No Boost???

[andyeagle19]

I cannot get boost in my mk2 mr2. I didn't d6 anything to the engine lately, what's happening?!? When it started I was cruising and slowly gaining speed, the boost rises slower than ever and when it hit .8 bar, my check engine light came on and it would no longer boost. Now whenever I drive at any speed the light comes on and boost is cut. I can't even pass 0 on my gauge. Any suggestions would be great!!

Sab

[JekylandHyde]

Do you know how to check codes?
I would start there as well.

It sound to me like you hit fuel cut, but turning the car off and then back on should clear that. You would be able to boost normally again until you hit 12 psi and then Fuel cut would kick in again.

As a test, along the firewall between the trunk and the engine is a little box (passenger side) that says "diagnostic" on it. Next to that is a blakc sensor with a small vac line running to the intake manifold. If you pull that vac line and cork it (put a screw in it and tighten it down with a hose clamp) that will get rid of fuel cut.
I would drive your car cautiously then and try to make boost and see if it is "normal".
Just watch your boost gauge and make sure you do not go over 14 psi or so.

You do have an aftermarket boost gauge - right?

[andyeagle19]

I did cap off that hose on both ends and I do have a boost gauge. It was the first time I had driven the car since I capped off the hose and unplugged the sensor. It also seems to be running richer than it usually does which is pretty rich. I will try restarting it tomorrow and see what happens. Thanks!

Sab

[JekylandHyde]

Did you say you unplugged the sensor?
... as in you undid the electrical connector?
That would be cuasing your problem.

The ECU needs to see a signal from that sensor.
If you unlplug it the ECU assumes a problem, makes you run rich and kills fuel when you boost.

All you need to do is cap the hose to the sensor, not unplug the sensor.

[Tach_it]

lol

[andyeagle19]

With all that you said JekylandHyde, I plugged that connection back in, the car runs fine, but I can't hold a steady amount of boost. What could be the problem with that? I have tried several time to keep that sensor plugged in but everytime I do it acts as if the aftermarket boost controller is fighting the stock controller. So I then just left the connection unplugged and it held boost steady and didn't fluctuate at all except near redline like the ct26 tends to do. Any ideas would really help me out.

Sab

[JekylandHyde]

What controller are you using?

Did you cap the vac line to the TVSV?
When you look at your turbo from the driverside, you will see two vac lines going into the wastegate actuator.

The one on the left should come from your boost controller.
The one on the right goes under the engine to the TVSV. That line should be capped if you are using a boot controller.

[andyeagle19]

I will look into that, thanks again. I am using a Greddy Profec B controller, TVSV has been capped and double checked, then checked again. So that is good.

[andyeagle19]

And the hose on the left side of actuator is coming from the boost controller(Out side). Anything else that coud be wrong?? Still can't hold steady boost levels. Thanks for the help so far though!

Sab

[andyeagle19]

Any suggestions would help out greatly.

[JekylandHyde]

I would suggest taking your boost controller out of the loop and seeing if you can run consistent stock boost. Just remember to re-hook up the TVSV or you will be stuck in "low boost mode"

[TRD2000]

try resetting the ecu, it will re "learn" your car/conditions, it remembers the last 40 starts so it might have some bad memories or something. I'd give it a go anyway before you try anything too hard... to reset the easiest way is to discon the battery for a couple of minutes, the hard way (but you dont have to reset your clock) is to discon the ecu power supply

[TRD2000]

oh... your idle might be a bit out right afterwards as the computer learns, so give it a few minutes to sit there and tinker with itself, then turn on the aircon and stuff and let it tinker some more.... it just helps it sort its idle settings but i never bother, i just drive it and it sorts its idle later on the turbo timer.

[andyeagle19]

Thanks, I will give that a go! I have tried just bout everything else.