Jake's First Boost Endeavour (Keepin' It Together)

[rajicase]

The picture he has shows a measuring tape that reads 16" unless I am looking at it wrong. But hell, even if it went to the trans brace , $1050 would be insane. At that rate it'd be a $4000 dollar full exhaust for christ sake ..

[rajicase]

Look at the pic. He needs a tight radius 90° bend and maybe 8" of straight. And a couple v bands. He already has a downpipe. He just needs his dp connected to the rest of his exhaust.

[jakeE36325]

Yup Raji has it right just need the downpipe connected to the rest of the exhaust.

[jakeE36325]

I got the tune burned to the chip this morning and was able to get the engine ready to run. Primed the oil pump as the motor was sitting for awhile and also made sure the turbo line was working. The engine fired right up. Idle was bouncing a bit so I unplugged the maf and there was no change. Realized I had looked at the connector backwards. Oops. Rewired the maf and the idle was rock solid. Still can't connect the wideband until my exhaust adapter is made. Went and put a parts deposit on that as well. Hopefully will be done by next weekend.

Hearing the motor run is just what I needed today. It'll make swapping the diff a little easier!

[jakeE36325]

Got my exhaust adapter finished by the shop today. They did a good job I was just being impatient and cheap I guess.

That was the last part I needed to be able to actually drive the car.

Good news is there were no major issues. My 0-15 psi hardware store air pressure gauge doesn't seem to like vacuum and doesn't seem accurate. Got a new vac/boost gauge coming tomorrow. Also going to put that next to the afr gauge for easier viewing.

I seem to have a slight occasional and random miss at idle and the afrs bounce around from 14.2-15.3. I am also getting a code for the mass air flow sensor. I did wire it wrong when I first installed it. Could that have done damage? Cruise afrs also bounce around about the same range. I did a couple wot pulls and afrs were low 11's to high 10's.

For the most part everything worked great. Only saw 5psi of boost. It was a good teaser but I'm ready for a stiffer spring already.

[vollosso]

No it isn't likely damaged. Check for air leaks.


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[jakeE36325]

I'm going to do another boost leak test today.

[JOutterbridge]

If it's a MAF then it runs on fuel trims right? So the key is to make sure the MAF itself sees even flow (it's air mass and temp) and also make sure your O2 sensors are good/responding properly. I had a similar setup and my radiator fan would blow some air over the air filter and cause quick fluctuations in the readings. It was an easy fix but make sure you have no unmetered air leaks or the tune won't be perfect

[jakeE36325]

Spent all day trying to get this thing to run right. Boost leak tested again at 20psi. Found a small leak at the throttle play shaft. Swapped the throttle body with a spare. Of course the tps was bad and the screws were seized. Swapped it out with a good one. Retested and could not find or hear any leaks at 20psi.

No change

Swapped the factory o2 sensor that was farther downstream with the wide band. Also no change

Pulled all the plugs and they looked like it's running lean

swapped coil packs with no change

Checked maf voltage at idle and it's 0.7-0.8vdc at idle. It goes up like expected when reved.

Cleared the codes. Went for for a drive and afrs are upper 14s to to low 15s and still bouncing around at cruise. They stay there up to 5-6 psi (6psi spring installed) unless wot then they drop to 11ish. The transition from 14s-15s to 11s seems to be abrupt. No codes after the drive. CEL bulb doesnt work even after swapping a good one in. Reading with peak scan tool.

Misfire doesn't seem to happen while the engine is warming up. After restarting there's no misfire for about 20 seconds.

No oil in the charge piping

Plugs are gapped at .022"

The only thing I can't think of at this point is checking the engine timing is off.

[vollosso]

How is the transition going into the maf? Is it 3" the whole way? Is the bov close?


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[jakeE36325]

3" all the way from the turbo. The bov is a little close to the maf.


IMG_0842.jpg

[vollosso]

See if the bov is sealing all the way at idle. It can create issues that close.




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[jakeE36325]

Clamped the vac line coming off the bov there was no change in the miss at idle or the afrs. I unplugged the o2 senor at idle and the miss is pretty much gone. Afrs got more steady but in the 13's. Feel like I'm getting closer.

[jakeE36325]

Without the 02 sensor connected things are better. Afrs still wandering. I'm going to get a new o2 sensor and retest.

[vollosso]

What boost are you at when that gauge is at the 12:00 position?


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[jakeE36325]

12 o'clock is 5psi. Or a little less then that.

