Not starting after carb rebuild
10-05-20, 11:10 PM
#26
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Thread Starter
https://www.rx7club.com/1st-generation-specific-1979-1985-18/idle-wont-increase-846768/
https://www.rx7club.com/1st-generation-specific-1979-1985-18/1979-rx7-carb-help-1132538/
I just found this, looks like out of the two together, one is mix and one is air speed. The small one to the right under the linkage is your idle speed!
https://www.rx7club.com/1st-generation-specific-1979-1985-18/1979-rx7-carb-help-1132538/
I just found this, looks like out of the two together, one is mix and one is air speed. The small one to the right under the linkage is your idle speed!
On a related note, I just went up to the car and reset the mixture and air speed screws to 3 turns out and started it up, let it get warm, and eased it down to idle. This time it was a hair over 1k... pretty lumpy at first so i tried adjusting the top screw to make sure it still had no effect on the idle speed, it didnt. So i left it where it was and adjusted the mixture screw how sterling recommended. This helped the idle a bit but its still somewhat lumpy. I have good spark all around. Giving it throttle from idle is insanely more responsive than it was before i rebuilt the carb, despite the idle being somewhat high and lumpy. No sputtering at all. However, when i blip the throttle from idle and let off, the engine sounds like it stays on the throttle for a second after my foot is off the pedal. Is this an issue or the accelerator pump working? Or something else entirely? The high idle makes me think vacuum leak, but Im stumped as to why it went from low yesterday and not moving, to high today and not going down when all i adjusted was the mix screws... I wouldnt think i developed a vacuum leak between those 2 times starting it.
10-06-20, 01:20 AM
#28
so does that mean its safe to mess with that one? And if so how would you go about making sure air speed is correct? I havent seen it mentioned when looking for how to tune it.
On a related note, I just went up to the car and reset the mixture and air speed screws to 3 turns out and started it up, let it get warm, and eased it down to idle. This time it was a hair over 1k... pretty lumpy at first so i tried adjusting the top screw to make sure it still had no effect on the idle speed, it didnt. So i left it where it was and adjusted the mixture screw how sterling recommended. This helped the idle a bit but its still somewhat lumpy. I have good spark all around. Giving it throttle from idle is insanely more responsive than it was before i rebuilt the carb, despite the idle being somewhat high and lumpy. No sputtering at all. However, when i blip the throttle from idle and let off, the engine sounds like it stays on the throttle for a second after my foot is off the pedal. Is this an issue or the accelerator pump working? Or something else entirely? The high idle makes me think vacuum leak, but Im stumped as to why it went from low yesterday and not moving, to high today and not going down when all i adjusted was the mix screws... I wouldnt think i developed a vacuum leak between those 2 times starting it.
On a related note, I just went up to the car and reset the mixture and air speed screws to 3 turns out and started it up, let it get warm, and eased it down to idle. This time it was a hair over 1k... pretty lumpy at first so i tried adjusting the top screw to make sure it still had no effect on the idle speed, it didnt. So i left it where it was and adjusted the mixture screw how sterling recommended. This helped the idle a bit but its still somewhat lumpy. I have good spark all around. Giving it throttle from idle is insanely more responsive than it was before i rebuilt the carb, despite the idle being somewhat high and lumpy. No sputtering at all. However, when i blip the throttle from idle and let off, the engine sounds like it stays on the throttle for a second after my foot is off the pedal. Is this an issue or the accelerator pump working? Or something else entirely? The high idle makes me think vacuum leak, but Im stumped as to why it went from low yesterday and not moving, to high today and not going down when all i adjusted was the mix screws... I wouldnt think i developed a vacuum leak between those 2 times starting it.
I found the adjustment in my Haynes manual, page 70, #15 & #16
If it’s a leak, start spraying around with some brake cleaner. The idle will go up or make it stumble a bit when you spray the leak and you will find it that way.
Acc pump is only actuated when the primaries make their initial movement open, then refill for another squirt when the throttle is closing. I doubt it’s acc pump related. Check the linkage/ butterflies while someone hits the pedal and see if it stays open or not..... otherwise it sounds like a vac leak. Is your carb stripped down?
Last edited by LEGALIZECHEY; 10-06-20 at 01:35 AM.
10-06-20, 12:09 PM
#29
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Thread Starter
I found the adjustment in my Haynes manual, page 70, #15 & #16
If it’s a leak, start spraying around with some brake cleaner. The idle will go up or make it stumble a bit when you spray the leak and you will find it that way.
Acc pump is only actuated when the primaries make their initial movement open, then refill for another squirt when the throttle is closing. I doubt it’s acc pump related. Check the linkage/ butterflies while someone hits the pedal and see if it stays open or not..... otherwise it sounds like a vac leak. Is your carb stripped down?
