Recent starting issues. Fuel problem?

Aviator44 · 07-06-2016, 09:08 PM

So up front, my car has the AAM TT kit, tuned with uprev, and it's been boosted for 20K+ miles without any issue regarding starting.

About a week ago I went to start my car after a week of sitting. The car took 6-8 cranks before it started. I didn't think anything of it since the cars been sitting and it ran perfectly fine once started. Well, ever since then the issue is replicated on every startup. It will fire up but only after 8-10 cranks

The battery was replaced 3 months ago. I had it checked just to make sure it wasn't the issue and it's good.

The car runs absolutley fine once it's running. Tuning is spot on and I'm reading 52 psi on fuel pressure at idle. I haven't checked the fuel px on startup yet. I did notice that the fuel pump prime does sound a little different than how It normally does.

Anyone have any ideas on where I should begin to figure this out?

JSur · 07-06-2016, 09:21 PM

I'm also running the AAM TT Kit and about the same mileage it's been on. Once it's been driven for a while and I go to turn her back on it fires up like a dream. Checked my plugs about a month ago and they were good. I'm real curious to see if anyone knows what's up with this.

11' 370z TT

Aviator44 · 07-06-2016, 10:31 PM

Quote:

Originally Posted by JSur

I'm also running the AAM TT Kit and about the same mileage it's been on. Once it's been driven for a while and I go to turn her back on it fires up like a dream. Checked my plugs about a month ago and they were good. I'm real curious to see if anyone knows what's up with this.

11' 370z TT

The strangest part to me is once it's running everything works perfectly fine. Normally issues with fuel pumps, injectors, bad fuel, ect would affect the engine when running as well.

VSS370z · 07-08-2016, 12:19 AM

If you find the problem let me know. I've been having similar issues for a bit now. I have a Fast Intentions tt. It always happen when the car sits for like 8 hours. It does crank but hesitant to do so then it revs all by itself to 2k rpms to get going. Afterwards the car drive normally and then cranks every time on the 1st try without any problem. I upgraded both injectors and pump 2 months ago. Hoping is not a damn injector going bad...they are expensive.

MAMotorsports · 07-08-2016, 09:51 AM

Starter may be going out? They can get real warm in these turbo cars.

TBatt · 07-08-2016, 10:40 AM

Check your fuel pressure before you start the engine. It should be around 50psi unless it has been setting for a long time (weeks). If the pressure is good then look elsewhere. If the pressure has leaked down try this. Turn the car on but don't start it. This will allow the pump to run a few seconds. Check the pressure again. If it is good then try and start the engine. If it fires up normally then you may have a fuel pressure regulator problem (leaking).

You might want to check your battery starting voltage too. It should not drop below about 10 volts when the engine is turning over. If it does then you have a weak battery.

Good luck and let us know what you find.

hjo1078 · 07-08-2016, 11:42 AM

i would check the spark plugs too, my spark plugs were shot after zdayz.

Aviator44 · 07-09-2016, 12:52 PM

Quote:

Originally Posted by MAMotorsports

Starter may be going out? They can get real warm in these turbo cars.

This is one of the things I was leaning towards.

Quote:

Originally Posted by TBatt

Check your fuel pressure before you start the engine. It should be around 50psi unless it has been setting for a long time (weeks). If the pressure is good then look elsewhere. If the pressure has leaked down try this. Turn the car on but don't start it. This will allow the pump to run a few seconds. Check the pressure again. If it is good then try and start the engine. If it fires up normally then you may have a fuel pressure regulator problem (leaking).

You might want to check your battery starting voltage too. It should not drop below about 10 volts when the engine is turning over. If it does then you have a weak battery.

Good luck and let us know what you find.

My fuel pressure gauge is reading zero prior to start. Fuel pressure is at 52 as soon as the car starts cranking and at idle. Pressure is also stable. It doesn't matter how many times I prime the fuel pump prior to start, fuel pressure reads 0 at the damper until cranking. I did find out that once the car is idling, if I turn it off and wait 5-10 seconds then turn it back on, It fires up like normal every time. You're saying fuel pressure should remain around 50 even if the car sits for an hour? I do notice a strong smell of gas right after startup. Possible leaking injector?

Quote:

Originally Posted by hjo1078

i would check the spark plugs too, my spark plugs were shot after zdayz.

