V8SMYMATE Posted October 9, 2008 Share Posted October 9, 2008 Hi All, My 96 D1 V8 doesn,t seem to start very quickly i have bought a new bosch coil new leads, dizzy cap and rotor and plugs and set them correctly. I seem What else can i change to try to get better starting? the only thing i have not replaced is the battery,the reason i have not done this is because it turns her over quickly enough. i seem to have to put a little pressure on the gas when i turn her over to get her to start. once started seems to be much better. Any idears? Dunc Quote Link to comment Share on other sites More sharing options...
teabag Posted October 10, 2008 Share Posted October 10, 2008 Are you talking about starting from cold, if so then you should let the engine management take care of it and keep your foot off the throttle as that lets in more air and weakens the mixture. My starting is not instantaneous like some cars, takes at least three seconds to fire. May be time to look at the fuel side of things. Have you replace fuel and air filters ? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 10, 2008 Share Posted October 10, 2008 Being '96 I'd assume it's a hotwire EFi, could be a duff coolant temperature sensor (the EFI one NOT the gauge sender), there's info on how to test them (and the whole system) in the tech archive. Quote Link to comment Share on other sites More sharing options...
V8SMYMATE Posted October 11, 2008 Author Share Posted October 11, 2008 Are you talking about starting from cold, if so then you should let the engine management take care of it and keep your foot off the throttle as that lets in more air and weakens the mixture.My starting is not instantaneous like some cars, takes at least three seconds to fire. May be time to look at the fuel side of things. Have you replace fuel and air filters ? r Thanks for your post I am talking about starting from cold. i have not replaced the fuel filter, i will try that next? but reading your post maybe i am being too crictal as it will normally start 1.5 - 2 seconds. Quote Link to comment Share on other sites More sharing options...
V8SMYMATE Posted October 11, 2008 Author Share Posted October 11, 2008 Being '96 I'd assume it's a hotwire EFi, could be a duff coolant temperature sensor (the EFI one NOT the gauge sender), there's info on how to test them (and the whole system) in the tech archive. Thanks i will look in the tech archive and test Quote Link to comment Share on other sites More sharing options...
ThreeSheds Posted October 11, 2008 Share Posted October 11, 2008 Thanks for your post I am talking about starting from cold. i have not replaced the fuel filter, i will try that next? but reading your post maybe i am being too crictal as it will normally start 1.5 - 2 seconds. That's about twice as fast as mine*, and I am pleased with that I think that maybe it takes a few firing pulses before the ECU gets going and starts putting fuel in. Rog *Not really a fair comparison since I have Megajolt and that takes a couple of spins before it works out where TDC is and starts applying sparks, and only after that does the ECU start giving fuel... To me what matters is not that it catches instantly, but that it catches reliably. Quote Link to comment Share on other sites More sharing options...
streaky Posted October 12, 2008 Share Posted October 12, 2008 Faulty 'Cold Start' sensor perhaps? Anyone know how to check one of them apart from changing it for a known good one? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 12, 2008 Share Posted October 12, 2008 Faulty 'Cold Start' sensor perhaps? Anyone know how to check one of them apart from changing it for a known good one? Hotwire doesn't have a cold-start sensor as such (unlike the total bodge thermotime switch on the flapper), it just has the coolant temperature sensor. You can chekc them by comparing the sensor resistance against the known values. The ECU should fire a priming pulse when you turn the ignition on, and there's no delay between the engine turning and the ECU injecting fuel on either setup. EDIS takes about one full revolution for the missing tooth to go past the VR sensor before it knows where TDC is but should then catch straight away. Quote Link to comment Share on other sites More sharing options...
ThreeSheds Posted October 13, 2008 Share Posted October 13, 2008 Apologies for misinformation. I'd get me coat, but this is the best place to learn so in stead I'll be more careful in what I say in future. I think that maybe it takes a few firing pulses before the ECU gets going and starts putting fuel in. Yes - I was wrong on this - the ECU will start injecting fuel as soon as it 'sees' the flyback signal from the ignition. The ECU should fire a priming pulse when you turn the ignition on, Are you referring to the 'priming pulse' (about three seconds) sent to the fuel pump? I can find no reference to the actual injectors firing until the ECU sees the flyback signal... EDIS takes about one full revolution for the missing tooth to go past the VR sensor before it knows where TDC is but should then catch straight away. Again - apologies for misinformation. I was under the impression that EDIS needed to count a full revolution of clean VR signals before doing anything, and that it would then fire on the approach to the next TDC. Cheers, Roger Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 13, 2008 Share Posted October 13, 2008 Are you referring to the 'priming pulse' (about three seconds) sent to the fuel pump? I can find no reference to the actual injectors firing until the ECU sees the flyback signal... I was meaning an actual priming pulse of the injectors, as I can't see any reason for a pump prime otherwise. MS usually only runs the pump if it's going to fire a priming pulse, although I believe these days you can do it separately. Again - apologies for misinformation. I was under the impression that EDIS needed to count a full revolution of clean VR signals before doing anything, and that it would then fire on the approach to the next TDC. You're making me doubt it now although I was actually referring to this comment: I think that maybe it takes a few firing pulses before the ECU gets going and starts putting fuel in. Which shouldn't be the case with Hotwire. Quote Link to comment Share on other sites More sharing options...
jwriyadh Posted October 13, 2008 Share Posted October 13, 2008 The working fuel pressure, 36psi, decays while the engine is not running. There will be minute leakages through the non-return valve in the fuel pump and through the fuel pressure regulator. The purpose of the fuel pump priming pulse at ignition switch-on is restore the fuel pressure prior to engine starting. This decay is noted in the LR hotwire system tests and limits are mentioned. Check the fuel pressure whilst running the engine and then note the pressure decay after switch-off. Fuel pump, fuel pressure regulator, dripping injectors or poor quality sections of fuel hose can cause rapid decay. If the vehicle is stood for long periods it is not uncommon for rapid pressure decay to occur in the fuel pump non-return valve, in my case this cured itself when the vehicle was used regularly. jw Quote Link to comment Share on other sites More sharing options...
V8SMYMATE Posted October 23, 2008 Author Share Posted October 23, 2008 The working fuel pressure, 36psi, decays while the engine is not running. There will be minute leakages through the non-return valve in the fuel pump and through the fuel pressure regulator. The purpose of the fuel pump priming pulse at ignition switch-on is restore the fuel pressure prior to engine starting.This decay is noted in the LR hotwire system tests and limits are mentioned. Check the fuel pressure whilst running the engine and then note the pressure decay after switch-off. Fuel pump, fuel pressure regulator, dripping injectors or poor quality sections of fuel hose can cause rapid decay. If the vehicle is stood for long periods it is not uncommon for rapid pressure decay to occur in the fuel pump non-return valve, in my case this cured itself when the vehicle was used regularly. jw Thanks i will check all hose and pressure. this does seem to fit my with my starting issues. Quote Link to comment Share on other sites More sharing options...
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