audi 7a not starting

[MISTER T 1997]

ok this is a strange one I had the car running i then removed the battrey to feed a vaccum pipe for my map sensor i put the battrey back and now it wont fire i have fuel and i have taken a spark plug out and checked spark it is sparking but it may be a little weak but not sure ever way when it is all in it dose not fire at all if you wnat to know i do have it an a aftermarket ecu but i reflased the map back on to it as well as ajusting timming in the map to see if that made a diffrence it didn't i also put the old ecu back in and nothing is any different on the new ecu i have signal from the crank, the refrance and the hall sensor i have replaced the rotor arm in the dizzy and checked the dizzy it looks fine i tested the coil that seams fine i did stuppidly forget to check the fuse but i dont know what els to do?
when i say it dosent fire i mean it realy dosent fire not tring no combustion on any cylider what so ever

[John.]

….. i have fuel

Be more specific?...…….you have fuel in the tank!?……..you have fuel pressure?...…… you have voltage at injector wiring and switched earth on the other?...….. or is it just that the plugs are wet?

Maybe all of the above?...…...could it be flooded?

Hitachi injectors with resistor pack??

[newsh]

Check all your fuses

[MISTER T 1997]

i will check the fuses but i am strugaling to find somthick that would stop it sparking
and yes the plugs are getting wet put i have dc the injectors and cleand the plugs and tried to remove the fuel and i know that when this car has been flued before it dosent do this even with cleen plugs and the injectors dc it still isnt tring to fire you would compltey thing the dizzy was not connected

[LHD_Kid]

But, you said you have spark... So dizzy is fine...

BTW, I almost ran out of breath trying to read and understand your last post!

[MISTER T 1997]

sorry about that
but yes i beleve the dizzy to be fine i checked the ohms through it agenst another one i had and they where the same, i can only imagine that the spark is not stong enough.
Dose any one know the amount of amps that i should see with a amp clamp on one of the ht leeds incase it is enough to spark on the engine but not under compression

[newsh]

Is the battery fully charged?

[MISTER T 1997]

charged and with a jump pack

[Bowie69]

Leads in the right place?

[John.]

I think you're wasting your time with amp clamp around HT leads?! Checking resistance of leads against each other will give an idea if any are suspect.
Dirt and dampness on the leads won't help either if the insulation on the leads is starting to fail, so make sure they're clean and dry.
Checking resistance of primary and secondary windings of coil might be an idea, there should be a spec for this but where to find this info I'm not sure.....been a long time since I've done it.
Assuming cap and rotor arm are in good condition?

When you say you checked the ohms through the distributer ??…...do you mean the cap? Hall sensor should be checked for feed and earth and LED test light on trigger(middle) wire. The way a multi-meter works, for resistance it will send a small voltage out one of the wires and it calculates ohms/resistance by whatever it gets back on the other...….as the hall sensor is polarity conscious, it could be damaged in this way. Worth bearing in mind next time.

Maybe worth removing all the plugs and try and leave a while for the fuel to evaporate/dry out, dropping a small amount of oil into each cylinder to help seal the rings might as well?

Might it be an idea to restrict the fuel when you next try and start it? Get rid of any fuel pressure, have the fuel pump fuse removed when you crank it then refit the fuse....maybe just touch it across the contacts briefly first to see if it responds?

Difficult on a forum to get a true idea of the fault, equally difficult describing the above!!

Good luck.

[MISTER T 1997]

So I fixed it I believe that the coil is braking down and not able to spark under compression so I changed the coil and the plugs and it runs.
I am now going to do what I should of at the start and put r8 coils on it so if anyone has a good guid on that I wouldn’t mind a bit of a reed thought.

[John.]

That's good you got it running.

Will your present aftermarket ECU/management system control the coil conversion?

[MISTER T 1997]

yes should run just fine

[newsh]

There’s a thread on here for the 3B to ABY pin swap which should have links to the guide but as yours is a 7A with aftermarket ECU I’m not sure how much help it will be.
Basically you have to add the extra wires from your ECU to the 5 coils, run power to them and switch your software over to 5 coil operation.

[MISTER T 1997]

o yea sorry i think the wiring is farlly simple its the fitting the coils into the engine im more unsure of