rb20 problems...

[240wootie]

i'm having a few rb20 issues...1) hard starting- takes a few minutes of trying to get it to start.

2) speedometer doesnt work (tach doesnt either, but i'm doing an aftermarket tach)

3) high idle- should i just adjust the set screw under the TB?

4) i've seen pictures of rb's with a filter on the right side valve cover vent or whatever it is on top of the valve cover. i know it has vacuum through it, should i cap it off or put a filter on it?

i think that is it... if anyone has answers let me know...

[240wootie]

ok, i found out some stuff on the speedo.. will check into that later, but does anyone have anything to say about the hig idle and starting issue? or the valve cover?

[DriftX]

as for the speedometer, mine didn't work at first, then i swapped to dohc one. Not sure if that was the case, maybe mine was broke.

For hard starting, vacuum leaks make it hard to start.

Have you drove it at wot yet? Mine is bogging real hard and if it's starting like that, u may have the same symptoms.

[240wootie]

i have driven it, and it doesnt bog.. as for vacuum, my question is does the BOV route back into the vacuum system anywhere? i've only seen pictures of a hose coming off the BOV and i dont know where it goes...i have a dohc speed sensor in the transmission, and i got a wire guide for it, so i'm going to try and fix it.

[devil_child]

You have to splice the wire in from the dash harness, so it will flatten the fuel maps on cold start.

It is part of the plug that you use that is next to the blower on the passenger side. Should also have the temp gauge sensor wire on it.

As for the idle, check the AAC or whatever. the long tube looking one with a diaphram in it. Its bolted down to the lower intake plenum. Open it up and check the spring. If its off, reset it, seal the unit plug it back up. Also, check timing and the adjustment screw on the IACV.

If it is still acting funny you can use one off a ka, but you have to change some plugs and splice some wires. The ka integrates the IACV and AAC so, you remove the iacv and replace it the plug on the aac is different , so solder the new plug on.

Also make a boost leak detector. Good to have around.

as for the filter, there is a pcv on one end o you can put a breather on it, but I pulled more vac for some reason when I put a catch on it and ran it back to the intake.

[AxiOn419]

I am no expert but I had the same issue with my RB20 (high idle). It was a combination of not routing the BOV back to the intake and having the IACV set way to high to compensate for it. When I had my BOV blowing atmospherically, the car would die when pushing the clutch in becuase the RPM would drop way low. The reason for this was that the ECU was expecting to have all that air from the BOV (recirculating valve actually) circulated back into the intake which would in turn keep the RPM up because it wasnt starving for air.

My suggestion to you: get a pipe running from your bov and route it into your intake (there should be a hole on the intake for a hose to attach). After you do that, adjust your IACV to lower the RPM. Get in the car, rev the engine, let off until it comes down to idle and see that has fixed your problem.

Like I said, I am no expert with this engine by any means but I dealt with the exact same issue for over a year until I recirculated my BOV, then re adjusted my IACV, problem fixed.

Here is picture of my now deceased car:



Add a hose where the red line is!

[MyLiLsKyLiNe]

i have that exact problem with rb . my mechanic had installed my HKS SSQV on the top intercooler piping as shown on your picture above (my hoses are done exactly like yours) -(by the way is yours side mount?) anyways yeah everytime i would high BOV it the ingage in neutral afterwards it would kill the motor (shot off) . so with that problem my mechanic then stated that i would need a fuel regulating system.....i guess that will keep the air fuel ratio good enough so that the problem with the BOV killing the motor wont happen....? (im no expert). i have a high idle as well on my RB but we have tried everything we could but no luck so far i know im not alone with this problem. but also too how do you propose i do that with the connection of the BOV to the intake? what material would suggest without leaking boost? if you have done it successfully please send me pics of on my e-mail or on this thread ... [email protected]

[DriftingisLame]

I believe your starting problem is an o2 sensor heater. If you dont have that wired up, the o2 sensor will be way too cold to read on a coldstart.

[mott6904]

your starting and idle problem could be a vacuum leak. I would check your start signal wire. It comes off of the dash harness plug which is located behind the right side of the glove box. I would also check your timing.