When I bought the car the boost guage worked fine. I had to take the turbo and mani out to replace some gaskets down there, because of a leak. Got everything up and running...idling around 1500-2k now though =/. But anyways, I noticed my boost guage dosnt work now... anyone got ideas? maybe I hooked some hoses up wrong or something? What affects this and what should I go double check to see if its hooked up right. I am assuming I just hooked something up wrong because it did work before I took the stuff apart. Just give me some ideas and I will try them tomorrow and give some feedback thanks.

 

When you say not working, do you mean it sits at the bottom of the gauge and never moves, or does it pop up to zero when you turn the ignition on but doesn't move from there?

The boost gauge takes its reading from the manifold pressure sensor on the front of the RHS strut tower. Check to make sure the electrical plug is secure and no wires are broken, and check that the vac line is plugged into the sensor and the manifold.

 

Probably gave yourself a vac leak and left that hose disconnected or something (explains the high idle)

 

well It actually Idled high before too :P but I will double check these vac hoses. And no the boost guage just dosnt work at all now.

 

I just looked for to see if the vacuum hoses were hooked up. It all looks pretty good. The hose that comes from the pressure sensor that is suppose to go to the ACV isnt attached because I have no ACV anymore... The hose is just closed off.

Is there any way to tell if the sensor is working? I will peak around the electrical work after work today

 

I am at work right now on break so I cant check stuff on the car. But on the way to work today I remeber the actuator that connects to the manifold was pretty hard to get the rod to move... i remember reading in the haynes manual that it is suppose to move freely. Also the flap that the actuator moves inside of the manifold didnt want to move freely.
But I wasnt sure at the time if it was suppose to be like that or not. I checked my old cracked manifold and seen that it moves pretty easly. Since I think all of that is cnnected to boost some way or another I was thinking that would be the problem, but now that I think about it... I am pretty sure my guage would atleast move to 0psi...it is just sitting there not moving at all. So I am thinking it is some electrical problem??? Im I assuming right here? Also if those flaps on the manifold dont move easly could that cause something else? another problem maybe?

 

^

 

Dude, mine works when it feels like it. I checked the signals when the gauge wasnt working, and the signal was still there.

Ive seen 3 or 4 TIIS with malfunctioning boost gauges and have come to the conclusion that its a problem with the dash.

Take the dash out and clean the contacts.

Jarrett

 

so after cleaning the dash guages , did the boost guage work again? mine is doing the same thing, i will try cleaning.

 

yes it did.

Jarrett

 

cool!!!!!!!! will try this tomorrow and let yal know.

 

Seriously though... That thing is worthless.

Steve

 

lol yeah..I got a aftermarket boost guage sitting here... But I would liek to make sure its working properly before I hook that up yeah know. anyways I have to go to my 2nd job..I will try to look around a bit tonight..maybe I just have a loose connection. I have a 6mb movie just havnt figured out where to upload it...can someone do that for me?

 

I agree completely... But I was just answering the question....

 

why is it worthless? how is it off? i know i need a aftermarket one because of my fcd but still, y?

 

So If the guage isnt even moving at all... Could it still be some electrical thign to the boost sensor? Or even if that wasnt working the guage would atleast move to 0 or so?? I am assuming since it dosnt move at all, it is some electrical problem with where the guage is..maybe a ground or something. Is all the electrical to the guage...ground and positive behind the dash?

 

That's the hose I was talking about! If the pressure sensor isn't connected to the manifold, how is the boost gauge going to work?!

You risk engine damage not having the manifold pressure sensor working. The ECU uses it to retard timing under boost. You need to reconnect that hose immediately. Tee it into the BOV line, and make sure the little restriction "pill" is still in the line.

 

pill? what pill? where is the pill located? got a pic what it looks like?

 

Ahhh I see... I havnt ran it much at all since I realized it wasnt working just incase I did hook up something wrong or nothing at all. I will go pick up a T somewhere...no idea where but I will find one. And yeah I see the restricter pill thing...

Also I hook up an aftermarket boostguage to that line too couldnt I?

Anyone know places that sell Ts? menards, homedepot?? auto shops??


The pill he speaks of, is located on the hose that goes from the pressure sensor. That is located on the passenger side strut tower. Its a little black box. The hose should be connected to your ACV if you still have it. there should be a little metal pill looking thing that looks like its crimped. That is the pill he is talking about.

 

The pill is a little plastic orrifice inside the vac line. You can't see it, but Mazda put a little paint dot on the line where it's located. It's at the manifold end of the line. You'll feel it when you squeeze the line.

 

hmm weird...my hose has a little pill looking thing that is crimped....Thats why I really never hooked it up. Thought they just did that to block it off because the airpump and such was gone. Oh well...thanks for the help NZ.

 

ok so if the vacumm line has been replaced many many many times, then there is no pill, right? if so do i really need one? and why?

 

aha no Idea :P

 

It stops pressure spikes tripping fuel cut too early. Many people who've replaced the vac line and not swapped the pill over have reported hitting fuel cut at very low boost.

 

sometimes they just go out, like my last one did. For no reason. i was still boosting. but the gauge read 0