I'll take a look. What symptoms did you have?

hjo1078 · 07-09-2016, 01:15 PM

When i was hit the gas hard it would cut out. Almost like it was choking. We did a lot tests on the fuel system and it was the spark plugs all along

Sent from my iPhone using Tapatalk

Jhill · 07-09-2016, 02:09 PM

Quote:

Originally Posted by Aviator44

This is one of the things I was leaning towards.

My fuel pressure gauge is reading zero prior to start. Fuel pressure is at 52 as soon as the car starts cranking and at idle. Pressure is also stable. It doesn't matter how many times I prime the fuel pump prior to start, fuel pressure reads 0 at the damper until cranking. I did find out that once the car is idling, if I turn it off and wait 5-10 seconds then turn it back on, It fires up like normal every time. You're saying fuel pressure should remain around 50 even if the car sits for an hour? I do notice a strong smell of gas right after startup. Possible leaking injector?

I'll take a look. What symptoms did you have?

If you're at 0 psi before cranking then you are having a residual fuel pressure drop issue. Now you need to find what is not holding pressure wether it be a regulator, pump check valve or injector. Need to start pinching off sections of the system to determine what part is not holding.

TBatt · 07-11-2016, 09:59 AM

Fuel pressure should be good for days if the system is healthy.

phunk · 07-11-2016, 01:46 PM

If you have a return fuel system on your turbo car, usually fuel pressure will not hold more than a few seconds after the pump is off. Aftermarket regulators are not designed to hold pressure.

To crank from zero pressure rather then a primed system should only add an extra 2 cranks or so until it starts.

If the car starts hot, but doesnt start cold, (assuming plugs are good and nothing strange is going on) it is most likely an issue in the calibration. Getting a perfect tune that starts quickly in every circumstance can be harder than it sounds with many computer systems. In my Z, I used to have a random problem with hot starts that I never fully worked out in UpRev, but it would cold start E85 1000cc injectors dead middle of winter 0 degrees out like it was factory stock on a summer day. My mustang is tuned by one of the best tuners in the industry for that platform and it has intermittent issues with cold starting where sometimes it doesnt even start on the first cycle.

Its worth chasing it a bit, to make sure nothing is actually wrong physically with the fuel system or plugs etc. But if you get it nailed down to the ECU calibration, it may or may not be easily correctable.

Aviator44 · 07-11-2016, 09:34 PM

Quote:

Originally Posted by phunk

If you have a return fuel system on your turbo car, usually fuel pressure will not hold more than a few seconds after the pump is off. Aftermarket regulators are not designed to hold pressure.

To crank from zero pressure rather then a primed system should only add an extra 2 cranks or so until it starts.

If the car starts hot, but doesnt start cold, (assuming plugs are good and nothing strange is going on) it is most likely an issue in the calibration. Getting a perfect tune that starts quickly in every circumstance can be harder than it sounds with many computer systems. In my Z, I used to have a random problem with hot starts that I never fully worked out in UpRev, but it would cold start E85 1000cc injectors dead middle of winter 0 degrees out like it was factory stock on a summer day. My mustang is tuned by one of the best tuners in the industry for that platform and it has intermittent issues with cold starting where sometimes it doesnt even start on the first cycle.

Its worth chasing it a bit, to make sure nothing is actually wrong physically with the fuel system or plugs etc. But if you get it nailed down to the ECU calibration, it may or may not be easily correctable.

Thanks for the reply! The car is still running non-return. I've been meaning to get a return kit for awhile, but never got to it.

The car has the starting issue regardless of temperature. The only time It doesn't have the starting issue is when I start the car immediately after turning it off. I'm assuming the quick restart isn't giving the system enough time to lose pressure. If I wait 10 mins or so, the problem is back.

I should also note that the car has nearly 20K miles being boosted. The tuning has always been spot on and it still is once the car is running. The car has always started fine in the coldest Ohio winters and even on the hottest summer days since moving to Florida. The problem just randomly started a few weeks ago.

I have your mini fuel gauge. I've noticed that while the car is cranking, fuel pressure increases a little bit each crank until finally reaching 40-50 psi after 10 cranks or so, then the car fires. It's like the system is unable to instantly provide the necessary fuel pressure anymore.

