Boost solenoid not controlling boost (boost spiking to 30lbs) which pins on Chrome EC

[Dougal]

Hey All,

I have been using a Tactrix 3 port boost solenoid but it seems that its not actually controlling boost pressure as I have had some nasty 30lb spiking and knock as a result.

The plumbing to the controller was correctly installed and I tried pulling WGDC down to 0% and target load down to 100 but still spikes pretty badly.

In the end I bypassed the solenoid and running directly to wastegates and boost only goes as far as 7lbs holding at 5-6lbs steady.

What pins on the Chrome ECU v2 for 91-93 GTO are used for the boost control?

As far as I am aware the solenoid pulls the signal to ground in the circuit within the ECU. Is there a way I can test this ground circuit?
I have already had a large amount of other wiring issues that I have had to sort through and it would not surprise me if I had wiring issues for the boost controller also!

Aside from this trouble when I ran the car on just wastegate boost I found the car running sweet.

Virtual Dyno pulls that were recorded on the same stretch of long flat road has my car at 207kw 473nm torque on wastegate boost.
See below

VD%203rd%20gear%20WOT%20Wastegate%20Boost.jpg

[mojo3120]

In Evoscan, there's an actuator test for wastegate....you can use that to test it. You should be able to hear and feel the solenoid click on for like 5 seconds, then back off.

[Dougal]

Yep i have used this and it does click.

My issue is that my engine harness is a 25 year old hacked up thing and i have already had issues with the wiring affecting sensors (i found those nasty copper/brass crimp things causing havoc)

I have a feeling that the wiring for the boost solenoid is affected the same way which is causing my overboost issues.
In order to properly confirm this i need to know what wire pins on the ecu are for this solenoid so i can unplug them and do a resistance test on the wires from the harness plug on the ecu to the pins in the plug to the solenoid itself.

If the resistance is high and or jumps around when the harness is wiggled then i can unwrap the darn thing to find the cause of the poor connection.
If the resistance is low then i dont have to do this....it means the issue i have is not related to the wiring but rather to something else....potentially the tactrix solenoid itself.

Anyone know what pins are for the boost solenoid?

[mojo3120]

91 - 93 should be pin 105

There's only one wire at the ECU. The solenoid gets +12 from the MFI relay, the ecu supplies ground to activate the solenoid.

[Dougal]

That's the information i need! Thank you mojo3120!

Now im onto testing this wire to see if I need to replace this length of wire or not!


Thanks again!