Need help. Poor running. OBD-1 w/rk tunes. Not sure what else to look at.

[vr6dubny]

So i have been fighting to figure out what my issue is with my car for a week now. Car started to bog/hesitate/show lean AFR while cruising. Started out just did it once. Next day ran fine, filled tank, ran terrible. Threw cam sensor and maf/o2 code. Replaced cam sensor/o2/plugs/fuel filter. Same thing, once warm at low rpm stumbles, bogs, lean (16,17,18).

spa t3, 2.5" cold, 3" hot, treadstone 1235, tial wg to atmosphere, tial bov, hallman rx pro, 3" turbo back, aeromotive 340.

400 miles on everything at most.

things replaced
cam sensor
crank sensor
plugs 4554's gapped at .020
fuel filter

things checked:
fuel pressure 51-53ish at idle, drops 10 psi when shut off, goes up a little when reved, builds a ton when line is clamped
checked for leaks, over and over
cleaned idle control valve
gooseneck is epoxied in, vacuum fittings are all epoxied
sprayed with carb cleaner around all welds, fittings, couplers, connections. No change

unplugged maf at idle...smoothed out. Did not realize car was running rough...but was def smoother unplugged

only things left i can think of are:
iat
coil packs
bad maf?

how can I test the maf?

i also need to test fuel pressure under load. I just don't think it is the pump.

[e30polak]

Have you emailed Jordan about it?

[vr6dubny]

Yes, I have. Looking for anyone else's thoughts because I might as well keep troubleshooting while awaiting his reply.

this post is in no way blaming Jordan, nor the tune. Just happens to be the tune I am running. Car ran fine on tune for 300 miles or so then didn't.

[crazyyardie]

U need to get it boost leak tested to 20psi.


Sent from my iPhone using Tapatalk

[vr6dubny]

Jordan replied within 12hrs. Gave me a couple things to look at. I will report back.

this thread was not started as a bashing thread. I just know there are people out there with obd1 rk tuned cars.

still willing to accept other ideas

i am running another boost leak test tonight

[Butters Stoch]

Make sure MAF isn't coated with oil.

[vr6dubny]

So. To update. here is what I have replaced thus far and done.

Crank sensor
Cam sensor
plugs
fuel filter
02 sensor
Coil packs
swapped fuel pump relay. (the relay in my aftermarket relay setup)
cleaned icv...then replaced icv
cleaned maf


tested fuel pressure was good at no vacuum, bled down 10psi upon shut off. I was not able to test while driving.

I welded up a boost leak tester...aka a piece of sheet metal onto the end of a pipe that was tapped with a schrader valve and a pressure gauge.

I tested for boost leaks. I found a major leak. though i don't know how i missed it before. i fixed this major leak. I was HAPPY. YAY, I found a leak. I fixed said leak. My system is leak free.

I thought everything was good. Drove car after having battery disconnected overnight to hopefully reset fuel adaptations or trim , or whatever you call it.

Things seemed good. Parked car...tried to restart car. Car started and immediately died. Tried again. Same thing. Tried again while giving it some gas got it to stay running. Started to drive car to work. Same thing as before. At low rpm bog, cutting out, super lean. Got it home and parked it.

Then today replaced the ICV and the coil packs. Same thing. Idling very rich, ran like crap, cutting out bogging etc...

Went and swapped the new o2 sensor for the old o2 sensor. retested for boost leaks. Car actually idled better in the high 13's. Went for a test drive same thing.

So I put my tools away, went upstairs and decided that I was going to go back down and ohm test the crank position sensor that was in the car.

Test it and it shows 1.2k ohms...then settles at 1.04k ohms. Test the old one I took out, which I know was at like 540 when I removed it. It was reading 516. I also tested the new one before I put it in the car and it was at 580...which from what I understand a little high but within 10% of the 540 it is suppose to read. Went and removed the new one...retested it...916. Not sure what is going on besides the fact i removed a sensor that was reading properly at least on the ohm meter and put 1 in that is junk.

I of course ruined the old 1 removing it.


So at this point. I have a walbro 255 coming tomorrow per Jordan. I am going to re-replace the crank sensor and see what happens.

I also have located a maf to borrow to test if tomorrow goes poorly as well.

If it still runs like crap after that I guess it is a compression and leak down test.

[vr6dubny]

We can cross out the fuel pump and another crank sensor

going to borrow a known good maf in the morning to test this. I am going to be highly annoyed if it is the maf and I have spent hindreds of dollars on replacing good parts

[E36 328is]

This sounds a bit like the issue that 328ifun is having with his car. Have you looked into the engine wiring harness?

[vr6dubny]

I have not looked into the harness itself yet. I will try and find 328ifun right now though.

