turbo Q's

damonmlime · Post by **damonmlime** » Sun Feb 20, 2005 8:42 pm

i have a 91ss 5spd w/143,000 on the clock, at what rpm does the stock turbo stop pulling, it seems like between 3k-4krpm it pulls like hell, then it just starts to pull like na, the cars all stock and as far as i can tell just about all original. the reason i ask is because my gf has a 91ss 4eat and it seems like it pulls alot harder than mine, but i noticed that her car shifts at about 4krpm, maybe thats the effiency range of the turbo? btw, i pulled the codes last week, had knock sensor code and idle air control valve code, changed the knock sensor and the cleared the codes at the shop, now no more codes. thanks damon

vrg3 · Post by **vrg3** » Sun Feb 20, 2005 8:50 pm

It should continue to pull beyond 4000 RPM. When was the last tuneup? Did you replace the air filter recently?

damonmlime · Post by **damonmlime** » Sun Feb 20, 2005 10:31 pm

I just put plugs and wires in last week, i thought that was the problem, airfilter is new as well, btw are the na and turbo wires the same? i used a set that was supposed to go into my 95l that i never got around to installing. i thought my problem was a vacuum leak, the hose that goes from recirc valve back to intake tube was cracked, i replaced that and it seemed to help a little, the hose i have on there now is slightly kinked, would that make a difference?

vrg3 · Post by **vrg3** » Sun Feb 20, 2005 11:53 pm

Turbo and non-turbo wires are the same on first-generation models. I don't know for sure if 95s have the same wires.

I don't see why a little kink in the recirculation hose would cause sluggishness at the top end.

I wonder if maybe you're not making enough boost. Have you measured manifold pressure?

damonmlime · Post by **damonmlime** » Mon Feb 21, 2005 12:25 am

how can i measure boost? i'm new to the joys of turbo cars, i dont have a boost gauge, the turbo sounds normal as far as i know, how will i know if theres something wrong w/my turbo? how long do they normally last? sorry for all the noob questions. thanks damon.

vrg3 · Post by **vrg3** » Mon Feb 21, 2005 12:28 am

You can measure boost with a boost gauge or with my scan tool.

If you're getting low boost it's most likely not the turbo's fault but rather something else in the boost control system (vacuum lines, ECU, boost control solenoid, etc). Normally, the wastegate is set to open at around 6 psi but the ECU uses the boost control solenoid to raise boost up to about 8.7 psi.

damonmlime · Post by **damonmlime** » Mon Feb 21, 2005 12:35 am

So basically i can plan on spending my summer replacing the miles and miles of vacuum line under the hood

where would be a good place to start? thanks vrg3 i appreciate your help.

vrg3 · Post by **vrg3** » Mon Feb 21, 2005 12:39 am

The vacuum hoses actually aren't that complicated:

http://www.graphics.cornell.edu/~v/vacuum/

But I would start by building the scan tool if you have a PC-compatible laptop with a printer port that you own or can borrow:

http://www.graphics.cornell.edu/~v/bcbfscan/

damonmlime · Post by **damonmlime** » Mon Feb 21, 2005 12:49 am

thanks vrg3, im gonna try to build the scan tool this week, if there was a problem w/the ecu wouldn't there be a trouble code?

vrg3 · Post by **vrg3** » Mon Feb 21, 2005 3:22 am

I'm not saying there's a problem with the ECU... it's just that the scantool can tell us what the boost level is and whether or not the ECU is driving the boost control solenoid (if it's not that might indicate another problem).

In general, it's possible for engine management problems to occur without throwing trouble codes.

damonmlime · Post by **damonmlime** » Mon Feb 21, 2005 4:48 am

well here's great news, my gf's laptop is out for repair, that plan didn't last long. anyway, is there any other way i can find my problem? how do i measure boost at the manifold? will the scantool that my mechanic uses be able to do the same thing the laptop program could do? would the "D-Check mode help me at all? thanks damon.

J-MoNeY · Post by **J-MoNeY** » Mon Feb 21, 2005 4:53 am

Go get a mechanical boost gauge and splice it into the only hose comming off the intake runner. It's a small black hose.

vrg3 · Post by **vrg3** » Mon Feb 21, 2005 3:20 pm

If the mechanic has an actual scan tool that can interface with our cars, then it should be able to tell him manifold pressure. Chances are that it doesn't interface with our cars though.

Any decent mechanic should have a pressure gauge that he can connect to your intake manifold though.

But J-MoNeY's advice is sound; it makes good sense and doesn't cost very much to install a boost gauge in your car, especially if you think you might ever modify the car.

free5ty1e · Post by **free5ty1e** » Mon Feb 21, 2005 3:36 pm

I second the boost gauge solution. If you ever want to modify your car's performance you'll need one anyway, not to mention it's very helpful for diagnosing problems such as this. It's probably the most important, essential gauge for a turbocharged vehicle. It'll also give you a good vaccuum reading, bringing the health of your valves into light. It's just all kinds of good.

Besides they're available new for under $50. Very simple and common mechanical item. Look on eBay if you want 'em cheaper.

And the standard cup mounts attach nicely to the a-pillar without any special molded plastic pieces. Just takes a little thinking in three dimensions...

damonmlime · Post by **damonmlime** » Tue Feb 22, 2005 1:11 am

now the car is really pushing the limits of my patience, last night i went to take it out for a little drive, ran decent although still not what it should be, i stopped for a minute and it started to idle really rough, tonight i'm gonna try to see if i'm getting any codes. and on top of that the damn drivers door window wont go up or down now! bastard car.

J-MoNeY · Post by **J-MoNeY** » Tue Feb 22, 2005 5:41 am

damonmlime wrote: now the car is really pushing the limits of my patience, last night i went to take it out for a little drive, ran decent although still not what it should be, i stopped for a minute and it started to idle really rough, tonight i'm gonna try to see if i'm getting any codes. and on top of that the damn drivers door window wont go up or down now! bastard car.

I'll give you 50 bucks for it. Cash MONAYY.

damonmlime · Post by **damonmlime** » Tue Feb 22, 2005 6:26 am

thanks.

free5ty1e · Post by **free5ty1e** » Tue Feb 22, 2005 4:48 pm

hahahaha.... I was thinking about posting the same thing - if you want to sell the turbo legacy Damon I wouldn't mind having two

If you decide not to deal with the car any longer there are plenty on this board who want an EJ22T... (or another)

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turbo Q's

turbo Q's