89 turbo supra 5 speed dies in mid shift????

[jtown125]

My supra is dying in the middle of a shift. The idle is good, is doesn't die any other time. It only seems to die when it drops from a higher rpm to a lower one...it just doesn't seem to catch back at idle all the time. No check engine light. Any suggestions?

89 turbo supra 5 speed...
new motor with about 6,000 miles on it.
rebuilt tranny as well...

[jtown125]

acutally I just got to looking back at the original post of the problem when it first happened...which happend to be last april.

Im 80% sure that its the BOV due to the fact of all the boost buildup between shifts.

Oh, and it isn't throwing any codes btw.

But, my options....

Get a new BOV, but will that fix the problem? Is the problem that it is releasing the build up air too fast or that it isn't releasing the air like it should?

Bypass valve...

or OEM stuff...which is horrible....

[btwilson86]

Is it an aftermarket BOV venting to atmosphere? If so, then that's very likely the cause of your problems. It isn't that the air isn't released properly, the problem is that the computer is expecting that air to still be in the system (because of the factory BPV). Since the air isn't there, the engine runs extremely rich during shifts, and this can be enough to stall the engine.

[jtown125]

@btwilson...
in my original post last april you were the one who suggested that it was the aftermarket blow off valve...
Question: It is an older type blow off valve not a ssqv.
From what I read, the newer style valves allow for the air not to completely escape unless under extreme load.
So, my question is will a newer style bov help out any?

I don't want to go back to the OEM style, I would rather go with an aftermarket bypass valve.

Also, in the original post I said in my last post that I had reset the computer and I had no problems out of it....until now....
ten months later... which confuses me beyond all belief...

I reset the computer last night and took it out with no luck...

I have a really retarded question too:
If I was to take it too a shop and get them to tune it to where the timing was retarded a little would it make up for the stall?????
The car runs extremely rich in the first place....

[cre]

ROFL..... you really should stop asking for advice if you're just going to ignore it.

You have a couple options: Ditch the BOV for a BPV. Connect a BOV AND a BPV OR find a dual outlet BPV which will recirc one of the two ports and blow off the other at the same time.... they *help* for half the build and for the other half they don't make a difference... they're pretty hard to find and I think they're pretty expensive. The only other option is to buy a fuel controller with throttle tip-in and tip-out tuning and get the system tuned for it.

Timing isn't going to do shit but cost you more power and has absolutely NOTHING to do with how much fuel the ECU thinks the engine needs. No, newer BOVs do not let out any less or more air than older ones... it depends entirely on how the BOV is tuned (if it's adjustable; a feature even many old ones had). There isn't a design out there that I know of that is so vastly different that I'd believe that line of crap.

[jtown125]

@cre...

this is the bov that is on my car

if its adjustable, i don't know how to.

I was wrong in the earlier post it is a ssqv bov, just a older discontinued item.


http://www.streetunit.com/HKS_SSQV_B...1421-sa001.htm

[cre]

There are spring kits and a re-circ kit available for those. The intent in adjusting a poppet or valve isn't to limit the amount of air that's exiting as that also induces surge (the whole reason for the BOV/BPV to begin with)... The purpose is to set the amount of vacuum required to open the valve. You should get the hardware to tune it OR run it re-circ and get over the "uber cool whistle", IMHO.

[cre]

By the way, adding a tighter spring or adding a restriction to the reference line (which I didn't discuss) won't fix the problem... they're hacks which will cause another type of problem and just REDUCE the existing one... you'll still spike rich when shifting (which has NOTHING to do with how rich the car runs normally) and you may still run stall periodically. They're just hacks.

With a healthy turbo a LITTLE surge isn't a huge concern and will improve throttle response during a fast, high load shift (see automatic transmission )... It's not something you want to expose an old turbo to as much as possible.

[jtown125]

"get over the "uber cool whistle", IMHO. "

I think that the uber cool whistle makes the car....
the one thing I enjoy most about the supra is when someone who has a very expensive car with a v8 pulls up beside me at a redlight... I laugh.

and i know that everyone on here can appreciate that.

Im not going to drive it for a while since the kit is just as much as a bypass valve or an offbrand bov. I know it isn't good for it.

And if it is still going to do it with a new spring kit I don't see that being the best idea.

I like putting both the bov and bpv on...

If I was to recirculate...where would i put the other end of the hose?
Cause its a cold air intake with the bov.

[btwilson86]

It would have to recirculate to the intake hose between the AFM and the turbo.