Hard starting when hot

[1996maxima]

Hello everyone I am new here I have a 1996 maxima with 151k on it I am having a problem when it gets hot restarting it I have to wait till it cools down and then she will start right up anyone else ever have this problem and what caused it any help would be appriciated... Thanks Ryan

[robo_geek]

In general there are two things that may be happening:

One is that an electrical component such as an ignition coil, fuel pump, or fuel pump relay is marginal, and high temperatures push it over the edge. In this case you would need to test for spark and/or fuel pressure when cranking to see if either one is not up to spec. On many cars you can hear the electric fuel pump start when you turn the key.

The other is that a coolant temperature sensor is shot. If the engine control computer thinks the engine is cold, the fuel mixture will be way too rich when the engine is hot. Too much fuel makes for very hard starting.

Other clues that it's a sensor problem would be gasoline smell, black exhaust on startup, fouled spark plugs, or even blackened residue on rear bumper.

[Ryan Heo]

I have the same problem. I replaced the battery, starter, spark plugs, fuel pump relay, ignition switch, spark plugs, fuel filter, coolant temp. sensors, and knock sensor but it doesn't help me at all. Even I cleaned the engine grounds, throttle body, and IVAC valve. I found nothing...

[xerexabante]

try your fuel pressure regulator. see if it holds vacum you might have a leak.

[Ryan Heo]

Would you tell me about the fuel regulartor?I want to check it.Thanks.

[Fezzik]

Another possiblity you could try is that the coils could be cracking and when warm the coils cracks are bigger. Its a possibilty that entered my mind. The coils are notorious for having microcracks. You could try spraying some silicon around each of the coils and see if that helps.

[xerexabante]

get avacum pump and test the regulator. if it holds vacum, its ok.

[MaxiBee]

Just carious what is the octane # in the gas you are using?

I notice a hard hot start in the 3 maximas I owned, in the hot weather the car starts but always very hard to start if I had regular gas in it.

[Ryan Heo]

Finally I went to check my car which has the same problem in repair shop where the import car is specialized. They found the error code "p1320" even the car didn't have CEL. I wasted $80...This is what they showed me.

1. The code show P1320. Primary ignition... Replace all of the ignition coil - $950. 2. The ECU could be malfunction. It would be need reprograming. - They can't do that. It should be dealer.3. The carbon is inside the engine.

Thanks.

[Ryan Heo]

I will try to replace the fuel pressure regulator. What do I need to do?Only the brand new regulator. Is there any seal or something to be replaced at once?Thanks.

[Fezzik]

If you are going to try the coils first try putting a silicone coating on the coils to seal up cracks. I've also heard of people just electrical taping the coils. I guess that could work, but just to seal up the coils. If it starts working better then you have figured out possibly its the coils.