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VQ V8 Electronics

Parker

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VQ Caprice V8
Hi, To all those out there with a 5ltr VQ etc. I have noticed many guys have had numerous electronic problems.
I had a very frustrating time with my 5ltr. Mostly because nobody had a clue, and that included professional mechanics. The scenario went like this.
Travelling home last Feb. the motor suddenly lost power and started to miss something shocking. I managed to limp home , about 8klm in fits and starts . Local mechanic said it was fuel pump, I had a spare ,changed it . No change to miss problem. I bought a Haynes manual and it said if there was fuel in the return line the pressure reg. was faulty. Changed it . still had problem. Found a guy in Sydney who said it was probably Ignition Control module . I bought an exchange reconditioned and updated
( improved economy and power) for $125 ,exchange from him. Still had problem. I then changed the IAC, the Hall FX unit in the dizzy and the MAP sensor. All this time the ECU gave a 12 readout meaning there was no prob ?? which really confused the issue. I then acquired an ECU from a VN V6 ,changed the MEMCAL chip to the V8 and bingo Problem solved. All this time everyone had said the last thing that would need looking at would be the main computer. How wrong they were. l During this exercise I had checked all the relevant voltages and they all read as per specs.
My only minor prob. now is that recently the motor needs to wind a bit longer than I would like before it starts, but only when hot after a run . Starts instantly when cold. And the starter is fine. Maybe the battery voltage is a bit low when hot?.
Next job when I get around to it, is to rebuild T700R 4 tranny . it is a bit slow to move off when cold but is fine when hot. That will keep me busy for a while, but is a heap cheaper than giving it to a workshop.
 

jdodd

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i had the same issue with my first vn v6, had a bad miss when it got hot, replaced coils (2ndhand) , leads, plugs, crank angle sensor, dfi module (2ndhand), brand new coils and then eventually the ecuwich fixed it. its just one of those things. so now i always keep spares for testing, got a small collection going, ts astra ecu, vz alloytech ecu, camira/vn/vp ecu etc etc. the only quick way to test them is to swap them.
 

Brett_jjj

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Ive had a faulty ECU in my VSV6,it was not turning the cooling fans on.The last place I thought the problem would have been was the ECU.It actually had a hole burned through the main ECU board where the connector pins for the ECU plugs are soldered onto the board..And it was the cooling fan wires and pins that got hot and burned by the look of it.It really suprised me how it didnt effect anything else considering the damage it did to the board.There was no moisture in there either.
 
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kniever

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mine did the same in my vn 5ltr, i was just lucky that the 1st thing on my list was ecu, saved me all the trouble of everything else
 
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