1994 Infiniti Q45 wont start in the COLD!

[somogon]

Hi i am new to this forum and this is my first post. I am really hoping someone would help me because i love my Q45 and want it back and fully functional.

Backround

Its a 1994 Infiniti Q45 with 260, 000 km. I bought it in the summer (250,000 km) and it was running beautifully. My problems is that im in Canada and we have very cold weather right now (just dipped to -20 degrees celcsius). So my car wont start, i turn the ignition and it the engine turns fine but doesnt start. Then (with the help of my firends) we push the car inside my garage and violla in the morning (i guess after warming up) it purrs like a kitten!. Now i have had it start in the cold a few times only to run for a few seconds then stall. I tried giving it gas (after it starts to rev up the engine) but it only seems like this is what kills the engine.

What have i done to it

I have tried to put fuel line antifreeze in it, wintergas and i also changed the sparkplugs (surprisingly the left side was never changed) because of these problems but still no CURE!

Please help me out!

Thanks you in Advance!

[DAEDALUS]

It may be running too rich because of the temp. Next time try holding the gas pedal to the floor while you crank it, as this will actually shut off the injectors to clear a flooded condition. Also, if there's any water in the system it may have created a blockage somewhere. I bet it's just flooded though.

[somogon]

Hey thanks tommorow i will try to fix what you said. but would you please go into a little more detail on what you mean by flooding?

-somogon

[DAEDALUS]

Flooding is when there's too much gas in the cylinder. There won't be any combustion in the cylinder if there's too much or too little gas. The longer you crank it the worse the flooding gets because the injectors are spraying gas in the cylinder, and even more gas if it's cold out. Close the injectors and eventually the flooding will clear out and the engine will fire.

[VA99Q45]

My accord won't start in the cold a couple of times. I notice that if I turn the key to ON and let the fuel pump pressurize the system before I start, then it starts fine.

[driverdriver]

Welcome fellow Torontonian.

Is your fuel line frozen? Sounds like it. Go to Canadian Tire and buy some of that fuel line antifreeze that the sell in the little bottles. Dump it in your fuel tank, wait 10-15 minutes and fire her up.

[somogon]

I have an update!

Today i went to start the car and it was -7 below. I turned the key and the engine turned over fine but no fire. So i kept tring for like 5 minutes with no success. Then i left the key in the "on" position while i was flipping through the manual. then i heard this noise from the back (im guessing its the fuel pump) then i turned the ignition and it started in a heartbeat.

My analysis

I think its the pump or a controller that controls the pump. By the way its not overflooding because my mechanic unhooked the feul lines and when i started the car no feul came. And it cant be fuel line freezing cuz i poored like 4 bottles of fuelline antifreeze over a span of like 4 days and to top it off i filled up with wintergas (i assume it has antfreeze in it).

My conclusion and your help

I need to see if its the pump or some electrical unit that operates the pump.

Thanks in advance for any suggestions!

-Somogon

[DAEDALUS]

Check voltage to the pump. I'd get this fixed ASAP--I'd guess the motor's locked up and the current overload could burn out the controller. Check the relay as well.

[PalmerWMD]

If the pump is your problem, like Rob said it could burn out your controller.Which is a lot more $$ to fix than the pump.

Fred..

[somogon]

Well i found out it wasnt the pump because i purposely left the car outside and checked if the pump got any current when the key was in the "on" position. and guess what? no current.

This led me to a couple of options

1) The relay is faulty2) The relay is not being turned on by the controller3) The battery is weak and is not giving the controller enough voltage for it to recognize that the key is in the "on" position4) The controller is faulty5) A sensor the controller depends on (to start the pump ogpile ) is faulty 6) Some wiring is faulty and is affected by the temp (Highly unlikely)

My solutions so far

i bypassed the relay and heard the sound of the pump, after i let it run for around 20 seconds. Then I turned on my car and voila it started.

I removed my bypass and the car kept working (ie turning on the pump peroidically) --> which rules out option 1 (The relay is faulty)

This led me to my conclusion that the relay is not bieng turned on when the key is in the "on" position. But why?

After the engine got cold again (and wouldn't start without my modification) i connected another battery (from a running car) and tried to start it, no budge. I measured the voltage and it was almost 14v at the relay and the battery.

so its not the battery.

Therefore I have 3 options left which I plan to test soon but would like your imput.

4) The controller is faulty5) A sensor the controller depends on (to start the pump) is faulty 6) Some wiring is faulty and is affected by the temp (Highly unlikely)

Thanks for any comments you have

-Somogon

[maxnix]

If it's the controller, it's probably the pump too because the pump probably took it out when the pump failed some time ago.

[Q451990]

Pull your pump controller to see if there's evidence of overheating on any of the components or board. You'll have to remove the back seat and finisher that covers the rear deck to get to the screw that holds it in place. There are apparently two failure modes... toasted transistors (or transistor-like parts) on the board, or toasted leads going into the connector.

If you need a controller, Natsoundup (a member here on NICO) is parting out a 90Q and I helped him remove his. I opened it and it's in good condition.

Heath

[Q451990]

Check here too...