rb25 exhaust tune with cas

[Voltron240]

I finally go my rb25 in and its running pretty good . I did have a few issues though. when I first started it it ran good until I gave it a little throttle and then it went in to Loop mode. I was running just a short elbow from the turbo. so I figured the o2 sensor might be detecting too much air and telling the ecu to run rich. so i made a ghetto down pipe and it seems to have solved the problem about 70 percent. It stills go into loop mode though i read in hear that it is probably the CAS sensor on the exhaust cam and that I need to time it. unfortunately I don't have a timing light and I don't really know what I am doing when it comes to timing. So my question is can I just adjust the CAS and listen until it gets outta loop? O yea when i give it gas it is sputtering a little bit. New plugs NGK. Sorry I am kinda a rookie dont flame me

[s13point5]

sounds like it just needs to be timed right. it might be pulling timing. do a search for timing and there should be a couple threads that will tell you how to check your timing. you cant just "guess" where you timing is at by listening to the motor

[Voltron240]

OK well that is helpful. On the ka I would always turn the distributor and it sounded like it ran better. Even passed emissions one doing that. I know the CAS isn't the same but I is worth askingThanks

[mello88]

I must know what loop mode is

I assume you mean it's just not idling well.. Timing lights are pretty cheap, go pick one up. Sounds like you've needed one for a while now I'm sure you have a friend who has one if not.

To set the timing, get the engine warmed up then unhook the TPS. Hook the induction clamp for the gun up to the loop of wire sticking out near the transitor pack aka ignitor. Give it a few revs then aim the light at the crank pulley. Read the FSM for your timing, I think rb25 m/t ecu wants 15 dbtdc. The marks start at 0 then 5,10,15,20,25 and 30 (DEG BTDC). The whole process is in the FSM if you want to look it over first to be sure of what you're doing.. When you're done hook the TPS back up..

[gawdzilla]

btw cheap timing light is like $20, or you can rent one at advance auto

[rb25drag]

If its like my motor the tune seems to change with the weather so Im always re-timing mine. So your better off just buying a light. Look for one at a flea market or yard sale.

[l0nestar]

btw cheap timing light is like $20, or you can rent one at advance auto

You beat me to it. :-\

[Carl H]

set the cas in the middle of the bolt slots and 90% of the time thats 15* assuming the belt has been changed and has not streached.