TII Overboosting

[19luis8510]

I have a Mexican 93 TII Spirit R/T with the SBECII. The OEM coil pack was not working anymore so I bought a replacement one from AutoZone while I got a good OEM one. I was running 17psi without calibration and it never ever hit over boost. When I installed the AutoZone coil pack, it started boosting passing 14.7psi. After I got a good used OEM coil pack, over boost was still there. Another weird thing is that the boost controller is not regulating boost anymore, so I replaced it for a new one and still doesn't regulate pressure.

I'm thinking that the coil pack could just be a coincidence and that it's something related to the wastegate that failed when I changed the coil pack.

Anybody have any ideas what could be going wrong or what I need to check?

[ajakeski]

Check for codes

Check for a broken vacuum line

[19luis8510]

Check for codes

Check for a broken vacuum line

No check engine codes. Car runs great if I don't go over 14.7psi.. I will re-check vacuum lines, but last time I couldn't find any leaks. I will use a boost leak tester.

[streetpirate]

iirc tII boost control the solenoid needs a vacuum signal to regulate boost, while tI defaults low boost when the line is unplugged. verify vac lines and apply 12v to the solenoid to see if it clicks

[19luis8510]

iirc tII boost control the solenoid needs a vacuum signal to regulate boost, while tI defaults low boost when the line is unplugged. verify vac lines and apply 12v to the solenoid to see if it clicks

Solenoids are not connected anymore. I simplified the vacuum lines when I intalled the boost controller. Worked perfectly for a year until this happened. I already have a diagram to troubleshoot overboost. It says it could be BOV, wastegate, MAP sensor or coil pack.

[tryingbe]

Solenoids are not connected anymore. I simplified the vacuum lines when I intalled the boost controller..

Sounds your boost controller is broken.

[19luis8510]

Sounds your boost controller is broken.

Already replaced it with a good one and still doesn't regulate and overboost is still there. I think it could be a problem with the wastegate. I will check it next Monday and maybe a new wastegate will solve the problem.

[GLHS60]

Have you tried running a single vacuum hose from a vacuum/boost source directly to the wastegate actuator??

Working actuator should hold a steady approx. 6-8 PSI.

Thanks
Randy

[19luis8510]

Have you tried running a single vacuum hose from a vacuum/boost source directly to the wastegate actuator??

Working actuator should hold a steady approx. 6-8 PSI.

Thanks
Randy

Haven't tried it. Like using the boost reference from the intake, close to the TB, and connecting it directly to the wastegate? All of the vacuum lines come from a vacuum tree. The only one that is connected to the manifold next to the TB is the BOV.

[streetpirate]

no, he's saying bypass whatever boost controller you have (you said you are not using the factory solenoid) and run manifold vacuum straight to the wastegate can. that should open it at 6-8psi. if it's not opening then your issue is in the wastegate

[19luis8510]

no, he's saying bypass whatever boost controller you have (you said you are not using the factory solenoid) and run manifold vacuum straight to the wastegate can. that should open it at 6-8psi. if it's not opening then your issue is in the wastegate

I will try it this weekend, I still don't have the car with me to check right now, but I'm pretty sure wastegate will be the problem.

[19luis8510]

Problem solved, BOV was the problem. I replaced the OEM one for a 1G DSM (uncrushed) and holding 18psi again. Appreciate all the help!