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Faulty DFI module?

Discussion in 'VR - VS Holden Commodore (1993 - 1997)' started by tezza, Jun 26, 2011.

  1. tezza

    tezza New Member

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    Hi everyone,

    Can a DFI module in a 3.8lt Ecotec just die all of a sudden and not allow the car to start? There have been no problems with the starting and running of the car. Or should I be looking at other things?
     
  2. greenacc

    greenacc Searching for the billion

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    Hey Tez, DFi's can develope a mind of their own when they get old. I had 2 that died suddenly while driving along, the first one at 100 km/h which was quite an experience.

    It will throw a code or 3, so check that before you go buying any parts. Probably somewhere around 46,47,48
    They can be real headaches too, cos there can be hidden issues in other parts of the system that can keep blowing DFI's once in a blue moon.
    When you get it started again leave it to idle for a good 10 min in your driveway to check it's not going to konk out again.
     
  3. ben315vz

    ben315vz Donating Member

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    Yes it is possible. I took off from a set of traffic lights, got up to about 30km/h then all the sudden the engine cut out and wouldn't start anymore. Luckly I just got it off the road, had to get it towed. Turned out to be the DFI Module.

    EDIT: I knew it wasn't the fuel pump because it wouldn't run on petrol or gas.
     
  4. tezza

    tezza New Member

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    Ok can DFI modules be tested at all, or is the easiest to get another one to try?
     
  5. ben315vz

    ben315vz Donating Member

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    Well the electritian at work had one with him that he uses to test to see if thats the problem. He came to work at put it on my car until I got a new one then I gave it back to him. I got the DFI Module, Coils, Spark Plugs and Leads as a set from Repco for $320. Just the DFI on its own from Holden was $450, and they sell the coils seperately.
     
  6. tezza

    tezza New Member

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    So faulty DFI modules should throw up a code? I'll check it out.
     
  7. ben315vz

    ben315vz Donating Member

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    Mine didn't bring up a code. I ended up changing the crank angle sensor, harmonic balancer, some relays and was still not starting, changed the DFI Module and started straight away.
     
  8. commo tech

    commo tech New Member

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    If the dfi fails it will not log a code, the ecu isnt smart enough to recognise a fault in the dfi, but as the dfi is the link between the ecu and the crank angle sensor it may in some cases log a crank angel sensor code
     
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  9. iwishmyVNwouldstart

    iwishmyVNwouldstart New Member

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    mate pretty common problem. check the connector from the harness, they can corrode and cause a bad connection leading to the no start.

    I had the same problem, the connector was fouled up badly. I replaced the female connector on the engine harness side, scaled back and reinsulated the pin on the DFI module and it has been going sweet for 18months. cost me about 30c in connectors and silicone, and about 2 hours.

    better than forking out 400 bucks for a new DFI module, or going to wreckers and getting one that could be near shagged anyway.

    if the connection is good then yeah, probably up for a DFI. from memory there is a test for the DFI, but there is no test other than a SCAN tool for the CAS. both could possilby cause this condition, as could a problem in the immobiliser, that would produce a code though.
     
  10. bloke04

    bloke04 New Member

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    Thanks ilwishmyvnwouldstart. Fixed my car issue. Cheers good site this very helpful!
     
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  11. Bowen

    Bowen New Member

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    You can test the cas with a test light or multimeter , you just put pos on pin in dfi connection and earth on chasis and watch as somebody (not female going to bug u and get annoyed at you ) cranks the engine, you can test both the 3x and 18x signal

    Iv read a lot recently that the earth can actually be to blame on these engines (cas and cam get earth from dfi) which gets it from the engine earth sometimes the alloy plate can corrode and cause a shitty connection
     
  12. tonym

    tonym New Member

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    Interesting reading, thank you all. My sons XY Berlina V6 began stopping while driving it, usually once a week. Then it got 3-4 times per week. It then would not start one morning. A friend of mine said to disconnect the harness to the DFI and put it back on. Sure enough, it started just as he said it would. Problem solved! NOT quite. It still intermittently stops while driving and won't start sometimes. Remove the DFI plug/harness and it will start again. I've cleaned the pins and the harness best I can. Any ideas as to the "root" of the problem please. I am about to buy a DFI module, am debating buying just the module (about $145) or the module and coil pack ($229) Any advice please?
     
  13. EYY

    EYY Well-Known Member

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    Best advice is to steer clear of aftermarket products.
     
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  14. outlander

    outlander New Member

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    With the car running, pass a hair dryer over the dfi. If it starts to idle rough, change the hairdryer to fan only to cool it down. Thats how I found out my DFI was faulty.

    I replaced it with a second hand unit from ebay for like $30
     
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  15. losh1971

    losh1971 Well-Known Member

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    Question, what causes these to fail? Im n thinking of grabbing one one at the wreckers to keep in the ute incase the ute breaksdown. I just want to choose one of the right wreck, if i pull it myself.
     
  16. greenacc

    greenacc Searching for the billion

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    As EYY said aftermarket DFI's are terrible evil things and you'll be back in the break Down Lane with the same problem next year.
    Losh, age and heat slowly kill them over the years. Any wreck of similar age should be fine with the lowest ks possible.
     
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  17. losh1971

    losh1971 Well-Known Member

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    Are Delphi units any good? They seem to have come down in price since i last looked a couple of months ago.
     
  18. greenacc

    greenacc Searching for the billion

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    Delphi should be the real thing.
     
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  19. EYY

    EYY Well-Known Member

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    Poor connections/high resistance is usually the killer for coils and DFI's. Bad plugs and leads mean more resistance and the coils can't do their job properly and things start to heat up. They do just die every now and again. It happened to me once, took me ages to diagnose. It all happened very suddenly and it was like it was running out of fuel.
     
  20. tonym

    tonym New Member

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    Had to bight the bullet and put a new DFI unit in. Changed spark plugs too as they were due. I've been driving it all day, perfect! :)
    Son took it an hour ago, just rang to say it stopped again! :-(
     

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