hwvigo Posted March 3, 2016 Share Posted March 3, 2016 Hello my good Zfamily: My et swapped 260z has been running well up to this last weekend. I changed the radiator, thermostat, fan belt, and wrapped the downpip, and now it's running very lean under load. I did remove the fmic to install the radiator but have checked all the clamps and joints for leaks. It starts getting lean as soon as the vac starts to switch in to boost, and if you give it more throttle it goes very lean 19-21 on my gauge. Now when your just cruising it seams to be ok 14.3-15. Has any one had these issues. I have tested the afm,tps,and chts via the fsm. Thanks for any help. Quote Link to comment Share on other sites More sharing options...
Enginerd81 Posted March 4, 2016 Share Posted March 4, 2016 is it giving signs of misfiring? bad spark/no combustion will give lean readings. symptoms happened as soon as you finished cooling system work? Bryan Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted March 4, 2016 Share Posted March 4, 2016 Drive it with a fuel pressure gauge and make sure the pressure follows the boost.If you are running in the stock efi system you will soon find out why people switch to aftermarket efi.I bought a pressure gauge 0-100 psi from a local industrial supply and put my own fittings on it.The fuel pressure regulator should add fuel pressure under boost.The oem zxt regulator was one of the few old parts I never had any problem with. Quote Link to comment Share on other sites More sharing options...
hwvigo Posted March 4, 2016 Author Share Posted March 4, 2016 No signs of missfire. And yes as soon as I fished the coolant system. I have a in line gauge and at idle I have 40 psi and have changed both fuel filters. And if I pull the vac line off the stock fpr it increases 9psi. I hvae pulled the afm and run the car with it hooked up and set to the side with me minlupating the flap and I can correct the lean at idle by doing that I'm thinking the afm might be the issue. And I have the stuff to do the z31 swap along with a new fuel system including fpr. Quote Link to comment Share on other sites More sharing options...
Metro Posted March 4, 2016 Share Posted March 4, 2016 You need to check the fuel pressure under load, while driving. It has to be extremely bad for low fuel pressure to show up at idle. Messing with the AFM is almost always the wrong answer. Quote Link to comment Share on other sites More sharing options...
hwvigo Posted March 7, 2016 Author Share Posted March 7, 2016 Fuel pressure under load is great gaining 1.5 psi per Quote Link to comment Share on other sites More sharing options...
hwvigo Posted March 8, 2016 Author Share Posted March 8, 2016 Well it's fixed, the exhaust wrap was holding to much heat in the pipe and causing a lean conditions. Found a old articles about then benefits and risk of exhaust wrap and lean condition was one of the risks so I trimmed back my wrap job and took the car for a drive and woot all good Quote Link to comment Share on other sites More sharing options...
Curtball Posted March 12, 2016 Share Posted March 12, 2016 Thanks for the update Quote Link to comment Share on other sites More sharing options...
Curtball Posted March 12, 2016 Share Posted March 12, 2016 Thanks for the update Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.