etepsnewo

OK, I have a question about the fuel pump operation while the key is turned to the Start ( starter motor engaged) position.

My 1995 200sx 1.6L automatic trans floods out when the engine is cold. First start of the day. No codes ! No check engine light etc. The only way I have found to prevent this is to disable the fuel pump by interrupting it's power supply after it has pressurized the fuel system but before turning the key all the way to start. Then as it fires up return the power to the fuel pump and the car runs fine. I installed a normally closed push button switch to a relay wired with it's own fuse and it plugs into the Fuel pump fuse slot of the fuse box in place of the fuse.

My question is: This just hit me . . . Does anyone know if this problem might be the fuel pump relay? I am wondering if maybe the fuel pump's power is suppose to get interrupted by it when the ignition is turned to the position to engage the starter. Just a thought.

I have had both the local Nissan dealer's service department and an independent mechanic specializing in Japan imports try to diagnose/fix this problem with no success so I figured out the solution I described above. I installed the switch and relay and my daughter has driven the car for the last four years starting it this way. She now has another car and I have the car back and would like to fix this problem correctly. Any ideas / suggestions would be appreciated.

jdg

Sounds to me like you've either got a leaky injector or a bad coolant temp sensor. I suppose it could even be the wrong plugs or a mis-adjusted TPS, or pressing on the gas pedal when starting.

When you turn the key on, the pump runs for a few seconds, then shuts off if there isn't a cam signal from the distributor (i.e. engine not turning).
As soon as you turn the key to start, you get a cam signal, and the fuel pump kicks back in. And it keeps running until you shut the engine off (or it stalls).

Otherwise, if you're having the normal cold start/flooding problem that the rest of us have, about all I can say is keep your foot off the gas pedal, and don't do any of those extremely short drives (i.e. moving the car 25ft, 15 seconds, etc). Seems to be a relatively common thing.

__________________
95% of the questions that are "STRANGE" or "PECULIAR" usually have a dirt simple answer...usually answered or prevented by a dirt simple search.

Just pointing out the obvious...
Is it just me, or does the majority overlook the obvious?
Some people shouldn't breed.

Why do people continue to run a vehicle when a warning light comes on, or worse, starts flashing? Isn't that a clue that something is wrong and you probably should NOT drive it?
Is this whole car driving thing really freekin' brain surgery? Are people that stupid?

Here's something new for the crowd/clowns...
"A little bit of Google goes a long way!"

And if you can read this, you don't need glasses! :)

And yes, I am diggin' it...

etepsnewo

Thanks for that response, nice to know we think a like on the trouble shooting.

The first time it did it was in the early fall when the temps dropped below 50 degrees or so outside. The weather warmed up and she didn't have the problem again till a month or so later when the temps dropped again. I went ahead and changed the plugs with new plugs from Nissan but no improvement.

That's how I thought the fuel pump operated but was hopeful that I was wrong. Yes, it comes on with the ignition and stops until I crank the car and stays on till the engine is turned off just as you described.

No, I don't touch the gas pedal ever, before or when cranking the car.

I had the same idea about the temp sensor so I changed it out but the temp gauge has always seamed to work fine. That didn't make any difference either.

Since the car had over 150K on it at that time I went ahead and replaced the fuel injectors with a set of reconditioned ones before giving up and taking the car to the two different mechanics. The first mechanic worked on it off and on for four days and the dealer had it two days. We tried swapping out the Mass Air Flow Sensor with two other I had from parts cars but no change. The dealer said it needed a new Mass Air Flow Sensor but they also said that would make the car run better after it's running but probably would not fix the flooding problem at start up. I replaced that and still no change with the flooding. It did run a bit stronger when warmed up like they said.

jdg

Ok then...sounds good so far.

From the hip, a few ideas to start with...(a lot of people hate that, but, I don't have my wrenches on your vehicle, so............)

Get your hands on a real-time OBD scanner and see what your long term fuel trims are running at, as well as the CTS readings, and make sure they're viable readings and they make sense.

Crank position sensor. Even though the ECU isn't showing a code for it, CPS's are weird that way.

NGK plugs? Or something else?
If something else, then throw those away and get NGK. 'nuff said.

