Ignition Issues (similar to a flooded engine, but not?)


#1

I have a problem starting my car, it used to be rare but is now happening more frequently.



It’s a 99 Nissan Sentra w/ 95000 miles. When I turn the key you hear the starter running and all the lights are on (so it’s not a battery issue). But sometimes the engine just won’t ignite. I hold the gas pedal to the floor while keeping the key turned to ignition, and the car begins to cough and shake a bit. The RPMs will kind of jump between 100 and 300. After a while of trying this, when I’m lucky the combustion will catch and the engine will start, but then I need to give it a little gas to keep it from stalling out for the first 5 seconds or so.



Other possible factors… I’m in Denver & I have no idea if the elevation is a potential problem. 85 octane gas, and the temperatures have been in the 30s when I have this problem.



Other searches seem to show that this is similar to when an engine is flooded… but this is obviously a fuel injected car so I don’t know what the cause might be.



Any ideas? Thanks in advance!


#2

When you step on the gas while starting the engine, it tells the computer to go to the flooded mode. The computer then cuts the injector pulse widths in half to clear the flooded condition.

One thing that can cause this is a leaking fuel pressure regulator. Here’s what it looks like. http://www.autozone.com/shopping/repairGuide.htm?pageId=0900c1528005f87c. Remove the vacuum hose from the regulator, and if gas is found at this connection the regulator is faulty and requires replacement.

Here’s the regulator for your vehicle. http://info.rockauto.com/getimage/getimage.php?imagekey=47110&imageurl=http%

Tester


#3

If you’re not running life-time-guaranty 1,000,000 mile spark plugs, or it has the original spark plugs, change those. And, change the air filter.


#4

Have the engine temperature sensor checked with a scanner when the engine is cold.
Are you using the manufacturer’s starting procedure?


#5

Ahhh, the flooded mode is interesting, I didn’t know that. So thanks, that helps the symptoms make a little more sense.

And the spark plugs may be an issue, I have no idea when the last time they were replaced might be. Are bad spark plugs consistent with the fact that the car will eventually start if you hold both the ignition on & the gas pedal down? Would the mileage of the car have gotten really bad first?

I’ll take a look at the plugs and vacuum hose on the regulator. A couple questions before I dive in, since I’m new to all of this.

I took a picture of the engine compartment:

I circled an area in red, before I go unhooking things, are those the hoses you’re suggesting I should check?

And second, I see there’s a stain surrounding the leftmost spark plug wire. I think it’s oil that was spilled when the oil was being added, but I also wanted to make sure that isn’t a symptom of something bigger instead.

Thanks again for the help!


#6

The canister below the throttle linkage looks like the fuel pressure regulator.

Tester


#7

Question – does this sound like it could be the starter? I showed it to a friend and he thought there might be a tooth missing, as the sound is a bit uneven. It starts easier once the car is warm, and runs fine after it’s been started. The only thing I don’t understand is why I would need to give it gas for a few seconds after it starts to keep it from stalling.


#8

It sounds like you battery may be getting weak. If it is more than 4 years old, it is suspect. A battery load test at any parts store or garage can verify the condition of the battery.

The reason giving it gas keeps it from stalling is because your actually giving it extra air. That extra air also has extra oxygen that keeps it from stalling as the flooded condition clears up.