Lude Posted September 4, 2012 Share Posted September 4, 2012 cold starts are fine. if its the mornings itl fire straight away. over the last 2 weeks though its got this issue, if i drive a mile to the shops, it will never fire 1st time? it takes 2, 3 maybe 4 times ti fire. the starter motor turns fine. i can only describe it as the starter motor does its job, the car starts but dies before it actually fires to life. (you dont just turn the key and starter for ages and ages and nothing happens) any ideas? or clues? Quote Link to comment Share on other sites More sharing options...
Suprab1 Posted September 4, 2012 Share Posted September 4, 2012 Could be plugs have a poor spark. How does it idle when you get it running? Quote Link to comment Share on other sites More sharing options...
Lude Posted September 4, 2012 Author Share Posted September 4, 2012 idles a little low when its warm. again, cold starts are great, coudnt ask for better. its only when warm and short journeys, i can change the plugs to see if that rectifies. anything else possibility? car drives fine, its just this starting episode... Quote Link to comment Share on other sites More sharing options...
Suprab1 Posted September 4, 2012 Share Posted September 4, 2012 Is it stock ECU? Is the car pulling strong in all gears without missfiring? Quote Link to comment Share on other sites More sharing options...
Digsy Posted September 4, 2012 Share Posted September 4, 2012 Maybe fuel vapour lock? Is the engine running unusually hot? Quote Link to comment Share on other sites More sharing options...
Ian C Posted September 4, 2012 Share Posted September 4, 2012 Apparently vapour lock went out with carburettors after I mentioned it to someone, dunno if that's true though. I get this and I finally caught it on a datalog on the E-Manage. Hot start is fine, cold is fine, but hot-then-left-for-5-minutes is a disaster, it'll turn over but won't catch, or catches badly and instantly dies. The datalog I took shows an injector duty of 6.3ms on key-turn when the car starts ok, and this is completely missing when it won't start. I'll get a graph up showing this in a moment. Quote Link to comment Share on other sites More sharing options...
Benjy Posted September 4, 2012 Share Posted September 4, 2012 I had this on a XK8 the other day. Replaced the crank position sensor and all is well. Quote Link to comment Share on other sites More sharing options...
Ian C Posted September 4, 2012 Share Posted September 4, 2012 (edited) Okay here are the three graphs. One is a perfectly good start, one is a start that went to a slightly ropey idle and a blip of the throttle sorted it out, and one is a complete failure to start. The failure to start is really different, it doesn't do an initial burst of 6.3ms injector duty, it just goes straight into the warm-idle 2.4ms duty. I think this is why it won't start, I guess at the low rpms the starter motor turns, it needs a big bang to kick it all off. The injector duty is the bright green line on the graphs, big square bit at the start. Hopefully Ryan can have a look and comment on starting strategy, see if this makes any sense The failure to start one has me giving it a bit of WOT to try and persuade it into life, alas it's the same green colour as the injector duty, whoops, so don't get that confused I'm tempted to try downgrading the EMU firmware to a previous version, see if that makes a difference. Might try that tomorrow when I go and put petrol in it (the Supra, not the EMU) seeing as this problem manifests mainly at the fecking pumps, just to make me look like an eejit. -Ian Edited September 4, 2012 by Ian C (see edit history) Quote Link to comment Share on other sites More sharing options...
Ian C Posted September 4, 2012 Share Posted September 4, 2012 I had this on a XK8 the other day. Replaced the crank position sensor and all is well. How would a dodgy CPS only cause a problem with a warm start? I would have thought you'd have all sorts of running problems with a dodgy CPS. Quote Link to comment Share on other sites More sharing options...
Benjy Posted September 4, 2012 Share Posted September 4, 2012 Was breaking down when warm. The car wouldn't cut out, but once switched off wouldn't restart. Plugged in, live data, no crank signal. Replaced and retested. All ok. Quote Link to comment Share on other sites More sharing options...
David P Posted September 4, 2012 Share Posted September 4, 2012 Try starting it with a touch of throttle, if that works, check the ICV. Quote Link to comment Share on other sites More sharing options...
dr_jekyll Posted September 4, 2012 Share Posted September 4, 2012 this happens on mine with an emb too . i just apply throttle and all is well Quote Link to comment Share on other sites More sharing options...
Ian C Posted September 4, 2012 Share Posted September 4, 2012 I always try the throttle trick, to no avail Quote Link to comment Share on other sites More sharing options...
Ian C Posted September 5, 2012 Share Posted September 5, 2012 I've done some reading, and apparently what I'm seeing is the Prime Pulse. The Megasquirt forums seem to think that this only purges the fuel system of air/vapour before cranking, others think it helps the cold start. It makes sense that if it doesn't happen, I get some sort of vapour lock problem, but surely it'd start after a few cranks anyway, with the fuel pump thundering away? Mine won't have any of it until I key off and back on to try again, though. Quote Link to comment Share on other sites More sharing options...
