Press on brake then idl low.... - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

pink godzila · 12-29-2008, 09:28 PM

Ok, there is a previous post about my idl problem that when I turn on the head lights and heater the rpm drop to 700 or lower. Been told to check my alternater.

Now I discover that when I stop at the light and step on brake my rpm drop to 600 or lower... HELP...

bejota180sx · 12-29-2008, 09:50 PM

check the vacuum hose that goes to the intake manifold from the brake booster, that happened to me and i checked it out adnd it wasn't on tight enough...
now second thing you should do is take of the part that goes from the firewall to the brake booster, blow on it TOWARDS the brake booster it should NOT let you blow into it, but if you do it on the other side it will let air pass... good time to check that 'valve' also...

maybe this helps you, hope it does...

reinvent · 12-29-2008, 10:10 PM

Quote:

Originally Posted by pink godzila

Ok, there is a previous post about my idl problem that when I turn on the head lights and heater the rpm drop to 700 or lower. Been told to check my alternater.

Now I discover that when I stop at the light and step on brake my rpm drop to 600 or lower... HELP...

How much of a idle drop?

my car does that with heater and lights. cant remember what happens when i depress brake. i think idle goes up.

It is normal for a slight drop in RPM since when you turn on the lights it causes the alternator to take more HP to spin it to keep up with the amperage demand. My car drops about 50 rpm when I turn my lights on and I have no electrical issues.

HalveBlue · 12-29-2008, 10:12 PM

+1 on brake booster.

WERDdabuilder · 12-29-2008, 10:58 PM

same problem here. i was told to check my vacc lines to my brake booster.

still haven't done it ha.

cwallace12 · 12-29-2008, 10:58 PM

Brake booster vacuum lines could be it. Also could be electrical though since hes already having problems with his heater and head lights causing low idle.

B_mart24 · 12-29-2008, 11:00 PM

had same problem on my old s13, just replaced the vacum hose and all was dandy!

WERDdabuilder · 01-06-2009, 04:47 AM

bring it back sorry.

ok i replaced the vacc line(had a small cut) and everything is good but when my heater is on full blast the idle drops when i brake/coast to a stop. also my dash light/etc kinda go dimmer. alternater/ground issue?

g6civcx · 01-06-2009, 01:00 PM

Quote:

Originally Posted by WERDdabuilder

when my heater is on full blast the idle drops when i brake/coast to a stop. also my dash light/etc kinda go dimmer. alternater/ground issue?

Weak battery current. Could be caused by anything, including alternator, ground, battery, wiring, current leak, big amp/subwoofer, etc.

Z U L8R · 01-06-2009, 10:41 PM

Quote:

Originally Posted by g6civcx

Weak battery current. Could be caused by anything, including alternator, ground, battery, wiring, current leak, big amp/subwoofer, etc.

REPS for great advice, right on the money

on most cars the two biggest electrical drains (besides big ass dual fans) occur when you hit the breaks and when you have the defrost on.

Dave

reinvent · 01-07-2009, 02:15 AM

Quote:

Originally Posted by Z U L8R

REPS for great advice, right on the money

on most cars the two biggest electrical drains (besides big ass dual fans) occur when you hit the breaks and when you have the defrost on.

Dave

how does braking create an electrical load?

adrians_s13 · 01-07-2009, 02:22 AM

Quote:

Originally Posted by reinvent

how does braking create an electrical load?

brake lights turning on. 4 bulbs to be exact.

Getting better grounds usually helps... make your own grounding kit.

12-29-2008, 09:28 PM	#1
pink godzila Post Whore! Join Date: Dec 2007 Location: SoCal / Japan Tokyo Posts: 4,179 Trader Rating: (226) Feedback Score: 226 reviews	Press on brake then idl low.... Ok, there is a previous post about my idl problem that when I turn on the head lights and heater the rpm drop to 700 or lower. Been told to check my alternater. Now I discover that when I stop at the light and step on brake my rpm drop to 600 or lower... HELP...

12-29-2008, 10:58 PM	#6
cwallace12 Leaky Injector Join Date: Jul 2008 Location: Bowling Green, Ky Age: 42 Posts: 59 Trader Rating: (2) Feedback Score: 2 reviews	Brake booster vacuum lines could be it. Also could be electrical though since hes already having problems with his heater and head lights causing low idle. __________________

12-29-2008, 11:00 PM	#7
B_mart24 Leaky Injector Join Date: Dec 2007 Location: Snohomish, WA Posts: 88 Trader Rating: (0) Feedback Score: 0 reviews	had same problem on my old s13, just replaced the vacum hose and all was dandy! __________________

12-29-2008, 10:12 PM	#4
HalveBlue Zilvia FREAK! Join Date: Mar 2004 Location: I'm somewhere where I don't know where I am! Posts: 1,549 Trader Rating: (0) Feedback Score: 0 reviews	+1 on brake booster.