Jump to content
SAU Community

Losing Revs While Ideling...


SKYNET
 Share

Recommended Posts

My stock standard rb25-det runs smoothly until after about 10 minutes it starts to lose revs & the car shudders randomly-but only while its ideling

it doesn't stall either but feels like its going to

i've been running it on BP ulitimate-added injector cleaning fluid to fuel & cleaned the airflow meter but no luck

has anyone else had a this problem before?

any advice will be appreciated

Link to comment
Share on other sites

My stock standard rb25-det runs smoothly until after about 10 minutes it starts to lose revs & the car shudders randomly-but only while its ideling

it doesn't stall either but feels like its going to

i've been running it on BP ulitimate-added injector cleaning fluid to fuel & cleaned the airflow meter but no luck

has anyone else had a this problem before?

any advice will be appreciated

what RPM does the car normally idle at? because i know after about 10mins, the revs drop on my stag, im thinking its some sort of automatic warm up program.

does turning the Aircon on bump up the revs and make it idle smoother?

Edited by BIT SUS
Link to comment
Share on other sites

As soon as its warm (around 10 ish or so minutes) in comes out of Cold start. this is where it revs higher to help it warm up and stop it from stalling ect.

Should idle with no accessories on at about 700rpm

so is it just missing on idle?

Link to comment
Share on other sites

As soon as its warm (around 10 ish or so minutes) in comes out of Cold start. this is where it revs higher to help it warm up and stop it from stalling ect.

Should idle with no accessories on at about 700rpm

so is it just missing on idle?

it idles at about 1000rpm for about 10 mins then drops to 700rpm

runs smooth as above idle speed

my mechanic suggested it could be either a faulty airflow meter or

faulty/leaking vacuum hose/s [it could be 1 of a 100 different things unfortunately]

gonna to blast out the air-idel motor with carby cleaner asap & replace sparkplugs too

Link to comment
Share on other sites

i did have a go at cleaning the AAC(Auxiliary Air Control)valve last week but didnt completely remove it so it wasnt done thoughly

thanks for the link[to removing it,etc]

ill give it another go

PS-carby cleaner smells good-kinda sweet :P

Link to comment
Share on other sites

lol @ smell :D

heres an oddball:

- replace spark plugs but it'll cost ya, $20 NGK BCPRE6 .8m copper vgruve

- more carby cleaner, just for the smell

- hitemp Selleys 401 industrial strength silicone sealant; $15 incl corking gun from bunnings, and swathe a lather of silicone stinkyness ALL over your coilpacks.

- use carby cleaner a little more on the AFM just for old times sake

- drive for 10mins, check base idle, use base idle screw for slight positive adjustment

this ^^ should help, unless you have already done it, or are using Splitfires

mine idles at 400 ? nice and low. however, with the headwork it might be different..... waiting, waiting.

SO need my stag back !! :(

Link to comment
Share on other sites

thanks to everyone for their help & advice

i've already sprayed the AFM with "mass air flow-sensor cleaner"

[got it from supacheap $20]

apparently u can use carby cleaner instead

ill get stuck into next weekend as the cars not being used atm

been drivin the neanderthol toyota work van during the week :)

Link to comment
Share on other sites

Wow! My RB25 is doing the EXACT same thing! I'm going to try cleaning the AAC valve tomorrow and doing an idle adjustment. I'm also going to check the timing.

Please update if you figure out the problem!

Link to comment
Share on other sites

Hi everyone. I drive a non turbo R34 Skyline with the RB25DE and its AUTO

I also have some idling issues.

When in parking, it idles around 900rpm but with my windows closed already but just using my switch to make them close the idle slowly drops to like 300-400rpm and feel like it wants to stall then it goes back up agian

Same with when i have the air con running and at stop at the red light with my foot on the brake, rev will be like 700rpm then drop alittle then goes back to normal again.

I changed to a new battery hoping it will solve it but it didn't.

I needed a new battery newaiz, it was like the original one since 1998. hahaha

Link to comment
Share on other sites

Hi everyone. I drive a non turbo R34 Skyline with the RB25DE and its AUTO

I also have some idling issues.

