Hello to all again
I have a new problem with my daughter's maxima. It stalls after first firing up. Tach goes up to about 1500 rpm and then drops to 0. You can get it to catch and run if you feather the throttle when cranking. Once it catches, it goes through a normal warm up flawlessly and then drives flawlessly. There are no other problems with the car. Everything else is as it should be. The following is the diagnostics and part replacement I have done:
The problem manifested itself as a "cold start only" problem initially. It now does it on cold starts and intermittently on hot start. I will explain below. Also wants to die if engine is idling and you rev the engine at or above 2500 rpm (engine cold/hot; worse when cold). On the way down it stalls (cold), almost stalls (hot; then recovers to a normal idle).
Because the problem was initially on cold start only I first suspected lack of fuel as checked all cylinders for proper spark (ok) and IACV seems to be operating normally (opens when key shut off and goes to start position when key on). Throttle body is clean and pcv valve has been replaced. Checked fuel pump pressure - good. Swapped fuel regulator and damper with another set - no change. When I depressurized the fuel system by pulling the fuel pump fuse and cranked the engine to relieve the pressure I was surprised when the engine started right up normally and ran properly until it ran out of fuel. Tried this several times. Same result every time. At this point I got thinking too much fuel; possible leaking injector(s). Pulled intake and injectors/rail. Hooked up all injectors and fuel supply/damper and primed system by reinstalling fuse and ign on several times. No leaks. Tested each injector while connected to rail with seperate 12v source. All injectors spray. Removed and cleaned all injectors. Put everything back together. No change except that it would now intermittently exhibit the start problem when engine warm too :wacko:. So I can get the engine to start correctly if I:
1. turn ign on (fuel pump starts and stops)
2. pull fuel pump fuse
3. crank engine over (it starts and idles up fine)
4. put fuse back in before engine dies (will continue to idle normally with no other problems)
Confused - yes! There are no codes being spit out or indications of any other problems.
Because the engine starts properly when the fuel pump fuse is pulled it seems to suggest that there is too much fuel on initial start up. After doing the injector test with no luck I though that perhaps the coolant sensor may be sending a bad signal to the ecu causing it to pulse the injectors open too long but it does it when warm now too (intermittently). I am at a loss as to why it does this and have run out of possibilities that would cause this condition. Any ideas/similar experiences out there?
I have a new problem with my daughter's maxima. It stalls after first firing up. Tach goes up to about 1500 rpm and then drops to 0. You can get it to catch and run if you feather the throttle when cranking. Once it catches, it goes through a normal warm up flawlessly and then drives flawlessly. There are no other problems with the car. Everything else is as it should be. The following is the diagnostics and part replacement I have done:
The problem manifested itself as a "cold start only" problem initially. It now does it on cold starts and intermittently on hot start. I will explain below. Also wants to die if engine is idling and you rev the engine at or above 2500 rpm (engine cold/hot; worse when cold). On the way down it stalls (cold), almost stalls (hot; then recovers to a normal idle).
Because the problem was initially on cold start only I first suspected lack of fuel as checked all cylinders for proper spark (ok) and IACV seems to be operating normally (opens when key shut off and goes to start position when key on). Throttle body is clean and pcv valve has been replaced. Checked fuel pump pressure - good. Swapped fuel regulator and damper with another set - no change. When I depressurized the fuel system by pulling the fuel pump fuse and cranked the engine to relieve the pressure I was surprised when the engine started right up normally and ran properly until it ran out of fuel. Tried this several times. Same result every time. At this point I got thinking too much fuel; possible leaking injector(s). Pulled intake and injectors/rail. Hooked up all injectors and fuel supply/damper and primed system by reinstalling fuse and ign on several times. No leaks. Tested each injector while connected to rail with seperate 12v source. All injectors spray. Removed and cleaned all injectors. Put everything back together. No change except that it would now intermittently exhibit the start problem when engine warm too :wacko:. So I can get the engine to start correctly if I:
1. turn ign on (fuel pump starts and stops)
2. pull fuel pump fuse
3. crank engine over (it starts and idles up fine)
4. put fuse back in before engine dies (will continue to idle normally with no other problems)
Confused - yes! There are no codes being spit out or indications of any other problems.
Because the engine starts properly when the fuel pump fuse is pulled it seems to suggest that there is too much fuel on initial start up. After doing the injector test with no luck I though that perhaps the coolant sensor may be sending a bad signal to the ecu causing it to pulse the injectors open too long but it does it when warm now too (intermittently). I am at a loss as to why it does this and have run out of possibilities that would cause this condition. Any ideas/similar experiences out there?
