s52 fires but won't stay alive

[dmjensen]

just finished my swap and im trying to get the car to just run, when i turn it over it'll fire momentarily and die.

if i give it gas itll rev up and then let off the gas andd it dies.

its an s52 all obd2 in a 92 325ic, i've done all the wiring so i know it should be good.

its getting fuel and spark because its firing, i've replaced alot of parts / the motor has 40k on it so i should be fine there. it sat for a year without running so i took precautions of pouring oil on the cams and putting some really thin oil down the cylinders so i could make sure it turns over by hand without ruining the rings. it already smoked all of that oil out so its not like my plugs are fouled since it still fires.

where should i start looking or trying things to get it to idle? vac leak? electrical something? or is this a super common problem that no one has told me??

[BBDirtbiking]

Some things to check:

Unplug MAF, try starting. If it runs better could be a MAF, test it.

Plug MAF in, unplug TPS, runs? Test TPS.

Unplug both, it should run brilliantly as it will run off the tune, if it doesn't, you could have a bad vacuum leak somewhere. Mine ran perfect like this once, then not so excellent the next time, so I dunno how good of a test this really is, but in theory it should run perfect.

Make sure the ICV is clean! That was my problem... I had cleaned it some but I took it off again and cleaned it until the cylinder in it will open/close when I shake it in my hand, after that it ran perfect.

Let us know what you find.

[10Toes]

just finished my swap and im trying to get the car to just run, when i turn it over it'll fire momentarily and die.

If i give it gas itll rev up and then let off the gas andd it dies.

Its an s52 all obd2 in a 92 325ic, i've done all the wiring so i know it should be good.

Its getting fuel and spark because its firing, i've replaced alot of parts / the motor has 40k on it so i should be fine there. It sat for a year without running so i took precautions of pouring oil on the cams and putting some really thin oil down the cylinders so i could make sure it turns over by hand without ruining the rings. It already smoked all of that oil out so its not like my plugs are fouled since it still fires.

Where should i start looking or trying things to get it to idle? Vac leak? Electrical something? Or is this a super common problem that no one has told me??

Sounds like EWS if only runs for a second and then stops?

[328ijunkie]

^ EWS wont let it fire at all.

[dmjensen]

I got that flashed out

[dmjensen]

could having the two fuel lines on the fuel rail switched around when going into the pressure regulator assembly cause this? Which of the two lines goes to the fpr? The one at the end of the fuel rail or the one that loops over to the front of the rail?

[BBDirtbiking]

If it fires and runs (with accelerator) then the lines aren't backwards.

I had mine backwards at first and all it did was over pressurize my gas tank and make it leak out underneath the back seat, wouldn't start at all, since fuel wouldn't get to the injectors.

[dmjensen]

Okay so i can rule that out. Soo ill have to unplug the maf and tps and if that dosnt work then clean the icv

[BBDirtbiking]

Okay so i can rule that out. Soo ill have to unplug the maf and tps and if that dosnt work then clean the icv

By having MAF and TPS unplugged your ICV isn't even used. It just runs the car off the tune. (I believe!?) So if it runs like crap, check for vacuum leaks. If it runs good, clean that ICV. I would personally clean it really good anyway, just so you know.

[DesertBMW]

just finished my swap and im trying to get the car to just run, when i turn it over it'll fire momentarily and die.

if i give it gas itll rev up and then let off the gas andd it dies.

Did you get your DME MS41.1 flash trough Tecnica? This sounds same as the problem that member Volta had with his tecnica ecu. I sold him one of my ecus and his car runs great. He sent his ecu back to tecnica and 3 months later they still haven't sent it back, he is asking for full refund now.

http://www.r3vlimited.com/board/showthread.php?t=249764

[328ijunkie]

Did you get your DME MS41.1 flash trough Tecnica? This sounds same as the problem that member Volta had with his tecnica ecu. I sold him one of my ecus and his car runs great. He sent his ecu back to tecnica and 3 months later they still haven't sent it back, he is asking for full refund now.

http://www.r3vlimited.com/board/showthread.php?t=249764

I believe this was an isolated issue. I have sold numerous Technica flashes and have run them in multiple customer cars here at my shop without issue. Every time the car has fired perfectly on the first try.

OBD2 S50 running front crank sensor first start with technica ECU. Pardon the mess. Late night.

https://www.facebook.com/video/video.php?v=4411358132302

[10Toes]

Did you get your DME MS41.1 flash trough Tecnica? This sounds same as the problem that member Volta had with his tecnica ecu. I sold him one of my ecus and his car runs great. He sent his ecu back to tecnica and 3 months later they still haven't sent it back, he is asking for full refund now.

http://www.r3vlimited.com/board/showthread.php?t=249764

How does this even sound like the same problem, one car will not run at all and one stumbles above 3k? You just like to jump right into bash a competitor mode.

[328ijunkie]

Also the OP is welcome to contact me for troubleshooting help...

[DesertBMW]

How does this even sound like the same problem, one car will not run at all and one stumbles above 3k? You just like to jump right into bash a competitor mode.

Read the original post on this thread again, and you will see this:

if i give it gas itll rev up and then let off the gas andd it dies.

To me sounds the same problem

[BBDirtbiking]

if i give it gas itll rev up and then let off the gas andd it dies.

To me sounds the same problem

Because it won't idle...