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Discussion Starter · #1 ·
Occasionally I’ve experienced a hard start that is accompanied by a slow crank. The Rpms slowly rise up roughly.

Doesnt happen on first starts of the day. It mainly happens if the vehicle is started, turned off and then restarted soon.

I had a hot start stumble about 4 months ago which went away after running a can of bg44k through. Should I put another can in?

Thanks
 

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This sounds like the, start, move 20ft, stop, restart problem. had this with two 97s, sentra and Ser plus 2003 pathfinder.
This is due to over rich starting mixture and shuting off before it can be burnt off.
This was a well documented problem here in the day.
I learnt to "dont do that" !
BTW my 2018 doesnt seem to do that, but I will admit I havnt pushed my luck.
 

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Discussion Starter · #3 ·
This sounds like the, start, move 20ft, stop, restart problem. had this with two 97s, sentra and Ser plus 2003 pathfinder.
This is due to over rich starting mixture and shuting off before it can be burnt off.
This was a well documented problem here in the day.
I learnt to "dont do that" !
BTW my 2018 doesnt seem to do that, but I will admit I havnt pushed my luck.
Is it normal for this to happen?

Anything that can prevent this from happening besides not shutting off right away?

Sometimes I have to move the vehicle a short distance, such as bringing in and out garage.
 

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Occasionally I’ve experienced a hard start that is accompanied by a slow crank. The Rpms slowly rise up roughly.

Doesnt happen on first starts of the day. It mainly happens if the vehicle is started, turned off and then restarted soon.

I had a hot start stumble about 4 months ago which went away after running a can of bg44k through. Should I put another can in?

Thanks
I had an "on and off" stumbling problem with my '91 240SX for quite sometime; tried the BG44K; fixed it for about 6 months. The final solution was to replace all the fuel injectors.

In your case you may have one or more leaking injectors that cause raw fuel to enter the cylinders; this causes what's called a hydrostatic lock condition which makes starting extremely difficult; the engine barely turns, if not at all. To justify this condition, a good way to test for leaking fuel injectors is to Tee-in a temporary fuel pressure gauge between the fuel filter outlet and the fuel rail. Turn the ignition key to the run position but DO NOT TRY TO START THE ENGINE; wait about 10 seconds, then turn the ignition key to OFF. The fuel pressure reading should be around 43 psi which would be a static reading. Now watch the gauge; if it starts dropping down fast, that's an indication of a fuel injector(s) leak.
 

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Is it normal for this to happen?

Anything that can prevent this from happening besides not shutting off right away?

Sometimes I have to move the vehicle a short distance, such as bringing in and out garage.
my 97 senta, 97SER from new, and 2003 pathfinder from 2004 all did this. It was reported on the forums as a common issue.
If this is leaking injectors, then all must leak from that time frame.
 

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Discussion Starter · #6 ·
Is this something I can live with or can I try replacing the three outer ones? The other three are under the plenum.

I am hesitant to open that up now as those plenum screws sometimes seize after all these years. And then on top of that the egr valve.
 

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Is this something I can live with or can I try replacing the three outer ones? The other three are under the plenum.

I am hesitant to open that up now as those plenum screws sometimes seize after all these years. And then on top of that the egr valve.
Before you condemn the fuel injectors for leaking, run the very simple test I outlined in my previous post:
"A good way to test for leaking fuel injectors is to Tee-in a temporary fuel pressure gauge between the fuel filter outlet and the fuel rail. Turn the ignition key to the run position but DO NOT TRY TO START THE ENGINE; wait about 10 seconds, then turn the ignition key to OFF. The fuel pressure reading should be around 43 psi which would be a static reading. Now watch the gauge; if it starts dropping down fast, that's an indication of a fuel injector(s) leak."
The pressure should hold fast for at least 5 or more minutes. So if they're not leaking, you might be wasting your money/labor and finding out that was not the fix.
 

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Discussion Starter · #8 ·
So, the issue with the rough, slow startup happened twice yesterday with the engine failing to start once. Check light came on.

I got the code P0135 O2 Heater Circut Bank 1, Sensor 1.
 

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So, the issue with the rough, slow startup happened twice yesterday with the engine failing to start once. Check light came on.

I got the code P0135 O2 Heater Circut Bank 1, Sensor 1.
Either the heater circuit harness connector is open or shorted or the heater element inside the sensor is bad. Bank #1 is on the right side of the engine and it's the top O2 sensor.
 

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Discussion Starter · #10 ·
Either the heater circuit harness connector is open or shorted or the heater element inside the sensor is bad. Bank #1 is on the right side of the engine and it's the top O2 sensor.
Thanks Rogoman.

could this be a possible culprit of the random issues upon startup?
 

