Hi All

 

Car was running OK apart from a intermittent starter motor problem (Would not crank just clicked and all the lights went out) Starter now sorted so I thought I would give it a service, so have just changed the Oil, Oil Filter, Air Filter, Fuel Filter.

 

While changing the air filter found that the Y shaped rubber hose that goes from the MAF to the two round Steel Intakes was cracked right through 3/4's of the way round where the Jubilee clip fastens it to the LH Steel Intake which was presumably letting Air in after the MAF.

 

As a temporary measure I borrowed the rubber Y hose from the other car and continued with the service, when all complete attempted to start it up so I could run it for a few minutes to check for oil leaks and Level and it fired but immediately died, cranked again and the same result

 

Switched off Ignition, turned on again waited for the fuel pump to stop running and cranked it started so I quickly feathered the throttle and she picked up but lumpy, I had to keep reving it to prevent it from stalling and then it started ticking over smoothly but at 12-1300 rpm and sits at that high tick over even after running for 3-4 minutes

 

Am I just unlucky and the split hose was just coincidence or has it got a bearing on the strange new running.

 

Just to clarify having left it overnight, this morning it has retained its post service starting routine HELP !

Any Info on what to adjust if the volume of Air through the intake has reduced due to the repair of the split hose (Y piece) I am clueless, have searched on here and can't get a clue from any existing threads

 

Any ideas no matter how outlandish gratefully received

 

Thanks in advance

I would probably be starting with a leak check of all the pipe work to ensure the system is nicely sealed and then carry out a 6p’s check. Has the idle ever been setup as per the FSM to your knowledge? It’s possible that the idle was setup with the split hose and is incorrect as the leak is now sealed, but as it’s intermittent, it’s possible that the IACV system is at fault. Also try unplugging the MAF to see how this affects it.

 

http://twinturbo.net/nissan/300zx/forums/technical/view/922678/The-6-Ps-Proper-Preparation-Prevents-Piss-Poor-Performancegt.html

 

Having it setup on a ConZult or similar is very important to keep these running nicely and I would recommend checking the parameters of the idle setup every year as part of a service schedule.

Hi Joel

 

Thank you for the reply, I have had a good look round the Hoses and all seem to be in good nick although the PRVR solenoid is missing and there is a hose connecting the two hard lines that go to the valve on the other car, I have no idea if its been set up to the FSM as I have not long had the car, what I can tell you is that the last time the car had the Oil changed was Aug 2013 at Z World as they had written it on the Filter, previous owners since then really should have had their act together, thats taking long life oil to extreems.

 

First thing I do when I get a new car is to do the Oil, Oil Filter, Air Filter and Fuel Filter before looking at anything else but there is loads of stuff not working which I will get to as time permits.

 

Do you know if there is anyone with ConZult who is anywhere near me or you come to that, I have run the check from the OBD and it came up 55 so presumably the ECU thinks everything is ok which it isn't, I will try disconnecting the MAF what should the car do when I disconnect it ?

 

Incidentally thank you again for the Number Plate Bracket which is installed, that was incredibly Kind

Disconnect the MAF, then start the car. If it starts and keeps running, then you've got a dodgy MAF or connection.

 

Although your issue is different to mine, there's a lot of info on how to track down and clear idling problems here https://www.300zx.co.uk/forums/showthread.php?190301-Intermittent-rough-idling-next-diagnostic-steps . Probably worth a read and follow the various diags suggested by the forum gurus. Helped me fix mine anyway (thanks, guys).

Hi Mike

 

Thank you for the Info, I have read a lot of your thread and you have done a lot of testing, I will try the MAF test you suggested disconnecting it before starting the car and report back, all help VERY gratefully received.

 

Regards

 

Marc

Just to add, unplugging the maf be it good or bad with the engine running will cause a stall in most cases as the ecu cannot respond quick enough with the average / mean voltage it uses when maf is disconnected or failed, of course if your quick enough to rev it at the same time you can often "catch it" but simply easier to disconnect with the engine off, oh and remember it will generate a fault code ( 11 ) in the ecu that can be read later and will need resetting.

 

Jeff

I will try the MAF test you suggested disconnecting it before starting the car and report back

1. watch out for the little spring clip that holds the connector to the MAF and don't drop the fiddly little b*stard. It's covered in the how-to Joely P found for me on that thread.

2. what JeffTT said ^^^