My S4 B5 wont start.

[StefenJ]

Hello! I just bought a Passat with a 2.7l biturbo engine (S4) in it. Only problem is that it wont start.

When i trye to start the engine it cranks but there is no fule comming from the injectors. It will start with startgass but the injectors wont take over.

According to the last over the fule pump is new and working, and the fule reatches all the way to the injektors. Yesturday i read the error codes and there were an error on a O2 sensor (lambadsonde), can that be the reason the injectors dont open?

Anyone had same problem or know what the diagnosis might be? :) heeelp :D

[vavJETTAw36]

No. The 02s should not keep it from starting as it will be in open loop.

What's your fuel pressure at the rail? Has the car ever started before (without the starter fluid)


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[StefenJ]

I have not cheked the fule pressure since the last owner installed a new fule pump, i will chek tho just du be shure.

Yes the car have been working before, but after a turbo swap (it has k04 hybrid turboes) the fulepump stopped and the problem with the injectors started.

[vavJETTAw36]

You shouldn't take the word of the previous owner. I don't care how much you trust him maybe he installed it incorrectly.

Do you have vag com? If so you can quickly test the injector pulses. As it goes through the test you will hear the injectors buzz. If they all buzz you can rule out wiring.

If you don't have vag com jump right into checking fuel pressure to the rail. A quick test is also to trigger the fuel pump and listen for it. This will rule out if the pump itself is bad.


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[bmoreS4]

Should change title to "2.7tt Passat", no B5 S4 in here.

[StefenJ]

Okey, im getting hold of a vag com this weekend and i will test the injector pulses. I can hear the fule pump running but i will check the pressure in the rail. Ty for the tips :D

[jballou]

Probably a bad CPS

[vavJETTAw36]

Probably a bad CPS

This is true I didn't think about the CPS. But I'd think the car wouldn't ignite and the OP said he started it with fluid.

[Timtheguru]

FPR hahaha

Also, probably the Crank Position Sensor.. typically won't start on a hot start, will usually start on a cold start, if it is failing. Already failed CPS would not allow you to start at all.

[aysix]

CPS won't cause a no start condition

[Timtheguru]

CPS won't cause a no start condition

Yes it will.

[aysix]

Yes it will.

I read cam position sensor, not crank. Crank position sensor will.

[Timtheguru]

I read cam position sensor, not crank. Crank position sensor will.

Gotcha.

[Zba]

I second FPR

[jballou]

Did the car ever run? Before you even purchased it?


Doing a google search on this issue and this car pops up. Sounds like a can of worms. There needs to be more detail. Being that it is a swap. You need to first find out if this car ever ran on its own. If it never has... have fun as you have a lot of hours tracing things down.

[Timtheguru]

I second FPR

Did you change yours recently?

[StefenJ]

I will uppdate this when i get my hands on a cps (gona arrive tommorow most likely) and a vag com :)

[Zba]

Haha, no it's just fun to hop on the FPR bandwagon :)

[Timtheguru]

Haha, no it's just fun to hop on the FPR bandwagon :)

Good! Quite frankly, my car has never been as peppy as it is now, over the last 10+ years. I have correct fuel pressure in all driving conditions at the moment, which most people just test fuel pressure when they are idling (not a great test). As soon as I give the throttle a press, it just goes. Never before has the car done that. No hesitation, no nothing. I thought that the 2.0 coil conversion would help, and it might have a little bit, but not anything like this $30 part. My fuel economy has improved, as well as no more black tailpipes after 2 weeks of driving (usually would turn black again after a couple days). Seriously, I will push this until everyone has a new one. Your car will love you for it. In all my years on the forum, no one ever suggests the FPR, I wish I had thought about it sooner.