Rb20 Problem

[who's next]

I need some advice. i just completed my A31 conversion, i bought a r32 gts front cut and moved over everything, also changed to the r32 diff. I have been driving the car for a week now, idles nice and moves real good, engine is really healthy but i am having two problems.

1. i find the brakes are a little soft, i have bleed the lines twice and still the same thing.

2. when you mash the brakes all the way down the idle drops to 100rpm and picks back up to 800 or sometimes it would cut off. so this makes it difficult for when you are bleeding the brake lines

any suggestions?

Thanks

Roger

[White GTS-T]

It sounds like a problem with the brake booster. Get yourself another one and give that a try. It might be worth trying another master cylinder while your at it.

[daisu]

Shouldn't need the engine running while you are bleeding the brakes.

Did you swap the brake calipers from the R32? And the Master cylinder?

If you swapped to the R32 calipers, check that you have not put the RHS caliper on the LHS. If the bleed nipples are on the bottom side of the caliper then you have them backwards and you will not be able to bleed the air out.

If you swapped the calipers only and not the master cylinder then the pedal will always feel soft, you need to upgrade the master cylinder.

If you still can't get a solid pedal feel your master cylinder may have worn seals.
As for the stalling issue, check for leaks on the vacuum hose between the engine and the brake booster, check the one way valve, otherwise could be the brake booster itself.

[who's next]

Thanks for the info. i had on 300z rotors and callipers before the engine swap, i did not use the r32 master as it had only two lines coming out of it and mine had 3 but the car was down for a few years so it is possible that the rubbers in the cylinder are all bad, i would replace it with new rubbers and pistons and see if it helps. i would also look for leaks and the check the valve as well. thanks for the info.

Roger

[who's next]

quick update, i replaced the r32 booster with a r33 one, same problem, i even put back the original booster that came with the cefiro and same issue. so i think i could rule out this option. this weekend i change plugs, cleaned the maf and the idle control valve, changed a vacuum hose by the throttle body that was looking cracked. car started up and was working good, then after it warmed up same issue at idle it is searching then when you drive it and come to a stop it drops to about 100rpm and then picks back up and begins to search again. one of the plugs (no. 5) looked a little rusted like if water settled on the top but it was burning good. could it be possible that water also affected the coil pack? if so would it only when the engine warms up. i have an extra set from the rb20de would this work? is it the same coil pack? i also dont think it is the check valve by the booster as when i was about to swap the r32 for the r33 and i pulled the hose you actually heard the air escaping so to me it means it was functioning correctly. any ideas? would a bad maf do this?

thanks

roger

[who's next]

next update, i cleaned the throttle body and so far it is working good. would continue to use for the rest of the day and see what happens

would update by Friday

[who's next]

ok new updat same problem, just not as bad. so i would try changing out the idle control valve.