T1 Misfire/Boost Cut Shennanigans
Posted: Sat May 30, 2015 4:34 pm
Okay, so just bought a T1 from down on the south island to use as a company car for our new employee (seriously!). Looks like it's forum member "QikLude"'s old car?
It's got a bigger turbo, which I believe is the Isuzu/Holden Rodeo based hybrid thingy and a 2.5" exhaust.
When we first got it the wastegate was seized shut, and it'd spike straight to 15psi and stutter/cut out. This seems to be the ECU boost cut, that'd make sense right?
Now we've just had the exhaust housing media blasted and generally cleaned up, and the wastegate opens properly. It's still a bit small though, and between about 5000 - 6000rpm it starts to creep and gets to about 11psi.
The weird thing though, is now when it gets around 10 - 11psi, it starts backfiring/stuttering, as if it's hitting the boost cut, however the boost cut shouldn't be that low should it? It certainly wasn't before.
Leads and plugs are fresh, Coil is some big fancy external unit. Unsure of condition of Distributor though. Apparently has a bosch "910" fuel pump too.
Any hints where to start with diagnosing this one?
It's got a bigger turbo, which I believe is the Isuzu/Holden Rodeo based hybrid thingy and a 2.5" exhaust.
When we first got it the wastegate was seized shut, and it'd spike straight to 15psi and stutter/cut out. This seems to be the ECU boost cut, that'd make sense right?
Now we've just had the exhaust housing media blasted and generally cleaned up, and the wastegate opens properly. It's still a bit small though, and between about 5000 - 6000rpm it starts to creep and gets to about 11psi.
The weird thing though, is now when it gets around 10 - 11psi, it starts backfiring/stuttering, as if it's hitting the boost cut, however the boost cut shouldn't be that low should it? It certainly wasn't before.
Leads and plugs are fresh, Coil is some big fancy external unit. Unsure of condition of Distributor though. Apparently has a bosch "910" fuel pump too.
Any hints where to start with diagnosing this one?