuelpressure regulator, that will cause trouble too. I was taking the engine out and put it back in and put the regulator on backwards and it was not able to go to full throttle because gas wouldn't flow through it easily that way.
Might want to get a fuel filter that is cleanible. Since then you don't have to buy new ones all the time. I upgraded to the GSL-SE sender unit coming from the tank which is much larger and also larger line all the way under the car going to the carb. You really can use the stock line though, it will flow enough, but I was thinking farther down the road because of my bridgeport engine. I'm getting a 51mm weber for that once I can afford more goodies.
Might want to get a fuel filter that is cleanible. Since then you don't have to buy new ones all the time. I upgraded to the GSL-SE sender unit coming from the tank which is much larger and also larger line all the way under the car going to the carb. You really can use the stock line though, it will flow enough, but I was thinking farther down the road because of my bridgeport engine. I'm getting a 51mm weber for that once I can afford more goodies.
