Have You tried cleaning your Air Flow meter, testing throttle pos sensor, right heat range plugs + plug gap, and before going to all the trouble of removing plenum to get to the injectors try getting a pressure and flow test done on the fuel system
i have ended up taking it back to mechanics he has ran diagnostics and nothing came up he checked timing and all fuel lines said they were fine he was checking fuel injectors and if that wasnt it he was going to take motor out he cant work out why it wont start himself
He doesn't need to take the motor out. * Pressure test the fuel rail, will show up a leak quick smart, internal or external. * Swap out FPR and Dampner with known good ones. * Replace plugs with correct gapped coppers (cheap) * Check Timing * Failing all that, do a compression test. The only reason to take the motor out is if it's poor compression causing the start problems. And I haven't noticed that even being tested. New Mechanic.
If he takes the motor out, it definatley won't start. There is a procedure for following these faults, if he hasnt gone near it with a fuel pressure guage and multimeter, take it elsewhere.
I posted this a while back for someone with the same problem. Worth a try. http://www.aus300zx.com/forum/showthread.php?p=761554#poststop
Try testing the ETS when cold and when hot for resistances. If the resistances do not change then replace the ETS. Or remove it and place the metal piece in hot water, test it that way.
Yeah, whatever it is called. CTS. I still call it a CHTS Mine has both a CHTS cylinder head temperature sensor and CTS (VG30DET's still kept with the CHTS for whatever reason and had to plug my coolant pipe with something lol. When one fails i'll plug the connector into the other one lol.
i have found in the hot weather the car starts ok but as soon as there is a cold night it wont start for ages still i have found that it has an exhaust leak could this be part of the problem
I know of 2 cars that have this problem and both have low compression on 2 cylinders, may just be coincidence, just something to think about.
Once you've checked /eliminated the fuel pressure regulator and dampner as others have suggested and where I would have also checked first, then investigate the air regulator. This controls the cold start function. Run a multimeter across the terminals, you are looking for 60-70 Ohms resistance. The fuel smell may be related to the fact that the ECU dumps fuel into all six cylinders when starting from cold so you can expect some fuel smell.
i have found that cylinder 5 seems to not b firing if i had low compression would disconnecting the connector to the coil make it run any diff as when i do this there seems to be no change not sure if this could be because of low compression
Best to always eliminate the cheaper easier causes before you rip into the engine. There would appear to be plenty of other things to try before an engine rebuild... You need a baseline. Trying too many things at once can confuse. It also could be a combination of things which you won't identify if you change too many things. Go back to the basics ... Lack of fuel and or spark are the usual suspects. Things to check off: FPR dampner air regulator fuel pump control unit fuel injector(s) leaking wiring etc ... Don't be discouraged, these sorts of problems are common and are always fixed eventually. A systematic approach starting with the cheapest/simplest fixes first is encouraged.