Konstantin

#1 and #2 cylinders are perfect.
any idea what can casue this. we checked injectors (are brand new)
FPR is brand new. The whole engine is brand new, the wires seems to be o and the spark plugs WR5DC are also ok.
what is the problem. the spark plugs have a white color on them.. the other two looks perfect.

we also checked the injectors with the rail and all of them sent fuel. of course we checked that only on idle with the DME relais bridged

Konstantin

Duke

You say you have checked injectors and wires etc, but have you tried to switch everything inbetween the cylinders?
Like putting injector #1 in cyl #3 etc, then the spark plug from #1 in #3 etc.
Following that route with all possible sources of error, sooner or later you will find the source of your problem.

Good luck!

Peckster

Must be the injectors. You could swap them to confirm or just have them all flow tested and cleaned.

TT

Follow what Duke said.

3 & 4 are wired to pin 14 of the DME and 1 & 2 are wired to Pin 15. If a connection or wiring is bad the problem will show up in pairs. If the wiring is not the problem, swap out the DME.

Konstantin

The injectors are BRAND new.
we tested them and ALL flow the same!
Maybe the flow well on idle but not on high rpm?
they are 799 CC Siemens Injectors

Konstantin

Konstantin

the problem is that a lean runing car will destroy the engine. this already hapened once (ok it was another problem but a blown 3L Turbo engine is not cheap)

so we must know BEFORE we test with another DME.
If we put another DME an dthe engine still runs lean this will destroy the engine for the second time. The first one lastetd only 4000 km

Konstantin

M758

Hmm you could do a in car injector test.

Pull the rail and crank the engine with the injectors in the rail put pumping fuel down onto cold headers. Sure not pretty, but you can visual the flow patter and roughly tell if those two injectors are not following right. If they are not then check into the the eletrical system.

Konstantin

already done that
it works :-(

Konstantin

Mike Murcia

It's a long shot, but could you have a leak on your 1 and 2 intake gaskets, giving them less boost, and therefore a proper a/f ratio while 3 and 4 are sealed properly and lean? Or an even longer shot...an obstruction in the 1-2 runners?

Konstantin

we thought about that. we took the intake manifold out since it is also sealed with loctite AND the gaskets.
We could see that it was sealed perfectly.

Konstantin

jsonnen

Hey Konstantin how old are the wires going to your injectors? If they are original they tend to crack as they age and have been known to send irratic signals to the injectors. I've seen it in the past, could be your issue.

Good luck cause lean sucks!

TT

They all four come together inside the DME.

Check continuity from the injector connectors to the DME plug. Have someone shake the wiring under the hood while checking. Also check 12V supply continuity from injectors 3&4 to the same pins on injectors 1&2. They should all be connected together to the common 12V supply line.

If that all comes out OK, then you will need to crack open the DME and remove the bottom board to check the traces and solder joints for Pin 14.

Mike B

jsonnen and TT have a point. The continual removal of the intake or fuel rail causes the brittle wires to get worse leading the breaks and shorts in the wires. I had a similar problem which was a cracked injector wire. Very frustrating to diagnose.

Best of luck Konstantin

Peckster

Could be the wires I guess, especially if the pair go to the same DME terminal. A bad conection would mean less fuel to those cylinders.

TonyG

>>Maybe the flow well on idle but not on high rpm?<<

Have the injectors flow tested on a real machine.

If you had.. you'd know for sure at x pressure, and at x duty cycle, what each injector flowed.

Because they are new means nothing.

TonyG