Porsche 911 fuel injector replacement 911 (1965-89) – 930 turbo (1975-89) pelican parts diy maintenance article gas laws worksheet chapter 5 answers


Comments: My SC starts well, but runs a bit roughly first minutes. I have to press little bit gas to keep it run. After warm up it idles fine. In operating temp engine makes sounds like broken stud sound during. I think sound comes somewhere near cylinder 6. Could it be a broken/leaking injector?

Comments: 1976 911S stumbles bad at about 2500-3000 rpm idles rough sometimes too… Checked for vacuum leaks by spraying carb cleaner with no results even by the injectors, replaced the vacuum lines, new fuel pump. Noticed one of my injectors is really really loose in the sleeve. Can pull the sleeve vertically about 1mm did this when the engine was running rough while parked and at operating temp. It smoothed out and ran fine instantly. Do you think this may be the problem?

Comments: I have Motronic on my 86 Carrera and I had my injectors cleaned by Marren. They did a perfect job and sent me a copy of my injector fuel rate and compared each. The injectors came back within 2% of each other. When they were dirty two were not functioning within specs and they were definately not even.

I think this article should have an update describing the Motronic version and how it differs and also later versions. I think it is a waste to throwaway original injectors because they are dirty. Marren did mine for $25 each and gave me a printout on their performance. They look new and work great.

I had some trouble removing the injectors from the head and then pulling out the fuel rails. The injectors just pull straight out but may stick so it is important to apply enough force I didn’t try WD40. Disconnecting the fuel rails first allows fuel to drain but you should catch as much as possible in a container. I also cleaned the fuel rails and had them replated with yellow zinc. I replaced the fuel filter as recommended by Marren and adjusted the fuel rail lines to reduce bending and kinking. I had some problem with refitting the rails and fuel lines so they matched and had a major fuel leak on restart. TO avoid this I sealed the connections with teflon tape but making sure the fuel line and fuel rail connectors meet evenly is important and is not mentioned here. My car runs much better and I recommend this maintenance for every Porsche that has over 100K.

Comments: Bob, I am about to follow your instructions above and change out the fuel injectors on my 83 911 SC. While I was ordering the injectors and sealing o rings, I noticed an injector sleeve part number 911-110-886-03-M260 in the catalog. Should the sleeves be replaced along with the injectors? If so, once the injectors come out, are the sleeves easy to remove and replace? Thanks for your assistance

Comments: Good advice. In my ’79 911SC, the Injector Sleeves were shot as they get brittle and tend to leak over time. They install into the intake runners much like the injectors, captured by an o-ring. I used a large easy-out to first break them loose, then pull them out.

Comments: Hi Bob,how can I do for test my injectors nozzle? When I stop engine,the fuel burn inside of exhaust mufler,making a "boom" and a shoot fire on the tail pipe.And when I start again 3 minutes after,it running flooded…You understand-me? My inglish is not good.

Followup from the Pelican Staff: Hi there. You can take out the injectors and place them in a clear glass bottle and watch as the engine is turned on. If you’re not sure what they should look like when injecting then compare one to the other. – Wayne at Pelican Parts