If it’s a leak, start spraying around with some brake cleaner. The idle will go up or make it stumble a bit when you spray the leak and you will find it that way.
Acc pump is only actuated when the primaries make their initial movement open, then refill for another squirt when the throttle is closing. I doubt it’s acc pump related. Check the linkage/ butterflies while someone hits the pedal and see if it stays open or not..... otherwise it sounds like a vac leak. Is your carb stripped down?
10-06-20, 12:39 PM
#30
Full Member
Thread Starter
I just tried checking the timing and it is off but the car wont idle long enough for me to adjust it and it was starting with throttle before but now it just cranks. too warm maybe? wouldn't think its flooded since its been running but what do I know. This is a pain in the ***.
10-06-20, 07:58 PM
#32
It could be all the vacuum stuff/accessories on the carb. Both of mine are stripped down following these guides, so I'm not really sure how to diagnose with the stock equipment
https://www.rx7club.com/1st-generati...i-carb-912089/
http://foxed.ca/rx-7/Carb%20Stripping%20Draft%201.pdf
https://www.rx7club.com/1st-generati...i-carb-912089/
http://foxed.ca/rx-7/Carb%20Stripping%20Draft%201.pdf
10-07-20, 10:53 AM
#33
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Thread Starter
It could be all the vacuum stuff/accessories on the carb. Both of mine are stripped down following these guides, so I'm not really sure how to diagnose with the stock equipment
https://www.rx7club.com/1st-generati...i-carb-912089/
http://foxed.ca/rx-7/Carb%20Stripping%20Draft%201.pdf
https://www.rx7club.com/1st-generati...i-carb-912089/
http://foxed.ca/rx-7/Carb%20Stripping%20Draft%201.pdf
10-07-20, 10:58 AM
#34
I’m just saying that the emissions gear on the carb is not necessary unless you have the rest of it on the engine and manifold. If not, and the carb has all this vacuum stuff on it, it could be creating different affects because the equipment has no job now. In my opinion these cars are so simple you’d have to be a fool not to strip everything down to its bare necessities....just my opinion though.
post a video of it starting and (trying) to idle, I’m curious if it’s like mine was when I rebuilt my carb
post a video of it starting and (trying) to idle, I’m curious if it’s like mine was when I rebuilt my carb
Last edited by LEGALIZECHEY; 10-07-20 at 01:16 PM.
10-07-20, 01:23 PM
#35
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Thread Starter
Heres a few videos to show what its doing. The engine was shaking like crazy.
Is carb stripping and rats nest removal actually beneficial? Ive heard some say to do it and others say it makes the car run less smooth and ruins gas milage.
Is carb stripping and rats nest removal actually beneficial? Ive heard some say to do it and others say it makes the car run less smooth and ruins gas milage.
10-07-20, 01:55 PM
#36
Senior Member
Sounds like it's only running on one rotor. In the video of it idling, I can see the distributor is pretty off of what most people have as standard. The stud and nut that holds the distributor in place should be close to center, slightly to the right. Definitely try setting the distributor closer to the center of the slot.
If adjusting the distributor doesn't do anything, while it's running like that hook a timing light up to each of the plug wires and see if it's registering spark all the way around.
The timing could be way off if the timing light flashes on all four wires.
If adjusting the distributor doesn't do anything, while it's running like that hook a timing light up to each of the plug wires and see if it's registering spark all the way around.
The timing could be way off if the timing light flashes on all four wires.
Last edited by Ta-Aikah; 10-07-20 at 02:06 PM.
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LEGALIZECHEY (10-07-20)
10-07-20, 02:39 PM
#37
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Thread Starter
Sounds like it's only running on one rotor. In the video of it idling, I can see the distributor is pretty off of what most people have as standard. The stud and nut that holds the distributor in place should be close to center, slightly to the right. Definitely try setting the distributor closer to the center of the slot.
If adjusting the distributor doesn't do anything, while it's running like that hook a timing light up to each of the plug wires and see if it's registering spark all the way around.
The timing could be way off if the timing light flashes on all four wires.
If adjusting the distributor doesn't do anything, while it's running like that hook a timing light up to each of the plug wires and see if it's registering spark all the way around.
The timing could be way off if the timing light flashes on all four wires.
10-07-20, 02:45 PM
#38
Senior Member
It should sit pretty close to the center of the slot. Maybe the distributor is off of where it's supposed to be set in relation to top dead center.
It running like that is most likely ignition related. Do you have a Haynes Manual?
It running like that is most likely ignition related. Do you have a Haynes Manual?