TBatt · 07-12-2016, 09:26 AM

If you are still running the stock (non-return) system then you do have a problem. It could either be the fuel pump check valve or the pressure regulator. Hope it is the fuel pump because that is an easy fix where the regulator isn't. The stock pressure regulator is a part of the fuel pump assembly and isn't sold separately. A new fuel pump assembly will run you around $500. I would think that this would be the perfect time to go to a return fuel system and external regulator with boost compensation. Good luck!

Give Charles (Phunk) a call. He is super easy to work with and has quality products!

Aviator44 · 07-23-2016, 10:11 PM

Finally figured out what was giving me issues with my fuel pressure on startup. I was leaning heavily towards a bad check valve, but I pulled the fuel pump assembly today and found this.

07-06-2016, 09:08 PM	#1 (permalink)
Aviator44 Enthusiast Member Join Date: May 2014 Location: Pensacola, FL Posts: 299 Drives: AAM Twin Turbo 370Z Rep Power: 11	Recent starting issues. Fuel problem? So up front, my car has the AAM TT kit, tuned with uprev, and it's been boosted for 20K+ miles without any issue regarding starting. About a week ago I went to start my car after a week of sitting. The car took 6-8 cranks before it started. I didn't think anything of it since the cars been sitting and it ran perfectly fine once started. Well, ever since then the issue is replicated on every startup. It will fire up but only after 8-10 cranks The battery was replaced 3 months ago. I had it checked just to make sure it wasn't the issue and it's good. The car runs absolutley fine once it's running. Tuning is spot on and I'm reading 52 psi on fuel pressure at idle. I haven't checked the fuel px on startup yet. I did notice that the fuel pump prime does sound a little different than how It normally does. Anyone have any ideas on where I should begin to figure this out? __________________ www.aamcompetition.com AAM Twin Turbo System

07-08-2016, 12:19 AM	#4 (permalink)
VSS370z Enthusiast Member Join Date: Apr 2012 Location: Puerto Rico Posts: 380 Drives: 09 Nissan 370z CY M6 Rep Power: 13	If you find the problem let me know. I've been having similar issues for a bit now. I have a Fast Intentions tt. It always happen when the car sits for like 8 hours. It does crank but hesitant to do so then it revs all by itself to 2k rpms to get going. Afterwards the car drive normally and then cranks every time on the 1st try without any problem. I upgraded both injectors and pump 2 months ago. Hoping is not a damn injector going bad...they are expensive. Last edited by VSS370z; 07-08-2016 at 12:23 AM.

07-08-2016, 09:51 AM	#5 (permalink)
MAMotorsports Track Member Join Date: Jul 2015 Location: Glen Arm, MD Posts: 872 Drives: 370Z Rep Power: 17	Starter may be going out? They can get real warm in these turbo cars. axmea? likes this. __________________ Daelen @ MA Motorsports MA-Motorsports.com https://www.facebook.com/pages/MA-Mo...C/125379858828

07-08-2016, 10:40 AM	#6 (permalink)
TBatt Track Member Join Date: Apr 2013 Location: Huntsville, AL Posts: 832 Drives: 2019 GT-R Rep Power: 20168	Check your fuel pressure before you start the engine. It should be around 50psi unless it has been setting for a long time (weeks). If the pressure is good then look elsewhere. If the pressure has leaked down try this. Turn the car on but don't start it. This will allow the pump to run a few seconds. Check the pressure again. If it is good then try and start the engine. If it fires up normally then you may have a fuel pressure regulator problem (leaking). You might want to check your battery starting voltage too. It should not drop below about 10 volts when the engine is turning over. If it does then you have a weak battery. Good luck and let us know what you find. SouthArk370Z, axmea? and Aviator44 like this. __________________ RJM pedal, Hotchkis Sway Bars, FI TDX, FOG Light, Z1 Slotted Drilled rotors, Stillen SC, Quaife ATB, Z1 Oil cooler, AEM Gauge Set, Galeforce gauge mount, Avant Garde M590 Hypersilver w/RE-11, TopgunZ A2A kit., ECUtek tuned by Seb: ROLL TIDE!

07-09-2016, 01:15 PM	#9 (permalink)
hjo1078 Track Member Join Date: May 2011 Location: virginia Age: 46 Posts: 572 Drives: twin turbo 370z Rep Power: 5395	When i was hit the gas hard it would cut out. Almost like it was choking. We did a lot tests on the fuel system and it was the spark plugs all along Sent from my iPhone using Tapatalk Aviator44 likes this.

