We're building up a 1.9L and keeping the stock 1.7L D-jet system. We're utilizing a 1.8L cam. Looking for info from others who've done this upgrade with success.

What about injectors? ... are the 1.7L injectors adequate, or will they run too lean? If they won't provide enough fuel, which injectors have you guys used with good results? ... 1.8L, 2.0L ?

I understand the MPS will probably need to be re-calibrated. How did you go about doing this? ... sent it out somewhere or just fiddled with it until the A/F readings were good ?


Any other recommendations, tips, etc. you can provide ?

TIA ...

Hey Mark, free bump and my thoughts. Others may have better info.

I have no personal experience with this setup, but others seem to have had no problem using stock 1.7 D-Jet parts for the 1911. Not sure if or how the 1.8 cam could change that. If you have a hard time sourcing injectors, I think the 2.0 are easier to come by, but it seems the 1.7 would work.

I would definitely invest in a wideband sensor to make sure you're not running too lean. You can either bump up the fuel pressure slightly if needed, or, probably better, tune the MPS closer to 2.0 specs. Do you have a working MPS? If not, pick up a core and get Chris' repair and tuning kit. Either way you're going to have to carefully chip out the plug to get access to the inner and outer screws on the diaphragm. If you don't have an inductance meter (and have no desire to acquire one), have someone here help (I would be glad do it gratis, although there are others here that are most likely better).

That just gets you close. Then use a dyno or at least street tuning with your wideband to dial it in closer to optimum.

Here's some good reading for a rainy day. Gives you MPS theory and tuning instructions: https://members.rennlist.com/pbanders/manif...sure_sensor.htm

Good luck.

All stock FI cams are the same.

Bump the fuel pressure and you should be fine, if it's still too lean at higher pressue, then swap to 2.0 injectors.

I have a set of new 1.7 injectors in the classifieds.

Thanks for the feedback guys.

I'll read up on the link, Rob. I have a few working 1.7 MPS units, and one leaky 2.0 unit. Also have an Innovate LM-2, although I seem to have misplaced the case with all the automotive diagnostic tools in it (I think it's at the AZ house, but will be going there in November - making a list of items I need to bring back to CA).

Thanks, Mark, I saw those injectors. I currently have two good sets of 1.7L injectors, so we'll try them first and see how it goes. It'll be a while yet, still need to round up all the F.I. components to clean/prep/paint everything (all that stuff is in AZ too).

Thanks to Rich (914werke) for the info he PM'd too ...

Kjell Nelin tweaked his D-jet to run on a 1911cc. He did so without the benefit of a wide-band O2 meter, so you should have a bit of an easier time, I would think.


https://web.archive.org/web/20050228144643f...et:80/djet.html

--DD

Thanks, Jeff & Dave. Really nice nuts & bolts write up, Dave. I'm not that familiar with the F.I. systems, so that unlocked some of the mysteries

Hi Jeff and all others here...

be carefull with this document. The flow rates reported there are not correct, following Bosch.

Correct values are:

265 ccm / yellow injectors (1.7)
318 ccm / <dark> green injectors (2.0)
380 ccm / blue injectors (no VW / Porsche D-Jet-application, but Mercedes, Volvo, BMW...)

- very old injectors made by Bosch are always black, look for part-# then.
- L-Jet-injectors have different electic connectors, more massive. They can match electrically, but mostly don't.

Hae a look at the page of Stan Weiss, too.

Correct information / documentation about BOSCH products is to be found here: BOSCH PRODUCT INFO

- Maybe you have to register there <for free>, I highly recommend this, you find authentic information there -

Regards