Edelbrock in the winter - tuning troubles
#1
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Edelbrock in the winter - tuning troubles
Driving my 84 GSL in winter in Canada. Average temps right now are about -15 to -25 celcius, but she starts right up with a little cranking and gas.
I have a 6-port 13b with the RB holley intake and an Edelbrock thunder series 650 w/electric choke, and RB header to custom exhaust. Ignition is stock from the old 12a.
First problem - adjusting the electric choke, I just can't seem to get it right. If I adjust it far enough that the choke turns completely off when the car is warm, the choke becomes too cold-blooded overall. I leave the beast in a parking lot for an hour and when I come back the engine is cold but the choke won't engage.
So I readjusted the choke and now it never quite turns off...
GEEZE
Second question. How do I and should I set up a vac-advance to the dizzy? I did at first but used the wrong port.
Third question, possibly related. If I pull hard in 1st to redline, then pull hard in 2nd and 3rd to redline, she stutters in the high end from about 5k to 7k. My fuel pump is a Carter 4070 and fpr mounted on the firewall keeps my fuel at 5psi.
Finally - last night I left her outside warming up, idling at 2500 from the choke, while I talked to my sister. After about ten minutes I came back out (the edelbrock mechanism kicks down once you touch the throttle - until you touch the throttle the choke keeps it at the last rpm) and it was still at 2500, more warmed up of course and so must have been burning quite rich. The header was glowing red through the heat tape. This hasn't happened since last year when my timing was off.
Any ideas?
I have a 6-port 13b with the RB holley intake and an Edelbrock thunder series 650 w/electric choke, and RB header to custom exhaust. Ignition is stock from the old 12a.
First problem - adjusting the electric choke, I just can't seem to get it right. If I adjust it far enough that the choke turns completely off when the car is warm, the choke becomes too cold-blooded overall. I leave the beast in a parking lot for an hour and when I come back the engine is cold but the choke won't engage.
So I readjusted the choke and now it never quite turns off...
GEEZE
Second question. How do I and should I set up a vac-advance to the dizzy? I did at first but used the wrong port.
Third question, possibly related. If I pull hard in 1st to redline, then pull hard in 2nd and 3rd to redline, she stutters in the high end from about 5k to 7k. My fuel pump is a Carter 4070 and fpr mounted on the firewall keeps my fuel at 5psi.
Finally - last night I left her outside warming up, idling at 2500 from the choke, while I talked to my sister. After about ten minutes I came back out (the edelbrock mechanism kicks down once you touch the throttle - until you touch the throttle the choke keeps it at the last rpm) and it was still at 2500, more warmed up of course and so must have been burning quite rich. The header was glowing red through the heat tape. This hasn't happened since last year when my timing was off.
Any ideas?
#2
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No experience with the e-choke on these carbs.
On my SE with the e-brock, I ran a hose from the "timed" port on the lower left front to the vac advances via a "T".
The high RPM stuttering sounds like a possible restriction in the fuel system. What type of FPR are you using? Some are more restrictive than others.
The glowing header could be from either a rich mixture, a lean mixture, or timing not quite right.
On my SE with the e-brock, I ran a hose from the "timed" port on the lower left front to the vac advances via a "T".
The high RPM stuttering sounds like a possible restriction in the fuel system. What type of FPR are you using? Some are more restrictive than others.
The glowing header could be from either a rich mixture, a lean mixture, or timing not quite right.
#3
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You might want to take a look at the inside of the choke mechanism and MAKE SURE the spring is in the tang slot .. lots of times they don't get assembled proper then they work good one way and only half the other way . Don't know how much power the choke should get but check and see how much you are getting and compare to what they say. ( There should be some adjusting marks around the e choke housing there not accurate they just give you some kind of idea of where you were at ) . It needs to be clean inside to work proper . When the engine is cold the choke should close tight with one press of the throttle and after starting the vacuum pull off should open the choke plates just the right amount to let the little engine run comfortable with out the rich or lean problem . ( I've never had any luck trying to set them when they are warm ) As the electric coil warms up it should pull the choke all the way open relieving the job from the vacuum choke pull off . The vacuum choke pull off must be set proper to enable the rest of the system to work adequately .
Depending where the power comes from to energize the choke some applications deliver power as soon as the ignition is turned on and starts the choke warm up immediately so if the vehicle sits very long with the key ON before starting the engine the choke is already warm and will not work or set proper .. I hope I haven't confused you to much . Have a good one . Gerald m.
