Guest chalkie2326 Posted August 10, 2011 Share Posted August 10, 2011 First of all this is my first post, so hi all! So here the story goes Went and bought a '91 cabby with the 1.6 cvh efi fitted and all is running well but smells a little bit like it is overfueling. 1. Clean all the throttle body 2. Change the fuel filter 3. Change the air filter 4. Do all the plugs and leads 5. Change the oil catch filter(from the rocker breather pipe) 5. Reset the ecu (as done by the topic) Still after all of this i decide it is now time to set the emmisions as it is still stinking of fuel and after all the above all that has happened is the idle speed has increased to 1500 rpm as soon as iput any load on the engine, no matter how hard i try to get it lower it just dont want to budge!! Anyway, i have taken it to the the garage and they have tried and tried but the CO potentiometer is just not making any adjustments and you can spin the screw freely each way with no change So if anyone knows the resistance range i need so i can try and get some sort of replacement that would be awesome seen as no-one seems to do the potentiometer anymore!! Thanks in advance adam Quote Link to comment Share on other sites More sharing options...
Guest Lee81 Posted August 10, 2011 Share Posted August 10, 2011 The co adjuster as i'm aware will only set the co at idle. Since its running at 1500 rpm it way above normal idle speed. Could be numerous things but a few to check are:- The throttle body has been cleaned as you said. When put back in place did you make sure it was set so the throttle is fully closed. So the ecu knows no throttle is applied. Some system have a link wire for this or an adjuster for throttle position sensor. Have you checked the idle speed valve is working correctly. Disconnect it if idle speed does not lower it is either faulty or you have a air leak in the intake system. You have a compound problem as high co at idle wont cause the engine speed to rise so that needs sorting first You need a co machine to check if its overfueling. The smell of fuel doesn't mean its actually overfueling Quote Link to comment Share on other sites More sharing options...
Guest chalkie2326 Posted August 10, 2011 Share Posted August 10, 2011 The co adjuster as i'm aware will only set the co at idle. Since its running at 1500 rpm it way above normal idle speed. Could be numerous things but a few to check are:- The throttle body has been cleaned as you said. When put back in place did you make sure it was set so the throttle is fully closed. So the ecu knows no throttle is applied. Some system have a link wire for this or an adjuster for throttle position sensor. Have you checked the idle speed valve is working correctly. Disconnect it if idle speed does not lower it is either faulty or you have a air leak in the intake system. You have a compound problem as high co at idle wont cause the engine speed to rise so that needs sorting first You need a co machine to check if its overfueling. The smell of fuel doesn't mean its actually overfueling Hi, thanks for the advice, gives me some things to play with tommorrow, just a few questions/answers first. How exactly to i make the ecu think the throttle is fully closed? I did clear all faults after cleaning all the throttle body and left the tps in place throughout the cleaning. Also i wound out the idle adjust screw 3 turns and then went on another topics method for gaining correct idle speed ( disconnecting iscv, half a turn, reconnect and carry on until idles correctly) but i have fully screwed in this screw now and still the revs are high! Another thing i have noticed is it sounds like it is slightly missing at idle and this is giving a bit of rev hunting. Lastly i did think about the iscv being the cause of my problems but it does make a difference when disconnected and i did try a another iscv i gained from the scrappies and it was exactly the same! I will go over the engine again tommorow and post up any findings! Thanks again! adam Quote Link to comment Share on other sites More sharing options...
Guest chalkie2326 Posted August 11, 2011 Share Posted August 11, 2011 hi all, so tried all the above ideas today. . . . the iscv is now not responding if i disconnect it??!? why i dont know! Also the idle is at around 1800 rpm now However if i completely disconnect the CO pot. the idles drop down to 1000rpm so could this be my problem? Any ideas much needed! Adam Quote Link to comment Share on other sites More sharing options...
thomasn Posted December 20, 2011 Share Posted December 20, 2011 Might be a bit late to reply to this but i think the pot can only be adjusted when the ecu is in diagnostic mode, will have to go back to my notes on the engine to see if this is the case, if so you may have to get a tester like the gunson to put the ecu in diagnostic mode and take ot from there as per the instructions. Also check your plugs to see what colour they are,black for a rich mixture etc Quote Link to comment Share on other sites More sharing options...
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