745i waste gate issue?

[m5chaser83]

Yesterday I was given a 1984 745i for free, the car had not run in 11 years some fresh gas and a new batterie and the car ran and ideled perfectly. As I drove it around the block I noticed the car would seem to kill its self short after the turbo kicks in. I assume it's due to a stuck waste gate and the car is sensing over boost and cutting ignition to prevent damage. I was wondering if there is any saving these waste gates after they start to stick perhaps some sanding and lubrication ? When I remove the waste gate is here a gasket that needs to be replaced or are there any other parts needed before removal for install?

[m5chaser83]

My apologies for posting under the wrong section.

[davidu]

make sure its the right wastegate, if the 6 psi wastegeate was replaced with the 9psi this will happen....i found this out today after installing a 9psi one

[demetk]

I sprayed penetrating oil in mine and just let it sit for a week. It freed up and it's still working fine.

I think any detonation will cause a cutout if the boost controller can't get things under control fast enough.

[m5chaser83]

where did you spray it in ? is there a gasket between the waste gate and the exhaust manifold or dose it just bolt on?

[demetk]

It just bolts on. I sprayed into the vacuum/pressure port. After a week, I moved the piston by hand in small increments and eventually it freed up. It was pretty seized up.

And congrats on the free car. I always like getting cars for free but rarely do.

[m5chaser83]

thanks ill be doing a thread on the car soon.

[wkohler]

I'm glad your free 745 runs. Mine doesn't. If you need any parts, let me know. Haha.

[m5chaser83]

I'm glad your free 745 runs. Mine doesn't. If you need any parts, let me know. Haha.

I believe ill be parting mine theres some mold and some rust and someone put american bumpers on the thing its got a lot of usable parts that i can use on my euro 735i. but id like to get the thing running right so i can move it.

[Greg E34]

make sure its the right wastegate, if the 6 psi wastegeate was replaced with the 9psi this will happen....i found this out today after installing a 9psi one

Haha. It will run like a raped ape once or twice before it goes into limp mode though.

[SicStang03]

What do you mean by kill itself short? Does it just not pull? Does it cut fuel and fall on it's face? Post a pic of the wastegate setup currently.

[Hit Man X]

What do you mean by kill itself short? Does it just not pull? Does it cut fuel and fall on it's face? Post a pic of the wastegate setup currently.

Never drove a stock Motronic? The ECU/knock system shuts down the party so the motor stays together if they lean out, have crap fuel, or in the event over overboost. Pretty slick stuff since it debuted in '83.



It could be overboost or lean out aka knock like Demetk pointed out. Only way to tell for sure what situation you are encountering, is with a wideband and a boost gauge. I tend to believe the lean out/knock as the car sat for a decade... so no telling how the vacuum lines are routed/cracked, how much unmetered air is around, how poorly the injectors flow, etc. Who knows, could be as simple as a stuck WG as believed.

Play safe.

[SicStang03]

Never drove a stock Motronic? The ECU/knock system shuts down the party so the motor stays together if they lean out, have crap fuel, or in the event over overboost. Pretty slick stuff since it debuted in '83.

Never had mine shutdown so not sure what it does. I assume I can't overboost since I'm chipped... I guess a lean situation would still make mine shutdown.

[m5chaser83]

update the waste gate is not stuck so I guess its somthIng deeper the powersteering pump high pressure line blew up yesterday so I think she telling me she had it and its time to part her concidering she has over 370,000 miles on the clock and sat for 11 years. without any major motor work in her life. shes done more than anybody would expect all a 84 turbocharged bmw to do