Z1 Performance

Hey guys - I am hoping someone can help me out here. Bought my g/f a 2001 Infiniti I30 a few months ago...since the winter weather arrived, she has had cold start isues with it. You would need to crank it about a dozen times before the engine would start. Now that its been tundra-like here in NY, the car will not start at all, so the car is literally just useless at the moment.

I know cross posting generally is not allowed on the forums, but I initially posted about it here: https://maxima.org/forums/showthread...491post2639491

Any suggestions?

Thanks in advance!

Adam

paralyse

First thing I would do is let the car sit overnight. In the AM hook up a fuel pressure gauge to the schrader valve on the fuel rail. It should read a positive number, at least 10 psi, but NOT 0. Then have someone turn on the key. Does the pressure come up with the key on? Next, have someone crank the engine over while you watch the reading on the gauge. It should remain steady while cranking the engine. I'm not sure what PSI max fuel pumps run at but most EFI run at least 25-30 PSI if not more.

Did the engine start up and run? If it does start and run, verify that the reading on the gauge holds fairly steady while the engine is running.

Finally, turn off the key, and leave the car parked, with the gauge attached, for at least 6 hours. The fuel pressure reading should HOLD STEADY the entire time.

Diagnose as follows:

- If fuel pressure reads 0 when you connect the gauge, with the key off, OR after you let it sit for a few hours and it reads 0, the engine's losing pressure while it sits. Fuel leak (unlikely), bad check valve(s), bad fuel pump.
- If fuel pressure stays at 0 after turning the key on, the fuel pump is not turning on. FP relay or pump assy itself is bad. Unlikely since you say the engine eventually starts.
- If fuel pressure comes up with key on but drops down to 0 or a low # when cranking engine over, fuel pump is bad.
- If fuel pressure is erratic while engine is running, and drops down to a low reading when you rev the engine, fuel pump is bad.

I betcha one of the above is true.

Other long shots:
- Bad ECM (very rare), crank or cam sensors open or shorted..? Would usually manifest as random engine stalling, not extended crank.

njmaxseltd

iTrader: (19)

Check your engine coolant temperature sensor. Hard starts in temperature changes is caused by that sensor, not your fuel system. It may be working but grosly out of spec causing your ECU to think you constantly have a warm engine. The error can't be detected by your cars ECU to throw your check engine light but always causes hard starts in cold weather. Also clean your throttle body, instructions can be found at www.motorvate.ca

paralyse

Was always under the impression that if the CTS failed open or shorted the specs called for the computer to assume closed loop mode and run the mixture rich? CTS failures more often show up as excessively rich mixtures after engine goes into open loop.

Worth checking though. Definitely. If fuel pressure is good use an OBDII or CONSULT tool to read the CTS output with engine cold and warm, it should show accurately. (probably should stay around 190 when engine warmed up)

BTW -- How is a throttle body cleaning going to resolve a no-start issue?