virtuoso23 10 Posted May 14, 2018 1993 OD1 VR6 Hey guys, so went to use the VR the other day to discover a flat battery. Jumped the car and got it running, but unlike normal it sounds terrible. Sounds like it has cams in it!! Feels extremely lumpy! Idle is stable on the Rev counter at 1k cold start and 750 warm, but sounds like a chugging or misfire, exhaust farting etc. Engine movement is present on idle. On the road it seems to pull okay maybe a little flat but with no signs of misfire/kangarooing. MAF has been unplugged with a noticeable change so I think that can be ruled out. Checked and changed the plugs, top bank looked fine bottom bank were oily. Leads/dizzy and rotor arm were changed a year ago. Anyone with suggestions Please Thanks Quote Share this post Link to post Share on other sites
fla 9 Posted May 14, 2018 Might be a blocked injector. Post up some pics of the spark plugs - this can tell a lot Quote Share this post Link to post Share on other sites
virtuoso23 10 Posted May 14, 2018 Unfortunately I threw them away however after changing the plugs it seemed to run okay, that was yesterday now it's back again. The car seems fine when driving just not so great when at idle. Quote Share this post Link to post Share on other sites
Gti_Jamo 10 Posted May 14, 2018 Have you checked the voltage at the battery? Since it was flat it could be not charging properly and the ecu is not getting 12v on idle. Quote Share this post Link to post Share on other sites
virtuoso23 10 Posted May 14, 2018 Interesting! I did check the voltage at the battery when it wouldn't start and it read around 10.5v I shall indeed re-check the voltage shortly. Quote Share this post Link to post Share on other sites
dr_mat 0 Posted May 15, 2018 The ECU will likely have lost adaptation to your engine if it has lost power from the battery. Now usually, in my experience, this results in the car running smoother for a while as it will tend towards overfuelling until it adapts again but you may find issues if it's not had a clean power loss and re-apply so I would suggest doing the ECU reset process in a controlled way. That just means disconnect the battery fully for 30 seconds before reconnection. And of course you want the battery fully charged when you do this. Car power supply is very messy, the ECU should tolerate voltage drops as low as 8v during cranking, but if you have a flat that can't start the car at all it's possible this can cause issues for the ECU too. A Corrado is for life, not just for the MOT. Quote Share this post Link to post Share on other sites
fla 9 Posted May 15, 2018 Then take it for a good drive for at least half an hour at motorway speeds. When the temps are up to normal do some hard acceleration in 2nd and 3rd. Quote Share this post Link to post Share on other sites
virtuoso23 10 Posted May 15, 2018 Hi, Okay so re-checked the battery and the voltage is all good. I decided to disconnect over night to see if it presented any remedy, unfortunately not. Had a spare blue coolant sensor knocking about so decided to fit that. Measured the pins on the current sensor and it seemed off so replaced it. Car is still running lumpy on idle. I put a cone filter on the car prior to the idle issue and all was fine but decided to re-fit the factory air box incase that was affecting the MAF, still no good. So to recap: Fresh Plugs Dizzy Rotor Arm Blue Coolant Switch MAF okay Engine fires immediately No noticeable power loss when at WOT RPM fluctuate slightly at idle Car sounds like it's chocking at idle At low speed and accelerating it sounds like there is resistance from the engine but above 2000rpm it pulls nicely. Can I achieve anything plugging in via the ODB1 ports? Could the ISV be causing these issues potentially. Much appreciated for all responses. Quote Share this post Link to post Share on other sites
dr_mat 0 Posted May 15, 2018 The ECU will tell you if there is a fault, yes. That's always worth doing. Yours is a 93 with the OBD2 socket? A Corrado is for life, not just for the MOT. Quote Share this post Link to post Share on other sites
fendervg 32 Posted May 15, 2018 Check for any vacuum leaks on the inlet elbow and manifold, and the PCV tubing. Quote Share this post Link to post Share on other sites
virtuoso23 10 Posted May 16, 2018 Problem solved. Just an update, managed to locate the issue, the exhaust was was blowing quite substantially on the down pipe in turn messing up the lambda and the idle. All fixed now :cheers: Dr Mat it is definitely ODB1:p Quote Share this post Link to post Share on other sites
dr_mat 0 Posted May 17, 2018 Problem solved. Dr Mat it is definitely ODB1:p The protocol is obd1 but the later cars had an OBD2 socket.. Quote Share this post Link to post Share on other sites
virtuoso23 10 Posted June 5, 2018 It's an early socket type mat, but I know what you mean. Quote Share this post Link to post Share on other sites
dr_mat 0 Posted June 5, 2018 It's an early socket type mat, but I know what you mean.:) A Corrado is for life, not just for the MOT. Quote Share this post Link to post Share on other sites
