I have about 20,000 miles on a reman engine in a 94. Mods: Petit Downpipe and MazdaComp Radiator (I bought it that way). A month ago it was doing a nice 10-8-10. Boost is now at 5lbs across the board. A little bit of hesitation at low RPMs.

My mechanic is out of town until next week. I called one shop and they said that maybe my turbos are dead. I have no idea how to check vacuum lines. The diagrams I found by searching this site are intimidating like a rubic's cube. Any thoughts and insights would be appreciated. Thanks in advance.

..H

 

Reads like a vacum line problem on the wastegate soleniod. Perhaps its popped off.....??

Your 5-psi is pretty much wastegate spring pressure

 

wastegate spring pressure is 7-8psi, not 5.

Check for boost leaks in your couplers, starting with the y-pipe coming off the turbos. Remove each coupler and really LOOK.

Dave

 

Agreed - this is the most common and easiest to fix problem with these symptoms.

 

I will check for boost leak. It spools a bit then there sounds like some air is just getting blown into nothing like something is loose. Thanks for the advice guys, much appreciated.

 

Definitely sounds like a "simple" leak vs a control system problem. Physically (not visually) check all couplers. Also check the 1" hose from the y-pipe to the BOV...that's notorious for slipping off a little bit at higher mileage.

 

I had the same problem and it was the coupler connecting the cross-over pipe to the y-pipe. Had about a 2" long tear in it.... Took several trips to the shop and hours in my garage to find it! So LOOK hard

 

turn them inside out and really look at the couplers..just as rynberg said...happy hunting

 

im having the same problem lol. almost sounds like there is no filter on the turbos a real loud intake noise by the passenger side firewall. sorry for the highjack

 

Whats Up Guys Im Having A Boost Problem Too... But Instead Of Stay At 5 Psi Or Anything Like That My Boost Spikes Up To 14 Psi Some Times...the Car Is Basicly Stock With A Racing Beat Exhaust(no Mid Pipe) And Plug Wires And Fluidyne Radiator

 

If you remove it from the car first, tears are very easy to see.

Dave

 

Do the same thing.

 

yea now i feel like a real rx7club member now that ive had my first problem with the car

 

fixed my boost issue after reading this 20+ times

http://www.autosportracetech.com/RX-7/rx7stuff.htm

 

so a friend stuck his head in my engine bay as i reved. it ended up that the pipe that goes under my strut bar was loose. I think that is what you call the y-pipe? (black plastic and about 3 inches in diameter). I put the pipe back in and tightened the clamp around it. 10-8-10 again. However the mount that goes around/under the pipe has one end that seems to be missing a bolt. There is also something attached to that mounting point (small black box of some sort). That black box now dangles and the other mounting point it has is broken also (it looks like it attaches to something that looks like a header). Im bringing it to the shop this week to see if that needs to be replaced. Thanks for the help guys.

 

Thanks for coming back with your results.

The black box is the pressure chamber. It doesn't really need to be bolted down at all, as long as it's not leaking.

The bracket under the y-pipe crossover pipe connects to the pressure chamber on one side, and nothing(?) on the other.

In any case, you have nothing worth scheduling an appointment about IMO.

Dave