91 mr2 fuel cut, just installed boost controller

[Shorty305sr]

I installed a "Turbo XS Manual Boost controller" on my 1991 MR2 and now everytime im driving i get a fuel cut. This is the only modification i have, i have tried tighting all the hoses and so on... what can the problem be???

[Mr Snuff]

if you don't have a fuel cut defensor, then that's why you're getting fuel cut. the stock fuel cut level is something like 11.x psi.

[SW20 MR2]

You can either build your own FCD or buy one from Greddy or HKS. Otherwise, if you opt for the Techtom ECU, that will eliminate fuel cut as well.

[rainforestsw20]

zenen diode mod like $1. and the fuel cut is 13 psi. if you wnat to ahve a fuel cutt wich is safer get the hks it is adj you can have your fuel cut anywhere you want 17.5 tahts safe.

<font size=-1>[ This Message was edited by: rainforestsw20 on 2002-05-28 11:14 ]</font>

[krum]

Where is the sensor located? is it under the throtle body? please help...

[Piddy]

If you want you eliminate fuel cut all you have to do is block the vacuum hose that leads to the boost pressure sensor.

[TheEngineer]

Originally Posted by Piddy

If you want you eliminate fuel cut all you have to do is block the vacuum hose that leads to the boost pressure sensor.

Bingo. I was hoping someone was gonna say that. The map sensor is located on the back of the wall toward the trunk, sortta near the intake manifold. Just disconnect the vacuum line and block it with a bolt or something and viola no more fuel cut (however you stock boost gauge wont work anymore.)

[ModifierMR]

Doesnt the boost pressure sensor do other functions besides just fuel cut? Wouldnt that be imperetive to letting the ECU know how much fuel to add.... beacuse when a turbo boosts it creates a lean condition and you need more fuel... if the engine sees no boost then you could run super lean.

[4DMR2t]

Originally Posted by ModifierMR

Doesnt the boost pressure sensor do other functions besides just fuel cut? Wouldnt that be imperetive to letting the ECU know how much fuel to add.... beacuse when a turbo boosts it creates a lean condition and you need more fuel... if the engine sees no boost then you could run super lean.

The boost pressure sensor doesn't factor into how much fuel the ecu adds. It simply sends a signal to the ecu to control fuel cut and the factory boost gauge. When the ecu sees 5 volts coming from the sensor, it initiates fuel cut.

When u mash the throttle and u get boost, the ecu dumps added fuel to keep the engine from running lean. This is controlled by the throttle position sensor. When the ecu sees wot, it adds fuel additional fuel, which makes it run pretty rich, but safe from going boom!

I use the vacuum line that originally ran to the boost pressure sensor for my Omari gauge. It eliminates fuel cut, and provides a free/clean line for my gauge.

[Piddy]

Originally Posted by ModifierMR

Doesnt the boost pressure sensor do other functions besides just fuel cut?

Besides operating the useless stock boost gauge..... no.

[krum]

You guys got any pics on that sensor and hoses that lead to it. I just got a 3sgte installed in my corolla so the sensor may have been installed somewhere else. Pictures will really be helpful or just a description. thanks guys.

[4DMR2t]

On the 2nd gen MR2, it sits on the rear firewall closest to the trunk on the passenger side. There is a vacuum line running to the bottom of the sensor coming from the intake manifold. The sensor has "turbo pressure" written on top.

I'll try to take a pic of mine tonight.

[krum]

I found 2 hoses connected to the back of the intake manifold near the TWIN TURBO badge cutted and plugged. Is that it?

[4DMR2t]

If they are plugged, there's a chance one of them used to run to the pressure sensor. Check for the little black sensor on the rear firewall. If there is an empty nipple on the bottom of it, you won't have fuel cut and your factory boost gauge will be non-functional.