FC vert, won't stay running, laggy throttle. - RX7Club.com



FC vert, won't stay running, laggy throttle.

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Old 03-05-17, 04:33 PM
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FC vert, won't stay running, laggy throttle.

my buddy owns a 91 FC that won't stay running. At first, it had some issues with the TPS so I adjusted that and it seemed to help (the idle settled down). A few months later it started revving to 3k when started then dying after warming up. I'm pretty sure from what I've read this is a thermo wax valve or whatever but now the car just won't stay running at all. When you turn the ignition on the horn just stays on (I assume it's unrelated but it's annoying and will need fixed cuz we just pulled the fuse). When I got it running it started, revved to about 3 then wanted to die immediately. I was able to keep it alive by pumping the throttle but there was virtually no throttle response. In the video you can see it almost die. I was giving it gas immediately after the revs start to drop. After it dies it won't try to start for a bit, then repeats. For now, I was gonna have him buy a thermo wax valve but we kidnapping wanted to get everything at once. Unfortunately I'm not near the car and won't be for a week so any extra questions may not get a proper answer but I may be leaving something out. Any help will be greatly appreciated.
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Old 03-05-17, 04:38 PM
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Originally Posted by Al Capwned
my buddy owns a 91 FC that won't stay running. At first, it had some issues with the TPS so I adjusted that and it seemed to help (the idle settled down). A few months later it started revving to 3k when started then dying after warming up. I'm pretty sure from what I've read this is a thermo wax valve or whatever but now the car just won't stay running at all. When you turn the ignition on the horn just stays on (I assume it's unrelated but it's annoying and will need fixed cuz we just pulled the fuse). When I got it running it started, revved to about 3 then wanted to die immediately. I was able to keep it alive by pumping the throttle but there was virtually no throttle response. In the video you can see it almost die. I was giving it gas immediately after the revs start to drop. After it dies it won't try to start for a bit, then repeats. For now, I was gonna have him buy a thermo wax valve but we kidnapping wanted to get everything at once. Unfortunately I'm not near the car and won't be for a week so any extra questions may not get a proper answer but I may be leaving something out. Any help will be greatly appreciated.
This smells like a vacuum leak. These cars are old, and the vacuum lines are extremely brittle. If anyone has performed any maintenance or modification, chances are some vacuum lines are damaged. Gaskets are getting old too, possibly reused the last time someone was tinkering. I would start by inspecting and/or replacing all the vacuum lines. Anything behind the AFM could be leaking, causing your symptom.
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Old 03-05-17, 06:44 PM
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This smells like a vacuum leak. These cars are old, and the vacuum lines are extremely brittle. If anyone has performed any maintenance or modification, chances are some vacuum lines are damaged. Gaskets are getting old too, possibly reused the last time someone was tinkering. I would start by inspecting and/or replacing all the vacuum lines. Anything behind the AFM could be leaking, causing your symptom.
this seems to be the consensus, am I right about the thermo wax thing and any idea about the horn?
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Old 03-05-17, 06:58 PM
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only low coolant or low oil causes the horn, nothing to do with the thermowax or your issue.

i agree with vacuum leak, check your brake booster hose off the engine.
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Old 03-05-17, 06:58 PM
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Originally Posted by Al Capwned
this seems to be the consensus, am I right about the thermo wax thing and any idea about the horn?
The thermowax would increase the idle when cold, but won't in and of itself cause the car to not stay running. Usually it sticks extended, causing permanent high idle. So unless your idle is set too low already, it's not your problem.
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Old 03-05-17, 07:11 PM
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OK, I'll have him check the oil and coolant levels for the horn. He likely wouldn't be able to locate a vacuum leak on his own.
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Old 03-06-17, 04:33 PM
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He says the coolant and oil are good. What else could be causing the horn?
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Old 03-08-17, 11:08 PM
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Originally Posted by Al Capwned
He says the coolant and oil are good. What else could be causing the horn?
You keep using the word "horn". Do you mean the actual horn, or do you mean the "buzzer"?

Low oil and coolant trigger the warning buzzer. If your horn is actually blasting, you possibly have an issue at the trigger in the steering wheel, faulty alarm, etc.

What fuse did you pull?
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Old 03-09-17, 12:19 PM
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Im having the same issue just here for info, dont mean to thread steal but my issue isnt a vaccuum leak what else could it be?
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Old 03-12-17, 10:37 PM
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You keep using the word "horn". Do you mean the actual horn, or do you mean the "buzzer"?

Low oil and coolant trigger the warning buzzer. If your horn is actually blasting, you possibly have an issue at the trigger in the steering wheel, faulty alarm, etc.

What fuse did you pull?
Yes, I mean the horn. The stop fuse. That's why it's really important we find a fix. Though we could just pull the horn plug. I guess I'll look for it later. If there's any other ideas we're trying to fix it in a pretty small time period so if there's something else to order we probably will. Save a brand new engine of course.
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Old 03-13-17, 10:58 AM
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just test continuity of the horn button in the steering column switch. any issues are likely to be there.
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Old 03-20-17, 05:24 PM
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Finally getting into the car and I found this. What's up with it? I'm thinking air pump. Is that a thing on FCs?
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Old 03-20-17, 05:32 PM
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It rather that there was an air pump. Blue there isn't.
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Old 03-20-17, 06:59 PM
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Apparently I'm a wizard. Car runs. Even whithout the air pump area being blocked. Only other thing I did was pull and connect one of the main hoses off of the intake.
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Old 03-24-17, 07:55 PM
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care to explain about this hose? I am having the same issue where my car wont idle at all, but as long as I keep blipping the throttle it runs great...
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Old 03-25-17, 12:07 AM
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inadvertantly fixing a large vacuum leak isn't really wizardish.
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