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LEGALIZECHEY (10-07-20)
10-07-20, 03:08 PM
#39
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Thread Starter
I do. I set the distributor to that position following the manual a few months prior to the carb rebuild and it was right on the mark. I'll do some more reading and try adjusting it again, but I don't think anything else could be wrong with the ignition. Both point sets are fairly new and gapped to spec, plugs are newer and all getting strong blue spark, and I've got good spark when checking all of the wires. It still seems hard to believe that my issue isn't intake related. Even if the timing WAS off before the carb rebuild, it was still drivable. So if all the shaking and low idling stuff started after the rebuild, it would have to be related, right? I could be very wrong, but that's just my train of thought.
10-07-20, 03:50 PM
#40
Senior Member
There is a mark that lines up the gear and the shaft of the distributor, but there is also the pin that holds the gear to the shaft. The pin and the mark have been known to be confused at times. It's very easy to double-check that the distributor is stabbed correctly.
Like you said, it was running before, but this simple check shouldn't add any more variables. Double check it's installed correctly.
Maybe the 79 points ignition sits farther to the side of the slot vs the later 85 dizzy I have swapped into my 79, but I feel like it should sit near the middle to give you the most adjustment both ways.
Like you said, it was running before, but this simple check shouldn't add any more variables. Double check it's installed correctly.
Maybe the 79 points ignition sits farther to the side of the slot vs the later 85 dizzy I have swapped into my 79, but I feel like it should sit near the middle to give you the most adjustment both ways.
Last edited by Ta-Aikah; 10-07-20 at 03:53 PM.
10-07-20, 06:51 PM
#41
Full Member
Thread Starter
There is a mark that lines up the gear and the shaft of the distributor, but there is also the pin that holds the gear to the shaft. The pin and the mark have been known to be confused at times. It's very easy to double-check that the distributor is stabbed correctly.
Like you said, it was running before, but this simple check shouldn't add any more variables. Double check it's installed correctly.
Maybe the 79 points ignition sits farther to the side of the slot vs the later 85 dizzy I have swapped into my 79, but I feel like it should sit near the middle to give you the most adjustment both ways.
Like you said, it was running before, but this simple check shouldn't add any more variables. Double check it's installed correctly.
Maybe the 79 points ignition sits farther to the side of the slot vs the later 85 dizzy I have swapped into my 79, but I feel like it should sit near the middle to give you the most adjustment both ways.
10-07-20, 07:21 PM
#42
Senior Member
I know very little about the factory points ignition setup.
I do know if you install the distributor at TDC, you should be able to draw a figurative "line" from the distributor rotor, to the cap, to the L1 sparkplug. The path that the current will follow to ignite the spark. Does that make sense?
So if you've got everything installed and everything is as it should be, the rotor should point to the pin/output for the leading front spark plug (L1) on the distributor cap. I don't know if that means everything is okay statically, as far as timing is concerned for points ignition though.
I do know if you install the distributor at TDC, you should be able to draw a figurative "line" from the distributor rotor, to the cap, to the L1 sparkplug. The path that the current will follow to ignite the spark. Does that make sense?
So if you've got everything installed and everything is as it should be, the rotor should point to the pin/output for the leading front spark plug (L1) on the distributor cap. I don't know if that means everything is okay statically, as far as timing is concerned for points ignition though.
10-07-20, 08:43 PM
#43
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Thread Starter
I know very little about the factory points ignition setup.
I do know if you install the distributor at TDC, you should be able to draw a figurative "line" from the distributor rotor, to the cap, to the L1 sparkplug. The path that the current will follow to ignite the spark. Does that make sense?
So if you've got everything installed and everything is as it should be, the rotor should point to the pin/output for the leading front spark plug (L1) on the distributor cap. I don't know if that means everything is okay statically, as far as timing is concerned for points ignition though.
I do know if you install the distributor at TDC, you should be able to draw a figurative "line" from the distributor rotor, to the cap, to the L1 sparkplug. The path that the current will follow to ignite the spark. Does that make sense?
So if you've got everything installed and everything is as it should be, the rotor should point to the pin/output for the leading front spark plug (L1) on the distributor cap. I don't know if that means everything is okay statically, as far as timing is concerned for points ignition though.
10-07-20, 09:01 PM
#44
Senior Member
Just as close to the center of one side of the gold tips on the rotor, not necessarily the side with the arrow. I'd say your timing should be good from what I can see. Where at in the slot does this put the dizzy? I can't quite tell from the images.
10-07-20, 09:14 PM
#45
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10-07-20, 10:27 PM
#47
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I switched to the other notch and readjusted the gear so the marks lined up. Then ran into the same issue. When turning the housing clockwise after placing the dizzy back in, the rubbing block on the lead point set doesnt pass over any of the corners, so theres no spot where the points are "beginning to separate."
10-07-20, 10:39 PM
#50
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