[vr6dubny]

swapped MAF and took out my soldered connections and put in butt connectors to make sure the connection was good. Car ran super rich at idle for a while, I went and looked at the engine and looked over everything. Walked back around to the window and amazingly idling at 14-ish. I took it for a drive to hope that it wouldn't do the same thing. the fuel adaptation seemed to reset or did its thing. I feel like it got better the longer I drove it.

Tomorrow I will drive it on the borrowed maf. if all is good, I will swap maf for the old one on monday and see if it is indeed the maf.

I wonder if my maf has any type of warranty on it?

in other news I also had a leaking valve stem on my rear wheel which ended up in a flat tire, and broke the screen on my phone today....yet...I'm still smiling after 2 weeks of replacing every part I could think of. Was so nice to be in boost again even if I backed it down to 8lbs.

[ty20404]

I just received a new MAF from Jordan today... Been chasing an eerily similar thing on my OBD-1 RK tune for about a year now so I feel you on the chasing ghosts stuff. Won't have a chance to install it tonight, but hopefully tomorrow. Keep us updated on what you find! BTW, I've replaced and fixed just about everything BUT the MAF on my car.

[dunebuggyjay]

Any Updates?

[vr6dubny]

MAF was the issue. Getting a new one to put in.

[Butters Stoch]

MAF was the issue. Getting a new one to put in.

This alone makes a standalone more appealing. I can't stand that MAF's are so heavy dependant on the tune.

[ty20404]

My new MAF made a difference for sure but it's now running quite rich. I looked back at some emails that Jordan had sent John during tuning and there was a mention of an "old MAF tune (2013)" due to my first couple of runs being a bit lean. Now that I've got a new MAF I'm wondering if this is why I'm running rich. I've got an email in to Jordan but I believe my MAF was on its way out as well. My AFRs are much more stable across the spectrum. Idle usually settles down to 13, cruise at 45 is 12.5ish and cruise at 80 is 11.7ish.

[Butters Stoch]

My AFRs are much more stable across the spectrum. Idle usually settles down to 13, cruise at 45 is 12.5ish and cruise at 80 is 11.7ish.

Cruise at any speed should find 14.7 something ain't right with that. Either O2 or adaption issue

[vr6dubny]

At cruising it is now right around 14.7...waivers between 14.3 and 14.9

and I missed a post. Was not referring to me.

have you driven the car much? My car took a bit to adapt

afr at cruise should be the same no matter what speed...correct?

[ty20404]

At cruising it is now right around 14.7...waivers between 14.3 and 14.9

and I missed a post. Was not referring to me.

have you driven the car much? My car took a bit to adapt

afr at cruise should be the same no matter what speed...correct?

I've put about 20 miles on it I believe with a fair amount of idling here and there. I wonder if my "en V5.bin" is with adaptation off and "en V5 o2 on 7 23 16.bin" is with it on? And yes, just cruising at any speed should be 14.7ish, so it looks like your AFR is great! Glad that fixed you up!

[dunebuggyjay]

This alone makes a standalone more appealing. I can't stand that MAF's are so heavy dependant on the tune.

My thoughts exactly. Thats why I too am on the Megasquirt group buy.

[vr6dubny]

My thoughts exactly. Thats why I too am on the Megasquirt group buy.

I agree. However, i'd still be waiting for it to ship. Although, at this point i'm about in the same position sorting through things to make car run right.

[dunebuggyjay]

I agree. However, i'd still be waiting for it to ship. Although, at this point i'm about in the same position sorting through things to make car run right.

Yup I hear you. I stupidly sold my turbo tune setup, thinking June for the megasquirt, and here I am....no car to drive all summer as I wait and wait and wait. Once I get it in, and sorted now, it will be time to put it away for the winter. FML.

[vr6dubny]

Thats why I ended up with the RK, i am happy with the tune. Just working out kinks. I know there would be kinks no matter what tune option I went with. Just want it 100%

[vr6dubny]

Update: Car is running much better though still not perfect. I am having an odd fuel issue. When I am just driving fuel pressure is around 57 psi at -22 vacuum. Then when I step on gas pedal vacuum goes to 0 but my fuel pressure goes down to 51, which is where I believe it should be. Then once in boost fuel pressure builds as normal.

once pressure builds afr is around 11.6 or so at 16-18lbs of boost. Idle is high 13's low 14's.

i'm running the obd1 rail with a brand new bosch fpr. I did add a fuel pressure sensor fitting in line on the feed side, so there is some extra fuel line to make it fit without kinks.

I am going to try a known good fpr and see if that makes a difference. Fuel filter and walbro 255 are like 100 miles old.

if that doesn't help then I am going with an aeromotive 13109

i am also having a hot start issue where car does not want to idle and will die if I don't give it some gas.

i am going to try a new oxygen sensor and a new icv.

[Butters Stoch]

I think what your experiencing is normal for a stock regulator and 255 or bigger. Your overpowering the regulator. Run with it till u get an aftermarket regulator.