When in parking, it idles around 900rpm but with my windows closed already but just using my switch to make them close the idle slowly drops to like 300-400rpm and feel like it wants to stall then it goes back up agian

Same with when i have the air con running and at stop at the red light with my foot on the brake, rev will be like 700rpm then drop alittle then goes back to normal again.

I changed to a new battery hoping it will solve it but it didn't.

I needed a new battery newaiz, it was like the original one since 1998. hahaha

Sounds like your issue could be the alternator...

Link to comment
Share on other sites

  • 2 weeks later...

Problem solved-changed the sparkplugs :P

also thoughly cleaned out AAC valve on the same day but i think it was the old plugs causin the problem

two of em were lookin pretty haggard with a yellowish buildup of crap around em

now she's runnin smoothly again :)

Link to comment
Share on other sites

Had I seen your thread earlier, I would have suggested the plugs. The crap that was fitted to my C34 for compliance (Autolites) made my car start & idle slow (occasionally stalling just after startup), and the idle would also sometimes drop off when slowing to a stop. I cleaned the AAC (which was spotless) without improvement. Changing the plugs to good-ol NGK (I spent up big & got the platinum - copper plugs weren't on the list where I bought them from at the time) fixed the problem 100% and it hasn't misbehaved in the 4 years since.

Link to comment
Share on other sites

Had I seen your thread earlier, I would have suggested the plugs. The crap that was fitted to my C34 for compliance (Autolites) made my car start & idle slow (occasionally stalling just after startup), and the idle would also sometimes drop off when slowing to a stop. I cleaned the AAC (which was spotless) without improvement. Changing the plugs to good-ol NGK (I spent up big & got the platinum - copper plugs weren't on the list where I bought them from at the time) fixed the problem 100% and it hasn't misbehaved in the 4 years since.

That's pretty much what happens with mine. I'm using NGK bcpr6es-11 gapped down to .8mm What plugs are you using?

Link to comment
Share on other sites

NGK Laser Platinum PFR5G-11

The only other thing I changed at the same time as fitting the new plugs was the O2 sensor - it was confirmed as being stuffed by the 12:1 idle mixture... That might be worth a look too.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share



  • Similar Content

  • Latest Posts

    • And yes would be going to tomei Japan for sure as it’s closer to me … 
    • Yeah I heard the same. Might be hard to order one. But then I guess can go to hks or go to a more expensive n1 block with tomei. Guess will jump the hurdle once I get there next upgrade around. I can’t get work done in the states as the lead time will take for ever on top of shipping to Hong Kong. 
    • https://www.platinumracingproducts.com/en-us/products/nissan-rb26-cast-blocks This is the solution I was thinking of. I would stay away from Tomei USA, their quality is a question mark to me. If you want an engine machined in the US contact Club DSPORT: https://clubdsport.com/ Tomei JP is probably fine but I recall they stopped doing pre-assembled short or long blocks. In general it's pretty tough to get any kind of RB26 block at the moment with Nissan so severely backordered.
    • PAR specifically offers stock ratios in their gearset and you could do whatever ratios are physically possible supposedly for no extra cost. I agree 6 ratios is better than 5, the factory 2nd gear is equivalent to the Getrag 2nd gear if you account for the differing final drive ratio though. The Getrag 3rd gear with a 3.916 final drive is equivalent to a 1.6 2nd gear in the FS5R30A. I'm about to swap the transmission out on my car, I'm tempted to send the one I have now out for rebuild with the standard "cross ratio" gearsets out there to see if it really makes such a big difference the next time I pull the transmission.
    • This is what I was looking at next:  https://www.z1motorsports.com/engines/tomei/tomei-rb26-28l-short-block-assemblies-p-45479.html as we can’t bore the cylinders out in hk so better just buy the whole lot in one and install then retune. Everyone saying the weak link are the bolts holding the rods together. I already did valve springs, arp head bolts, hks racing coils, nismo fuel pumps and pressure regulators, injectors etc for the top of the engine. 
×
×
  • Create New...