Please help with RB20 diagnosis...

[Eikon]

Hey guys.. I have been very patient with the various issues that I've dealt with so far. But, I am starting to loose it.

First I had cooling issues, and it turned out my water pump was completely worn out. That is solved.

Then I had cold start issues. In the recent thread about "high idle and cold start problems" I learned that most S13 RB20s don't get the start signal wired correctly. So, I took it to my mechanic (he works super cheap, and I don't have much experience) to have that wired up. I also got an adjustable fuel pressure regulator installed as well. Plus he figured out how to keep my steering column from rubbing.

I talked to him and he said that the car fired right up after sitting out all night in the cold. He's always been right in the past, so I posted the other day that it was fixed... Well.. it's not!

Please help before I drive this thing off a cliff.

I can't get the thing to start very well... it cranks and eventually starts to shudder, then pops a bit and comes to life eventually.

For the first time though, I noticed a funny thing by the tail pipe..



It's oil. What does this mean? Please, somebody help me!!

[Eikon]

I started it again just to move it over in the garage so that I can get another car in there.

Looked in the back of the tailpipe and there was a couple ounces of fluid.

It looks black, so I grabbed some paper towel and soaked it up. Mostly water.. but did have some black like oil in it. (Oil and water don't mix). But I couldn't tell if the oil was at the top or something like that.

They poped the hood. The coolant is a little brown. Still mostly green, but sort of brown a bit. Seems to be a consistant color though. If there was oil in the coolant, I would expect to see streaks or splotches because again oil and water shouldn't mix. So this is strange to me.

I haven't pulled the dipstick yet...

[JonPowell]

#1 are you sure thats oil? could just be dirty water which is normal(soot from the exhaust makes it dirty, especially if youa re running way rich)

#2 what is the fuel pressure set at with the vacuum line DISCONNECTED at idle?

#3 what is your timing set at with the engine fully warm at factory idle speed?

Check all 3 of those babies and let me know.

[Eikon]

Here's a little history on the engine. When I got it, it had a bad water pump, so it would threaten to overheat after a short while. So I never drove it much at all. We replaced the thermo, radiator, and finally the water pump. The cooling system is much better now. It doesn't overheat. I have driven the car 4 times since I got the water pump fixed. A total of about 50 miles at most. I did about 30 miles on one of those trips... it did not overheat or even think about it... in fact it was almost not warm enough.

The car was probably traded away in Japan because of the cooling issue. Because of that it is possible that it had a bad head gasket from being overheated.

But, I have had a coolant pressure test done, and it showed no signed of any pressure loss at all. So coolant shouldn't be leaking or draining into the engine.

[Eikon]

Jon,

I really appreciate your help!! Thank you.

I guess it could just be black, sooty, dirty, water.

The fuel pressure with hose attached was at about 38 psi. To test without the pressure hose.. Do I pull the hose off before I start the car, or do I do that while it's running?

As for timing.. I honestly have no idea. I am such a novice mechanic. I just paid my mechanic to put on a new timing belt when he did the water pump... (He only charged me $150 for the whole job... said it took him 3 hours).

How to I check my timing?

[Eikon]

Is it possible that I just have bad spark plugs?

I got a new set.. I just haven't put them in yet. I could do that today.

To check timing... Do I have to pull of the CAS sensor, then remove the timing belt cover, then see where the little lines match up?

[Eikon]

I checked the oil and the coolant again.

I am not an expert, but I don't see any signs of mixing.

Maybe I am blowing this out of preportion. I am just frusterated that I've spent all this money on this car, and I can't make it work like I want to.

I will work on figuring out how to check the timing. I will also check the fuel pressure again after I let it idle for a while.

I wish I had a video camera with sound... One of the belts is a little noisy...does it take a timing belt a little while to settle in? I have about 50 miles on it.

[JonPowell]

The fuel pressure with hose attached was at about 38 psi. To test without the pressure hose.. Do I pull the hose off before I start the car, or do I do that while it's running?

Start the car, pull the vacuum line & plug. Fuel pressure should be ~43PSI set it to that nad dont worry about any of the readings with the vacuum line hooked up

[QUOTE-Eikon]As for timing.. I honestly have no idea. I am such a novice mechanic. I just paid my mechanic to put on a new timing belt when he did the water pump... (He only charged me $150 for the whole job... said it took him 3 hours).

How to I check my timing?[/QUOTE]

Look at the crank pulley there should be hash marks there...all the way to the left is a red one that is 0º and as they go to the right(clockwise off the white mark) each line after is 5º. Your engine likes 20º BTDC.

You need to warm your engine, disconnect the TPS and set timing by loosening the 3 10MM bolts on the CAS and rotating it. Clockwise to retard and counter-clockwise to advance.

You will need to get an inductive timing light and hook the pickup to the little loop at the back of the coil cover...point it to the crank pulley and each time #1 cyl fires it will flash a light at the pulley.

