Follow up to 3K sputtering thread

[asher4857]

I've been looking for that thread but I can't seem to find it. Anyway, I sorta thread jacked it about a similar problem dealing with hesitation at 3k. I had recently installed my 3" exhaust system and when being taken for a drive, around 3K rpm, it started to stutter pretty bad.

I believe it was float who suggested that I check if i was hitting fuel cut due to boost.

Well, I installed my boost gauge today and he was correct. At 12 lbs of boost at around 3 - 4K, the car stutters and no longer boosts. Just putting this info out there..

[rico05]

For me, with my .80AR T25G, I can hit 1bar spikes without any drama. I think you still have another issue.

[asher4857]

i think you're right as well, my boost gauge on the vac side only reads 10... where as anumerics reads 20.. so were looking into that..

[sideways danny]

i think you're right as well, my boost gauge on the vac side only reads 10... where as anumerics reads 20.. so were looking into that..

worn CAS splines on the cam, plug gaps not correctly set, timing not correctly set, O2 sensor wires have a bad connection. could be any of these but I think most likely timing

[asher4857]

no timing is dead on... we did that when i first got the motor and it was such a pain in the *** to get it dead on that im positive that it is

[ca18hatch]

I had a similar stuttering problem at low RPMs, I replaced the O2 sensor and it runs great now...May not be your problem, but just an idea.

[kapower06]

i think you're right as well, my boost gauge on the vac side only reads 10... where as anumerics reads 20.. so were looking into that..

You have a leak somewhere if its only pulling 10 in. hg. at idle. Thats bad. It should be around 18-21 in hg. depending on your idle rpm and engine temp.

Once you sort that issue out, come back and let us know what its doing. Also what MAFS are you using?

[asher4857]

I believe im using a SOHC KA mafs. I'm gonna do some tests sometime this weekend probably to see if i can find the leak