forum.audiv8.com Foren German V8 Motor V8 don't start anymore

Hello,
sorry for the englisch but my german in writing is not good enough.
Changed the timing belt on my V8, 3.6 pt , did it with the audi blocking tools, after changing it, i did a start test( radiator not mounted yet) just to see if it starts, and yes it did, i go on with my work, mounting everything, once the antifreeze was in the motor, i test again, and yes still starting and runs fine, ùounting air filter box and all the rest to finisch the job, start it, it seems to run on only few cylinders, check everything again, timing belt , zundverteiler, everything perfect, with laptop and vag com software i look for any errors, no errors, only engine speed sensor, but i gues this is normal coz engine is not running.
With stroboscoop light i can see there is ignition on all 8 cylinders, even the rpm meeter needle is moving when i am cranking the engine. Removed then the timing belt and did all the work again, with the same result, as for now, i don't know anymore.
Who can help???? thanks in advance. gruss

Morning,

Today i test with vag-com software , in the output mode, it seems that fuel injectors are not triggered anymore, disconnect fuelinjector cable , and measure voltagr, white cable comes from E7, plus verbindung leitungsstrang motronic, the other one for example injector # 5 black/lilla, comes from motronic computer. cable from e7 is alway's 12 volt, but when i do output test or starting car the cable from motronic computer stay 12 volt,. I think it schould go in pulses to 0 volt so that injector opens. When i put 12 volt straight to injector, i hear a click, so i am sure it works.
So , could it be possible that motronic box is broken?

gruss ous Belgium , Jean-Marie

i think also the motronic box have problem or the fuse,best is you borrow a 2nt box from a audi v8 and take it in your car for test.
regards guenter

do you know wich fuse it is? i checked already all fuses in the right hand side of the car, everything fine.
gruss

Hello Jeanmarie,

before you make some works switch off the Mainaccu and wait a short time. After a time without the electronic system make a reset.
Make a test, its the cheapest thing.

i did it already, disconnect batterie, disconnect motronic computer, reset codes, ( engine speed sensor error) but i think that's normal if engine don't run?
how to do a reset?? curieus about that?
or maybe look for other motronic box?

gruss, jm

problem solved, car starts again, after testing everything over and over again, only one thing according me could be the problem, the sparkplugs,.

Get them in local audi/vw garage, and replaced them. Car starts again and runs fine.

maybe because of a lot of short running periods, the plugs got fooled and misfires.
The plugs they sold me are the one with 4 groundelektrodes, is that the correct type ?

By the way , testing the fuelinjectorswith the software works, but you 've to push on the throttle every time. until all eight are done.
Every injector is then triggered 5 times and you can hear it very well.

Ok, i am glad, the car is running again, next job is automatic trans, oil and filter change.

gruss,