volley1

Hey, I have a totally stock 93 with 68K on it. When I got it just a month ago my boost pattern was 10-8-10. The only things I have done are boost gauge, mobil 1, MMO in the fuel, fuel filter, air filter, belts. A couple of days ago I drove the car in the morning and it had a pretty bad 3K hesitation. The last time I drove the car it ran totally fine but the primary boost was going up to 11-12 psi. I obviously backed off and haven't done a boost test on the car. Any ideas of what might be wrong? I did a search, but didn't find much on primary boost being too high, it is usually the other way around. Any help would be greatly appreciated.

spurvo

How did you know the 10-8-10 before you got the boost gauge? Or am I just confused?

My boost goes to 11 or 12 with the addition of a downpipe and moderately cool weather...

volley1

Sorry, I installed the boost gauge right when I got the car. The problem has only surfaced within the last few days.

n/arotary

iTrader: (1)

I seem to be having the same problem.

I just bought my 94 Rx7 a couple of months ago with 60,000 miles. It is completely stock. I just installed an Autometer Boost Gauge, because I was pretty sure my second turbo was not boosting all of the time. When, I drove the car for the first time. I noticed after driving a little while, whenever I would give it a decent amount of throttle the boost gauge would go up to 12psi. This happened in first and second gear.

Also, I did confirm that my second turbo wasn’t working all of the time. Initially when I got on the highway it seemed to have the 10-8-10 pattern, but right after that my second turbo would only put out 5psi, and then I noticed that I was getting 12psi from the first turbo. Both made me worry, but I am more concerned about the 12psi.

Is there any possibility that the gauge line has some problem? Maybe a kink or bad connection, but I would think these would lead to an under boost reading.

Also, at idle I initially read 18 vacuum, then after driving the car the vacuum was right around 20.

volley1

Bump, really need help on this one. I am afraid to even do a boost test because I have been hitting 11-12 psi with letting off when I see the gauge going too high. What should I do?

volley1

bump

skunks

home depot boost controller or eletronic boost controller.

volley1

So, you think that will fix the problem or do I maybe have some kind of vacuum leak? I am planning on doing the vac lines here in the next month once I get my gauges, dp, and exhaust installed. Should I just kind of granny drive it until I do the vac lines or buy the boost controller now? Thanks for the help.

apneablue

You could add the home depot controler and open up the turbo precontrol a bit and it will lower it...that's if you don't want to spend $320 on a boost controler...

LAracer

You are in Denver?

High primary boost maybe due to high altitude. It is actually supposed to boost higher at high altitude - your boost gauge says 12psi, but that's 10psi absolute pressure (boost gauges read pressure relative to local atmospheric). Therefore, you should be safe driving the car. Do a 3rd gear run and see what the post-transition boost looks like. typically it is lower at altitude. If your post-transition boost is also higher than 10psi, you may have a problem. Also, let me know when transition actually occurs - at 4500rpm or a little after?

There's quite a bit of info on boost at altitude on this forum now - just do a search on my name. (I'm at 7000ft, by the way.)

I brought my boost closer to normal by installing needle valves (the "home depot" boost controller). Info can be found here:

http://www.rx7turboturbo.com/robrobi...controller.htm

Good luck

DarkHeaven

Yeah!! mine goes to 16 PSI sometimes!! I have a d/pipe and a blitz nurspec exhaust.. why is that? is it dangerous? how do I fix it? and why do i sometimes get secondary and sometimes i dont?? thanks for your help!

bureau_c

Well, if he originally had 10-8-10, nothing intentionally changed, and then suddenly he's hitting 12...I would try to understand what broke/malfunctioned/changed before applying band-aids. Case in point: Me! I just installed a pair of ball-and-spring manual controllers Damian-style (do a search on 10-8-10, I don't have the thread link handy) and even at the most wide open setting (from the perspective of the controller) I'm overboosting on my primary by a lot...very much what is being described in this thread. Once in twin mode I seem to be rock solid at 10psi. I thought I was just seeing spiking due to a more open exhaust than the ECU was calibrated for, but it turns out maybe there is something else going on. What, I have no idea.

jds

bureau_c

Dude, you need to get your car to someone who knows the boost control system, and stay out of the throttle until you do! Yes, its bad to hit 16 psi with only a dp and catback, and there are umpteen billion reasons why you may not be boosting consistently but its really impossible to diagnose further without more info.

Flyrx7

iTrader: (1)

I find it hard to believe you are reaching 16#'s without hitting fuel cut. I didn't see anywhere in your post's what boost gauge you have. YOu might try to borrow a friends gauge and compare. Also, where did you hook up your gauge?

Frank

SleepR1

Uhh, the posts above are merely guesses @ what your problem is. Here's a real reference guide for troubleshooting sequential turbo control problems. http://www.autosportracetech.com/RX-...leshooting.htm

volley1

I will check out the troubleshooting site. I have an autometer gauge. The only thing I can think of is I changed the belts and started to take off some of the heat shielding for my dp install. I don't know if maybe the intake and intercooler piping was not put on tight enough and caused a leak. I would think that would lower my boost, not raise it. Anyway, the only other thing that I removed was the little plastic bottle with two hoses that go into it. It is just in front of the UIM next to the crossover tube from the y-pipe. I am sure I hooked it back up the same way it was before. I will do some looking around this week and see if I can find anything. I plan on doing a hose job here soon so maybe that will cure my problem.