Hey guys running a technica stage 1 obd2 s52 with cutring/spacer and stock bottom end. first start it starts up and dies, with foot on the gas it will stay alive kind of bogging but as soon as you let go it dies. thought it was a genius idea to get plx's bluetooth wideband, currently fighting to get some afr data from that but currently have no readings, it definitely smells like its running pig rich, pulled some spark plugs and they are dry so far.
fuel system consists of..
-technicas 60 lb injectors
-technicas 255lph fuel pump
-new bosch fpr
-new fuel filter
new sensors
-ect
-crankshaft position
-camshaft position
-o2 sensor (plugged into the correct tune based connector)
-rebuilt vanos with beisan
-technica maf (when unplugged it starts up and dies faster)
pre start checks
-base tune uploaded with battery charger attached
-boost leak up to 20 psi (no audible leaks but it drops pretty steady which i assume is air going past rings)
-smoke test (no visible leaks other than coming out of the wastegate dump)
-cleared codes and adaptations
having no afr data im pretty much shooting in the dark but i would appreciate some input from the experts on here. im kinda at a loss here, only codes im getting is secondary air (unplugged) and after cat o2 (unplugged)
Last edited by glockroulette; 04-18-2018 at 07:31 PM. Reason: critical info
When you start it does it rev up and then settle down and bog out or is it having trouble even getting up and going?
No it just stays low in rpm. letting go of the gas pedal it drops and dies. revving it produces a bog/sputter, barely a sputter. i dont think its timing, i spun it by hand atleast 5 times and cam blocks slid on everytime.
Maybe Idle air control valve related? sounds like the engine either is getting way too much fuel, or less air than it thinks.
Sounds like the tune didnt stick.
Did you make sure you bridged pins 14 & 18 under diag cap to give the ecu programming voltage?
Last edited by ba114; 04-18-2018 at 11:11 PM.
What? i had no idea i had to do that, i just flashed it with a laptop and the supplied cables. tell me more about this bridging
Under the hood there is a 20 pin diagnostic connector. It has a black cap on it on the exhaust side of the engine bay. By bridging pins 14 and 18 you give flashing voltage to the obd2 port.
its gone over on the open ms41 wiki page https://sites.google.com/site/openms...1/enable-write
Last edited by brokeneck; 04-18-2018 at 10:59 PM.
is this standard operating procedure when uploading tunes? i flashed with this https://www.amazon.com/VAG-COM-409-1.../dp/B01NAV01PV plugged into this https://www.amazon.com/OBD2-OBDII-Di.../dp/B01JBM1GOG plugged into the under hood 20 pin connector.
Yes it is standard. If you dont do it, you havent actually written the tune to the ecu.
haha holy shit.. so bridge the pins and flash through the 20 pin connector or through the obd2port? and im assuming bridge the pins from underneath the connector?
Okay, if you have the 20 pin connector I don’t think you don’t have to bridge the pins.
may not be tune related then unless the cable isn’t working. But my first thought was tune related too, but I figured it wasn’t because it was a purchased tune. What program do you use to flash it?
the program was called Arges.
Ok here goes:
If you flash through the 20pin you still need to bridge 14 to 18 to enable write mode. I have never come across a 20pin adapter that has this internally bridged already. You do not need to bridge anything else.
If you flash through the OBD port, you need to bridge 14 to 18 in the diagnostic port, and also pin 2 to 17 to enable the OBD port to work inside the cabin.
In summary, you always need to bridge 14 to 18, regardless of where you decide to plug the cables in
^
so i bridged 14 and 18 turned the key on, flashed through the 20 pin round connector, cleared adaptations, no change. still running rich as shit. pulled the booster line off the manifold and it started and maintained a decent idle for a little bit then corrected back to a low and boggy idle.
finally got some data, afr at idle 11.3, vacuum is bouncing between 5 and 10 in/hg and fuel pressure is 52psi at idle. also put a stethoscope on the iac and its sounds alive.
Sounds like low vacuum. Mine is around 18 in/hg i believe
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if fuel pressure is above 43 psi at idle, you're missing a vacuum fitting to the FPR.
apparently the new bosch fprs are trash so i put my oem one back in, havent checked pressure with the old one but the idle is still terrible. the line at both points is intact, it shouldve showed in the smoke test if otherwise.
i took the valve cover off to verify timing, im 99% sure the exhaust cam was off. the blocks wouldnt slide on over the exhaust cam. intake looked straight. im thinking the rich condition is a symptom and the problem is something hardware related. i doubt technica gave me a bad tune im sure they put out thousands a year. thoughts?
If its rich, the car either thinks its getting more air than it is, or its getting more fuel than it needs.
How is the MAF wired?
A MAF based system always knows exactly how much air is coming in. The tune adjusts fuel based on how much air is registered - If the MAF hasnt been scaled in the tune correctly, there will be lots of issues.
Either the MAF is registering too much airflow, causing the injectors to inject more fuel, Or you're getting too much fuel based on the injectors flowing more than they are supposed to.
I assume since technica sell this setup alot, they would have scaled the MAF appropriately which leads to either the injector scaling being incorrect in the tune, or too high fuel pressure causing all fuel calculations to be out.
The reason it ran a bit better with the booster unplugged, is because you introduced un-metered air into the system to counter balance the excess fuel i.e. leaning out the mixture.
It'd be nice to have pictures of your setup. But you need to verify timing first. Most rotate the motor 4-5 times to verify that cam blocks fit correctly. Especially since we have interference motors stock. I would check all your electrical connections: IAT, ICV, MAF(arrow pointing right way/wired correctly) then look for vacuum leaks. Vac lines to BOV, FPR, booster, boost gauge, etc. Then verify fuel pressure. Most people here go to an aftermarket aeromotive FPR 13109. After installing a high pressure pump, it will most likely overpower the regulator. At least mine did. Pressure at idle should be 43psi and 51 psi with no vac line hooked up. You should have between 18-21 in/hg of vacuum at idle.
The tune is almost never the problem.
what do you use to post pictures?
timing is dead on now, maf is wired per technicas instructions, i had it wrong when i first wired it up but its good now.
so fuel pressure with the old fpr is still 50-52, shoots to 58 when vacuum line is removed. maybe low vacuum is keeping it at the 50-52 range? also technica says their 255 pump is okay with the stock fpr. im getting way too much fuel pressure though and introducing air after the maf will let the car have a good idle until it corrects its self back down to 400 and dies. literally wont stay running with out the gas pedal, and even then its terrible.
should i go aeromotive or?
I've used flicker or you can use the "insert image" command on bimmerforums. Even with just a 255lph I've seen some overpower the stock fpr so it can't hurt. With the aeromotive at least you can cross this off the list.
But before spending money, I would verify timing and do a compression test. Then boost leak test and verify all electrical connections. Its most likely something simple. It always is.
timing is dead on. and i did piston rings while i was in there and they havent been broken in and seated yet so i dont think a comp test would be accurate would it? boost leak test was up to 20 psi, it falls but im guessing thats air going past the rings. i cant find any external leaks. all electrical connections are good, not getting any codes other than the ones i listed in op. engine grounds are good and tight as well. i sanded the paint off the motor mount arm to facilitate good contact.
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