sr20det HELP!!!11!!

[NumberOne]

If anyone on here is VERY familiar with these...let me know...i need some help It's dying when coming to a stop...Im thinking its either the MAFS or the IAV...but not sure...maybe a vacuum leak?

 

[HazelGod]

maybe a vacuum leak?

This is the most likely culprit...the VG30DETT behaves much the same way.

But why would you ask this here rather than someplace like TwinTurbo.NET - Our servers have more track time than yours?

 

[NumberOne]

because i already have an account here...and im busy doing other things and too lazy ATM to make an account somewhere

 

[NumberOne]

yes...im about to give a low blow on this one...im bumping my own thread...because im in such a tizzy

 

[D_Geffarde Phartsmeller]

All I can do to help is bump the thread. Sorry.

 

[HazelGod]

because i already have an account here...and im busy doing other things and too lazy ATM to make an account somewhere

That makes about as much sense as asking for a tuxedo at Kroger because you're too lazy to drive to the mall.

Besides, I've already given you an answer. Locate your vacuum leak...and be thankful you're not trying to find one on a VG30DE-class motor.

 

[NumberOne]

right...but that doesnt MEAN its a vacuum leak...ive browsed other threads and there are three ideas... idle air valve. mass air flow. or a vacuum leak somewhere. the problem is the VG motor is made here in the US...so its really not that big of a deal...sr20det is made in japan...its a lesser known engine, with parts lesser available...was just asking if someone here was pretty familiar with it...

 

[HazelGod]

right...but that doesnt MEAN its a vacuum leak...ive browsed other threads and there are three ideas... idle air valve. mass air flow. or a vacuum leak somewhere. the problem is the VG motor is made here in the US...so its really not that big of a deal...sr20det is made in japan...its a lesser known engine, with parts lesser available...was just asking if someone here was pretty familiar with it...

I don't know where you're getting your misinformation, but my VG30DETT was made in Osaka...as were those of every Z32 owner I know. It's a common topic amongst Z owners that the car will stumble or even stall when you release the throttle at speed, particularly if you coast in neutral or press the brakes. The problem is 10+ year old vacuum lines that crack, leak, and break.

Nissan uses similar vacuum control designs in most all of its motors...the SR20 is a much smaller engine, and therefore easier to check for busted lines. The VG30DETT, by contrast, is a fucking PITA because it's shoehorned into the engine bay with virtually no clearance to work. It doesn't help that the wastegate control plumbing runs from the topside of the engine down to the underside, and the car sits all of 6 inches off the ground. So my point was that you should begin with the easiest of the issues to check (not to mention the least expensive to fix), instead of pulling out and testing EF&EC system sensors and components.

But what the fuck do I know? I'm just some guy on a big dick forum, right?

 

[NumberOne]

yaeh...i didnt mean that the engine is manufactured here...but its sold here...in a car of some sort at least..which the sr20det is not found in any car sold in the US.... its just usually if the MAFS is messed up...like on my maxima... it will mess up everything dealing with air flow..not just idle...not normally anyways... i'm hoping its just old vacuum lines, like you said, that are cracked and worn...

 

[HazelGod]

its just usually if the MAFS is messed up...like on my maxima... it will mess up everything dealing with air flow..not just idle...not normally anyways...

When the MAFS throws an error, the ECU will not allow the engine to rev above 2400RPM. Unless you're seeing that behavior, I'd consider that component a longshot.

BTW, have you pulled the diagnostic codes off the ECU yet? That will tell you very quickly if there are any faults in the EFI systems.

 

[NumberOne]

When the MAFS throws an error, the ECU will not allow the engine to rev above 2400RPM. Unless you're seeing that behavior, I'd consider that component a longshot.

BTW, have you pulled the diagnostic codes off the ECU yet? That will tell you very quickly if there are any faults in the EFI systems.

i think what you just said about the engine not reving about 2,400 rpms would be in a newer model car...above 1995... keep in mind this engine could possibly be before 1995... the obd II codes are the only ones that will pull from a MAFS...anything before 1995 was OBD I codes and wont show alot... havent tried getting the codes yet... but... my maxima is a 1995 and had to have the MAFS replaced...it would go well above 2400....im taking it to a mechanic friend of mine that is going to try and get codes off of it tomorrow...guess we'll see then

 

[HazelGod]

i think what you just said about the engine not reving about 2,400 rpms would be in a newer model car...above 1995... keep in mind this engine could possibly be before 1995... the obd II codes are the only ones that will pull from a MAFS...anything before 1995 was OBD I codes and wont show alot

Wrong.

The 2400RPM rev limit is standard "limp-home" behavior on all Z32 models, which began in 1990. I can make mine do it, and it's a Z32D (1993). It's also part of the ECU design for RB25/RB26 series engines, so I would imagine the SR20s aren't any different. Try it yourself...disconnect the MAFS from the wiring harness and go for a little drive.

OBD-II changes only affected the exhaust side of the ECU diagnostic system, not the intake...the biggest difference was the inclusion of O2 sensors downstream of the main cats as well as upstream for finer-grained tuning control of the combustion cycle with an eye toward reduced emissions. But that's irrelevant, because it's an American emissions requirement; and as you've already pointed out, SR20DET engines were never used in cars originally sold in the USA.

 

[NumberOne]

well my MAFS isnt a z32...not on my maxima nor my 240sx....so...thats irrelevant to me anyways...but its not the MAFS...mechanic pointed that out today...also eliminated vacuum leaks with a series of tests and blah blah... its the idle air valve...just gotta take it off and clean everything out and see if that helps...if not i guess its a new IAV...yay...