Cranks for a while but starts

[MisterRoy]

You mentioned replacing the COPs but we’re the plugs replaced when you did this? All over this site it’s recommended to replace all COPs and spark plugs at once.

However, the typical symptoms are poor idle/rough running so it’s probably not your problem although it’s a possibility with the misfires.

The plugs were replaced right before I purchased the car. They have about 4K miles on them.

Outside of the misfires, which only happen on startup with the long crank, the car runs fine. No poor idle or rough running. The car runs like a champ.

When the car starts after the long crank, the exhaust will burn your nostrils; seems real rich. I suspect there is a flood condition it's just what is causing it? Leaky injector or bad mixture...or something else entirely.

 

[joegr]

Does this happen every time? Only after refueling? Only when the tank is fairly full?
Do you have a noid light to see if the coils are being fired?

 

[MisterRoy]

If there is a long crank, the exhaust will smell rich, but just on startup. Once the car is running, the rich exhaust smell no longer continues. I do not have a noid light to see if the coils are being fired. Seeing that this issue doesn't happen when the car sits overnight, I would have to assume so. I am not objected to getting a kit, though.

 

[MisterRoy]

I was able to find camshaft position sensor level in Forscan. (It was "low" when the car was running in park) I was not able to find the crank position sensor level. Does anyone know if it goes by another name?

 

[joegr]

CPS
Both sensors should be pulsing when the engine is turning. If Forscan can't capture that, you may have to turn the crank by hand and watch both go high and low and high and low and...

 

[MisterRoy]

I've really got myself confused...

I tried this last night, car has beem off for almost 3 hours:

Turn key on, connect iPhone and open Forscan. Fuel Rail Pressure is 26 PSI. (I do realize this action caused the fuel pump to cycle once, leading me to believe the fuel pressure was very low). Turned key off and back on, FRP up to 34 PSI. Turn key off and on, FRP PSI up to 36 PSI. Now, I start the car. It cranks for a second or 2 and once the FRP hits 40 PSI the car fires up. During this sequence of events, the long crank was shorter than normal. NO MISFIRES DETECTED. Very important...

This morning, after the car has sat for 9.5 hours, I turn key on, connect iPhone and open Forscan. FRP is at 27 PSI. I turn the car over and it fires up between 36 and 39 PSI then drops to 30 PSI and 9 MISFIRES ARE DETECTED. Then the FRP hits 40 PSI, misfires stop. This all happens in the span of a second or 2.

I think it's become obvious that I have a fuel pressure issue. What I think is happening is the fuel is ether back filling the check valve in the pump or leaking into a cylinder, leaving air in the fuel rail between the fuel and the injectors. I don't understand why the misfires happen and don't happen on the varying sit times before startup. It's hard to determine if I have a leaky/clogged fuel injector or if the check valve in the fuel pump is failing...

Any and all thoughts are appreciated.

 

[joegr]

Yeah, I hadn't thought about a weak fuel pump. So, troubleshooting this is more complicated because of the two pump setup.
The pump on the passenger side is the electric pump. It's driven by the REM. It speeds up or slows down the pump as it is told to by the PCM according to the fuel pressure. This approximately regulates the pressure, and the PCM adjusts injector on times to compensate for the not exact regulation.
The pump on the driver's side is a jet pump. It transfers fuel from the driver's sump in the tank to the passenger side sump. It is powered by the fuel pumped from the electric pump. So, if it is a leak down problem, then it could be caused by either side. It seems like more often it is the electric pump getting weak, failing.
Some aftermarket brands seem to be okay, but at least one is terrible. I don't remember the brand, but it has been posted on here a few times.

 

[MisterRoy]

I think I am at a point where I need to focus on the where the fuel is going, cylinder or back into the tank. I have a mechanics stethoscope coming soon. I will listen with the injectors with the car on and off. If there is a leaky injector, hopefully I can hear it. If not, looks like i need to clamp the fuel line and check to see if the pressure is still lost. If yes, injector. If no, pump.

When I got to the train station this morning I added short and long term fuel trims to Forscan. Short term was 0 on both sides, long term was 0 on 2 and close to 10 on 1. On the surface this tells me that bank 1 is running lean but I am not sure that is certain.

Is there a way to clear memory so I can see newly calculated long term trim values?

Thanks again for all your help.

 

[joegr]

If you use the clear code (even with no code) function, it should clear all the adaptations. Otherwise, you could disconnect the battery negative for a few seconds and then reconnect.

 

[MisterRoy]

If you use the clear code (even with no code) function, it should clear all the adaptations. Otherwise, you could disconnect the battery negative for a few seconds and then reconnect.

I cleared them a few weeks ago when I changed my COPs. That means this new calculation is pretty current. I was reading that a dirty MAF can cause incorrect calculations due to an incorrect reading. I think I should clean that, too.

Thank you Joe