Still no ignition. I have tried........

[AudiCoupeParts]

I keep getting Crank position sensor.


I have 5 used sensors that come off of running cars. I tested all of them per factory manuel and all come out good. However NONE get to the approximate 1000 ohms. They all come up short. Ranging from a low of 930 up to a high of 982 ohms. I have swappes all in and out of the car and still get bad sensor code.


I checked all the continuity from the sensor connection of the firewall to the ECU plug. I Checked 19, 47, 48, to the 3 wire sensor connection. all show good continuity.


Checked the main ground straps. All are clean. The car cranks over smooth and fast.


I checked the crank pin on the fly. It is there and it is clean and shiny. does not appear bent or damaged.

I then swapped ECUs with a know good unit. Same code for crank sensor appears.


What could I possibly be missing?


I checked all that the manuel points to in the trouble shooting.


I checked on the forum and read over other posts but nothing stands out.


Could anyone please give their thoughts on this?


regards,
joe

[Tonks4x4]

Hi Joe is it 3B or ABY?
Is it operating the relay in position 10 in the fusebox when cranking?
Vag-Com always gives a fault for crank position sensor when not running...

[AudiCoupeParts]

It is an ABY...

Hi Joe is it 3B or ABY?
Is it operating the relay in position 10 in the fusebox when cranking?
Vag-Com always gives a fault for crank position sensor when not running...

Its ABY, and the fuel relay is coming on when the key is turned and cranking over the engine. I can also feel the fuel entering the rail and fuel regulator. (I have a remote starter) Fuel pump is also heard on while cranking


joe

[Tonks4x4]

Have you tested the power output stages/Coils? Is it letting fuel into the bores?
The fact that the relay is switching means that the flywheel sensor and the cam position sensor are working correctly.

[AudiCoupeParts]

No.

Have you tested the power output stages/Coils? Is it letting fuel into the bores?
The fact that the relay is switching means that the flywheel sensor and the cam position sensor are working correctly.

I have not tested the coils or POS units.


I figured since the crank sensor was not "working" per code then nothing else would work.

No fuel is present in the bore or smelled. Fuel is at the rail and injectors but it is NOT being shot into the IM.

No spark detected. I sprayed fuel starting fluid into the IM and not a single pop, fizzle or back fire happens while cranking.


What is the best way to check POS and coils?

Joe

[mcandmar]

Whats the backround story to this Joe, Engine conversion, rebuild, any engine mods? Might be worth double checking the timing marks incase somethings out, and also the POS/Coilpack wiring as its easy to get them mixed up.

Quick test for coilpacks is to stick a plug into each boot and prop it up so they are earthed to the cam cover, would be usefull to know if there firing at all.

[AudiCoupeParts]

conversion project

Whats the backround story to this Joe, Engine conversion, rebuild, any engine mods? Might be worth double checking the timing marks incase somethings out, and also the POS/Coilpack wiring as its easy to get them mixed up.

Quick test for coilpacks is to stick a plug into each boot and prop it up so they are earthed to the cam cover, would be usefull to know if there firing at all.

No mods except for Fidanza fly wheel. everything is stock Audi Rs2 and ABY parts.

I checked al the timing marks about a dozen times.

Cam shafts are right on and spocket is at the top mark on valve cover.

Fly wheel is dead on in the bell housing window.

Harmonic balancer wheel is dead on the lower T belt cover plate notch.


joe

[mcandmar]

Maybe the crank sensor error is real, you do get a code when the engine isnt running but maybe the sensors arent getting a good signal. From memory the speed sensor that reads the flywheel teeth has to be set within a few mm from the teeth, and the same for the position sensor that looks for the small pin on the backside of the flywheel. There must be some way to verify there working with a multimeter...

Just checked the Bentley manual, both sensors should have .5 to 1.25mm clearance.

Testing sensors is as follows,

Pin1 and Pin2 must be ~1000ohms

Pin2 and Pin3 must be open (infinate ohms)

Unfortunately the manual doesn’t say what you should see when the flywheel teeth or timing pin pass the sensor. I would expect to see a noticeable change in resistance as they are triggered.

