when I bought my TII, the stock boost gauge never worked. The turbo spools up fine and everything so I don't worry about it. I'm not looking to install an aftermarket because I like that 80's look and feel to the rx7's interior. Anyway my question is what's the best route to fix the problem and make my stock boost gauge work again?

 

A dead boost gauge MIGHT mean the ECU is also not recieving a signal from the pressure sensor on the right front strut tower. Not a good thing. Check to see if the elec plug is on the boost sensor first.

If it is, then go to pin 2B on the ECU and backprobe it with the engine running and see if it has voltage. See the FSM for the value.

Is this a stock TurboII or one of those n/a to turbo swaps?

 

I believe he is saying its a Stock TII otherwise he would know how to fix this proab

 

The way the gauge works is: the boost sensor has an output wrie. It also has a spliced in wire in that output wire. One output wire goes to pin 2B of the ECU and the other wire goes to the boost gauge. There is a ground wire at/in the boost gauge that leaves the gauge and ties in with other gnd wires such as the afm gnd, tps gnd, water thermo gnd etc.

So you could have an open in the gnd wire or the signal wire from the boost sensor. First find out if the boost sensor is putting out a signal to the ECU. If it is, then you need to ohm out the wire at the boost gauge back to the boost sensor and or the ECU pin 2B.

https://www.rx7club.com/forum/attach...hmentid=180805

 

thanks for all your help i'll see what I can find this weekend. oh yeah one more thing, is it bad to drive around with a dead boost gauge ?

 

not on a stock RX. that boost gauge doesnt tell you jack anyways. You really should get an aftermarket. there are inexpensive ones out there.

In the mean time, there is a screw on the back of the intrument cluster for eack of the gauges. You can check to see if the boost screw is in place, loose, rusted...

Did you just buy this car?

 

Sorry to say, but I believe your mistaken. The boost GAUGE and the ECU both get their inputs from the same output wire of the boost sensor. If the gauge is not showing anything, then it's LIKELY the ECU is also missing the signal from the boost sensor.

If that's the case, then the ECU isn't going to make corrections for boost over say about four psi and up. That can't be good at all.

The thread author NEEDS to determine if his ECU is receiving the boost signal on pin 2B. See the FSM for the voltage at idle and see if your car at idle more or less matches the FSM figure.

IF the ECU is seeing the output from the boost sensor, then yes, it matters not if the boost gauge is working or not. But think about that for a minute. You can get an aftermarket boost gauge and all the bells and whistles with it, but its still good to have a stock gauge that works (as best it can), just so you can verify once and a while that the boost sensor is outputing.

See the jpg I attached in the other post and see how the wiring works for the sensor/gauge/ECU input 2B.

 

So what your saying is that, if the boost sensor is shot or the wire is dead somewhere before the ECU, the ECU won't compensate for boost and the injectors will spray too lean?

That, of course, is bad. I guess I should've thought that through.
I'm used to running with a FCD, my gauge didn't work after that was put on.

 

Well, The FCD changes the output reference voltage the ecu sees to a low boost value and it's generally right at the boost sensor. So if your boost gauge got a reading after the FCD fudged the nunmbers then I would assume it would skew the meter as well.

 

Damn I need to use spell check and reread my sentences lol.

Coffen dance:

 

I have a similar problem. I just bough an 87 TII. Pretty much the same deal with the boost gauge. Turbo is still boosting. But, SOMETIMES, the gauge show's boost. And sometimes it DOESN'T? Does this sound like theres an open ground somewhere?

 

Any help? =]