So ive been fighting an intermittent misfire for ever...

jchammond · 05-20-2019, 02:51 AM

I have also heard a few members speak of throttle body issues causing similar issues...but unsure all details.
Confirm all connections to them are clean & even put a touch of dialectical lube on connection.

Ommateal · 05-20-2019, 03:02 AM

Quote:

Originally Posted by jchammond

Definitely sounds like low fuel pressure/ sounds like it’s an old carbureted car trying to vapor lock.
You can pick one of these up cheap & extend the line,so you can view while driving...just keep outside of vehicle.

I have deff considered it being some kind of vapor lock when it is the hot start part of the issue... I have even heard of fuel rail vapor locks before on these IIRC.... But that seems odd and if any case you think it would be a rare issue...

Ill take a look at that part right now.

Vapor lock doesnt explain the colder engine issues...but bad fuel flow can. Either way its a Lean condition for sure ether thats from not enough fuel from the basket or a bad sensor not letting the ecu know whats up... so frustrating.

Ommateal · 05-20-2019, 03:03 AM

Quote:

Originally Posted by jchammond

I have also heard a few members speak of throttle body issues causing similar issues...but unsure all details.
Confirm all connections to them are clean & even put a touch of dialectical lube on connection.

Way Back when the issue first started I cleaned Mafs, new spark plugs, and took off and cleaned the TBs real good. All that seems fine.

jchammond · 05-20-2019, 03:06 AM

Quote:

Originally Posted by Ommateal

Way Back when the issue first started I cleaned Mafs, new spark plugs, and took off and cleaned the TBs real good. All that seems fine.

How many miles on engine & did it sit through winter with tank of fuel?

Ommateal · 05-20-2019, 03:06 AM

Quote:

Originally Posted by jchammond

Definitely sounds like low fuel pressure/ sounds like it’s an old carbureted car trying to vapor lock.
You can pick one of these up cheap & extend the line,so you can view while driving...just keep outside of vehicle.

I Deff might buy this right now just because its cool and handy regardless.

jchammond · 05-20-2019, 03:07 AM

Also, is it throwing a cel?

Ommateal · 05-20-2019, 03:08 AM

Quote:

Originally Posted by jchammond

How many miles on engine & did it sit through winter with tank of fuel?

55,xxx miles

Uhh I store it each winter in a garage with less then a quarter of a tank.

This issue has been going on for almost 2 years or so... prob not just bad fuel

jchammond · 05-20-2019, 03:09 AM

Quote:

Originally Posted by Ommateal

I Deff might buy this right now just because its cool and handy regardless.

If you get on their website; they actually have videos of installation instructions...fairly simple.
Just mount gauge in a place that you can view while driving,,,just not inside your car.

jchammond · 05-20-2019, 03:10 AM

Quote:

Originally Posted by Ommateal

55,xxx miles

Uhh I store it each winter in a garage with less then a quarter of a tank.

This issue has been going on for almost 2 years or so... prob not just bad fuel

Not good on 10% ethanol fuel,,,always a full tank & some ethanol shield to prevent corrosion around pump etc..

Ommateal · 05-20-2019, 03:15 AM

Quote:

Originally Posted by jchammond

Not good on 10% ethanol fuel,,,always a full tank & some ethanol shield to prevent corrosion around pump etc..

here is a pic of Nissans take on it

And here is a pic from my original post of all the codes I found with a 5000$ scanner lol.

jchammond · 05-20-2019, 03:22 AM

Quote:

Originally Posted by Ommateal

here is a pic of Nissans take on it

And here is a pic from my original post of all the codes I found with a 5000$ scanner lol.

I’d stay away from dealership & find shop familiar with the VQ....fuel pressure is low & definitely will cause a random cylinder misfire.
I don’t have specs in front of me...but should maintain 40psi....I’m pretty sure & in some cases more.
Your oil temp is fine...mine ran 220-230 a lot & wouldn’t pull timing & derate unless it got past 240-250

jchammond · 05-20-2019, 03:29 AM

Quote:

Originally Posted by Ommateal

I Deff might buy this right now just because its cool and handy regardless.

