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My 89 760s turbo spins out of control when given the gas. Replaced the upper long turbo hose that had a small hole, still spins wildly.
The only thing I have found per the FAQs is the red/grey vac valve leading to the intake from the CBV seems to be bad - as it blows easily one way, and slightly less the other - with the 'frup' sound.
SO I am looking for a source for that. Anyone know one? After a search here on the board it looks as if a dealer does not have it.
I did check and make sure the CBV was good, checked the vac hose under the turbo (on the front side) ...BUT, I noted when I put my hand under the turbo where the adjustment rod is, and rev the motor - it does not move at all. ??
Does anything I have mentioned give me a lead to a solution? Anything I am missing, I would love to know.
Oh ..the turbo spins easily and has little side movement when checked by hand.
Thanks so much.
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' Of all bad men religious bad men are the worst. '' (C S Lewis ; on Evil Men) 89 764 (170K), '94 940T (265K), 92 245 (150K)
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Thanks for all the feedback. All fixed.
I have learned a lesson in all this ...check ALL the hoses! It was the hose between the idle control valve and the metal turbo hose above. Split right down the side.
Wheen searching it was discovered that the hard plastic hose (insulated) from the oil breather hose under the intake across to the turbo hose at the #1 cyl. was broken - right in the middle. I was blessed to find a perfect one in a PnP ..3.00.
Thanks again.
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' Of all bad men religious bad men are the worst. '' (C S Lewis ; on Evil Men) 89 764 (170K), '94 940T (265K), 92 245 (150K)
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posted by
someone claiming to be fixit2002
on
Mon Sep 15 03:25 CST 2008 [ RELATED]
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Sounds like the intake hose may be collapsing. A dirty air filter will agrevate this porblem. The knock sensor may be ratarding the timing. Have you tried putting 91 octane gas to see if that helps?
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You may have hit on something there ...the collapsing hose part.
I just replaced that very hose coming from the AMM with an aftermarket item, and I noted when I put it on - it went OVAL on me (not round as the OEM was), somewhat flat on the sides - right where it was supposed to bend down, in the curve.
This may be it. That hose has been on for about 3 months. It would not surprise me that amount of time would allow it to weaken, especially under heat that close to the turbo heat.
As soon as I can, I will check it all under a load and post back.
Thanks.
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' Of all bad men religious bad men are the worst. '' (C S Lewis ; on Evil Men) 89 764 (170K), '94 940T (265K), 92 245 (150K)
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Not sure what you mean by spinning wildly. Turbo will spin regardless if you get into boost or not. Don't think you can get into boost by reving the motor. The check valve you speak or is not a "one way". They all work like you described. So what does the boost gauge do while driving? etc Are you getting into overboost?
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Post Back. That's whats makes this forum work.
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Sounds like a huge air loss ...a whoosh sound ..and you can hear the turbo spinning. Before this, there was no spinning, whooshing sound. It just started doing this recently, suddenly. As i said, I found a hole in the hose, replaced it - thought that was it. Should have known better, as I have had a turbo hose fail before on another brick, and ll it did was run terrible, rich, and burn a LOT of gas.
If you start off slowly and build up speed, you are OK on pretty level ground till you get to about 50, and it struggles to get past that without the turbo seemingly losing it's boost and spinning. If you hit a hill, it will start spinning - whooshing - and you have to get down to about 30 to keep the boost constant to get over the hill.
Gauge seems to be normal, same as before.
According to the faq's - the check valve should have some resistance both ways. Is it wrong?
Thanks for your reply and help.
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' Of all bad men religious bad men are the worst. '' (C S Lewis ; on Evil Men) 89 764 (170K), '94 940T (265K), 92 245 (150K)
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Are you sure your waste gate arm is still connected? Sounds like you are never getting into boost. Have you looked thru the turbo section?
http://www.brickboard.com/FAQ/700-900/EngineTurbo.htm
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Post Back. That's whats makes this forum work.
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Yes ...pretty sure.
