my new supra has the hiccups

[SUPERSNAIL]

i just got a 87 turbo with about 115k on it im am looking to make this baby my daily, I am slowly giving the car a full tune up and replacing all sensors hoses worn parts ect, I am having an issue with the car not bucking from around 2500 to 3300. It seams to be boost related, i can hear the turbo starting to spool but the gauge reads -4 and the car just sputters till i floor it then the needle will jump and the car will run fine to red line, its almost as if the turbo is spooling and the boost is not holding. I have searched and from what i have read its pointing to the stock bov "fluttering" or closing and opening a couple times before finally closing fully. I am hoping someone can shed a little light on the issue as this is my first turbo car, I am a honda guy looking to make my first honda/mustang smoking supra, Any advice will help thank you.

 

[Rennat]

check codes per the TSRM. and get use to going to this site.

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/default.aspx

how to check codes:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=23

list of codes:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=26
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=27
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=28

 

[Zumtizzle]

you seem to have classic signs of a boost leak.

this will NOT show up in any obd diagnostic tests.

Search Boost Leak Tester and it's pretty straight forward.

 

[Rennat]

dont boost leaks also cause fuel cut?... if so then it will throw the fuel cut code.

and its always good to show people how to check them, that way they'll know in the future too.

but if its just a boost leak, check the coupler between the throttle body and the "3000" pipe... and also check the pipe on the outlet of the turbo. those are the normal ones to cause issues.

 

[logan]

I had this problem, it turned out to be a vac. leak in the pcv pipes coming off the valve covers next to the 3000 pipe. Figured it went away under boost due to the check valve.

 

[Rennat]

theres no check valves in our PCV... especially the ones on the valve covers, those are just vents back to the intake.

 

[SUPERSNAIL]

You only throw codes if the check engine light is on correct??

 

[Rennat]

you could have stored codes from before. like the fuel cut code only comes on for a few seconds (while fuel cutting) and then goes away... but the light doesnt stay on or flash.

 

[SUPERSNAIL]

you could have stored codes from before. like the fuel cut code only comes on for a few seconds (while fuel cutting) and then goes away... but the light doesnt stay on or flash.

ok well tonight ill look for a vac leak and check for codes, So this does not sound like the bov getting stuck open? thats what it looks like to me just because of how it sounds spooled but theres no psi then it will jump on almost instant like but the turbo sounds the way it did when it was jumping.

 

[Zumtizzle]

the stock gauge is very very slow.

 

[SUPERSNAIL]

the stock gauge is very very slow.

That i know, i have read over 50 articles in the past couple days trying to gather all the info i can as the whole turbo thing is new to me. But the turbo is spooled a good while and the gauge goes up at the same time as the bucking stops, But like i said, noob, ill take the advice and check tonight thank alot ill update you all as soon as i am done.

 

[SUPERSNAIL]

Ok good morning everyone, I found a broken vac fitting on the back of the intake manifold so i replaced it and it appears to have resolved the issue and my car is also making about 5.5 lbs of boost now not 3 lbs so i am going to give it some more time make sure the issue is gone thanks for the help guys.

 

[SUPERSNAIL]

So i took a couple days to drive the car and it feels better but the issue is still not resolved,It does however happen less often. I am going to assume that there are other leaks elsewhere and i will be looking for them.

 

[SUPERSNAIL]

Okay so i have replaced and verified the route of every vacuum hose on the car, there all ok, no boost leaks ver that, also another piece of info that may help is i noticed that it goes away after a period of time, could be motor temp getting higher and i had a friend suggest it may be my egr? Would that cause a sputter between 2 and 3k at anything less then wot? this is driving me crazy, :aigo:

 

[SUPERSNAIL]

my issue is just like this guys issue

http://www.supramania.com/forums/showthread.php?t=85322

 

[jdub]

You really need to check ECU codes as previously suggested

 

[SUPERSNAIL]

You really need to check ECU codes as previously suggested

I have there are none stored and i have never seen the light on

 

[nosman4]

You said in your very first post that the car sputters until you floor it and then it goes away. Does this mean it doesn't do it if you floor it in the begining? I'm kinda unclear on what exactly you are doing when it does this? I would also check all your intercooler couplings and pipes, especially the one right off the turbo. This one tends to be the first pipe to get old and crack from all the heat.

 

[SUPERSNAIL]

You said in your very first post that the car sputters until you floor it and then it goes away. Does this mean it doesn't do it if you floor it in the begining? I'm kinda unclear on what exactly you are doing when it does this? I would also check all your intercooler couplings and pipes, especially the one right off the turbo. This one tends to be the first pipe to get old and crack from all the heat.

thats correct if i floor it right off the go no sputter, and i checked for boost leak with the diy boost leak info found here on sm no leaks at all

 

[SUPERSNAIL]

Just so everything is on one page and so we all know where the car stands as is ill start over, the car is bucking from around 2200 or so till just over 3k rpm ONLY out of wot, if i floor it from below the rpm or while bucking it stops, I have checked codes and there are none stored, I have replaced and ver all vac hose routes, Replaced bov and adjusted.I checked ic pipes for leaks and found none. afm and tps connections are tight. plugs and wires are ok. and the issue will suddenly go away after about ten min of driving after the car is warmed up. so i am just looking for direction at this point, any help is appreciated.