I hate electric chokes as much as Aaron cake hates carburetors.
Depending where the power comes from to energize the choke some applications deliver power as soon as the ignition is turned on and starts the choke warm up immediately so if the vehicle sits very long with the key ON before starting the engine the choke is already warm and will not work or set proper .. I hope I haven't confused you to much . Have a good one . Gerald m.
I hate electric chokes as much as Aaron cake hates carburetors.
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Cheers guys, I'll take a look inside the choke and make sure that's on. I don't know what the vac pull-off is, but the carb was missing the fast idle screw when I got it. Ebrock sent me one for free though (with two big edelbrock stickers to make my car faster.)
Rogue, I may have a restriction in the fuel system. For reasons I can't remember I had to have some sections 1/4" although most is 3/8". Can there be low flow even with good pressure? Or perhaps the gauge drops when the stuttering happens and I'm just not able to see it.
Rogue, I may have a restriction in the fuel system. For reasons I can't remember I had to have some sections 1/4" although most is 3/8". Can there be low flow even with good pressure? Or perhaps the gauge drops when the stuttering happens and I'm just not able to see it.
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Cheers guys, I'll take a look inside the choke and make sure that's on. I don't know what the vac pull-off is, but the carb was missing the fast idle screw when I got it. Ebrock sent me one for free though (with two big edelbrock stickers to make my car faster.)
Rogue, I may have a restriction in the fuel system. For reasons I can't remember I had to have some sections 1/4" although most is 3/8". Can there be low flow even with good pressure? Or perhaps the gauge drops when the stuttering happens and I'm just not able to see it.
Rogue, I may have a restriction in the fuel system. For reasons I can't remember I had to have some sections 1/4" although most is 3/8". Can there be low flow even with good pressure? Or perhaps the gauge drops when the stuttering happens and I'm just not able to see it.
There will be a Rod I think that goes to the choke mechanism kinda behind the e choke , somewhere in there . The rod will be in a slotted little plate the rod needs to be adjusted so that when the vacuum pulls the rod it hits the end of the slotted plate and then opens the choke. Some you need to bend some are adjusted with a screw . I will try to find a blow up diagram and post it when I get time . You should be able to find a nice blow up diagram of your carb on Google study it a bit and you will see what I mean .
Yea I got some stickers with my knobby tires too, But the only way sticker go on my bike are if the tires are free .
Last edited by gerald m; 12-22-12 at 08:00 PM.
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Rogue, I may have a restriction in the fuel system. For reasons I can't remember I had to have some sections 1/4" although most is 3/8". Can there be low flow even with good pressure? Or perhaps the gauge drops when the stuttering happens and I'm just not able to see it.
#7
Put a "T" in your fuel line just before the carb, plumb in a vac/press gauge with a length of hose, and tape it to the windshield. Watch the pressure during the next pull. If the pressure drops significantly, then you have a stumble, you're fuel flow is insufficient. This may sound like a lot of work, but it will positively answer the fuel supply question.
Regarding the choke: I'm old enough to have dealt with a lot of carbureted cars. I agree with a previous post that electric chokes are a PITA. I put a mechanical choke on every carbed car I've owned and never regretted it.
Regarding the choke: I'm old enough to have dealt with a lot of carbureted cars. I agree with a previous post that electric chokes are a PITA. I put a mechanical choke on every carbed car I've owned and never regretted it.
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#8
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Update:
Since it's still around -25 c here and I don't have anywhere to work on the car, so far I have taken the choke apart. It's a simple coil and nothing was sticking. I have a suspicion it may be improperly grounded though; it seems to have a very random on-off pattern.
Also last night I got stumbling in 4th and 5th if I gave even slight pressure on the throttle, even at about 3k rpm. However that could be because the damn choke took that opportunity to come full on, trying to hold 2500 rpm. After the car was running and driving for a half hour.
Electric choke is a sneaky bastard. I need a warm place to work on my beast!
Since it's still around -25 c here and I don't have anywhere to work on the car, so far I have taken the choke apart. It's a simple coil and nothing was sticking. I have a suspicion it may be improperly grounded though; it seems to have a very random on-off pattern.
Also last night I got stumbling in 4th and 5th if I gave even slight pressure on the throttle, even at about 3k rpm. However that could be because the damn choke took that opportunity to come full on, trying to hold 2500 rpm. After the car was running and driving for a half hour.
Electric choke is a sneaky bastard. I need a warm place to work on my beast!
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