# Any of you boys know the rb20 well? Vitesse needs help!



## Vitesse (Apr 6, 2004)

Hello, I'm Vitesse, first time poster... glad to be here today...

Okay, AA meeting over, onto the problem:
I have an rb20det in my s13 240sx, and my baby has some problems. For several reasons I am absolutely unwilling to go back to the guy who installed the motor, but I am having such a helluva time finding anyone I trust who actually knows their stuff about this engine! First off for whatever reason, it appears the installer has ELIMINATED my DRB port. Without that, I can't say I trust my own mechanical experience enough to attempt to diagnose it's quirks, as this is an expensive toy I've built, & funds are not limitless, thus there is little room for error. Over the months, in response to various irregular behavior I've replaced plugs, coilpacks, MAF sensor, the list really goes on...
I know she's running rich as hell to prevent running lean till I get my hands on an AFC, but lately she's really really dumping the fuel. She doesn't want to idle hot, stumbles & stalls at stops, and between 35-60mph at steady neutral throttle (neither acc/decelerating, just maintaining steady speed) a repetitive hesitation can be felt. For example, today I'm driving at 50 and every second or two it feels like a huge invisible hand is resisting the car. Get it? I've also noticed a general performance decrease pretty much overall. My friend's mustang beat me the other day! NO mustang has gotten me thus far. Something's wrong. If I had a MAP sensor it would seem that would be it, but...
My mechanic fiancé (who has actually dealt with marrying into this car I built quite well since he came into the picture, considering he's a domestic dealership tech not accustomed to hi-perf foreign turbo mysteries,bless his heart! But a very quick learner.) has tried toying with the timing a bit, etc. but guys I gotta tell ya, without ANY sort of specs or diagrams to work with, there's only so much he can safely do! If anything, I think the timing has perhaps made it worse, but it's hard to tell. 

Has anyone had similar issues, have any suggestions for me, or know of any specs/tech data & settings that might be of help, etc?
Or how I can replace my DRB?? That right there would be a big help in enabling me to do what I can myself & figure this big fast headache machine out! 
Thanks for ANY help provided, & thanks more for dealing with the lengthy post.
~Vitesse


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## scourge (Feb 27, 2003)

www.meggala.com


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## chimmike (Oct 17, 2002)

check for exhaust leaks...the hesitation can be caused by that I've found.......as fo the running rich...hmmm where in FL are you?


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## OPIUM (Aug 18, 2002)

Yeah I got the "invisible hand" thing going on right now as well, but its only within the first moments of driving. I attribute this to the temp sensor. Also the timing should be set at 20BTDC. I had it at 15 like the factory service manual recomends, and I did it all by the book, but 20 BTDC is where its at. Just a quick thing for you to test... Start the motor and let it idle. Pull the MAF plug and see if anything happens. Then after that pull the AAC plug. See what happens. If there is no reaction it could mean that one or even a few sensors are bad. I also had the coil pack problem. if you ever need to replace them and can't find any spare ones, the coil packs from an infiniti Q45 will work. So do GTR coil packs if you happen to have access to a spare RB26 like I did. I think even CA18DET packs may work, but I'm not sure on that one. They looked similar but I never check the #'s. Anywho, the reason I kept blowing coil packs was later sourced to a bad ground. Also make sure your ignitor chip is facing with the 'grill' marks upwards. this helps keep temps down.










Reason I say this is because mine was tangled up and facing down. Not good.


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## Nizmodore (May 9, 2003)

I had a similar problem with a RB25DET at work yesterday, I found it was the connector to the Computers coolant temperature sensor. When the sensor went open cct, the computer was thinking that the car was cold and automatically richened up the fuel mixtures to warm the motor up. Fine in the morning, but once it came up to temperature...well...

The fault was intermittent, you would be driveing and the thing would be stuffing around and then next second it would be fine >: 

Get the sensor checked, also check your fuel pressure and fuel pressure regulator + vamume lines


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## GTES-t (Jan 2, 2004)

If your having problems running rich, idling, stalling, etc. You may want to go through and check all of your hoses between your turbo and intake. If you have any loose connections or air leaks, it'll cause all those symptoms. Especially the running rich. 
Also, do you know what type of MAF sensor you're using? It says you've changed it, did you get an RB20DET one or do you know? The reason I ask is if you use a different MAF (Old 240sx Stock MAF for example) the readings your ECU is getting are calibrated differently. For it to work, your ECU has to be remapped to understand the new readings. Here's the stock RB20DET Air Flow Meter part# 22680-02U00.

Meggala has a great site, here's his part # page and MAF sensor info:
http://www.meggala.com/partcss.htm

Another good site is this:
http://www.rb20det.com/index.html

Good luck!


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## rsx84 (Nov 2, 2003)

this is a pic of my rb20det, its a 92' model, i'm just posting this as the pic above with the red circle is a different part than the one i have?? that part circled i think is from the red top eccs version???
http://www.skylinesaustralia.com/forums/attachment.php?attachmentid=13757
what power are you making as have you ever throught of the intercooler....


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## Vitesse (Apr 6, 2004)

chimmike said:


> check for exhaust leaks...the hesitation can be caused by that I've found.......as fo the running rich...hmmm where in FL are you?



Gainesville FL


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## Vitesse (Apr 6, 2004)

*Intercooler Hose Leak to Blame*

Well, most of it ended up being ... get this... a hole in an intercooler hose! And YES I did check that before, nothing _appeared_ wrong, because it was rubbed through where it touched the front structure... couldn't fit my hand there. Squeezed it though, & the fingers slipped right inside a hole on the other side.

Glad it was something simple!


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## Vitesse (Apr 6, 2004)

GTES-t said:


> If your having problems running rich, idling, stalling, etc. You may want to go through and check all of your hoses between your turbo and intake. If you have any loose connections or air leaks, it'll cause all those symptoms. Especially the running rich.
> Also, do you know what type of MAF sensor you're using? It says you've changed it, did you get an RB20DET one or do you know? The reason I ask is if you use a different MAF (Old 240sx Stock MAF for example) the readings your ECU is getting are calibrated differently. For it to work, your ECU has to be remapped to understand the new readings. Here's the stock RB20DET Air Flow Meter part# 22680-02U00.
> 
> Meggala has a great site, here's his part # page and MAF sensor info:
> ...


Thanks! You were right, it was an intercooler hose, of all the simplest of things! The MAF is am RB20 MAF, btw.
Thanks for your help!


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