Problem finally solved!!!!
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Joined: Jun 2004
Posts: 11,359
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From: Grand Rapids Michigan
Problem finally solved!!!!
Well, finally some good news!
After a year and a half of chasing this issue, it has finally been resolved. I would like to thank all of the forum members that helped out with suggestions and questions. This problem was covered in two separate posts, and included a whole bunch of suggestions as to what might cause this situation.
https://www.rx7club.com//showthread.php?t=418888
https://www.rx7club.com/showthread.p...12a+power+loss
What I have learned from this (and I hope that it will provide good information to others with similar problems) is this;
If the car consistently loses power only at wide open throttle, even if you coast for a while before gunning it, the most likely cause is going to be a partially clogged main jet in the carb rather than a fuel filter/fuel pump issue. This is because the carb gets it's fuel supply from the float bowls, not from fuel pressure...
Common suggestions such as fuel filter, weak fuel pump, etc. failed to take this into consideration. If the power had been there at any time when at WOT then these could have been the cause, and would have eliminated the clogged jets as a potential cause.
Anyway, the power was good at partial throttle because I was not surpassing the amount of fuel that could get past the partial clog. But at WOT, I could not get enough fuel through to match the air that was being drawn in, creating a lean condition (which is why the plugs always looked good).
After clearing out the main jets, the power is finally back. I cannot describe how good it feels to have my car running right again after all this time (even my wife is happy!), but I'm sure that many of you probably can understand. I am finally able to hear my new Racing Beat exhaust at full throttle, and man does it sound sweet!
Thanks again for all the support that I received here. And although most of the input did not actually point to the actual problem, I have learned more about this car through the process of elimination than I ever could have on my own. I hope to be able to contribute some of this acquired knowledge to help my fellow forum members in the years to come.
Sorry this has turned into such a long post, but I really wanted to show my appreciation to you guys, every one of you totally kick butt! Thanks again!!!
After a year and a half of chasing this issue, it has finally been resolved. I would like to thank all of the forum members that helped out with suggestions and questions. This problem was covered in two separate posts, and included a whole bunch of suggestions as to what might cause this situation.
https://www.rx7club.com//showthread.php?t=418888
https://www.rx7club.com/showthread.p...12a+power+loss
What I have learned from this (and I hope that it will provide good information to others with similar problems) is this;
If the car consistently loses power only at wide open throttle, even if you coast for a while before gunning it, the most likely cause is going to be a partially clogged main jet in the carb rather than a fuel filter/fuel pump issue. This is because the carb gets it's fuel supply from the float bowls, not from fuel pressure...
Common suggestions such as fuel filter, weak fuel pump, etc. failed to take this into consideration. If the power had been there at any time when at WOT then these could have been the cause, and would have eliminated the clogged jets as a potential cause.
Anyway, the power was good at partial throttle because I was not surpassing the amount of fuel that could get past the partial clog. But at WOT, I could not get enough fuel through to match the air that was being drawn in, creating a lean condition (which is why the plugs always looked good).
After clearing out the main jets, the power is finally back. I cannot describe how good it feels to have my car running right again after all this time (even my wife is happy!), but I'm sure that many of you probably can understand. I am finally able to hear my new Racing Beat exhaust at full throttle, and man does it sound sweet!
Thanks again for all the support that I received here. And although most of the input did not actually point to the actual problem, I have learned more about this car through the process of elimination than I ever could have on my own. I hope to be able to contribute some of this acquired knowledge to help my fellow forum members in the years to come.
Sorry this has turned into such a long post, but I really wanted to show my appreciation to you guys, every one of you totally kick butt! Thanks again!!!
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Joined: Nov 2003
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From: The Net
That's awesome, good job in resolving the issue.
Loss of power at wide open throttle is almost always a fuel delivery issue. Everyone starts at the fuel filter because it's the most common source of it, and the cheapest to resolve. Then comes fuel pump. If those 2 don't resolve it, one would of course look into the carb next. I think this is covered in one of Sterling's long posts on the subject.
Loss of power at wide open throttle is almost always a fuel delivery issue. Everyone starts at the fuel filter because it's the most common source of it, and the cheapest to resolve. Then comes fuel pump. If those 2 don't resolve it, one would of course look into the carb next. I think this is covered in one of Sterling's long posts on the subject.
Thread Starter
Lives on the Forum
Joined: Jun 2004
Posts: 11,359
Likes: 14
From: Grand Rapids Michigan
Well, wish us luck.....
My wife and I are getting ready to take the 7 up to Traverse City for the night (about 175 miles).....
Its been a long time since we've gotten away like this, so hopefully everything will go ok. I'll post back when we return. Have a good weekend!
My wife and I are getting ready to take the 7 up to Traverse City for the night (about 175 miles).....
Its been a long time since we've gotten away like this, so hopefully everything will go ok. I'll post back when we return. Have a good weekend!
RTFFAQ
Joined: Jun 2003
Posts: 1,049
Likes: 0
From: Olathe, KS USA
Kentetsu - thanks for taking the time to write this up. It always pisses me off when somebody states a problem, collects possible fixes and then never replies with the results.
Have a great weekend.
Have a great weekend.
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Thread Starter
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From: Grand Rapids Michigan
We just got back into town, and the 7 did an awesome job. Absolutely no issues, other than the fact that I might still be running a little lean. Even averaging 85-90 mph I got 22 mpg. And overall, I'd say the power is down a little again, but nothing like it was before.
I think I'm going to have to pull the carb and clean it out once more. Not sure where these contaminants are coming from, but the ap is acting like its clogging up once in a while too. So maybe one more teardown/clean out will take care of it. I hope so. All the internal screens are in place and in good/clean condition and the fuel filter is good. So nothing new should be getting into the carb.
Anyway, car ran smooth as silk all the way there and back. Overall we put just over 500 miles on. I'll post some pics tomorrow when I have more time.
I think I'm going to have to pull the carb and clean it out once more. Not sure where these contaminants are coming from, but the ap is acting like its clogging up once in a while too. So maybe one more teardown/clean out will take care of it. I hope so. All the internal screens are in place and in good/clean condition and the fuel filter is good. So nothing new should be getting into the carb.
Anyway, car ran smooth as silk all the way there and back. Overall we put just over 500 miles on. I'll post some pics tomorrow when I have more time.
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