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Discussion Starter #1
Hi everyone, the 1995 Aero (manual) I just bought had the ABS relay pulled by the previous owner when he had ABS issues and couldn't figure out a fix. I dont need or want ABS, or certainly not enough to fix it.

is it true that no ABS relay / ABS system fault will keep me in base boost? (the boost gauge is also not working, so I can't see boost levels)

If the APC will limit boost with an ABS fault, Is there a way to mod the APC system to ignore the fault and provide full boost?
 

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New one on me.
I've had an abs issue (intermittent warning light) for over 12 years.
It has Zero effect on Boost. Or curiously on abs function either.
I long ago gave up on trying to fix it.
Unless yours is a TCS equipped car .. those are Very odd setups.. I'd look for the standard low/no boost causes.
Check / reconnect the wee boost hose to your dash gauge.. it's useful.
 

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Hi everyone, the 1995 Aero (manual) I just bought had the ABS relay pulled by the previous owner when he had ABS issues and couldn't figure out a fix. I dont need or want ABS, or certainly not enough to fix it.

is it true that no ABS relay / ABS system fault will keep me in base boost? (the boost gauge is also not working, so I can't see boost levels)

If the APC will limit boost with an ABS fault, Is there a way to mod the APC system to ignore the fault and provide full boost?
My ABS light is almost always on (F/L sensor wire to ground) my boost is fine.

1) why doesn't your boost gauge work?
2) you don't have an APC on a '95 9K -- you left that trash behind with T5.5 -- the one ecu controls fuel, timing, and boost -- trionic magic ;)
3) check/replace all your vacuum lines & check the hoses from the inter-cooler to the throttle body.
 

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Discussion Starter #4
My ABS light is almost always on (F/L sensor wire to ground) my boost is fine.

1) why doesn't your boost gauge work?
2) you don't have an APC on a '95 9K -- you left that trash behind with T5.5 -- the one ecu controls fuel, timing, and boost -- trionic magic ;)
3) check/replace all your vacuum lines & check the hoses from the inter-cooler to the throttle body.
Hey Banman, I fixed the gauge, it was a bad vac line, which I had suspected. As far as vac lines and charge hoses, the car boosts to the red with the wastegate unplugged from the BPC solenoid, so doesnt that mean I am not venting boost pressure due to a loose hose?
 

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Discussion Starter #5
And should add , I am boosting to halfway up the yellow on the boost gauge. If I remove the wastegate from the BPC, I hit the red.
 

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Hey Banman, I fixed the gauge, it was a bad vac line, which I had suspected. As far as vac lines and charge hoses, the car boosts to the red with the wastegate unplugged from the BPC solenoid, so doesnt that mean I am not venting boost pressure due to a loose hose?
You're doing the diagnostic correctly so far.

The first step is to isolate the problem - is it control/BPC valve related or a basic engine/turbo fault.

Due to the fact that full boost pressure was observed when you pulled the W hose from the BPC, a turbo/engine fault can be eliminated. That leaves just the control circuitry - or the BPC valve itself - as possible causes.

Next step is to check fuse 5 in the fuse block under the RH side of the dash. But I'm sure you did that. That fuse only serves two circuits - the APC system and the coolant circulating pump (only used with V6 engines).

A thorough inspection of the 3 hoses is next. Again, I'm sure you have done that.

Get your meter out and check the power supply:

Ignition switch in ON position.
Check that the valve is supplied with power (+54 circuit) by connecting one side of a test lamp/meter to pin 2 (the middle one) of the valve's connector and the other side to a good grounding point.

If you observe 12 volts at pin 2, that proves there is power available to the valve.

Check the resistance of the valve windings:

Take resistance readings in the valve's connector across:
Pins 1 and 2
Pins 2 and 3
Nominal resistance is 3 ±1 ohm in both cases.



Finally, check the lead connected to pin 3 of the valve:

Ignition switch in ON position.
Plug in the valve's connector. A weak buzzing sound should be heard.
If a sound can be heard, eliminate that part of the control circuit.


Unfortunately, that's about as far as you can go without an ISAT. I have had some success freeing up a sticking BPC with PBlaster. Just spray some into the 3 nipples, let it sit for a couple of days and hope for the best.
 

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IF ? your Boost valve Meters as having Intact Coils.
The unit ..can.. be disassembled and rebuilt.
Razor saw it open on the glue lines..
fix/replace the disc valve and or the brass valve seats, the damage will be obvious..
then reassemble and use.
I've done 2 of these and they are still 'fine' after 6 yrs use.

Good luck
 
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