skinner2k3 3 Posted August 6, 2007 Hi I have been trying to resolve a slight misfire I have on my 1900. The car is running the std late management which had the smaller coil mounted to the inlet. I made a bit of a mistake cleaning up and fitting an early manifold which had no mounting point for the coil. So I made up a bracket to fit the coil to the inner wing where the jack used to sit. In order to connect it up I had to extend the loom to reach. The loom going into the coil consists of a red and yellow from the ignition amp to the primary windings of the coil, plus a pair of shielded wires to a second set of primary tapings and also another thicker red wire to/from the ECU. There is also a thin grey wire which I have no idea of its function. Would I be right in thinking that the two shielded wires control the injector firing timing? And the red from the ECU is the coil supply? Could cutting and rejoining these wires cause the slight misfire I am getting throughout the rev range? Cheers Ben Share this post Link to post Share on other sites
pug_ham 244 3 Cars Posted August 6, 2007 The coil & ignition amp have no connections at all with the injectors & the other red wire comes from the fusebox via the brown plugs in the drivers footwell but doesn't go to the ecu at all. AFAIK the thin grey wire is the rev counter signal wire (112). When you say standard late management do you mean Jetronic or Motronic with a cat? How did you extend the shielded wires? If these are done incorrectly this could be a cause of a misfire imo but have you checked the obvious things like dizzy cap & rotor arm condition? Graham. Share this post Link to post Share on other sites
skinner2k3 3 Posted August 6, 2007 Thanks Graham. My guesses were miles out! The shielding now stops about 100mm from the coil. What do the shielded wires actually do? Its non cat, phase 1.5, 1989 ignition. So Jetronic? I did note that the secondary winding resistance of the coil was to neither the Valeo or Bosch spec in Haynes. It was somewhere between the two. Thanks for your help. Share this post Link to post Share on other sites
pug_ham 244 3 Cars Posted August 6, 2007 The shielding just prevents the wire getting interference from the other wires which come from the ignition amp but after thinking about it they probadly wouldn't cause a misfire but might give an inaccurate rpm reading (once you have it working again). Your car will be jetronic like most of the ones in the UK. When you said standard late I though you mean't newer than phase 1.5. What have you tried so far to cure the misfire? Graham. Share this post Link to post Share on other sites
skinner2k3 3 Posted August 7, 2007 I did try to keep the unshielded lengths to a minimum. Hopefully that wont have too much affect. So far I have fitted new HTs, cap, rotor arm, plugs, heat sink compound on ign amp, cleaned up the earths, checked primary and secondary winding resistance on the coil and checked the pins in the injector plugs. I have also tried altering the timing. I did find the coil secondary winding resistance to be out of spec, but not open or short circuit. Oh and the wiring between the hall sender and the amp appears in good nick too. I had to fit a longer king lead (1200mm) to reach the coil on the wing. Its only a 7mm Hotwires lead. I could try the 8mm version? Anthony is coming over tonight to drop off an engine, hopefully he will have a coil and amp with him we can chuck on, see if they make any difference. Share this post Link to post Share on other sites
pug_ham 244 3 Cars Posted August 7, 2007 I wouldn't suspect the king lead, especially not if it was new. Hopefully either the coil or ignition amp (or both) will fix it. Has this misfire only developed since you fitted the different inlet manifold & moved the coil? Graham. Share this post Link to post Share on other sites
skinner2k3 3 Posted August 7, 2007 Fingers crossed for the coil or amp. Unfortunately the car has been off the road for a couple of years and when last used had a 1600 engine fitted. This problem has been gradually getting worse (or I have noticed it more) since I first strated driving the car following the conversion to 1900. So I am unable to be confidently say whether moving the coil caused the problem or not! Will hopefully try a different coil and amp tonight so will let you know how I get on tomorrow. Thanks for your help. Share this post Link to post Share on other sites
pug_ham 244 3 Cars Posted August 9, 2007 If its been stood for a couple years & was last run as a 1600 GTi, what fuel was used in it & have you added any fresh fuel recently? 1900's need 97 ron minimum where the 1600 can run fine on 95ron or the fuel could even have gone off. Graham. Share this post Link to post Share on other sites
skinner2k3 3 Posted August 9, 2007 There was very little fuel left in the tank over that period, I generally put super in anyway when it was a 1600. Before I drove the car I put £5 worth of super in just to make sure I made it to the garage. Since driving it about I think I have probably used £30 of super. I used that BP Ultimate stuff. I have another coil and amp at home now, hopefully tomorrow I will get the chance to chuck them on and see if that helps. Share this post Link to post Share on other sites
skinner2k3 3 Posted August 13, 2007 Ok, so one by one I swapped over the test drove the following; Cap, Rotor arm, Ign amp, Coil and sparkplugs. Sod all difference, still missing. About to throw teddies from pram, when decided one of the only electronic bits left was AFM, chucked on a 1600 one I had and problem solved All I need now is a 1900 AFM. See wanted add Thanks for everyones help. Ben Share this post Link to post Share on other sites
skinner2k3 3 Posted August 13, 2007 Sorry, I said "everyones help"...I meant Grahams! Share this post Link to post Share on other sites
