Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Go Back   Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum > General > Tech Talk > Engine Tech

Engine Tech Technical discussion related to all relevant engines such as KA, SR, RB, CA, 2JZ , L24/26/28, VG, VQ, and LSx series.


Reply
 
Thread Tools Display Modes
Old 09-25-2019, 09:25 AM   #1
Reds13sr
 
Join Date: Jul 2019
Location: Dallas
Age: 28
Posts: 2
Trader Rating: (0)
Reds13sr is an unknown quantity at this point
Feedback Score: 0 reviews
Sr20det loses voltage at idle causing lean

After my sr warms up basically everything happens at once the idle drops to about 300 to 400 my voltage drops to low 12 volts and car leans out. Timings good, new alternator, wired small wire on alt plug to light to 12v, fuel pressure stay 40 psi, new fuel pump, checked tps voltage, cleaned iacv. I'm stuck at this point when driving it drives fine the ecu code is knock sensor which I have on the way cause it's all cracked. I have to put my foot on the gas when I come to a stop so it doesn't lean out and or just die out.
Reds13sr is offline   Reply With Quote
Sponsored Links
Old 09-25-2019, 05:18 PM   #2
S14rebuild
Zilvia Junkie
 
Join Date: May 2019
Location: Florida-FAIL
Posts: 559
Trader Rating: (3)
S14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud of
Feedback Score: 3 reviews
Voltage will drop cause the idle drops. Alternator is spinning as fast to create proper voltage.

Check if your tps/timing is set properly.
Check for vacuum leaks
Check idle air control valve operation
Atmosphere bov wont help either

Last edited by S14rebuild; 09-26-2019 at 09:41 AM..
S14rebuild is offline   Reply With Quote
Old 09-25-2019, 10:01 PM   #3
Jfornachon
Zilvia Junkie
 
Join Date: Dec 2011
Location: Caldwell Idaho
Posts: 300
Trader Rating: (3)
Jfornachon is an unknown quantity at this point
Feedback Score: 3 reviews
Try a new alternator. As they start to fail they can loose power after heating up.

Have a great day,
jared
Jfornachon is offline   Reply With Quote
Old 09-26-2019, 09:41 AM   #4
S14rebuild
Zilvia Junkie
 
Join Date: May 2019
Location: Florida-FAIL
Posts: 559
Trader Rating: (3)
S14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud of
Feedback Score: 3 reviews
Quote:
Originally Posted by Jfornachon View Post
Try a new alternator. As they start to fail they can loose power after heating up.

Have a great day,
jared
Did u read the post?
S14rebuild is offline   Reply With Quote
Old 09-28-2019, 08:55 PM   #5
Kingtal0n
Post Whore!
 
Kingtal0n's Avatar
 
Join Date: Jul 2005
Location: South Florida
Age: 36
Posts: 4,298
Trader Rating: (17)
Kingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to all
Feedback Score: 17 reviews
Send a message via AIM to Kingtal0n
1. new alt can be bad
2. voltage is control by alt so if voltage drop then alt isn't working

3. if alt is good the only way you can have voltage problems is if
one or more of the key wire groups (ground strap from engine, ground wiring lug by kick panel, ground strap on intake, ground strap on exhaust, ground strap for coils, ground strap for chassis, and main power feed/fuses)
is missing or bad, or one of the key wiring elements (ECU plug/sensors) is loose or bad,

or if the alt is undersized for the application.
Kingtal0n is offline   Reply With Quote
Old 09-29-2019, 06:18 AM   #6
S14rebuild
Zilvia Junkie
 
Join Date: May 2019
Location: Florida-FAIL
Posts: 559
Trader Rating: (3)
S14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud ofS14rebuild has much to be proud of
Feedback Score: 3 reviews
Again, hes checking voltage as the engine stumbles.

Have someone hold the rps at 2000. Then check voltage. Post what you got.
S14rebuild is offline   Reply With Quote
Old 09-29-2019, 07:07 AM   #7
RalliartRsX
Post Whore!
 
Join Date: Apr 2006
Location: Maryland
Posts: 4,318
Trader Rating: (32)
RalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfectionRalliartRsX is close to perfection
Feedback Score: 32 reviews
When you say new alt, is it used, new oem, or new reman?

If voltage is dropping, that's almost 100% indicative of an alt. Easy button is to just take it off and take it to your local auto parts and have it tested. It's not uncommon for even new reman alt do not work. Also, did your properly tension the belt? Belt may very well be slipping

Also, check your wiring to make sure.
RalliartRsX is offline   Reply With Quote
Old 10-01-2019, 09:33 AM   #8
jedi03
Zilvia FREAK!
 
Join Date: Jul 2008
Location: albuquerque
Posts: 1,509
Trader Rating: (8)
jedi03 is on a distinguished road
Feedback Score: 8 reviews
and don't underdrive the alternator lol, but also to thin of wiring creates to much resistance, I have been through 4 alternators this year due to same issue...low voltage or voltage regulators going out...my fault for sticking with same brand but free replacements are hard to say no to lol, check relays and fuses...a main fuse blown can cause similar issues...a new alternator doesn't mean a good alternator...check volts and make sure amperage is correct too
jedi03 is offline   Reply With Quote
Old 10-04-2019, 02:29 PM   #9
Kingtal0n
Post Whore!
 
Kingtal0n's Avatar
 
Join Date: Jul 2005
Location: South Florida
Age: 36
Posts: 4,298
Trader Rating: (17)
Kingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to all
Feedback Score: 17 reviews
Send a message via AIM to Kingtal0n
I've never had an OEM alternator failure on any sr20det nor have I even heard of it before this.


Alt should be the easiest part of the entire car, its like 2 wires and it spins. Try an OEM alternator with 222,000 miles and get on with life?
Kingtal0n is offline   Reply With Quote
Reply

Bookmarks


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 11:37 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
vB.Sponsors
Copyright © 1998 - 2019, Zilvia.net™