TPS voltage at idle? Is it in spec? Again, an OBD scanner would tell you a lot, as well as a volt meter.

Base timing? Is it set right? For that matter, how about the base idle?

Fuel pressure bleed down? Put a fuel pressure gauge on it, pressurize the system, let it sit overnight, come back in the morning, the reading should be practically identical.

__________________
95% of the questions that are "STRANGE" or "PECULIAR" usually have a dirt simple answer...usually answered or prevented by a dirt simple search.

Just pointing out the obvious...
Is it just me, or does the majority overlook the obvious?
Some people shouldn't breed.

Why do people continue to run a vehicle when a warning light comes on, or worse, starts flashing? Isn't that a clue that something is wrong and you probably should NOT drive it?
Is this whole car driving thing really freekin' brain surgery? Are people that stupid?

Here's something new for the crowd/clowns...
"A little bit of Google goes a long way!"

And if you can read this, you don't need glasses! :)

And yes, I am diggin' it...

etepsnewo

Thanks, When I get a chance I will check out these things.

I have a cheepy OBS II scanned but I bet you are talking about the expensive monitor kind the pros use. Right?

To be honest its been about five years now so I don't remember what brand plugs I bought for it.

Timing is a possibility since I took most of the engine apart fixing oil leaks and replacing both timing chains and timing chain components. I did reset everything after re-installing the engine trans in the car and reinstalling the distributor. Good idea to check and see.

I wonder if the dealer checked this stuff for my $90 when I took it in for a diagnostic/fix for the problem. ???

Thank,
Pete

jdg

Ya, I'd doubt it. The cheap kind just pull and reset codes. They don't show what you're ECU is doing "on the fly".

Yep. Just because you put the stuff back together in the same place it came out doesn't mean that the new parts are on the same side of tolerance or wear and tear. You could pull one distributor out, put an identical one back in at exactly the same spot and find a couple degrees difference.

You really think those clowns are going to do any more than they actually have to do???

__________________
95% of the questions that are "STRANGE" or "PECULIAR" usually have a dirt simple answer...usually answered or prevented by a dirt simple search.

Just pointing out the obvious...
Is it just me, or does the majority overlook the obvious?
Some people shouldn't breed.

Why do people continue to run a vehicle when a warning light comes on, or worse, starts flashing? Isn't that a clue that something is wrong and you probably should NOT drive it?
Is this whole car driving thing really freekin' brain surgery? Are people that stupid?

Here's something new for the crowd/clowns...
"A little bit of Google goes a long way!"

And if you can read this, you don't need glasses! :)

And yes, I am diggin' it...

smj999smj

I agree pretty much with the direction y'all are going. I would've first check the basics: spark plugs (5 years?..might be time for a set of new NGK's), air filter, checking/adjusting the base idle and ignition timing per the FSM, and performing a fuel pressure leakdown test (to check for leaking injectors) and fuel pressure test (to check for excessive fuel pressure). Even if the fuel pump was running constantly when you turned the key "on," it still shouldn't flood the engine as excessive fuel pressure would be vented back to the tank and fuel shouldn't enter the combustion chamber unless the injectors are spraying/leaking fuel.

One thing I've encountered several times on B14's is a starter that doesn't crank fast enough, causing engine flooding. Fix: replace starter motor. Another, more common, problem I've seen is bad IACV-AAC valves, especially on 95/96 models w/ the GA16DE. The reason properly setting the base idle speed is so that the IACV-AAC valve operates properly. There was an issue with some 95/96 Sentras and 200SX's with the GA16DE and air conditioning where a diode failed and caused a reverse polarity condition in the IACV-AAC valve. Fix was to replace the diode subharness (Nissan P/N: 24168-4B000), located just behing the dash on the right side of the center stack. Also, the IACV-AAC valve (Nissan P/N: 16188-1M210) needed to be replaced as well. The IACV-AAC valve controls an airport (as commanded by the ECM) of unmetered air to raise the idle for cold starts and maintain base idle under loads. Also make sure the oil in the crankcase is not contaminated with fuel.

speedy25

^^^^ What he said especially the fuel pressure leakdown part, IF the problem is "flooding."

I think the smj999smj post above is the MOST intelligent and well written post I have seen on any board.

-SP