RE_TurboFB

Out of the blue, my S5 Turbo just starts cutting out any time I give 25% or more throttle.. Kinda like it was running out of gas, But the air/fuel ratios went way rich like 9 to 1 insted of the 11 to 1 i was running.???



So I put new plugs in it, Disconected the MSD box, Threw a diffirent leading coil on it. That made it run a little bit better. replaced the coils 12+ VDC wire and leaned the A/F ratio way out, and that helped the most...



Now it stoped the cutting out like it is out of fuel BS. Now it just lack big time power and wont make more then 5 pounds of boost...



What could of happend to my engine.??? almost seems like my apexI fuel computer fried or somthing. any of you guys have a clue..???



Thanks for any imput.

j9fd3s

i notice these things are picky about plug wires... good time to start inspecting stuff, plugs, wires...

RE_TurboFB

well I put a timing light on one of the leading coil wire and fired it up. Right off the bat I noticed a little miss every second or so..



Then I wanted to see what the coil is doing at a higher RPM. when I give it a good amount of throttle the light misses quite a bit and when I throttle it above 4000 RPM's the light gos out completly!!! So I kept messing with it, then the light stops blinking all to gether even at idle ..



So I tested the wires going to the coil. The power wire is great but no signal from the signal wire...



So the ECU stoped sending out signal to the leading coil pack.



I take it that this ECU is fried..???

RE_TurboFB

OK... I got another ECU. Now the Car fires right up. Idles nice and smooth (it surges above 1000 RPM's). I take it for a test drive It still will not make more then 5 PSI of boost!!



On the test drive I step on it a few times it seems to work ok besides no power/boost. Then I go to give it some more gas and it just falles flat on it's face!!! I let off the gas and pop!! a wicked loud back fire! Then after that if i floor it it just dies. If i let off the gas it just gives me another POP!



So i limp it home if I give it a small amount of gas it runs fine.... go home shut it off. start it back up. Then I can floor it all i want... let it get a bit hotter then any time i give it some gas it gives me a loud POP then jumps up in RPM's... Like the timing is off..????



So I put the timing light back on it.. I could not even see the leading mark..?? So I rev it a few times, and on the 3rd time the leading mark shows up right on the pointer... I give it another rev and once again the leading mark disapeared....??? give it another rev and bam the leading timing mark is back. WTF..????



Could it be a bad MAP sensor..??? What would make my timing jump like that..???



Thanks for any input guys!!!

RE_TurboFB

I can Unplug the MAP sensor and the engine run's the same way..??? I take it that is not normal..???

FC_BOY

check you cat, the rich condition might have totaled it and thats why your not getting boost or power, a similar thing happened to me and my friend was the one who noticed the muffled exhaust note.

RE_TurboFB

It has a 3 inch turbo back strait pipe exhaust system... So we can rule out that.. I noticed that I have a n350 Map sensor.. wich is the N/A sensor.. But still It was running and boosting with a N/A sensor...



Could a vaccum leak cause it to jump timing..??

RE_TurboFB

Right on! The problem is solved.. I found a slit in one of my silicone 90's That was causing a wicked vacuum leak. I also intalled a N370 MAP sensor. After fixing those two problems It would fire right up. I retuned the APEXi Neo and now it's back on the road.



So it was a fried ECU, The wrong map sensor and a bad vacuum leak causing my problems.. Well these problems. I'm sure I'll have a new set of problems with it tomorrow...