Primary boost issue
 

Hi,

i bought a 99' jdm rx7 with stock engine (ok, thats what they told me ...) and i don't get any boost from the primary turbo. until 4500rpm the stock boost gauge shows nothing and then instantly it gets boost. The engine noise also changes a lot and you can feel the power increase. I didn't drive the car often yet (not legalized atm) and first did not notice that, but after reading some threads and learning about the sequential turbo system i think it is either non sequential or there is a problem somewhere. I took me a few hours to read all the FAQ/Threads about Troubleshooting for turbos and to learn how the system works, but i think i now got an idea. Someone else with the same problem had wires connected wrong to the solenoids and banzai-racing said they fixed that once by exchanging the turbo control solenoid. Is there another possible reason for such a behavior? For the case its a non sequential setup, is there a way to check this fast? Is it easy to get back to sequential?

Thanks for help.

i forgot a question - if i had leaks somewhere, i should at least see some boost right?

any ideas/comments?

1. build or purchase a boost leak pressure tester. Fighter's Garage has one. Use that to locate any possible air leaks.

2. if you aren't sure about whether this thing is non sequential or not, post some pics of the engine bay

i took some Photos and recognized that i dont have the black plastik box in front of the uim.
i mean this:

https://img521.imageshack.us/img521/...ovalmv5ly6.jpg

theres also one unconnected vacuumhose and the electrical connections of the ?solenoids? are marked with white dots. so somebody did something there :|... Thats what it looks like:

https://img705.imageshack.us/img705/2513/26207141.jpg

https://img220.imageshack.us/img220/8900/57475130.jpg

https://img257.imageshack.us/img257/3306/91571510.jpg

more engine bay shots:


https://img97.imageshack.us/img97/3962/rx7002.jpg


https://img257.imageshack.us/img257/8210/rx7001.jpg

Re-attach that hose.

i cant because this one attaches to the pressure chamber which i don't have. i also recognized a cap on one of the oil filler necks nipples. I also did not find the vacuum chamber yet. Sings for non sequential set up if i'm not wrong?

oil filler neck cap seems to be stock. where is the vacuum chamber located?

It should be right next to where your crossover pipe comes close to your UIM, between the UIM and the strut tower bar.

You can see it in the picture you posted with all the colored circles on it. The bottom blue circle shows the bolt that holds the vacuum chamber in place.

this is the pressure chamber, im looking for the vacuum chamber! as you can see on the other pictures (which show my car) i don't have the pressure chamber. im trying to find out if my car was converted to non sequential or if just some parts are missing. any hints much appreciated!

I misunderstood what you were asking, my bad =)

Looking from the front of the car, the vacuum chamber is to the right of the alternator, in front of the oil filler neck, right under the intake elbow.

From the pictures you posted, I don't see it there either

will have a close look again tomorrow. thank you!

pull the intake and ypipe off and see if the crossover valve is stuck. Not saying it cant be the solenoid. But if the butterfly valve isnt stuck then its one more possibility you can eliminate. its really easy to check

Hi, crossover valve = charge control valve? How can i test this?
i think someone deleted the turbo control actuator/valve, but i will find out. thanks!

when i had my ypipe off i pulled the actuator lever and it wasnt tight/jammed up. not sure how they are supposed to feel but when i put it back together everything ran great. i dont have all the vocab down can only say what i experienced

The crossover pipe is the top piece of the y-pipe that attaches to the intercooler.

The charge control valve is the valve that's inside the y-pipe. To test it have someone turn on the car as you watch the actuator arm pull itself in and it should stay pulled in the whole time. Then you shut off the car and remove the vacuum hose to it and the arm should pop right out again. It should be moving in and out very quickly and smoothly.

If you have a vacuum pump tester you can just attach it to that and test it without needing to turn on the car.

If someone deleted the turbo control then it would be to run non-sequential. You can also just see if the 2 green turbo control solenoids in front of the UIM are still there