The old lady's Shogun Sport, which is i believe an L200 with a jeep cabin slapped on top, more or less :-) has thrown a wobbly.
Engine went into limp home mode after a run up a hill. Limped home, restarted the next day without any bother. Driven to the main dealer garage, showing a code for overboost i think it is (she's not 100% sure). They were able to recreate the problem too.
When she said that i was thinking standard fayre, sticky VNT mechanism, but the garage have said it's the linkage between the vacuum actuator and the arm that connects to the variable vanes.
She's taken a rain check on their quote of just over a bag of sand, she's waiting to hear back from one of the places trading via 247 spares who say £212 delivered for a turbo with 30 day guarantee. Fingers crossed they say they can ship that, but seems too cheap so not holding breath.
You can see the actuator mechanism on this pretty clearly, access is surprisingly good for a jap 4x4 with a normally cramped engine bay. I can't move the actuator with the engine off, but i'm pretty sure one finger isn't as strong as 18 inches of vacuum or whatever a diesel vacuum pump does so i'm not putting too much weight on that finding.
With the engine running, the actuator responds to revs as you'd expect, however the linkage the garage fingered does appear to have mild play in it.
What's the assembled jury's verdict on diagnosis? Could slight play in the join of the actuator arm from the vacuum actuator to the VNT mechanism arm cause an overboost condition and force limp home? There's not enough play to allow the VNT mechanism to be more than a little out of kilter.
What about fix wise, to me this seems bodgeable. The joint is more or less a small rose joint, it also appears to be far enough away from excessive heat that i think bodging might be an option.
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T'internet says well known problem and the linkage is adjustable via 2 torx screws. One screw sets the stop the actuator bar rests against at idle, the other one sets the max the actuator can go to. Turning the latter down a quarter turn at a time and testing seems to be the proscribed mitsubishi answer!
Throwing away boost doesn't sit well with me. Another possible is the dealer can apparently change a parameter in the ECU to change the overboost threshold from 0.2 seconds up to 3 seconds + which seems a better candidate.
Wonder if the play in that rose joint is normal then. Shouldn't be, does seem slightly excessive play.
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Mitsubishi Shogun Sport - 02 2.5 Turbo Trouble - Skoda
