I've recently done quite a bit of work on my car. I installed a ceramic coated DP, Efini Y pipe, EGR block off, 180 degree thermostat, 185 degree thermoswitch, an AST, and a full coolant system service. I had to replace some vacuum lines along the way because they were crusty or just seemed a little too stiff for my taste. Now I'm having this issue that if I'm not already under boost when I hit 3000 RPM, my car bogs like I'm in a higher gear. During this time my gauge shows no boost. Once I hit 4500 RPM the secondary kicks in like it should and all is normal. So an example of whats happening would be: I'm cruising along in 3rd gear just above 3000 RPM. I floor it, my boost gauge goes to 0 and the car slowly accelerates until I hit 4500 RPM. If I let off the gas for a second or two then floor it again it will boost like it should. When I say it slowly accelerates, I mean abnormally. I've driven this car with no boost before and know it's capable of being much quicker than what's it does during these episodes. Any ideas as to what might be happening? Why do I not get any boost if I'm not already under boost when I hit this range? How does the secondary boost normally if the primary isn't?

 

^^Bump^^ Bueller? Can someone tell me if I'm even on the right path? I'm not sure if this is a symptom of the well known 3k hesitation, or if the problem is with something else.

 

it sounds like a vaccum line me be in the wrong place of a actator is not hooked up.

 

If that were the case it seems to me I wouldn't get any boost under any circumstances, not just in the 3k-4.5k range, and only if I'm not under boost already. If I'm already under boost it will continue to boost through that range. If I'm not already under boost and happen to be in that range it won't boost. If I let off the gas for a second or two and punch it again it'll boost too.

 

Definitely not the 3K hesitation. That has little to do with boost. It feels like someone let up on the gas and then went down a few times very rapidly. It's not spread across a 1500 RPM range.

I agree with evo koa given that you replaced some vacuum lines. Something is a-mis here. My guess is that something to do with the Charge Control or Charge Relieve valve / solenoids is mis-connected.

 

Ok, now that I have a clear idea of what symptoms are of the 3k hesitation, I can now rule that out. I was thinking more along the way of vacuum lines myself, but it doesn't seem to make sense that it only does it under particular circumstances. No problems with the secondary turbo, so that leads me to believe that the CRV is ok. I'll recheck all my vacuum routing and make sure something isn't kinked or maybe even come off completely. I remember there being a vacuum nipple on the intake manifold that faces to the left, and all the others in that line facing to the right and having a hell of a time getting that line on. I can't remember off hand what that vacuum hose controls.

 

let the fun begin:
https://www.rx7club.com/3rd-generati...-turbo-749702/

 

I agree with James Pavent, et al.

Take a carefull look at the vacuum circuits and solenoids controlling the TCA and possibly the CCV.

 

Well I checked the vacuum lines I replaced again yesterday and discovered that yes I had the lines for the CCV and the CCA mixed up. Easy mistake to make since they come from the same place and almost go to the same place. Since they're so close to each other I swapped the lines and life was good. Now the range where I wasn't getting boost makes sense. I appreciate everyones help. Thanks.

 

Glad you figured it out!