07-06-2016, 09:21 PM	#2 (permalink)
JSur Base Member Join Date: Mar 2016 Location: Orlando Posts: 84 Drives: 2011 370z TT Rep Power: 9	I'm also running the AAM TT Kit and about the same mileage it's been on. Once it's been driven for a while and I go to turn her back on it fires up like a dream. Checked my plugs about a month ago and they were good. I'm real curious to see if anyone knows what's up with this. 11' 370z TT

07-08-2016, 11:42 AM	#7 (permalink)
hjo1078 Track Member Join Date: May 2011 Location: virginia Age: 46 Posts: 572 Drives: twin turbo 370z Rep Power: 5395	i would check the spark plugs too, my spark plugs were shot after zdayz.

07-11-2016, 09:59 AM	#11 (permalink)
TBatt Track Member Join Date: Apr 2013 Location: Huntsville, AL Posts: 832 Drives: 2019 GT-R Rep Power: 20168	Fuel pressure should be good for days if the system is healthy. Aviator44 likes this. __________________ RJM pedal, Hotchkis Sway Bars, FI TDX, FOG Light, Z1 Slotted Drilled rotors, Stillen SC, Quaife ATB, Z1 Oil cooler, AEM Gauge Set, Galeforce gauge mount, Avant Garde M590 Hypersilver w/RE-11, TopgunZ A2A kit., ECUtek tuned by Seb: ROLL TIDE!

07-11-2016, 01:46 PM	#12 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,668 Drives: 370 Rep Power: 974723	If you have a return fuel system on your turbo car, usually fuel pressure will not hold more than a few seconds after the pump is off. Aftermarket regulators are not designed to hold pressure. To crank from zero pressure rather then a primed system should only add an extra 2 cranks or so until it starts. If the car starts hot, but doesnt start cold, (assuming plugs are good and nothing strange is going on) it is most likely an issue in the calibration. Getting a perfect tune that starts quickly in every circumstance can be harder than it sounds with many computer systems. In my Z, I used to have a random problem with hot starts that I never fully worked out in UpRev, but it would cold start E85 1000cc injectors dead middle of winter 0 degrees out like it was factory stock on a summer day. My mustang is tuned by one of the best tuners in the industry for that platform and it has intermittent issues with cold starting where sometimes it doesnt even start on the first cycle. Its worth chasing it a bit, to make sure nothing is actually wrong physically with the fuel system or plugs etc. But if you get it nailed down to the ECU calibration, it may or may not be easily correctable. GaleForce, TBatt, Elmo370z and 1 others like this. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph Last edited by phunk; 07-11-2016 at 01:58 PM.

07-12-2016, 09:26 AM	#14 (permalink)
TBatt Track Member Join Date: Apr 2013 Location: Huntsville, AL Posts: 832 Drives: 2019 GT-R Rep Power: 20168	If you are still running the stock (non-return) system then you do have a problem. It could either be the fuel pump check valve or the pressure regulator. Hope it is the fuel pump because that is an easy fix where the regulator isn't. The stock pressure regulator is a part of the fuel pump assembly and isn't sold separately. A new fuel pump assembly will run you around $500. I would think that this would be the perfect time to go to a return fuel system and external regulator with boost compensation. Good luck! Give Charles (Phunk) a call. He is super easy to work with and has quality products! __________________ RJM pedal, Hotchkis Sway Bars, FI TDX, FOG Light, Z1 Slotted Drilled rotors, Stillen SC, Quaife ATB, Z1 Oil cooler, AEM Gauge Set, Galeforce gauge mount, Avant Garde M590 Hypersilver w/RE-11, TopgunZ A2A kit., ECUtek tuned by Seb: ROLL TIDE!

07-23-2016, 10:11 PM	#15 (permalink)
Aviator44 Enthusiast Member Join Date: May 2014 Location: Pensacola, FL Posts: 299 Drives: AAM Twin Turbo 370Z Rep Power: 11	Finally figured out what was giving me issues with my fuel pressure on startup. I was leaning heavily towards a bad check valve, but I pulled the fuel pump assembly today and found this. hjo1078 and SwedeZ like this. __________________ www.aamcompetition.com AAM Twin Turbo System

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