Engine Pulses when brake pedal is depresed

mazdaguy1138 · Post by **mazdaguy1138** » June 22nd, 2005, 8:19 pm

please help me

When i press the brake and disengage the clutch my engine starts pulsing between 1k and 1500. It dosent do this when i have the clutch engaged only when the brake is down and the clutch is not engaged. But because my gas pedal seems a bit stickey i pull it back and the pulsing stops (the pedal will come all the way up when you let off of it though) also when i bress the brake pedal, the lights on my gauges dim (but my 94 RS ATX did this when i put the new battery in it also) Im thinkin im gonna need a new battery anyways or is it a sensor or a alternator prob. Please help me cuase its annoying the crapm outta me and i have having to reach down and pull on the gas pedal

Tunes67 · Post by **Tunes67** » June 22nd, 2005, 8:25 pm

But because my gas pedal seems a bit stickey i pull it back and the pulsing stops

To me this would indicate one of the following possible problems. Throttle body needs a good cleaning. Throttle return spring is worn and getting weak (a carb rebuild shop may be able to help you find a replacement spring.. but Mazda wont be any help). Possible that your throttle cable got kinked somewhere and is not sliding through its housing as well as it should be.

I did a write up on how to clean and adjust the throttle bodies of the 1.6L DOHC engines. Pt2 is in the 4cyl FAQ.. part 1 is floating around somewhere LOL best of luck.

Tunes67

sw-ontarioguy · Post by **sw-ontarioguy** » June 22nd, 2005, 10:54 pm

I agree with tunes, its deffinitly a throttle issue. Try what he said, or maybe even lube up your pedal abit with WD-40 or something. Pop uour hood, and rev the car with the throttle on the engine, when u let it go, see if you can push it farther to slow it down (if that makes any sence). If you can push it farther to lower the throttle, then you know its likely your actually pedal, or the cable is kinked.

projectmx · Post by **projectmx** » June 24th, 2005, 11:30 am

one of the mazda tech guys who kinda specializes in b series engines told me it is usually a two part thing one part being the iac valve clogged and the fact that the brakes pull an unusually large electrical draw and the grounds can't handles it causing the pulse and lights dimming... but that is just what he thinks..... so if you follow that though then take the tb and iac valve off clean them very well *tunes has a good walk through on that* and then replace all of the old tiny grounds with larger grounds that have low resistance and clean the spots on the car when the wires connect so they will get good contact