ignition problem audi 7a

[Mikemul]

Any other ideas ? What checked/checked/replaced

Wiring harness measured
New sparkplugs mounted
Compression measured 9/10bar at 1,2,3,4 and 5 have 8,5/9,5bar with closed throttle
Fuel pressure measured 3/4bar
Mapping checked
Injector flow test done
Crankshaft signal test done
Checked firing order
Sparks from plugs tested
Inlet valve checked if they open
Inlet gasket reassembled and additional liquid gasket used in between
Temperature sensor connected
Oil pressure sensor connected
Engine timing checked
Ignition time controlled with timing light
changed injector at nr 5


cylinder 5 is sparking while the engine runs on the other 4 cylinders

[Mikemul]

Why did you have to swap intake?

because the 7a intake comes over the head and than I can’t use the ignition coils on each cilinder. That’s the only reason

[Bowie69]

Why did you have to swap intake?

[Mikemul]

Any other ideas? I did a flow test and all injectors give the same amount of fuel and sprays good. I have remove change the 7a intake for a s2 intake but there is no turbo on it so is this the problem? If there is a spark
and fuel there is firing???

[Mikemul]

Number 5 injector bad or stuck open ? Have you tried swapping that injector with another one and seeing if the fault moves ?

Yes have try swap but the same problem on cylinder 5 any other ideas?

[Mikemul]

Number 5 injector bad or stuck open ? Have you tried swapping that injector with another one and seeing if the fault moves ?

I haven’t try that lets give it a try

[Mikemul]

Headgasket issue? or?

Have you checked the compression on each cylinder , both dry and wet ?

yes all the cylinders between 10 bar only 5 is little lower it’s about 9 bar all plugs dry and black only cylinder 5 wet.

there are new pistonrings on it and new headgasket

[simons2]

Number 5 injector bad or stuck open ? Have you tried swapping that injector with another one and seeing if the fault moves ?

[larsaskogstad]

Headgasket issue? or?

Have you checked the compression on each cylinder , both dry and wet ?

[Mikemul]

hey guys, i have a difficult problem on my audi 7a engine. it is build with pinbobines and a standalone ecu. everything is correct connect. i have test the hole wiringloom and the injectors sprays and the sparks spark. the firing order is 1-2-4-5-3. the engine is starting(very bad) and runs on 4 cylinders. all sparkplugs are black only cylinder 5 is wet. this cylinder run not. i have try to change the plugs and the bobines but no different. when i crank when all plugs in the bobines on top of the cylinderhead they spark all the time? so any suggestions? fuel pressure about 3-4 bar 123454.jpg