[wazzu70]

When you replaced the plugs, what did you gap them to? Most likely not the issue but something that could contribute. The AFR readings from the WBO2 and NBO2 are not necessarily trustworthy as they will read lean with a misfire. When you disconnect the O2 sensor the readings get more stable since you are in limp mode and its ignoring the O2 input.

If the O2 heater is not working properly that could be the issue as the sensor only works correctly in a certain temperature range. I think if the O2 heater relay is jumpered it wont be able to shut off when its at temp so it can get too hot and skew results.

Is the O2 relay constantly on during engine operation and the heater controlled by pwm or are there inputs for the ECU to switch the heater on and off by relay? I dont know how its controlled in this application. I have read the ECT and load are the inputs used to determine hearer demand, so if your ECT is not accurate it could be causing issues.

[jakeE36325]

So to update I have been chasing this misfire at idle for probably 2 months with little to no success. I have replaced a bunch of things and tested as many parts as I can.

This misfire sounds like a popping out the exhaust and usually gets really bad right when the engine goes into closed loop. Sometimes it seems as if it goes back to open loop as the afrs go rich again and the misfire stops or is faint. When this occurs the rpms aren't dropping. The afrs go lean and bounce between 14-17. Driving at cruise the afrs seem to wander between 14-16. Slowly rolling into boost they wouldn't drop like I would expect. WOT they drop into the 11's.

I have replaced

02 sensor
cam sensor
crank sensor
intake gaskets
tps
spark plugs previously gapped to .024" in an attempt to steady the idle I didnt gap the new ones
maf
knock sensors

I've checked

icv cleaned and it moves freely as well as hums with the key on

boost leak tested to 25psi and can't find a leak more then some pinholes in the intake piping welds

maf voltage at idle is .8vdc

compression 150-153psi

listened to injectors and they all sound even

used a test light to watch coil signal which all look even

coils are between .6-.7 ohms also tryed using a spare set

removed the bov vac line

fuel pressure 51psi drops to around 43-44 at idle

reseting adaptation multiple times

removed injector and spray air through to check spay pattern at 45psi and they all looked the same

Im sure that I have looked at more then this but those are the main things. It seemed like the o2 heater wasn't working but as wazzu notes it may not always be on. I drove the car a few times with the o2 disconnected and idle was rich but cruise was much closer to 14.7. Rolling into boost they drop smoothly into the 12's.

To update as of yesterday with the 02 connected but the heater relay removed the idle afr became the most steady I have seen between 14.4-15. The mis however was still there. Cruising the afrs stayed close to 14.7 and dropped nicely when rolling into boost. After some driving the idle would oscillate coming to a stop.

I really hope hope this is something I have overlooked. Any help would be really appreciated!

[jakeE36325]

Cold start when the car reaches temp and all hell breaks loose. O2 relay installed but no power at the connector according to my test light. Audio is garbage




The icv, maf, and bov are really close to each other...
IMG_0926.jpg

[Nutzy]

Injector dead time isn't correct?

I get a smooth idle and pretty even AFR out of 120lb Delphi's (with 22 to 24" vacuum) whereas the previous 80lb DEKA pencil jet were annoying as f***. But I'm pretty sure the dead time was wrong.

If you have closed loop idle, try pulling timing out of it at idle to put more 'load' on it which will open up the injector PW at idle to compensate. See if the idle improves.

[wazzu70]

Have you tried getting the engine warmed up and pulling the O2 sensor relay jumper to see if that helps? Do you get fault codes when looking with a scanner?

Pete, I believe he has a flash on an OEM controller, not a standalone.

[jakeE36325]

Yesterday I swapped the dme out with a spare to rule that out. I put the heater relay back in and I did see power to it with the test light. Does the o2 sensor have a thermostat in it? It doesn't act the same every time I have removed the relay or the jumper.

I also put in a 12psi wastegate spring in as that's what I intend on running for awhile. Took the car out to set the adaptations and see if anything had changed. I hadn't driven it since replacing some of the sensors and putting my 3.23 lsd back in the car. I also gapped the plugs down to .022".

Holy hell that was a big difference in power. It really made the car feel powerful. 6 psi felt good but I had expect more to be honest. This is what I had expected at 6psi lol. I drove the car about 35-40 miles and the idle afrs got more steady but the misfire never left.

[vollosso]

Is the missfire in one cylinder?


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[jakeE36325]

Seems random and the time between them is not consistent.

[rajicase]

Do you have a pre O2 exhaust leak? I had a misfire for months that I couldn't figure out, ended up being an exhaust leak infront of the O2.