Thread: SR20 strange behavior + video!

Thank you so much for your answer! I found enough answers of my questions.

I guess engine runs rich too. O2 is brand new 130$ titanium NTK and it works just great. So yes, showing 0v that often should mean rich condition. Plus the car is a bad fuel eater..
After 2000-2500 rpm engine runs really good, no hesitation, no nothing. I will make a short video of it. As higher the rpm are, as better it runs, revs fast, feels very strong + car is sort of fast too.

There is a local race shop I visited yesterday. I was told the same - it is possible to have a head/valve issue with good compression, but the chance is extremely small.

The Nistune ECU has the bin which I downloaded from my stock ECU. I haven't really played with it, just set the idle at 875 instead 850, increased the timing here and there with 1-2 degrees (but never played with the idle cells), increased rev to 7650.

Base idle is set properly in timing mode and base timing is set to 15*. I don't have a WBo2. Free Conzult and DDLReader are both programs I am using. I guess trial Nistune as well.

I will try to advance the idle timing through the ECU as suggested and I will leave feedback after that.

Many thanks,
Martin

Some other things to try.

Raise the idle speed to 900 or even 950. Not a bad idea to adjust the base idle speed to what you set in the ECU.

Lean out the cells that it is idling in. Nistune should be able to show you where that is. You probably should get the Nistune software and a wideband O2 to take advantage of the Nistune board.

Last night I changed again the coil, the TPS and the MAF. I used parts from good working SR20. It didn't help and I still had the problem.

Last thing left to do is to check the knock sensor. But I guess it will not change a thing.

Everything points me to a mixture issue. I will figure that out shortly as I am planning to finally dyno the car.

comparing your car to others i've used that same program on it looks like your injector pulse an duty are a tad high, an maf voltages a bit low... but i could be mistaken.

Yes, it is possible.
I am not using the P10 (B13) MAF any more. Instead I have the bigger 3" P11 MAF (I am not sure on what cars it comes on in US):
- old MAF - http://sphotos.ak.fbcdn.net/hphotos-ak-snc1/hs116.snc1/4971_1156444558371_1445438967_30423844_3033136_n.jpg
- new MAF - http://sphotos.ak.fbcdn.net/hphotos-ak-ash1/hs526.ash1/30904_1453737230502_1445438967_31182458_5961613_n.jpg
So it is possible to have different values as I changed the VQ map to fit this new MAF.

Anyway, I've decided to post all my findings here. Probably this issue will be gone after I dyno the P10. Will see..

Last night I tried to bypass the Idle Air Regulator (IAR - the thing sitting on the bottom of the intake manifold) and see if this will change a thing.
Well, engine was hot, so pretty much no room for such test. But still, I gave it a shot and as expected, it didn't change a thing.

I just read this - SR20DE Tuneup and Troubleshooting Guide: Background Info
I am afraid I tried everything so far. Next step - knock sensor and if not - dyno.

It is not the knock sensor as well Tried that a while ago and it didn't bring anything good.
Because the damn knock sensor is located in a place where not too many people can remove it without bitching, I did something else. I left the knock sensor on its place, didn't even touch it. Just unplugged its harness and connected it to a spare knock. That spare knock was screwed at the nearest possible place to my origin knock sensor.
Car started, didn't throw a code but engine was working the same way. And timing was jumping as well.
Now there is nothing left besides visiting a dyno shop..

my buddys de had this weird stumble at 2000-2500 rpms with is de, when he was drivin holdin the rpms steady at 2-2.5k it would jus have a slight stumble/miss but other then that it ran like a raped ape! it did this with 2 DE's.. an 2 ecu's, we swapped a 16ve in usin the same ol de harness an distributor ect ect.. (16ve ecu tho) an now it doesnt do it lol.. idk wtf the problem was but something somewhere got fixed an we dont know what it was lol

It is weird indeed. But it is also interesting. Because, if the dyno doesn't help, then it will turn to be something else I somehow missed to notice. And it might be the chain. I don't know if you have ever compared a brand new oem chain with used one (with over 60.000 miles), but they look funny next to each other.

For the past 2 weeks I haven't done anything trying to fix this issue. But I got few good ideas on my mind.
Today I left the car in a shop where a guy I know well made some tests. I really got tired of chasing ghosts so I decided to let other people look for the problem, of course - by paying them.

3 tests were performed:

1st is very simple - removing spark plugs one by one and 'pumping' the engine via air compressor. This should help to prove that my head is in great condition (double checking on the good compression tests I did). Well my head is good indeed. If there is a leak it is a piston rings leak, so really nothing to worry about.

2nd is a bit complicated bus still nothing hard to do (Kyle *Viprdude* did also give me an idea to use an antenna for this test). Anyway, antenna was not used, but the result is clear - my crank pulley is not off. We tried to figure out if I don't have my pulley off so maybe cams are installed wrong. Not such thing as well.

3rd is most sophisticated. I can't explain a lot about it as I won't be able to describe it well in English, but still. By removing front right wheel and getting an access to the crank pulley. A thing needs to be attached there. Then the valve cover needs to be removed so you can see the cam gears and the cam shafts. What comes next is to have the cams (S4) specifications so you can compare the paper numbers with what you actually measure. In my case - we measured 111 degrees on the exhaust cam (JWT state also 111 degrees). On the intake cam we measured 119/120 degrees when JWT state 117 degrees. So we are talking about 2 degrees retarded intake came. Or - nothing major to worry about.

The above 2 degrees might be due to a loosen chain. But for such small difference (about 1 degree at the crank) I won't soon change the chain.

For good or bad - my engine is in overall very good condition. At least from what I have done so far I have no reason to believe there is something wrong with it.

Hope this helps anyone at all.