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914World.com _ 914World Garage _ D-Jet question

Posted by: CatDaddy60 Apr 29 2017, 01:02 PM

Calling the DJet Ninjas. I picked up this intake manifold a couple of months ago and had some questions first how do you tell the difference between a 1.7 and a 1.8 liter manifold. The second question is on the throttle shaft there is a bit of play, enough that I'm sure this would cause an air/vacuum leak. Should I be concerned about it or is this a non issue. Thanks for your time.

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Posted by: clapeza Apr 29 2017, 02:30 PM

That's for a 1.7. It has the mounting arm to hold the AAR (Aux Air Regulator) on the front side, near the CSV (Cold Start Valve).

Pic found online:
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Posted by: r_towle Apr 29 2017, 09:23 PM

any vacuum leak is bad for any of these FI systems.
it can be fixed by drilling out the holes and fitting them with new bronze bushings reamed out to fit the existing shaft...

rich

Posted by: Krieger Apr 29 2017, 11:38 PM

I'm not sure that I agree with Rich on on the leaky shaft for the throttle body. Unless the shaft is so worn that it cannot open and close smoothly and the throttle plate is rubbing in the bore. Or you can't adjust the car to idle properly. The throttle plate has a hole in it (controlled leak). There is an adjustable idle screw on the side of the throttle body (adjustable leak to set idle speed). All of this is only important when the car is at idle and the throttle plate is closed. As soon as you open the throttle when your driving air will be flowing over the throttle plate.

Posted by: BeatNavy Apr 30 2017, 06:18 AM

I just went through this a few weeks ago. There was play in the throttle shaft so it would move laterally ever so slightly (but noticeably) in the body. The net effect is that sometimes the plate wouldn't close properly and the TPS would not "engage" the idle circuit. I'd get inconsistent idle mixtures. It was a minor issue, but sometimes those can drive you crazy. When it wasn't minor is when it got worse and the plate started sticking way open - usually when I started the car in the morning to go to work (I'm sure my neighbors appreciated it jumping to 3000 rpm immediately at 6:30 am).

I refurbed mine following the basics in this thread: http://www.914world.com/bbs2/index.php?showtopic=206017

Posted by: CatDaddy60 Apr 30 2017, 12:18 PM

Thank you guys for your assistance I'm looking at getting this car back to driving and need to make sure the components I'm putting together are functioning right. I'm using Anders site for reference s but it never said anything about shaft play.

Posted by: r_towle Apr 30 2017, 12:28 PM

If it moves and is out of spec, you will not have consistent performance.
ANY uncontrolled vacuum leak in ANY efi system needs to be fixed if you want any chance of a decent tune. A loose throttle body shaft is a very common thing to fix in older cars and bikes.....