If you phone & order this/ ask to speak with Jon P. (Their Tuner) & let him know your symptoms & what fuel pressure reading was at dealership.
He will be able to give you some helpful information on it

Ommateal · 05-20-2019, 03:29 AM

Quote:

Originally Posted by jchammond

I’d stay away from dealership & find shop familiar with the VQ....fuel pressure is low & definitely will cause a random cylinder misfire.
I don’t have specs in front of me...but should maintain 40psi....I’m pretty sure & in some cases more.
Your oil temp is fine...mine ran 220-230 a lot & wouldn’t pull timing & derate unless it got past 240-250

Yeah I wish I lived near some of the reputable Z shops lol. Guess Ill have to dig around a lot here in rural NE Ohio for someone knowledgeable in VQ to look at it.

Is there anything common that could just kill a new AF sensor? Bad luck obviously lol.

Wonder if there is any other issue thats the main culprit that kills upstream sensor?

Other then that I guess I could just attempt the CJ return or buy a Brand new basket... both are the same price baically, assuming my sensors are still good then fuel is the last thing i can think of...

And yea its not going back to nissan, i gave them their 1 shot at diagnosing it.

jchammond · 05-20-2019, 03:31 AM

Quote:

Originally Posted by Ommateal

Yeah I wish I lived near some of the reputable Z shops lol. Guess Ill have to dig around a lot here in rural NE Ohio for someone knowledgeable in VQ to look at it.

Is there anything common that could just kill a new AF sensor? Bad luck obviously lol.

Wonder if there is any other issue thats the main culprit that kills upstream sensor?

Other then that I guess I could just attempt the CJ return or buy a Brand new basket... both are the same price baically, assuming my sensors are still good then fuel is the last thing i can think of...

And yea its not going back to nissan, i gave them their 1 shot at diagnosing it.

Leaded race fuel will kill them or poor quality fuels,,,unless you’re somehow getting coolant down your exhaust.

jchammond · 05-20-2019, 03:33 AM

Also if your fuel injectors are clogged & not atomizing fuel properly- could be sending unburnt raw fuel down exhaust.

05-20-2019, 02:51 AM	#16 (permalink)
jchammond A True Z Fanatic Join Date: Nov 2014 Location: South Carolina Age: 57 Posts: 15,204 Drives: 13’ 370Z TS 7A/T Rep Power: 2684394	I have also heard a few members speak of throttle body issues causing similar issues...but unsure all details. Confirm all connections to them are clean & even put a touch of dialectical lube on connection. __________________ MazWorx built long block \| FI-TT-100 Stage 2.75 \| IPT built 7A/T http://www.the370z.com/members-370z-...s-musings.html

05-20-2019, 03:07 AM	#21 (permalink)
jchammond A True Z Fanatic Join Date: Nov 2014 Location: South Carolina Age: 57 Posts: 15,204 Drives: 13’ 370Z TS 7A/T Rep Power: 2684394	Also, is it throwing a cel? __________________ MazWorx built long block \| FI-TT-100 Stage 2.75 \| IPT built 7A/T http://www.the370z.com/members-370z-...s-musings.html

05-20-2019, 03:33 AM	#30 (permalink)
jchammond A True Z Fanatic Join Date: Nov 2014 Location: South Carolina Age: 57 Posts: 15,204 Drives: 13’ 370Z TS 7A/T Rep Power: 2684394	Also if your fuel injectors are clogged & not atomizing fuel properly- could be sending unburnt raw fuel down exhaust. Ommateal likes this. __________________ MazWorx built long block \| FI-TT-100 Stage 2.75 \| IPT built 7A/T http://www.the370z.com/members-370z-...s-musings.html

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