bureau_c

OK, now this is a weird problem. I just had my turbos replaced (stock sequentials) and a vacum hose job, checked all the solenoids (replaced two) etc. Unfortunately, things are very far from being right. I get essentially no boost at all in 1st or 2nd gear (gauge reads maybe 1 or 2 psi, max). There is no loud wooshing sound, which would be indicative of a major boost leak. In 2rd gear, I get full boost, although I'm not sure the boost pattern is right. First things first though, gotta get something going in the lower gears.

My mechanic says he was driving it yesterday and got a little mad and slammed the shifter into gear a bit harder than usual, and suddenly it worked fine for a couple runs. He thinks MAYBE the 1/2 gear switch on the transmission is bad, and this is somehow preventing the car from boosting in those gears. Now...is this even possible? What does this switch really do? The primary really is not rocket science...exhaust gasses spin the turbine, it rams air into the intercooler. I suppose the wastegate or precontrol could be stuck open, but even then I don't think it can flow enough to limit me to 1-2 psi. All the weird magic **** happens at the transition to primary+secondary. Assuming I'm correct and there is no split hose or something with a massive leak...what else could cause this? I guess maybe a bad primary turbo...bearings partly seized, can't get spinning enough until the exhaust pressure in 3rd gear? However given that the turbos have new cartridges that doesn't seem too likely. Any other ideas? Is this 1/2 switch thing even possible?

Thanks in advance,
jds

alberto_mg

Is it an auto? Don't understand that 1/2 gear switch thing. Never heard of it.

A few weeks ago I had a similar problem where I couldn't get boost in 3rd gear. I got decent boost in 1st, 2nd and 4th, but nothing more than 2psi in 3rd. This happened after replacing the fuel pulsation dampener. My mechanic went through my vac system a few times and couldn't figure it out. We finally re plumbed the entire vacuum system according to the simplified sequential diagram and that helped. The simplified sequential gets rid of a few solenoids. We also changed out solenoids to test if it was a solenoid and had no luck. Now my boost is 10-7-7 in all gears. We also just replaced the cat to see if it was an exhaust restriction, but it did not help. I think the pills are still in there so I know that is not it either. I remember checking for the pills and finding them both there.

I would suggest checking the rubber hoses and clamps for the BOV things as they get brittle and crack. If those are good, then you are gonna have to recheck the vac lines. Considering the turbos are new it has to be the vac lines. Actually, are the turbos new?

bureau_c

The turbos were just rebuilt. One would hope they passed muster when they came back from the rebuilder!

I really don't know anything about this 1/2 gear switch. The car is a manual. Is that switch really only on an automatic? If so I'm guessing that won't help! :-D Even if its present I can't find anything that describes what it does.

Supposedly, the rats nest of vacum lines was just redone...I'm sure something in there could have been done wrong, although these guys have done quite a few of them. Still...what hoses or solenoids really affect primary boost to the point of making it almost 0? Is that even possible, without a major boost leak somewhere?

jds

seandizzie

iTrader: (1)

I know this sounds dumb, but check the intake hose to the primary turbo and see if it is cruched in. mine did that and it would barely make any boost and wouldn't transition. I ended up having to get hard pipes.

impactwrench

SEAN, YOU ARE ON THE MONEY, HAD IT HAPPENED TO ME. FIRST GEAR SECOND GEAR SWITCH IS IMAGINARY. ANY BODY WITH A CAPS LOCK PROBLEM NEEDS TO GET A LIFE OR POSSIBLY A GIRLFRIEND. PLEASE NO HOMO REFERENCES, I HAVE BEEN HAPPILY MARRIED TO THE SAME WOMAN FOR 21 YEARS AND YES I AM A MAN. ALSO I STARTED OUT AS A MAN...... NO OPERATIONS.

RX7Wishing

lol.. just incase you didnt know... witch from your post you probly dont.



Also i just thought i might add.

bureau_c

That's a good idea, I had forgotten about that particular problem that occurs. One thing that doesn't seem consistent there is that I am getting boost in 3rd gear. However, I wonder if somehow in 3rd I'm operating in twin mode, it did seem to build boost a bit more sluggishly than I expected....

I'm not sure the best way to check for a collapsing intake hose, given that its only doing so under boost, rather than when I'm looking under the hood. The shop may have a spare though.

jds