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Guest Message by DevFuse

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Rpms drop when brakes applied?

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4 replies to this topic

#1 Subinoobi


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Posted 27 December 2013 - 02:11 AM

So I just got done doing a reseal on my motor, and now I'm having problems with my idle. If I apply the brakes, the first pump sinks to the floor, then it build pressure. And when I hit the brake my idle goes down and it almost dies. Now At first I though okay, maybe it's my brake booster, but my rpms drop when I turn on my defrost at full blast as well. I've checked every single vacuum line and ground I could find like 10 times, nothing seems out of place. i have a fresh battery and new cables as well, so my next thought is maybe the alternator. If it's not that, anyone have any experience with this and have some input? I have a 90 loyale spfi btw

#2 el_freddo


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Posted 27 December 2013 - 06:51 AM

The rev thing with the brakes applied points to the booster - make sure the one way valve in the line is working properly - it's under the metal clamp somewhere in the line, I can't remember where exactly.


The rev drop with the demist on could be a dodgy earth connection between the engine and the body - look into your earth strap on the engine and make sure it's securely fastened to the engine and the battery/body.



#3 Gloyale


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Posted 27 December 2013 - 04:10 PM

Brake booster.

#4 86 Wonder Wedge

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Posted 02 January 2014 - 09:10 PM

Make sure the vacuum line to the booster isn't kinked as well

#5 MilesFox


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Posted 02 January 2014 - 09:11 PM

Did you remove the brake booster line from the car side? there is a check valve in the line; make sure it is not installed backward. I take it this problem didn't occur before resealing the engine.

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