dfi module help

[ari666]

hi folks, the ol' burnt out dfi module trick.

thing is, im on dfi module number 3 now. need to know what can cause them to fry. all new modules were brand new "delphi" units, all the thermal grease was properly applied, coils are not new, but getting the apprentice to measure the primary and secondary windings as i type. pretty sure theyre ok, spark plugs are good, leads are good.

we did have a previous problem with this vehicles ABS module causing a no-comms error, but its been unplugged for all 3 dfi's.

anything i am missing?

cheers

 

[Immortality]

Hi mate,

How long between fitting and the module frying? Are they completely dead or only missing on one set of cylinders?

 

[ari666]

lost CKP signal through the module. no 3 or 18x coming up on scantool. no rpm. even though its cranking.

think the client only did a few kms, parked up then no start the next morning. we only did very short test drives due to vehicle being unregd

 

[EYY]

lost CKP signal through the module. no 3 or 18x coming up on scantool. no rpm. even though its cranking.

think the client only did a few kms, parked up then no start the next morning. we only did very short test drives due to vehicle being unregd

Ahoy!
Check the CAS wiring - make sure it hasn’t rubbed through or is damaged in any way. If this is shorted - there’s a good chance it’s frying your modules. ABS module shouldn’t have any influence over your problem imo.

 

[EYY]

See here for more info. Document is for vn/vp but info is all relevant to later models as far as I’m aware.
http://www.injectronics.co.nz/assets/Uploads/T19.pdf

 

[ari666]

confused as to whether the earth (red/blk, pin L) supplies earth to ecu or ecu supplies earth to dfi. if dfi is unplugged then red/blk is open circuit.

am i onto something?

 

[ari666]

ABS module shouldn’t have any influence over your problem imo.

we couldnt diagnose the original "no start" because we had no comms with ecu. after hunting round just comms (thanks again guys) found it was a known issue for abs modules to interfere with data bus. so once it was unplugged we regained communication and were able to find we lost 3x signal from CAS. replaced CAS first because DFI module replaced by previous shop (vehicle arrived on a truck after 6 months at another shop) but CAS didnt fix it, replaced dfi and all good.

sent the car and advised customer not to reconnect ABS until they had a replacement unit as we though it was the cause of the failure, car returned shortly after on a truck with the ABS module plugged in and another dead DFI module with same symptoms. so we naturally assumed the abs killed it so we put a new one in...

cool story?

 

[Immortality]

confused as to whether the earth (red/blk, pin L) supplies earth to ecu or ecu supplies earth to dfi. if dfi is unplugged then red/blk is open circuit.

am i onto something?

I think L & M ground via the module body and supply a reference earth back to the ECU. Should be easy to test.

If there is faulty wiring in the CAS or Cam Sensor loom it might be shorting out the power supply and killing the DFI module.

Where is that DFI module diagram from? The VT should have a Cam Angle Sensor. That almost looks like a VN series one DFI module wiring configuration.

 

[EYY]

I think L & M ground via the module body and supply a reference earth back to the ECU. Should be easy to test.

If there is faulty wiring in the CAS or Cam Sensor loom it might be shorting out the power supply and killing the DFI module.

Where is that DFI module diagram from? The VT should have a Cam Angle Sensor. That almost looks like a VN series one DFI module wiring configuration.

Courtesy of the Haltech site.


Any evidence that the vehicle has been on LPG in the past?

 

[Deuce]

Welcome back ARI

I get a feeling dfi modules are like injectors, it's the earth signal that triggers them.
Yes you are on to something. Keep at it mate.