`state
Yorkshire and The Humber
Posts: 1,215
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Jan 15, 2014 22:04:37 GMT
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Afew months ago I fitted a Isuzu 1.7td engine into my mk3 astra. Everythings been fine and its run well so thought id try to get abit more power out of it by following a guide on migweb on how to turn the boost up.
So I started by fitting a boost gauge which showed I had the standard 7psi it should have. Next was the white ring mod to get the pump plunger moving as far as it could. Still 7psi.
Next was to fit a bleed valve in the pipe from turbo to actuator and turn the max fuel screw up half a turn. Still 7psi!!
Now most people at this point see about 1 bar of boost. Not me. So ive turned the max fuel screw another half turn. Alittle more black smoke but not too bad but no extra boost.
Bleedvalve makes no difference what so ever. On someones advice I blocked the pipe going to the actuator with a bolt but still no extra boost, its stayed at 7psi through out.
Ive now turned the max fuel screw down to stop the smoke and the bleed valve is plumbed back in set to max and the boost is, yes you`ve guessed it, 7psi.
So. What do you guys think? Fuel pump problem? Or actuator problem?
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Look at all the plastic people who live without a care.Try to sit with me around my table,but never bring a chair.
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Russ
Part of things
Posts: 372
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Jan 15, 2014 22:31:14 GMT
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Do you have a cat fitted? Had the same problem with my mk3 astra tds only making 3psi on boost with a bleed valve fitted, knocked the inside out on the cat which was half blocked with soot, once that was done it went straight up to 15 psi on boost.
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`state
Yorkshire and The Humber
Posts: 1,215
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Jan 15, 2014 23:20:21 GMT
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No theres no cat fitted its a straight through pipe. Runs really well apart from this.
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Look at all the plastic people who live without a care.Try to sit with me around my table,but never bring a chair.
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benjy_b
Yorkshire and The Humber
Posts: 409
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Jan 15, 2014 23:39:16 GMT
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Do you know the 'bleed valve' is working? Do you have this type fitted? Check your actuator arm is moving correctly, then remove the vacuum hose to the actuator, block it with a bolt and take the car for a drive. Don't go daft, just make sure the boost goes over 7 psi. Increasing fuel won't increase the boost, you need to fit a boost controller to increase boost. |
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2005 Subaru Forester 2.5XT
1999 BMW E36 318i Touring with OM605 Mercedes Engine
1996 Lada Riva with Honda S2000 Engine
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`state
Yorkshire and The Humber
Posts: 1,215
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Jan 15, 2014 23:48:42 GMT
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As far as I understand on a derv engine you have to increase the fuel to up the boost. Just turning the boost valve up wont get you any extra boost like it will on a petrol engine with out the extra fuel been there. Or have I got that wrong?
Ive already blocked the pipe up with a bolt but made no difference just the same 7psi. I cant actually see the actuator arm so I`ll have to have another good look but should that move easily by hand?
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Look at all the plastic people who live without a care.Try to sit with me around my table,but never bring a chair.
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benjy_b
Yorkshire and The Humber
Posts: 409
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Jan 15, 2014 23:57:15 GMT
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Increasing fuel on a diesel without increasing boost will cause high exhaust gas temperatures. The idea is that you increase both to get more out of the engine. Increasin boost without fuel does not have the same negative affect as it does on a petrol, there is quite a bit more room for error.
Your actuator arm should move freely, it will have a slight resistance from the spring in the actuator.
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2005 Subaru Forester 2.5XT
1999 BMW E36 318i Touring with OM605 Mercedes Engine
1996 Lada Riva with Honda S2000 Engine
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slammed 66
Posted a lot
www.gtturbo.org
Posts: 1,672
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Jan 16, 2014 13:36:02 GMT
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Sounds like a knackered actuator to me. Soft spring that's caving in at 7lb
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86 Renault 5 GT Turbo 89 Renault extra 91 Skyline GTR 98 Mini 1275 mpi 99 Autech Rider www.gtturbo.org |
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Jan 16, 2014 18:17:57 GMT
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Sounds like a knackered actuator to me. Soft spring that's caving in at 7lb That would be my guess (from my petrol experience) but must be something else if you've removed the pipe to the actuator & plugged the pipe with a small (5mm ?) bolt. With actuator pipe off it should boost until something breaks (so don't go daft - just go for a run and if it now boosts over 7psi change the actuator) Or look around and see if you can find an adjustable actuator to make fine-tuning easier in future  |
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`state
Yorkshire and The Humber
Posts: 1,215
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Jan 16, 2014 19:16:27 GMT
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Got right under the car for a proper look today and they`ve put the actuator right up against the block so I cant actually get a hand to it. I managed to get a long screwdriver to it tho` and although it does move it takes a lot of effert. I could only just do it using one hand. So looks like a new actuator needed but all the manifold and turbo`s going to have to come off so I'm going to leave it til the weather warms up abit.
And yeah I put a bolt into the pipe with a jubilee clip round it and its not made a jot of difference.
Thanks for all the input guys I'm new to dervs and turbos too so I'm learning all the time.
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Look at all the plastic people who live without a care.Try to sit with me around my table,but never bring a chair.
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Jan 17, 2014 17:22:48 GMT
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If the actuator is stiff it works! (Unless it is siezed or damaged in some way)
If it's loose then it is weak.
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