[krayton]

Only read through a bit of it. But Jon is right. Its just ditry sooty water. i shoot the same stuff out.

[Eikon]

OK.. let's see if I have this right.. Please tell me if these statements are correct

I haven't checked yet, but lets assume my mechanic went ahead and set the timing at exactly TDC because he doesn't know any better... Even though he may have wired up the cold start on the ECU correctly, it might still not start well because of the timing?

If the timing is off, the intake cams would not be letting enough air into the engine, which would be especially important at start-up?

If the timing is off would the car seems to lack HP? I honestly feel like it has about as much power right now than my Sentra SE-R did... (about 140 at the wheels).

If I smell a strong gas smell is it possible that the timing is to blame? Is it making the car run very rich.. Not rich because it has too much fuel, but rich because it has not enough air to properly combust the fuel?

If the car still has it's original exhaust system because I am too lazy hook up my Megan Catback, would that have any effect on start-up?

If the factory catalytic converter was bad (I am not sure if it is or not), would that have an effect on start-up at all?

Thanks again guys (Jon, Krayton, anybody else who can lend some advice to a noob!!!)

[Eikon]

I decided that since I got new spark plugs, and I haven't yet put them in, that I should go ahead and do that.



Here are the old plugs.. Cylander 1 to the left 6 to the right

Look at how much build-up there is. Cylander 4 has carbon on top of the screw even. That one must not have sealed down very well.

Am I correct that this is a sign of running too rich? Does the timing control that, or do you think the fuel pressure reg or pump was doing that?

I just noticed how small the downpipe is.. Looks like crap. Can't wait to get a new one made up.

[Eikon]

I am just having a bad day!

I thought putting in new spark plugs would be a good idea. In the process, one of the plugs from the wiring loom broke on me. So now I have to get a new harness or at least a new plug or something like that so that I can get it back together.

So now, instead of an RB that doesn't start very well... I have one that doesn't start at all.

GRRRRRR anybody want to buy a car?

[Yellow4g63]

Having a really hard time starting after you fixed the cold start problem.... Did you check your intercooler pipes? Did you try to unplug the MAF and start it to see if it starts up ok? When I blew off a Intercooler pipe the car was very hard to start. I figured it out after I unpluged the maf and the car started right up. It was the pipe from the intercooler before it goes into the fender that blew off on me. Hope that helps you out. And think of it this way, Your a noive now but soon you will be a RB pro lol.

[USMCgetsome]

the wire from the harness can be repaired easily. Hell man if you can't do it send it to me and i'll repair it for you. i repaired plenty of wiring on my swap. Get a pic of it and i can show you how to repair it. As for cranking you have exactly what you need AIR FUEL SPARK. Have you checked your ecu for codes? You can disconnect the battery postive and negative and touch the two terminals together(disconnected from the battery) and i'm sure that your ecu would be reset. And if that is not helping check the idle control valve is the screw to it all the way in or out or half way?

[BoostFab]

In the process, one of the plugs from the wiring loom broke on me. So now I have to get a new harness or at least a new plug or something like that so that I can get it back together.

which harness? are you talking about the coil pack harness? if it is, i have an extra one here you can have, just pay for the shipping fee.

i would never take my car w/ an rb or sr to a general mechanic. he might have screwed up with the timing.

btw! who made that down pipe?! that is going to kill your power. it's like tightly squeez your neck with my two hands. take your car to a muffler shop and get them to weld up a 2.5" or 3" pipe....from the o2 housing to the cat.

[Carl H]

i would say that your problem is timing and its proly hella retarded, had this same problem on my car.reset the ecu, center the cas and check timing.then set timing to 20degrees with the cas and then go for some spirited runs, that will teach the ecu how to run the engine.

[Eikon]

which harness? are you talking about the coil pack harness? if it is, i have an extra one here you can have, just pay for the shipping fee.

i would never take my car w/ an rb or sr to a general mechanic. he might have screwed up with the timing.

btw! who made that down pipe?! that is going to kill your power. it's like tightly squeez your neck with my two hands. take your car to a muffler shop and get them to weld up a 2.5" or 3" pipe....from the o2 housing to the cat.

If you don't think you will need your extra coil pack harness. I would be very happy to purchase it from you. At least pay you for shipping and a little thank you on top of that. Let me know what your Paypal address is and I will send money right away.

I guess I could still attach the wiring and tape it to the coil pack, or I could get a new plug and solder it onto the old wires. But, i would feel safer with a new harness entirely!



It sounds like everybody agrees that my timing is most likely off. I will try to figure that stuff out after i get my coil packs wired up correctly again.

Thanks for everybody being so helpful. I really appreciate it. I wish Jon or Carl or somebody was close enough to come over for a while and help me, but at least you guys can talk me through it from afar.

