Just swapped a S52 into my 95 M3.
Before it was a supercharged S50 on stock VF setup with a RKtunes chip (stock MAF and 30lb injectors)
Swapped in the S52, kept the S50 manifold, changed to 42lb injectors, 2.62 pulley, 803 MAF, air/air intercooler, ltw flywheel. ect..
Started and ran on the RKtune chip that was setup for the stock VF setup, idle was fine and air/fuel was ~11-12 at idle.
Got a chip revision and swapped it in with current mods (unplugged the battery, waited). Now it starts up but air/fuel is around 9.0 at idle. Idle is stable unless I rev it any, then it tries to die . Seems to run better on the other chip. Since I swapped out so much at the same time, is there anything else that I should check or is it most likely the chip needs another revision?
Sorry for my ignorance, still new to the FI world. Thanks in advance for answers!
Update: Found out I bought trashy injectors, most likely my problem.
The tune is for 42 lb injectors and 3.5 inch Bosch 803 hfm, correct?
Could be issues with the bypass valve dumping air onto the HFM, confusing the measurement.
Can be a bunch of issues when you do a bunch of things at once.
Correct, that is what the tune is for.
I also upgraded the bypass valve to a metal one as well. It came with three springs and zero directions. I put the mid spring in it figuring I could swap it out with a stronger or weaker one if needed.
New fuel injectors did nothing. Still running super rich.
Do you have the resistor in the hfm signal wire? If using an 803 hfm, do you have the grounds bridged?
There is no resistor. The VF Kit came with one originally, but I removed it when I got the tune from RKTunes (he said there was no resistor needed). I did bridge the grounds after switching over to the OBD2 plug.
I finally drove it around and it actually got better. I am getting an intermittent MAF code now. So I'm thinking that I need a new MAF sensor. The one I purchased was used, so I bought a new genuine Bosch. Hopefully this will square it away. I'll update after it's installed.
New MAF installed. No change. Check engine light comes and goes as I'm driving and is always p1215 MAF code. Sometimes at idle if I rev it, the engine light will instantly go out for a little while but always comes back. There is a very slight miss at idle. Only noticeable if I get out of the car and listen to the exhaust. Its not even enough for the rpm gauge to fluctuate at all
I'm still using the plugs that came with my VF kit that are 1 heat range colder and gapped to whatever they gapped them at. Should I go another heat range colder or lessen the gap on the plugs do to the added boost? or will that even make a difference to my current issue.
I did not think it was injectors or HFM and don't think its plugs. I think it is a wiring or installation issue or the bypass valve is discharging onto the HFM sensor. I would check to make sure the HFM is not touching anything. I would also look for a loose hose, that might allow air for which fuel has been metered to escape. The idle valve hoses and the blower to TB hoses are possibilities.
I checked over every single hose and found two issues. 1. My bypass valve was installed backwards (Lol) and the second thing was I could see a piece of the oring sticking out where the plastic piece from the IACV connects to the intake manifold. So of course I took it out and (attempted) to fix that. It went back in fine, but it sits very loose and I don't believe it is sealing still. Is there a better made aftermarket part or solution to connecting the IACV to the intake?
The plastic piece and oring are brand new, as I replaced it when I was changing everything else. I'm unsure of what brand it is, and possibly it is a poorly made aftermarket part. If there isn't a better solution then I will just order an OEM one.
Also, pbonsalb, you're my new best friend. Thanks for the responses!
Try a new IAC to manifold fitting. They don't hold up great under boost. You can epoxy it in place. When I had my manifold off, I put a metal hose barb in there. It has held boost for over 10 years, up to 25 psi.
The bypass valve will actually work installed backwards if the boost is low. The inlet is at a right angle to the nipple obviously top for the the bosch plastic valve and the discharge is on the bottom (you can stick your finger in there and push up against the internal spring. If you have a bosch, what are the last 3 digits? 102, 103, 108, 110, 114? The low number ones won't hold more than 6-8 psi. The bigger concern is that if the valve is discharging towards the hfm, it can confuse the hfm reading.
After attempting to put the manifold fitting back in, it fell out while I was driving. Had to limp it home. Going to order another one and hope it fixes it, if not, I'll epoxy one in. I believe my original setup had a Bosch bypass valve, but the one I have now is metal and has no names or markings on it.
I'm still using the VF intake pipe, so the location of the discharge for the bypass valve hasn't changed, so I don't think that is causing any issues.
