J-Rat

iTrader: (2)

The problem...The fuel gauge does not read any fuel, even though its full. Thats probably not too hard to fugure out. The REALLY big problem is that the boost gauge never moves, even if I am pushing hard in 1st and second. I couldnt tell if it is boosting or not, it feels faster then my N/A but I have never driven a TII before, so I dont know.

Is there any way to test the boost gauge to see if its not working? Cause if it is, I am guessing I am not getting any boost.

Any help is greatly appreciated.

Rat

peacekeeper

My fuel gauge broke to. I'm still trying to fix it. Sorry I can't help.
Charles

J-Rat

iTrader: (2)

Thats okay, whatever I find out, I will be sure to post for you and everyone else with fuel gauge problems.

TheBigOne

hook up another boost gauge that you know works. That should tell you if your getting boost.

Rx7Nub

You can't hear the boost?

dr0x

You should hear the boost and when you let off the throttle the bov goes off.

J-Rat

iTrader: (2)

yeah, I hear the boost when I let off the throttle. I spoke to Soul Assassin, and he said that maybe something got disconnected when the FCD was installed. I was just wondering if there was any way to test the gauge...Like putting pressure on the vac line or anything.. I am not too up on how the boost gauge works...

Rat

Blowtus

my boost gauge has stopped working... it does occasionally work, and occasionally works but only shows tiny amounts... anybody know if this sort of thing could be fixed simply enough?

Charlie

J-Rat

iTrader: (2)

Well, my question is, how do you test the gauge?

Piranha

Hm... yeah, your stock boost gauge should move from the voltage coming from the boost sensor. Its a direct line, I believe. When you turn your key to on, with the engine not running, the needle should be at 0 at sea level. I'm in Michigan, and my needle is a little lower. But it should move.

No7Yet

Boost gauge: at key on, no engine, the gauge should read at or near zero. When the car is started, the gauge should be pegged down. At full throttle and no boost, it should read at or near zero. As boost builds, it will climb above zero.

Let me/us know which way it is failing (describe its behaviour) and we can start to diagnose it. Until then, drive your car civilly and avoid boost - your ECU mayn't know that you're boosting, and won't retard timing accordingly, which puts your engine at risk.

Brandon

HAILERS

So the answer to the question, is yes........just put a source of pressure on the nipple of the pressure/boost sensor, and see if the gauge goes up and down when you apply and release pressure to the sensor. I used a Mitty Vac.

One thing I noticed while doing this. If the key was turned on, the needle of the gauge did not reach Zero. It fell just below. About three needle widths. If I pulled the vac/pressure line off the sensor, then started the engine, the needle will hit the zero mark. So it would seemI need the alternator running for the gauge to be accurate.

While your hanging around the boost/pressure sensor, tap into the output of the sensor with a volt meter. Put pressure on the sensor up to ten psi. Note the voltage reading. If you have a FCD on the car, the voltage should top out at approx 3.60 volts. If it tops out under that figure, then in my opinion, the clamp voltage is toooooooo low. Needs to be adjusted closer to 3.60 to 3.65 volts.

J-Rat

iTrader: (2)

Cool, thanks HAILERS and NO7YET. Here is what its doing...

Nothing. It doesnt move when the key is on, when the motor is running or not, or when I am running hard. I am going to put some pressure on it tomorrow with a vac tester.

Rat

TonyTurboII

Although not a fix, you really should use and aftermarket guage, as the readings of the stock one are far off, rendering it useless.

HAILERS

It sounds like the wire is broken to the meter. The black/red wire that is the signal wire from the boost/pressure sensor, has a wire spliced from it going to the meter. Sounds to me like that wire has an open somewhere. I've no idea exactly where that wire splices off the brown/red.

Its important that you take a meter and ohm out the brown/red wire to the ECU. Its possible that the ECU isn't getting the boost signal, which is not a good thing. Its pin 2B on the ECU. The color of the wire that is spliced to the brown/red, is the color L/W and ends up at the back of the combination meter at C0-2. Thats the inboard, round connector on the back of the combination meter.

At least take to heart the part about the ECU needing the output of the boost/pressure sensor.

And, to go agains the grain of 99 percent of the remarks about the stock meter..........I found, that using a source of air pressure at the boost/pressure sensor, combined with a pressure gauge, that the stock meter followed rather well the pressure gauge. So I've got the one stock gauge that works.

J-Rat

iTrader: (2)

Here is another puzzler...How in the hell was I able to start the thing, with the AFM completely removed from the car?

There is no fuel jumper installed....WTF???

HAILERS

If it ran for any length of time........no idea. Unless the prior owner did some rework around the fuel pump resistor relay. Located just fwd and under the air filter

JPG BELOW:

J-Rat

iTrader: (2)

HAILERS,

Yeah it idles without the AFM, you just cant give it gas or it dies. My guess? There was residual pressure in the line from the start sequence.

Now here is the real bummer. When I started it with the radiator cap off, the coolant came FLYING out of the neck. Far as I know, that means the motor is toasted. So it looks like I am in the market for a new motor (or I may possibly rebuild this one) and a wiring harness. Looks like I got a winter project ahead of me...Time to buy a space heater for the garage!

Rat

P.S. Got any 88 TII harness lying around?

J-Rat

iTrader: (2)

Okay, here is the deal. When I am driving, sometimes the boost gauge comes up... When I turn on the key, it does nothing unless I rap on the dash panel.

Sounds like a bad gauge....


Jarrett

BogusFile

Does the car still pull hard? My stock gauge did the same thing, but my aftermarket gauge showed 9 psi.
The car had a dramatic loss in power when I got into boost. When the stock gauge did periodically work, the car pulled like a TII running 9psi should. I have a feeling that alot of the boost gauge failure has to do with the wires going to the boost sensor failing. They are routed right next to the extreme heat of the turbo, which over time will ruin the wires.

J-Rat

iTrader: (2)

It pulls the same if the gauge works or not. And it pulls HARD.

BogusFile

Does it sound different under hard accelleration? If your boost sensor isn't working properly it could effect your timing... I think... you know I never have been absolutely sure of what the Boost sensor does. I am pretty sure it effects timing though. If you aren't noticing and difference in the car I wouldn't worry about it. Just slap an aftermarket boost gauge in it and go on with your life. Out of curiousity.... what mods do you have? You have a FCD right?

BogusFile

If you do have an FCD what Kind is it? It could be defective. Maybe its eliminating the signal to the boost sensor rather than suppresing it.

J-Rat

iTrader: (2)

I removed the FCD and replaced the whole ECU harness because I wasnt sure of why the boost gauge wasnt working. No matter if the boost gauge works or not, it pulls the same.

HAILERS

Sounds like a bad connectin on the back of the combination meter. Similar to the rap on the plexiglass to get it to work trick I use on my 86n/a tach. Works for a couple of weeks then its rap time again.

You could put a wire tap on the ECU's boost wire and make sure its not intermittant there.

I'd take the combinatin meter out and take a look at the connectors, screws etc.

Turboii pulls quite a bit better than you n/a, eh?

Could be related to your fuel gauge problem also. Maybe a loose, white, round connector.