[AudiCoupeParts]

Maybe the crank sensor error is real, you do get a code when the engine isnt running but maybe the sensors arent getting a good signal. From memory the speed sensor that reads the flywheel teeth has to be set within a few mm from the teeth, and the same for the position sensor that looks for the small pin on the backside of the flywheel. There must be some way to verify there working with a multimeter...

Just checked the Bentley manual, both sensors should have .5 to 1.25mm clearance.

Testing sensors is as follows,

Pin1 and Pin2 must be ~1000ohms

Pin2 and Pin3 must be open (infinate ohms)

Unfortunately the manual doesn’t say what you should see when the flywheel teeth or timing pin pass the sensor. I would expect to see a noticeable change in resistance as they are triggered.

I get in the mid 950 to 980 ohms on pin 1 and pin2 It says approximate 1000 ohms. Is 980 close enough???

Pins2 and pin3 both are open. infinate ohms.


I tested all 5 crank sensors i have and all come to within those specs except for not acheiving 1000 ohms but close to it.

[Knight Rider S4]

When logging in to vag.com and on the engine -fault codes, when you clear codes does the crank sensor fault come straight back up with out the engine getting turned over?

[AudiCoupeParts]

Well...it did once.

When logging in to vag.com and on the engine -fault codes, when you clear codes does the crank sensor fault come straight back up with out the engine getting turned over?

I just tried it and the first time it came up crank sensor and speed sensor codes.

I cleared it again and then just got the speed sensor code.

What does that mean?


TIA
joe

[S2central.net]

Can you get hold of an oscilloscope to look at signal coming from G4 and G28 ... and G40 for that matter.

You don't need anything fancy.. I got a 20MHz handheld one from Maplin - equivalent of your Radio Shack in the yooessaaaa. In times like this its the only way to know if sensors are behaving right... measuring resistance of them tells you very little.

Stupid question, but did that Fidanza flywheel have the crank reference pin in place, or might you have inadvertantly broken the pin while fitting ?

Also check that you are getting 12V to one side of the coils - there is a separate fuse for coil feed... wanna say its #32 on ABY but your converted machine might have that fuse elsewhere of course.

[AudiCoupeParts]

Can you get hold of an oscilloscope to look at signal coming from G4 and G28 ... and G40 for that matter.

You don't need anything fancy.. I got a 20MHz handheld one from Maplin - equivalent of your Radio Shack in the yooessaaaa. In times like this its the only way to know if sensors are behaving right... measuring resistance of them tells you very little.

Stupid question, but did that Fidanza flywheel have the crank reference pin in place, or might you have inadvertantly broken the pin while fitting ?

Also check that you are getting 12V to one side of the coils - there is a separate fuse for coil feed... wanna say its #32 on ABY but your converted machine might have that fuse elsewhere of course.

I can call Radioshack tomorrow and see what I can find.


Yes I have checked the flywheel pin and it is there. Clean and shiny. No crap on it. Appears straight no bend etc.


My ABY harness is a GL 1994 production LHD loom from a German S2. Totally stock and uncut original. I used your diagrams and they are a great help. i will look into that fuse again. I have checked all of them numerous times.

If I get this scope to test the sensors what info should I look for? I have 5 of these sensors that all came from running coupes and sedans that I have parted out in that last few years. I cannot believe ALL 5 would be junk now.

[Ruffiano]

I recently did the same swap, lhd aby s2 harness into a coupe quattro that formally had a 7a. Followed the same guide that Paul made, it was very straight forward and mine went without a hitch.

My thoughts are this, check the simple things. Pull the coil cover with the coil packs attached and hook up a spark plug, hold it close to the valve cover and see if you are getting spark. check all 5. If you are getting spark, pull your fuel rail with injectors put bottles over the injectors and test to see if you are getting fuel. if both are present, you should be looking for air/compression problems, make sure everything is sealed up and perhaps do a compression check. **** happens, valves could have been bent at some point before putting on the new timing belt... start with the simple things then work into the electronic things. if you are getting fuel you know which wires to start following...

[Tonks4x4]

Get yourself a injector noid tester.

noid testers

This way you can see if your injectors are firing as it lights up when it gets a pulse from the ecu.