Ok so I took the manifold off and wired and epoxied a new fitting in. Put everything back together and no real change. I did notice when the car is running that the ICV hose from the intake to the ICV is sucked shut. Is this normal? When I had everything off I made sure the ICV was moving freely, but I guess the electric part of it could be bad possibly? or could I be mounting it backwards? If that even matters. Any suggestions? Thanks once again!
If you mean the icv hose is collapsing, it should not do that. Doubt that is your tuning issue but it is not right.
Took everything apart, remounted the ICV, put it all back together and now it runs terrible. Getting code p1281 (Control Unit Memory Supply), its running super super lean, and the ICV hose still collapses lol. Looks like I'll be taking it apart a third time. Won't have time till next weekend though. Still really have no idea what the problem is, but obviously it has to do with me not putting something together correctly.
I also ordered an EVAP smoke tester. Hopefully find any vacuum leaks I might have.
Last edited by badata1; 02-18-2017 at 03:49 PM.
??? How are you getting OBD2 codes from an OBD1 car?
Doubt that interpretation is correct. What are you using to scan it?
just doing a stomp test. Maybe I shouldn't have added the P.
Ah ok. I believe the error "Control Unit Memory Supply" is from the tune not having its checksums recalculated after the edits. In this older DME it makes absolutely no difference.
Fairly confident I figured out the issue. Did a smoke test and saw a small amount of smoke coming from around cylinder 1 where intake connects to the cylinder head. Got to looking and it appears when I put the intake back on I smashed the camshaft position sensor wire between the intake and head. Ordered a new Cam Sensor. Fairly sure this will solve my Check engine light/leak issue and hopefully get it running normal again. Once its up and running, I'm going to make a boost leak tester and make sure the IC pipe is sealed up correctly.
Thanks again for all of your help.
Still having no luck. Fixed the Cam Sensor. Did two more smoke tests and found zero leaks. It's still running extremely lean. I had a fuel pump that I wasn't planning on putting in for a while, but just in case I went ahead and swapped it in with no change. I was getting code 1222 (Lambda Control 1) before I reset the battery but not currently showing anything. Idles smooth unless I rev it, then it will bounce some before it evens out. Anyone have any suggestions? I'm currently stumped. Ordered a new O2 sensor to put on it tomorrow, however I'm pretty confident it will not solve my issue.
I also ordered a boost proof ICV hose from maximumpsi. Not really for my whopping 12psi of boost, but because I figured the hoses would be stiffer and I wouldn't have to worry about my ICV hose collapsing anymore. The hoses won't be in for a couple weeks though, they were out of stock. I also don't think the collapsing ICV hose has anything to do with my lean running condition.
Do you still have the cyclone seperator on the car? The regulators go bad under boost and seal closed. If you take the iacv off and its a 3 pin the center pin is ground. Ground it to a battery (9volt). Then take and touch pin 1 or 3 with positive. If the valve moves in either direction then the valve is ok but it does sound like you are pulling too much vacuum through the icv with some sort of restriction. Is the throttle plate sealed closed or is their a blockage?
Yes, the cyclone separator is still on the car. I have taken it off and capped the port on the VF intake to see if that was causing a leak also. There was no change either way. The IAC moves freely when off the car, but I have not tested it with a 9 volt and will try that sometime today.
Not sure what you mean by "is the throttle plate sealed closed or a blockage"?? I haven't sealed anything up though, other than when testing for leaks.
Most of us who ran 42 lb injectors with the 803 hfm had to add a resistor to the hfm signal wire. Maybe the RK tune is different, but I would look into that. I'd also check fuel pressure to make sure that is correct.
Checked fuel pressure. It's good. Also changed fuel filter, figured it was due. RK tunes stated I didn't need a resistor. I did a compression test got ~150psi each cylinder. I've also swapped, spark plugs, fuel injectors, MAF, O2 Sensor. Added an extra ground to the coils, checked and cleaned other grounds. A/F is like ~28. It's not throwing any codes now for some reason, even letting it get up to operating temp. Idle is stable unless I rev it, then it bounces some before it stabilizes. I'm out of ideas. I can do a leakdown test and see if something is funky there? Spark plugs were completely black, but not wet and there is black soot coming from the tail pipe as well.
Took the manifold off (again). Swapped back to my good injectors and tested the IAC. Works as it should. I put some copper pipe inside the IAC hose to make sure it doesn't collapse until my good hose gets here. Was gonna put it back together tonight, but going to wait until tomorrow just in case someone has any other suggestions before I do. If there is no change when I put it back together I'm going to try a leakdown test.
Is it worth checking to see if the timing is off? Will bad timing cause a lean running condition?
Last edited by badata1; 02-27-2017 at 07:33 PM.