VN V8 Rough ldle, Rough Revving and slight backfire

[seabs]

Hey guys, last night went to start my car (vn v8 manual) and the check engine light came on and it was idling quite rough. It also stalled once.

Put it into diagnostic mode and eventually got an error code 13 (o2 sensor). So I got a new sensor, put it in, cleared error code (disconnected main engine fuse for 10 seconds) started it up and no change, still rough.

Took it for a drive and it goes, but it is a bit down on power, has a rough idle and doesn't sound right.

Also, It's running rich (very strong fuel smell from exhaust, and a bit of unburnt fuel splutters out the pipes).

On a side note, when I try go into diagnostic mode, the engine light flickers really erratically, like it goes really fast and it just doesnt seem normal.

Any ideas? Possibly TPS?

[seabs]

Few other things:

Fuel pump sounds normal, replaced dissy a few months ago, TB is clean.

Cheers guys

[kniever]

it sounds like your ecu, happened to my vn calais 5ltr, just happened all of a sudden too.

you can use a vn v6 ecu as they are the same as the v8 ones but make sure you use your v8 memcal

[stockyvrcalais]

it sounds like your ecu, happened to my vn calais 5ltr, just happened all of a sudden too.

you can use a vn v6 ecu as they are the same as the v8 ones but make sure you use your v8 memcal

Agreed, i got stuck out in the bush last weekend, car was idling rough on the way there, started it up in the morning to come home, ran for a minute, stalled and would not start again, i thought it was the fuel pump as it was not making noise, but ended up being the ecu, changed that and now runs better than ever! So if you can get your hands on one to try out, i suggest you try it, and as kneiver said, make sure you use your memcal, good luck.

[stuntmanmike]

If you replaced your distributor then I'd hazard a guess that it was stuffed. I'd check the ignition module only because my experience with the 304s is that if either the dizzy or ignition module cark then the other part will also be stuffed (eg ignition module and then distributor or vice versa).
Maybe swap the coil with a good unit and see if that fixes the issue. If not then swap the ignition module and see if the does it.
A 12v test lamp will let you know if the ignition module is cactus and a good amp meter can test the primary and secondary windings in the coil as a simple diagnostic. Best of luck...

[seabs]

thanks for the replies. I'll grab an ecu from the wreckers, didnt realise the 6 and the 8's ecu are the same, so thats cool.

Nah, the dizzy wasn't stuffed when I replaced it, just replaced it cos I'm fairly sure it was the original one still.

Least the ecu is a sinch to replace, I'll do that then if it doesn't improve I'll duck under the bonnet again!

cheers for that guys, I'll keep you posted.

EDIT: Just picked up an ECU from the wreckers for $20, will chuck it in when I get home this arvo and see!

[seabs]

Just swapped in the ECU I got from the wreckers (with my v8 memcal) and started her up, good as gold!

I Let it idle for a few minutes and took it for a drive and its all good! Engine light isn't on either.

Thanks very much kniever and stockyvrcalais. Saved me lots of stuffinf about!

Cheers guys

[stockyvrcalais]

well done mate, always nice to see a good outcome, and $20 for an ecu is a bargain, mine cost me $50 from pick a part, bloddy rip off, i could of got one cheaper on ebay but didnt wanna wait so i got stung lol

[kniever]

good on ya mate, glad to see it worked out.

[stuntmanmike]

Awesome! Good on ya guys. This adds to the "success story" list. Isn't this forum a wonderful thing...