Gold FFM Sparky Posted June 25, 2022 Gold FFM Report Share Posted June 25, 2022 Sharing this interesting one from Denmark last week. Martin owns a stunning SE that had been off the road for many months due to an undetermined engine issue. The car would initially run seemingly consistently, but with little power, until turned off when warm. When restarted warm, it would run rough with evidence of missing, and be virtually impossible to drive. Felt like fuel starvation. Leave until cold, car would start and be marginally driveable again as long as it wasn't turned off. Martin had tried various things including coils to no avail. Blindly accepting the ignition diagnosis (naughty me) I first swapped the DI with a known good unit. Same issue. Tested spark, found OK on all 4. Then Freescan. Integrator, IAC and O2 were all showing silly numbers and knock count was high. Tested injector resistance. No.1 was only 1.3ohms. Fortunately we had a donor car to hand so I swapped out the offending injector. Engine runs perfectly. What baffles me is the fact that it would be sort of OK until the second start. Weird! Moral of the story: always check injector resistance. A simple task that may save hours. 2 Quote British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland. And Shitfaced Silly Sod to Sweden. Link to comment Share on other sites More sharing options...
Trevsked Posted June 25, 2022 Report Share Posted June 25, 2022 Some straw clutching. Have you tested the resistance when the injector is cold? I assume the reading you got was when hot? I wondered if the ecu sees a feedback from the injector when cold which is correct and says it’s ok to function. When hot it sees a different feedback outside its parameter and therefore can’t cope? if not, I’ll accept points out of 10 for story of the week. Trevor. 1 Quote I'll get around to it at some point. Link to comment Share on other sites More sharing options...
Gold FFM Sparky Posted June 25, 2022 Author Gold FFM Report Share Posted June 25, 2022 You're not as daft as you look! I didn't think of that, but will test it on my next visit... Quote British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland. And Shitfaced Silly Sod to Sweden. Link to comment Share on other sites More sharing options...
fjmuurling Posted July 1, 2022 Report Share Posted July 1, 2022 The primary injectors are Peak and Hold injectors ie a larger current is used for opening and after reaching the opening current the ECU (which measures the injectorpai current) throttles the current back. As the injectors are paired (1&4 and 2&3) the current through an injector pair is evenly distibuted between the 2 injectors if they are of equal resistance. If not then one injector gets more current then the other causing different opening times or not (fully) opening of an injector. 1 Quote Esprit Freak Link to comment Share on other sites More sharing options...
Guest Posted December 11, 2022 Report Share Posted December 11, 2022 The main injectors are peak and hold injectors, which means that when they open, a higher current is used, and once they do, the ECU (which monitors the injector pai current) throttles it back. Quote Link to comment Share on other sites More sharing options...
Gold FFM Sparky Posted December 11, 2022 Author Gold FFM Report Share Posted December 11, 2022 Well bugger me, I'd never have guessed. Quote British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland. And Shitfaced Silly Sod to Sweden. Link to comment Share on other sites More sharing options...
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