I did not go under the car, but I could easily feel it running horizontally - front to back, directly under the turbo. The clip and cotter pin was toward the back to my left, the adjustment nut was easily felt further up the rod, and the other end went into the vacuum device - toward the front of the car. Tried to move it ..all seemed secure.
I did read the FAQs ..the turbo section. That is where I read that the valve in upper vac line was supposed to have a bit of resistance both ways.
My daughter is driving the car - carefully - for the moment. I did remove the turbo hoses and check everything when she was here earlier, and after reassembly and tightening the bolts (4 total) a bit on the CBV, she said it was some better in that she was able to get it up to speed easier, just had to do it steadily / slowly and not gun it or it would spin out with no boost, and lose power.
Don't know. Open to ideas.
Thanks for your help.
--
' Of all bad men religious bad men are the worst. '' (C S Lewis ; on Evil Men) 89 764 (170K), '94 940T (265K), 92 245 (150K)
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Sounds like my car was acting when it had a hidden hole in the short (3-inches?) hose from the intercooler to the metal intake tube.
But you should indeed be able to see the air hoses bulge when you rev the motor under the hood and it will generate boost by revving the car. It may not read at the dash gauge, but there is a boost effect happening.
I'm not sure on yours, but I can see the end of the actuator and I can see it move when I rev the engine.
If the bar is not moving, you may have a blown diaphragm in the wastegate/CBV actuator.
You might try moving it by hand.
BTW, does the engine "buck" when you press the gas really hard and try to boost?
-Will
post back and Good Luck
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1990 740 Turbo, on its way to stock specs, maybe beyond
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Thanks Will.
I will check that small hose closer. There is no 'buck'. The boost will hold if the gas is applied gradually, but there comes a point when it just lets loose, speed drops like you cut off the tap - the engine revs higher, and the turbo can be heard spinning ...a whooshing sound. When you let back on the gas, it all goes back to normal. It will pick up speed to about 50 or so. You just have to creep over hills.
You made me recall that if someone is inside the car and puts it in gear, revving the motor, holding the brake really good - the hoses will bulge.
I will check the hoses and actuator rod under these conditions later and post back the results.
The CBV is up at the #1 plug, right? I have checked that and it holds vacuum. The other diaphragm down below the turbo itself is actually what I have been thinking might be the culprit.
Thanks again ..to all.
--
' Of all bad men religious bad men are the worst. '' (C S Lewis ; on Evil Men) 89 764 (170K), '94 940T (265K), 92 245 (150K)
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uhm, ok, don't get run over! haha... It should do it in park too, but it seems that the boost doesn't exist as long because the car revs freely.
I'll see if I can find or take a picture of my car's diaphragm moving under boost.
I think we have different turbos, what is yours specifically? a T3? I think I have a T4...
-Will
EDIT: Here's the photo http://www.brickboard.com/FAQ/700-900/ImagesProcedures/Images-Turbo/TurboMitsuTD04.gif
The diaphragm I'm talking about is the wrong one - it feeds the boost gauge. So I've been watching the wrong one the whole time.. haha..ha... anyway.
http://www.brickboard.com/FAQ/700-900/EngineTurboIdentification.htm
most of these in the photos show the actuator rod and will give you an idea of what you're looking for.
Good luck! post back!
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Thanks for the reply.
I will be careful. I was aghast the first time a mechanic held the brake, dropped my 940t into gear and revved it up pretty high. The car lurched, wanting to move and I thought the longer turbo hose would burst ..it swelled so much (it was a bit weak).
Thanks for the Mitzu link. My turbo is a Garret and the rod is underneath ...can't really see it, but it can be felt. Regardless, when I put the car in stress mode ..if the hose from the AMM collapses, I will know I have found my culprit.
I will be sure and post back ...soon as I can my daughter to drop by.
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' Of all bad men religious bad men are the worst. '' (C S Lewis ; on Evil Men) 89 764 (170K), '94 940T (265K), 92 245 (150K)
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