Upgraded fuel system not playing nice
 

I upgraded my fuel system with new fuel rails, 850cc primary, 1600cc secondary, aeromotive fuel pressure regulator, and steel braded fuel lines to connect it all. After installing the new fuel system my car started up on the first try. I was shocked and relieved. AFRs were a kittle rich at the idle then went lean when I rev so I credited that to not setting the right lag time. I needed to move my car in the garage so I gentally taxied it around the garage, when it died on me. It wouldn't start again. I had to leave for 6 months and when I got back I gave it a few cranks and it started again and ran for five minutes with an AFR of 13.4 before it died again and hasn't started since. I REALLY NEED SOME HELP ON THIS ONE!:scratch:

13.4 is too lean of an idle on most cars. your car needs to be completely retuned. 850 primary's is a quick way to make your car undriveable unless you get someone knowledgeable to retune it. What kind of turbo are you running?

What ECU do you have? you have to re-tune for those injectors...

gonna have to find someone to tune it with datalog if you have a PFC, it'll only go up to 1300 for secondaries - i believe.

Thanks for all the replies. I have the Pover FC ECU. I adjusted it for the new injectors as the distributer of the fuel kit instructed. I'm running the 850cc primaries with injectors set to 64.5% and a 0.08 lag time. The power FC only goes up to 1500cc for secondary injectors but those shouldn't affect the car while I'm trying to start it. I believe only the primaries spray while cranking and the secondaries only kick in at a higher RPM so they shouldn't be a factor. right? Additional investigation shows that the Fuel pressure regulator is steady at 32psi and the system is not leaking. What else can I check? As for getting it tunned I changed the settings that should be affected (if I missed anything please let me know) and the car did run for a few days after the system was installed just idling in my garage.

On the topic of the datalogit. I have the hardware for it hooked up to my power FC, but I don't have the software. How do I go about getting a copy of the disc.

did you turn off O2 Feedback? it's under etc.--> function select. do that first.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/how-make-your-untuned-pfc-basemap-safer-idle-better-no-datalogit-needed-841706/ discusses how to make changes with the Commander until you can get your car tuned. You can do all that with the Datalogit software as well, but faster. Check the sticky in the Power FC subforum, it may have the full version of the Datalogit software. I know it has the updates for sure.

Go to settings --> INJ/IGL/IGT is the name of the menu I believe, it's on the right side. that's the diagnostic mode. It makes temporary changes to fuel and ignition timing until the car turns off. Go to "INJ" under there and increase the values until your AFR's are in the mid 12's at least. It might take 10% correction or more, not sure. If that stabilizes idle, cut the car off to disable those changes.

Get your datalogit set up. go to the INJ map. Highlight the matrix of cells that consists of N2-N4, P3-P7 . those are the most common idle cells, depending on how much vacuum your car is pulling based on porting and engine health. add fuel to those cells with the "+" key.

you can also adjust with the commander: https://www.rx7club.com/attachment.p...1&d=1243484112 but that's really tedious. might as well use the software once you get it.

You can tune the FC to your injector setup, you just need a datalogit, or better yet have someone experienced do it for you.

Also, and someone correct me if I am wrong, but your fuel pressure with the vac line to the uim unplugged should read around 38psi and 40 with it plugged in.

Thanks for the tips. I would love to have someone smarter than me come by and help but I live in Guam so it's up to me for now. I will change some more settings with the ecu. Since the car isn't even starting now I will start with the cranking settings then adjust the map as suggested above. I just want to know why the car would start right up with the new fuel system and run at an idle for a week then it just stopped starting. What changed?

if nothing changed mechanically on the car, the tune was akready on the bleeding edge of undriveable, and some change in the weather resulted in it just cutting off.

The FPR should be set at 40lbs with the vac reference line disconnected. Are the 850 aftermarket or just the stock ones in a modified primary rail? If they are aftermarket 850 they may be low impedance, did you install resistors inline electricaly on the injectors? If you didn't that may cause the injector driver on the PFC to fry, thus causing a no run situation.

Yeah they are low impedence but I installed the resistors. Since the car isn't even starting I was thinking about adjusting the injector cranking settings. Since not much has changed with the fuel system mechanically or with the ecu between it running one day and not starting the next, do you think spark plugs could be to balme? If I don't crack this in the next few days I'm thinking about reinstalling the stock fuel system and putting this project on hold untill I get back to the states where there are tunners and dynos to help.

are you sure it's not flooded? did you pull the plugs and inspect them? pull the plugs, clean them, then push it and pop the clutch if possible

I replaced the spark plugs with the last set of RX-7 plugs they happend to have on Guam. Since the old ones were severly foweled with carbon and WET, I thought the engine may have been flooded. I pulled the fuse for the fuel pump and she started on the first crank. Now I will put the intake manifold and throttle body back together, reinstall the fuse pump fuse and hope I can get her running again!

sounds like you flooded it.