I’ve got an 89 780 with a standard B230FT engine, not the 6 Cylinder motor. Lately I’ve been having issues with the turbo, at least I think it’s the turbo. Whenever the turbo gage kicks in at the 12:00 position on the gage the engine starts to sputter and kick out. It’s REALLY bad on hills, i.e. I get on the highway going to work on a hill and I used to break 85 going up the hill, today I could hardly hold 40.

I’ve done some reading and my first thought is that the waste gate may be stuck closed; hence why the turbo would kick out. I haven’t tried replacing the fuel filter or changing the injectors yet as it definitely seems turbo related. Should I consider a rebuild kit? Any thoughts would be most helpful as I’d love for this car to come back to her former glory.

Also if anyone knows a way for sure, a marking or something, that I could look for to verify that this is indeed a Garrett T3 turbo system so I don’t buy the wrong parts. The car came with it, I just want to make sure since I’m the 3rd owner who knows what was done in the past.

I had this problem with a Garrett also. The compressor bypass hose was torn on the bottom. I had overlooked it because it's such a small hose.

Had the same sort of problem with mine. I could get a little boost if I was really easy on the "gas" peddle otherwise it would miss horridly with any kind of boost. Higher octane gas made no difference. Turned out to be cheap plug wires. I had gotten some with crimped ends in stead of proper ones that fit down onto the posts in the bottom of the distributor cap holes. Could be worn plugs also I guess. I also made a more direct ground from the intake manifold to the chassis (firewall). There's also a hard plastic tube across the valve cover that connects to the oil seperator(?). It often splits at that end and is hard to spot.

Checked the hoses and didn't see any obvious holes or cracks in them. Most of them are metal or hard plastic so those would be easy to spot. Any other ideas would be VERY helpful, I can't drive her this way.

Thanks

You can have a tear on the underside. Or a collapsing hose. Turbos really hate any type of airleak.

Sorry, I should have been more specific, I actually took all the hoses off and checked them. They are a bit squishy but I didn't see any cracks or holes. I took everything off from the turbo output over to the intake up to the throttle. The only hose I didn't take off was from the turbo box into the turbo itself as it's pretty hard plastic. Any other thing it could be? I was also looking into a rebuild kit, I can hear it spin up though and it sounds completely normal.

Pull the intake hose, and see if any shaft play. But is does sound like hose problem.. If the hose is soft, it can collapse under boost..

More likely you have a split in an intake hose from the turbo to the intake manifold. It is opening under boost pressure.
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Makes great sense too, thanks for that! I'll check after dinner. I've got the hood open to cool the engine so I won't kill myself when I take a look. Makes sense too because I can hear the turbine spin up but once boost kicks in it dies.

Was it the intake hose?
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Hi -
I am experiencing the same symptoms with my 89 740t. I first noticed it going uphill last week in the middle of a 3 hour trip. I pulled over and noticed the compressor bypass line was pinched. I replaced it and the car ran fine. The symptoms came back a couple days ago. They seem to come more often when the engine is very hot and it does not happen all the time. I have checked everything above and it seems fine. I do seem to have original wires though. Also, when i got the car in May i ran a compression check. The plugs were clean, now they are all carboned up. I don't know if this has anything to do with it, but also i seem to be losing a lot more oil out of the valve cover cap these last couple days. Anything else would be helpful!

Thanks in Advance,
Brant

PS I was wondering if it could be a tranny problem. I have an automatic which leaks a lot and was very low when i got it.