RX7Club.com - Mazda RX7 Forum - high acceleration when starting

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Bryan Garcia

03-14-19 05:16 PM

high acceleration when starting

i have a 86 NA when i start it up it revs to 5000 rpm and stays there. sometimes it doesnt do that but it surges a lot. the throttle feels really off too. i disconnected the hot start assist that is on the driver side from the top of the motor. i dont know what is wrong with it and ive looked and found some stuff but it doesnt really work. the throttle body seems to be good because its not stuck or anything.

Relisys190

03-14-19 05:42 PM

5k is a bit high, these cars have an accelerated warmup mode but that’s usually right around 3k Rpms until after about 30 seconds it will slowly drop and eventually level out below 1000. Have you tried starting it in 1st gear with the clutch pedal down? It should disable this. Otherwise I would check your throttle plates and be sure nothing is sticking open

Bryan Garcia

03-14-19 05:51 PM

yeah i tried the whole clutch thing but it didnt work. i checked the throttle body and the top two plates are open. are they supposed to be closed?

Akaviri

03-14-19 11:34 PM

Sounds like the idle speed adjustment is jacked up. Try fiddling with the screw on top the throttle body to tone it back down to a reasonable range.
The 3k warmup should go away if you disconnect the two pin plug on the bottom drivers side of the radiator. If your car is ramping up to 5k when cold you are risking damaging the engine.

chuyler1

03-15-19 03:48 PM

Quote:

Originally Posted by Akaviri (Post 12335651)

Sounds like the idle speed adjustment is jacked up.

I would assume there is a disconnected or cracked vacuum hose before I touched the idle speed.

Akaviri

03-16-19 04:30 AM

Quote:

Originally Posted by chuyler1 (Post 12335776)

I would assume there is a disconnected or cracked vacuum hose before I touched the idle speed.

That is a fair point I hadn't considered. However I would normally assume a loss in vacuum would cause it to stall, not surge higher? I once forgot to reconnect a vacuum line and my car wouldn't hold idle for more than 2 seconds without it.

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