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[Chicken]

Double check that the boost gauge you are using is accurate.

The stock XR2 gauge in the dash is not known to be extremely accurate.

The overboost module is suprisingly reliable.

The "misfire" may be the overboost module working properly. Some units activate btween 11 and 12 psi.

A "boost controler" can increase the the surge wave and the top pressure of this surge will trip the overboost cut.

[Gostlrs]

I think we all agree he is hitting the boost cut & that the dash gauge is crap...LOL

[SuperSport346]

I bought a Voodoo MBC, and only to lower the boost.  I'm not interested in raising it.

I agree that the stock gauge is probably not right, and that the overboost module is doing it's job.  I just need to find out why.

[Gostlrs]

Then you need to do what I said & it will get you in the right direction.

Run the vacuum line from boost source to the wastegate. If you are still getting boost cut then you have a boost leak or the wastegate could be bad.


Creep is when you hit the set PSI & then it will slowly raise while under boost. The way you explained it I don't think it is a creep problem.


You can check the wastgate by applying vacuum to it, increase it 1 psi at a time. and see when it actuates.

Check all your hose connections. A leak tester can be made cheap.

My last Capri was hitting boost cut from the time I bought it. Ended up being that the PO had all the vacuum lines routed incorrectly. Not sure if you just got this or it just started happening.

[SuperSport346]

It started happening when I installed a used turbo.  My old turbo hadn't grenaded yet, but had significant shaft play.  It would boost however, and it never cut off, but I'm not certain it boosted as high as this new one.

Could I have mixed up a line re-installing the turbo?

You said to run the vacuum line from the boost source (the red arrows in my pic) to the wastegate, right?  That is how that line was run, and I just spliced into it for the MBC.

[Rocketman]

Remove the boost controller for now, if you can replace the whole wastegate line there with new hose & see if that makes a difference

When you installed the turbo, did you connect the wastegate arm to the lever on the turbo's hot side? there's a c-clip or e-clip that retains it

Run some regulated (no more than ~15-20psi) compressed air into the wastegate line, see if you can watch the actuator rod moving properly

[Gostlrs]

Running the line straight from the boost source to the wastegate will make the car boost at wastegate pressure.

So that is why if your car still overboost when it is set like that you have a leak, or wastegate problem.

You have the old wastgate that you can swap back in if it still overboost.

[SuperSport346]

Well I just ended up taking it in to a shop that specializes in turbo'd cars.  He just called and informed me that it is the boost solenoid not working.  I plan on pulling the one off my old turbo (which never had this problem) and having them install it.

Hopefully this gets the problem taken care of, I will be glad!

[Rocketman]

Boost solenoid... the "Wastegate"? The Capri does not use a "Boost Solenoid"

Either way, hope that'll solve the problem

[Gostlrs]

I bet they did what I said....LOL

[azgtx]

You say you replaced the turbo...but with what? Is it another VJ14 or by chance does it have a bigger compressor? Did you swap over your old wastegate accuator or use the one on the replacement turbo?Just wondering...everything worked before the swap so there is where your issues started. Should be easy to find.

[SuperSport346]

They are telling me it's a boost solenoid, not the waste gate.  They're telling me that whatever they're referencing shows a boost solenoid on these cars.

This is supposedly a stock VJ14 I purchased on another forum.

[SuperSport346]

I did not swap the wastegate actuator off the old turbo.  If there is no boost solenoid on these cars, then I'm thinking that the actuator must be the problem and I'll probably have them swap that (or I'll just do it myself).

[Gostlrs]

I wonder if they are talking about the Overboost one. That is doing its job & preventing you from overboosting.

You have a Manual boost controller. Do what I said and report back. It will tell you what the problem is!

[SuperSport346]

What you said to do was run the vacuum line (the one pointed out by the red arrows in that picture I posted) straight to the wastegate actuator, correct?  Unless you're telling me to remove the MBC I installed on that line, that is how that line already runs.  The MBC is already removed.  I had the problem prior to installing it and at it's lowest setting it did not eliminate the problem, so I removed it.

I'm pretty certain the wastegate is sticking or opening late and the guy at the shop is wrong.  He told me that all of the lines are run correctly, which I believe to be true.  Searching the service manuals over at techcapri I cannot find anything about a boost solenoid, so I'm not sure where they ever got that idea.