Rb20 Running Rough/choppy

[s13rb20det]

Hi Guys

Have a problem with my s13 silvia. Its got an rb20det in it

Mods

front mount

3 inch turbo back exhaust

gtr fuel pump

mines chipped ecu

running 12psi

Problem:

when i start the car in the morning (cold start) it sounds like its running on 3 - 4 cylenders until temp is up to running temperature then it just idles normal. when i start driving all is good but the first time it comes on boost hard it misses 2 or 3 times then it runs perfectly after that. if i turn on again within next 5 - 6 hours it runs fine, only happens on a cold start. have swapped coil packs and still sme problem.

any input would be great

thanks guys

[dead32]

plugs, more specific the heat range of the plugs.. or potentialy stuffed all together

[s13rb20det]

plugs, more specific the heat range of the plugs.. or potentialy stuffed all together

hmm that makes sense, ill give it a shot thanks... i only changed them about 3 months ago with platinums.. ngk i think?

Edited October 22, 2006 by s13rb20det

[Trust33]

If its not affecting the performance of the car then dont worry.Its just the fact that the car is cold and needs a bit 2 warm up.

Plus the fact that the ecu could be feeding it a little more fuel than the stock item.at cold start i would imagine it to choke a little.

What kind of power is it making?

[Dose Pipe Sutututu]

I've got a S13 with a RB20DET in it as well ahahah..

and yeah, same problem....

I'm suspecting its the seals on my injectors, and when the motor is warm they expand causing no stray air to get in and run properly.

I've got big cold start issues as well, always have to put my foot all the way down to start the car, and the idle goes up and down and all this other crap.

I'm taking my injectors out, getting them cleaned and flow tested and the seals replaced this week. See how that goes, I'll keep you updated.

Gonna be a waste of a whole day =(

[FATGTS-R]

You might also have a small inlet leak somewhere that closes up from heat expansion when it warms up.

I had the same issue with my RB20 and thought I had gone over the entire inlet tract with a fine tooth comb and couldnt find it.

The leak ended up being in the inlet manifold gasket on the sixth cylinder facing the firewall hence I didnt spot it. I soon found it though when it blew out completely and left me stranded.

[s13rb20det]

If its not affecting the performance of the car then dont worry.Its just the fact that the car is cold and needs a bit 2 warm up.

Plus the fact that the ecu could be feeding it a little more fuel than the stock item.at cold start i would imagine it to choke a little.

What kind of power is it making?

yeah point taken, the good thing is i can still drive to work and get around, but it wasnt like this before so obviously something wrong, want to get it fixed as its going in for a turbo, injector, afm upgrade and dyno tune.

havnt got a power figure yet mate hasnt been dyno'd, but hopefully looking at 220rwkw with upgrades...

I've got a S13 with a RB20DET in it as well ahahah..

and yeah, same problem....

I'm suspecting its the seals on my injectors, and when the motor is warm they expand causing no stray air to get in and run properly.

I've got big cold start issues as well, always have to put my foot all the way down to start the car, and the idle goes up and down and all this other crap.

I'm taking my injectors out, getting them cleaned and flow tested and the seals replaced this week. See how that goes, I'll keep you updated.

Gonna be a waste of a whole day =(

yeah mine is usually ok on a cold start, have to kick it over 3 - 4 times but it used to start fine. as FATGTS-R says it could be an inlet leak, best of luck, hopefully getting ur injectors done will fix the problem.

You might also have a small inlet leak somewhere that closes up from heat expansion when it warms up.

I had the same issue with my RB20 and thought I had gone over the entire inlet tract with a fine tooth comb and couldnt find it.

The leak ended up being in the inlet manifold gasket on the sixth cylinder facing the firewall hence I didnt spot it. I soon found it though when it blew out completely and left me stranded.

thanks FATGTS-R ill go over it and check it thoroughly tonight, haha damn what a spot to get a leak, unlucky...

thanks for all the input guys i will give it a shot tonight and keep all posted on progress.

damn these cars are fun when they run properly!!