PDA

View Full Version : st185 Boost Problems



jdm_celica_gts
05-04-2013, 06:32 AM
Was going for a drive tonight and when I went full throttle I hit 10 lbs of boost and around 4700 rpms I hit what felt like fuel cut... And now I can't boost at all, as soon as the turbo starts to spool my car just stops accelerating. I already checked my intercooler piping and there are no leaks.
Any ideas?

Hookecho
05-04-2013, 08:55 AM
Check engine light? Go ahead and pull codes anyway. Could be the knock sensor died given your description. If it sputters when trying to build boost then it's probably a boost leak or ignition problem.

jdm_celica_gts
05-04-2013, 02:46 PM
No cel. I'll pull codes later today. It doesn't sputter, it literally feels like the car hits a wall, then returns to normal idle when I let off the throttle.

jdm_celica_gts
05-04-2013, 07:23 PM
Got codes. 1 2- (rpm signal) what is this?
3 4- (turbo pressure signal) fuel cut?
4 3- (starter signal) would this be related to code 1 2?

Shadowlife25
05-05-2013, 11:29 AM
Dude, you hit fuel/boost cut. Clear your codes from the ecu and it will be fine. The ignition thing can get thrown from a slow start as well so if that is related, don't freak out too much. Just check your vacuum lines and your ignition system and see where you stand afterward. Best of luck

jdm_celica_gts
05-05-2013, 02:24 PM
Thanks, I thought it felt like fuel cut, but I hit fuel cut at 10 psi. When I usually run my car on 12, and when I set my mbc wrong I hit 15 before and never hit fuel cut.....Hmm weird.

Nitro_Alltrac
05-05-2013, 03:39 PM
Which ECU do you have? Supposedly with the US ECU, the stock fuel cut is supposed to be about 10-11 psi. I can't say for sure as I've got a JDM ECU in mine and haven't hit it at 13 psi.

Like Mario said though, it does sound like you hit the fuel cut.

jdm_celica_gts
05-06-2013, 01:40 AM
Stock us ecu :/
I'll reset my car and see if the problems fix.
Thanks

185Performance
05-08-2013, 09:23 PM
Ya, I never used to hit fuel cut in my 92 US ST185 until 12psi. Check your grounds, too.

Shadowlife25
05-10-2013, 03:09 AM
Factory fuel cut for USDM ST185's is 11psi if I recall correctly.
Also, there are environmental factors to take in to account when discussing boost pressure such as temperature and heat soak of the intercooler.
Also, MBC's tend to not usually be the most reliable when it comes to dialing in your settings, so keep that in mind. :)

jdm_celica_gts
05-24-2013, 12:59 PM
Well I reset the ecu and it fixes the fuel cut. Now I hit 12 psi in 2-4 gears. I don't know why it hit fuel cut on 8 psi the other day.

Nitro_Alltrac
05-24-2013, 05:29 PM
Glad you got it fixed. Hard to tell what moved it down to 8.

jdm_celica_gts
05-24-2013, 11:30 PM
My only guess would be weather :/
Now my problems have shifted to a clunking noise under light load. Possible u-joint issues? I'm not really sure.

Nitro_Alltrac
05-25-2013, 05:24 AM
Could be that. Could also be front wheel bearings. Check them as well and soon. If it is bearings and you catch it early, you do just the bearing. Later, you get into replacing the hub as well.

Shadowlife25
05-28-2013, 07:00 AM
Could be that. Could also be front wheel bearings. Check them as well and soon. If it is bearings and you catch it early, you do just the bearing. Later, you get into replacing the hub as well.

I JUST had to do this last month. Thankfully it was bearings only.