Lude Posted September 5, 2012 Author Share Posted September 5, 2012 car doesnt overheat no. thanks for input guys, but im still no wiser as what to ? a new cps? i do try blipping the throttle tp try and get it firing but still no. (havent tries flooring it tho) Quote Link to comment Share on other sites More sharing options...
Benjy Posted September 5, 2012 Share Posted September 5, 2012 a new cps? It won't hurt. This is quite a common symptom of a CKP sensor, I've had it a fair few times. Vauxhalls do it all the time, done a few Audi's with the same fault. If you can get a data logger and see what the CKP is doing before you change it, it may well confirm the fault. Quote Link to comment Share on other sites More sharing options...
mellonman Posted September 5, 2012 Share Posted September 5, 2012 Okay here are the three graphs. One is a perfectly good start, one is a start that went to a slightly ropey idle and a blip of the throttle sorted it out, and one is a complete failure to start. The failure to start is really different, it doesn't do an initial burst of 6.3ms injector duty, it just goes straight into the warm-idle 2.4ms duty. I think this is why it won't start, I guess at the low rpms the starter motor turns, it needs a big bang to kick it all off. The injector duty is the bright green line on the graphs, big square bit at the start. Hopefully Ryan can have a look and comment on starting strategy, see if this makes any sense The failure to start one has me giving it a bit of WOT to try and persuade it into life, alas it's the same green colour as the injector duty, whoops, so don't get that confused I'm tempted to try downgrading the EMU firmware to a previous version, see if that makes a difference. Might try that tomorrow when I go and put petrol in it (the Supra, not the EMU) seeing as this problem manifests mainly at the fecking pumps, just to make me look like an eejit. -Ian i have the exact same thing with the AEM FIC, cold start great,hot start great, hot left for a hour dont want to start! i managed to get this better by adding fuel in my map around 0-400 rpm and in and around the cells at psia, i also removed all timing adjustments at the same area of cells. IE, you dont want timing retarded when cranking. Quote Link to comment Share on other sites More sharing options...
Lude Posted September 5, 2012 Author Share Posted September 5, 2012 i am stock ecu also. Quote Link to comment Share on other sites More sharing options...
DodgyRog Posted September 5, 2012 Share Posted September 5, 2012 I had this problem on my Seat a few years ago and it was the Coilpacks breaking down under heat, never a problem when cold Might not be your problem, but thought I would tell you anyway Quote Link to comment Share on other sites More sharing options...
SupraD06 Posted September 5, 2012 Share Posted September 5, 2012 Have you checked the ICV? Remember reading a thread Geo started on here about how he had to clean his after getting iratic idle, cut out after first fire up, dying once running etc Might be nothing to do with the ICV but worth a quick look. http://www.mkiv.co.uk/vbb/showthread.php?210956-How-To-Clean-Idle-Control-Valve-Cleaning-Aka-ICV-%28IAC%29 Quote Link to comment Share on other sites More sharing options...
Lude Posted September 5, 2012 Author Share Posted September 5, 2012 i had my idle vale off a few months ago and cleaned it all out then so wont be that. its not asif the car is getting hot after a short trip, i can literally go half a mile to the shop following a cold start, come out within 5 mins and it struggles to start.. Quote Link to comment Share on other sites More sharing options...
ashbuster Posted September 5, 2012 Share Posted September 5, 2012 reading this made me try starting mine and ahhhhh it wont start but i think i might be lucky and its the battery, it hasnt been started in a week and half and when i turn the key nothing at all happens. also my lights done work hope you get it sorted mate seems lately your car is being naughty Quote Link to comment Share on other sites More sharing options...
Lude Posted September 5, 2012 Author Share Posted September 5, 2012 the battery is pants in mine, ie if car isnt used in a week itl be dead. by battery is fine on cold starts tho and turns the starter fine so i think i can rule that out too... so can we sumarise what i need to get or test please? new plugs, coilacks, and maybe a cps? isit a fueling issue or spark issue? Quote Link to comment Share on other sites More sharing options...
Suprab1 Posted September 5, 2012 Share Posted September 5, 2012 First test for good spark, as said it could be coil packs starting to tire out. I've also seen the Crank position sensor cause this but never on a toyota. Something i would look into is the coolant temp sensor, should only be about £15ish for a new one. Quote Link to comment Share on other sites More sharing options...
thedirtycat Posted September 5, 2012 Share Posted September 5, 2012 the battery is pants in mine, ie if car isnt used in a week itl be dead. by battery is fine on cold starts tho and turns the starter fine so i think i can rule that out too... so can we sumarise what i need to get or test please? new plugs, coilacks, and maybe a cps? isit a fueling issue or spark issue? My mums car was strange. I remember it would start but if it was warmed up and she had turned it off for a couple of minutes and tried to start the engine again it wouldn't start. She had to wait for 5 or 10 mins and it would start again but eventually it just wouldn't start. Surprisingly it was the battery was dying. Would have thought it would be when it hadn't been run for a bit it would struggle to start. Quote Link to comment Share on other sites More sharing options...
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