Sorry, for so many posts yesterday. I was very frusterated!!! Anyhow.. I am going to get the harness situation solved first... then work on the timing issue. I may need a little more step by step instruction on the timing when I get to it.

Hopefully then I can get to the things that I feel more comfortable with... like downpipes, exhaust, interior, body panels, wheels, brakes, etc...

[Andrew85cm]

Yeah I too would check on that timing but with the rb20 and stock exhaust yeah it will only feel like you are making like 150 at the wheel because you probably are. My car pulls pretty hard and I am running the stock exhaust but a 3" will treat you much better and you will have much better response. My rb20 didn't make jack on the mustang dyno because I am running stock. Don't be lazy and don't get discouraged everyone has tons of problems especially if it is one of the first major jobs you have done. Is that really a picture of your downpipe? That is ridiculous. You will feel a huge power difference with that thing gone.

There is a post called "high idle and cold starts" and that will solve all of your cold start problems. There have been several on this forum that it has entirely fixed their problems so check that thread. I have been too lazy to do it but I am sure it will work because Powell is a freakin genious. I hate wires.~ANDREW~

[Eikon]

thanks for the words Andrew.

The cold start wiring is done already. That is why I got so frusterated.

The down pipe is definitely a joke. The guys who installed the engine were down to the wire timewise, so they took it to a different muffler shop, boy they did a terrible job.. Should have just used the steel shaft from my 9-iron.

I am not too concerned about the downpipe just now. I have pretty big plans for all the piping just as soon as I can get all the timing/electrical issues fixed.

[Eikon]

Just updating an old thread.

I have had the car at the shop for a while... my mechanic is so cool... he didn't charge me a penny this time. I had him hang my new Megan Racing exhaust for me (not that it's hard to do, but it was easier for him since he has a lift). He also went back and checked on the cold start wiring.

Here is what is strange... He said he took the ECU out and laid it sideways on the carpet... the car started perfectly. Then he stood it up and put it back in it's place, and the car didn't want to start. He took it out again and with the car running, he was shifting the ECU around.. and it affected the idle. Sounds like the connectors on the ECU suck. He checked a few of the pins and bent them back to a better contact position. But, there still might be something that is wrong with it overall..

So, I might keep my eyes on ebay or something for a new ECU.

I definitely notice an improvement in power with the new exhaust on. The Megan exhaust looks and sounds really nice!!! There is a huge differance with the silencer in. I like it better that way... it's pretty loud without it in... flows better, but a louder than I like it.

Should the RB20 turbo be loud? My turbo makes a pretty loud hiss... i think it's a pile of crap. I can't wait to get a new turbo. If I found a Z32 or RB25 turbo do they bolt straight in? Or do I have to change other things (wastegate, oil lines, etc..)? If I have to make other changes, I will just wait to get a new t3/t04e turbo. But, if I could get a decent RB25 turbo or something that would get me a bit of an increase without having to spend a lot on other mods, I would do it.

Anyhow... Thanks everybody for all the advice!!!

[Wulfgang]

Are you sure that hiss is not your BOV? The RB20 turbo is very quiet, almost quiet enough to run without an exhaust, due to its very, very small turbine.

[Eikon]

well... consider the source... I am not very experienced with turbos..

I assume the blow-off valve releases pressure from the turbo after you let off the gas.

I hear nothing but engine and exhaust from 1k to 3k rpm's.. When the turbo starts to kick at a little over 3k, I hear quite hissing sound. It builds as RPM's build up to about 5500 which is when the turbo pretty much runs out.

I hear a discharge of air anytime I let off the gas in the boost range. That discharge is what I assumed was the blow-off valve.

Are you saying that you don't hear much hiss at all from the turbo as it gains boost?

I wouldn't be surprised if I have a serious boost leak, or my turbo is shot.

The only other turbo car that I have much experience with is a Volvo C70 hi turbo... Their was a slight hiss as it built boost. I have driven a Saab turbo.. that also had a slight hiss.. I have also driven an Audi TT with the turbo.... all of these had an audible hiss... but it wasn't really very loud. My RB20 has a pretty loud hiss. I would say that the turbo sounds from the other cars was not much louder than a good cold air intake on an NA car. My RB20 starts to hiss, and you can only hear the hiss... you can't really hear the engine anymore.

[Wulfgang]

There IS some compressor noise, but not much. On a stock setup, the BOV hisses are much louder.

It is true that the BOV only hisses when you ease up on the throttle, but in normal driving that happens quite a bit, even as you speed away from a stop sign. The undersized turbo makes it happen much more than it should, and it would be possible to mistake it for turbo noise.

If you plant the gas pedal to the floor and keep it there you should only hear the turbo/wastegate.

[Carl H]

my rb20's turbo was quite audible with a pod filter on it.all the rb20s ive ridden in or worked on the turbo is very loud when it spools up, sounds like a gigantic vac leak.