fuel injection

wildthings · Post by **wildthings** » Sat May 01, 2004 9:54 pm

I replaced the stock fuel injection system on my '72 411 (1700 c.i.d.) with the complete fuel injection system off of a '78 van with a 2000 c.i.d. engine. The engine runs much better than it did before, but the gas mileage is poor and it is slow to restart when warm (you have to give it full throttle for it to grudgingly start). All sensors and other parts check out okay. I would like to figure out how to lean the fuel mixture out some what, how can this be done? I used the blue injectors off the '78 van, would going back to the yellow injectors that came with the 1700 c.i.d. be a good idea? Where could I find a chart that shows the different flow rates for different injectors? Is there anything else that I can do to lean out the mixture or better adapt the later fuel injection to the 1700 engine?

raygreenwood · Post by **raygreenwood** » Sun May 02, 2004 6:43 am

The blue injectors have a higher resistance for their system. The injectors cannot be swapped. There is a screw adjustment on the airflow meter box of the injection. Turning counter clockwise will give you some control of leaning out the fuel mixture. Also, since the vacuume signature of this engine is different, you may need to check your fuel pressure. This engine has a vacuum variable fuel pressure regulator. You will need to know the pressure at idle and at WOT. Ray

vwbill · Post by **vwbill** » Sun May 02, 2004 6:56 pm

Have you checked this site out http://members.rennlist.com/pbanders/DJetParts.htm or

http://www.rceng.com/technical.htm
The one shows the rates below:
http://www.autospeed.com/cms/article.html?&A=0102&P=2
This is where I got the above: http://vectorbd.com/peugeot/bosch.html

raygreenwood · Post by **raygreenwood** » Sun May 02, 2004 11:42 pm

It will probably be helpful at some rate...lots of information there, but he has moved from D-jet to L-jet....and bus L-jet at that. Ther may be some calibration issues in the upper rpm range. Ray

wildthings · Post by **wildthings** » Mon May 03, 2004 7:26 pm

I think I have my problem solved. I checked my fuel pressure as Ray suggested and found it to be right on, so I sat back and scratched my head a little. I finally decided to open up the Air Flow Meter and see what it looked like inside. I had thought that it was almost new rebuild as it was spotlessly clean on the outside and had a new tag from a rebuilder stuck to its side. The inside looked entirely different though, the contact area on the rheostat was worn, the wiper arm was so poorly adjusted that it swung past the end of the contact area, and the locking clamp for the tension adjusting gear was missing, with a poor subsitute in its place. The inside was generally dirty and a inside tag showed that it had actually last been rebuilt by another rebuilder way back in 1998. No wonder I hate buying rebuilds.

I dug around in my old VW parts pile and found a 6 pin Air Meter off of a 1800 and pulled out the resistor card and wiper. These I installed on the 7 pin unit I was working on. I also borrowed the locking spring from the 6 pin unit. Adjusting the wiper arm was easy and I guessed at adjusting the tensioning gear. A test drive showed that it was now running too lean so I lossened the gear two notches. It now drove pretty good, but because I was still worried about it being too lean I went for an additional notch looser.

The car now starts great and I hope that the gas mileage will be much improved. What kind of mileage do other people get out of their Type 4's? I will post mine after I have gone through a couple of tank fulls.