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Discussion Starter · #12 ·
I had a smoke test done on the engine to check for any vacuum leaks that can cause it.

The only thing leaking was the egr bpt valve. The one behind the egr. A lot of smoke was coming out of it.

Are they supposed to work like this because this was a new Nissan replacement part I changed a year ago.
 

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There should be no smoke coming out of the egr-bpt valve. Make sure the egrc-solenoid valve is working OK and inspect the hoses to those valves to insure they are good.
 

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Discussion Starter · #14 ·
There should be no smoke coming out of the egr-bpt valve. Make sure the egrc-solenoid valve is working OK and inspect the hoses to those valves to insure they are good.
Okay, ill check the solenoid, but should that affect the EGRC BPT valve and cause it to leak when the engine is off?

The smoke machine was hooked up to the intake hose after the air filter box and that was the only place smoke was coming out.

I've read that its supposed to leak when the engine is off because no pressure?
 

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Okay, ill check the solenoid, but should that affect the EGRC BPT valve and cause it to leak when the engine is off?

The smoke machine was hooked up to the intake hose after the air filter box and that was the only place smoke was coming out.

I've read that its supposed to leak when the engine is off because no pressure?
I don't like those smoke machines; IMO, that method is not accurate when testing automotive systems. I've always used a vacuum gauge when diagnosing for vacuum leaks while the engine is operating. To check the intake system for a vacuum leak, attach a vacuum gauge to a full vacuum source. With the engine fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be 21 InHg. If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. The gasket may have failed; spray a water mist at the gasket to see if the gauge reading changes. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.
 

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Discussion Starter · #16 ·
I don't like those smoke machines; IMO, that method is not accurate when testing automotive systems. I've always used a vacuum gauge when diagnosing for vacuum leaks while the engine is operating. To check the intake system for a vacuum leak, attach a vacuum gauge to a full vacuum source. With the engine fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be 21 InHg. If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. The gasket may have failed; spray a water mist at the gasket to see if the gauge reading changes. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.
I will try this method out.

Should I go along and replace that BPT valve though? Shop is ordering part, but I might tell them to cancel for now.
 

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I will try this method out.

Should I go along and replace that BPT valve though? Shop is ordering part, but I might tell them to cancel for now.
It's your call.
Using a vacuum gauge, while the engine is idling, you can unplug/replug various vacuum hoses around the EGR/BPT and see the effect on the gauge reading.
 

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Discussion Starter · #18 ·
Before you condemn the fuel injectors for leaking, run the very simple test I outlined in my previous post:
"A good way to test for leaking fuel injectors is to Tee-in a temporary fuel pressure gauge between the fuel filter outlet and the fuel rail. Turn the ignition key to the run position but DO NOT TRY TO START THE ENGINE; wait about 10 seconds, then turn the ignition key to OFF. The fuel pressure reading should be around 43 psi which would be a static reading. Now watch the gauge; if it starts dropping down fast, that's an indication of a fuel injector(s) leak."
The pressure should hold fast for at least 5 or more minutes. So if they're not leaking, you might be wasting your money/labor and finding out that was not the fix.
Before doing the fuel pressure test, should I pull the fuel pump fuse and run engine till cuts off to relieve pressure in order to remove the hose at the rail. Then I can tee in the gauge?

I see some say that the pressure should be 34 psi and they tested while engine is running. Is that correct?

Just want to make sure as I haven’t done this before and would like to get a proper diagnosis for my warm start problem.

Thanks
 

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Before doing the fuel pressure test, should I pull the fuel pump fuse and run engine till cuts off to relieve pressure in order to remove the hose at the rail. Then I can tee in the gauge?

I see some say that the pressure should be 34 psi and they tested while engine is running. Is that correct?

Just want to make sure as I haven’t done this before and would like to get a proper diagnosis for my warm start problem.

Thanks
Before hooking up a pressure gauge, pull the fuse for the pump and let engine run until it dies to relieve the pressure.

With the engine operating at idle, the fuel pressure would be 34 PSI. When the engine is shut off, the pressure would be 43.
 

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Discussion Starter · #20 ·
Before hooking up a pressure gauge, pull the fuse for the pump and let engine run until it dies to relieve the pressure.

With the engine operating at idle, the fuel pressure would be 34 PSI. When the engine is shut off, the pressure would be 43.
So I performed the fuel pressure test. With engine idling it was around 34 PSI. When engine off it was around 42 PSI. After turning key to off position it dropped to 39 PSI.
After 10 minutes the pressure dropped to 36 PSI. After 15 minutes 33 PSI. After 20 minutes it was around 30 PSI.
 
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