My Z (91 auto TT) is driving me nutz. When she gets hot (after about 5 - 10 min of driving) it hesitates. But more frustratingly if you turn it off it is impossible to get it started unless you let it cool down about half hour with the hood open. I have been through the hesitation tech faq, checked most the sensors connections which are all clean now. Replaced the fuel pressure regulator (hopefully with a good one). ECU gave code for det sensor which has now been bypassed with 1Meg resistor trick. Still no change. Any ideas? Does the whole not starting thing imply I should look in a certain area? I can hear the fuel pump going when it wont start. I doubt it would be pump or FPCU given they are not related to engine temperature. on very rare occasions it doesn't play up and all works fine which is why I started looking at the electrics. any ideas appreciated, Thanks.
common causes of hesitation and starting problems bad PTU bad injector connectors Huge boost leaks bad cas bad injectors dying fuel pump dead fuel pump id check the ptu tho that would be my bet
I was under the impression that the ptu either worked or didnt (or dropped a cylinder). Given she can be running, you turn it off and straightaway you cant start it made me think it must be a timing or fuel supply related problem. But your right its probable better to check. I'll swap the ptu with my 2nd Z (which also aint going at the moment!)
Depends on how the PTU fails. If it's due to no earth on the plenum then it will blow the arse out of the ground tracts on the circuit board and just will not work. If it fails from heat and vibration then it has the exact same symptoms as you describe. Works when cold, stuffs up when hot. Try another one.
You may be leaking fuel from the dampener into the balance pipe. It has happened before. This condition makes you run rich (hence hesitation), and makes warm/hot starting difficult. You could also check the Coolant temperature sensor and it's terminals/wiring. Incorrect temperature reporting to the ECU could also cause this. Just something else to look at
2nd on the temp sensor! have seen it so many times, poor ECU thinks eng is cold as so dumps in tonnes of fuel = eng no go.
Yup these guys are on to it ... I agree to check the water temp sensor for the ECU ... there is two sensors ... the left one is the ECU ... the other is the water temp gauge. I had this problem (confirmed it with BlaZt checking ECU error codes) until I replaced the connector ... you can try cleaning it first too with sandpaper and cleaner. http://www.cazracing.com.au/catalog/product_info.php?cPath=38&products_id=217
the AFM is also a possibility, i had similar symptoms to that before it finally cacked itself completely, made it a bastard to start sometimes, especially when it was hot.
You guys nailed it. The Temp sensor is bung, or in this case intermittent. Will try swapping it over tomorrow with the one from my udder Z. Now is that a Nissan specific part or can one get an equivalent from repco. Thanks again
