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Light Throttle Issues.

Shaun O

By Shaun O,
in Engines & Forced Induction

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Shaun O Enthusiast

Shaun O

Posted
Posted

Annoying problem that's crept itself up, on very very light throttle, the engine stutters a little, like, super light throttle (1k-1.5k~ or so RPM while in neutral) - it's not the throttle cable either because it does it when you manually give it throttle off the throttle body.

Any ideas?

Giving it a tad more throttle and it's no problems. It just makes the ride really jerky sometimes when driving in like 2nd gear at low throttle. It's an RB25DET throttle body (S2)

Cheers.

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Shaun O Enthusiast

Shaun O

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Sounds like its running lean there, possibly due to the airflow meter being dirty. Give it a clean first with a can of CRC airflow meter cleaner and see if that fixes the issue first.

Cheers, I don't have any CRC AFM cleaner, will something like Isopropyl Alcohol work?

260tech Proficient

260tech

Posted
Posted

Yup, isoprophyl alc is good, absorbs water & leaves no residue, also check plugs for gaps, & coilpacks for moisture & crap that will make things (sparks) track. give the coilpaks a wash with the iso & spray with a silicon inhibitor. Quote gospel from PI #116

Cheers GW

Shaun O Enthusiast

Shaun O

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are you using an aftermarket ECU?

add some more accel enrichment and see how you go

Nah, just a standard chipped ECU, it hasn't always been an issue and just seems to be intermittent, it barely did it at all on the way to work this morning. I'm still at work though so haven't tried the cleaning stuff yet.

FULL RABBIT OR NO RABBIT!!!!!! noone likes a tortoise, light throttle is for wimps.

Haha, unfortunately that doesn't work so well in peak traffic :(

Plus, I wish my car had a lawnmower style throttle instead of an accelerator pedal :P:D

NZM.031 Grand Master

NZM.031

Posted
Posted

ok so you want it fixed then.

afm or sticky butterfly would be a good place to start... get out with some carby cleaner.

slight vacuum leak.

dodgy injector, may be spraying to much or dribbling out and flooding one cylinder or not spraying enough due to blockage and running lean in one cylinder.

dodgy plug, same as dodgy injector but different.

Shaun O Enthusiast

Shaun O

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Well I just sprayed the AFM and all the coilpacks with iso alc - left it for a bit to dry then fired her up, it was doing the up n down up n down up n down revs at low throttle still but only for like 10 secs, from then on it seemed all good.

I didn't have any long sockets for the spark plugs but will find some if it happens again over the next few days.

Cheers guys.

Shaun O Enthusiast

Shaun O

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Changed the spark plugs, no difference - thought I wanted to change them anyway :) (and only $20NZD for the set, can't go wrong)

Until on my way home, hit a little boost and FSHHHHH, the silicone joiner between the turbo and the intercooler piping blows off.

I have a feeling this has been the problem all along, leaking out of top of this joiner.

Gotta try my best to get it on real good tomorrow morning, will post back results.

Shaun O Enthusiast

Shaun O

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good work man... that will do it. hope its all good.

Yeah cheers, I tried my best but I think my hose clamps are being shit as well as the 90 degree silicone bend.

Getting a 90 degree stainless welded onto the end of the intercooler piping to eliminate the 90 degree silicone bend and put a straight silicone joiner between the turbo and IC piping instead.

Actually works out to be similar price in the end anyway, just a little more hassle but becomes better off in the long run.

Going to get a new hose clamp as well to replace the one that I think is no good.

Will post back results tomorrow night ;)

Shaun O Enthusiast

Shaun O

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Just f**ked around with hose clamps and shit just to see if I can have it running a bit nicer for tomorrows driving.

Started the car up, idling like f**kin' shit, hunting up and down, getting worse and worse and then stalling.

'f**k this' I think to myself, get in the car and just go for a wicked thrash.

Park back up again, idling like a f**kin' dream and not being gay on low throttle, WTF!

So see what happens tomorrow morning on the way to work! - Still going to replace the silicone 90 degree with stainless steel though.

Shaun O Enthusiast

Shaun O

Posted
  • Author
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What AFM are you running? It might have the dreaded bad solder joints on the board inside.

It's an RB25DET S2 AFM, I have a 300ZX AFM here ready to go in whenever I can get the car tuned/chipped.

Is it something that I can fix myself? Or if I open it up will it be easily spotted?

Cheers.

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