IS300 not starting as well as usual
Discussion
Our generally faultless elderly IS300 ( 04 plate ) has recently not wanted to start with the immediacy we've come to expect......it will either crank for several seconds and start reluctantly, or won't start after several seconds, but then fire up straight away at the 2nd time of asking. It then runs fine, and will start with no problem later in the day, unless left for some time, at which point it will misbehave again.
There are several posts about this issue on various Lexus forums, with different opinions about the cause, but seemingly no definitive solution.
If I turn the ignition on for 5 seconds or so before cranking, it seems to help........that would seem to indicate a fuel pressure issue, with the pump needing a few seconds to restore pressure. Any other thoughts?
There are several posts about this issue on various Lexus forums, with different opinions about the cause, but seemingly no definitive solution.
If I turn the ignition on for 5 seconds or so before cranking, it seems to help........that would seem to indicate a fuel pressure issue, with the pump needing a few seconds to restore pressure. Any other thoughts?
I left Lexus before these came out, but I'm still in contact with a lot of the lads that stayed and worked on them, none of them can remember any issues, but the Lexus specific forums are full of tales of woe with the same issue..........I'm going to turn the ignition on in the morning before it's been started, let the pump prime, and crack the fuel feed into the injector rail and see if there's anything going on there pressure wise. I don't think these models have a serviceable fuel filter, so that rules that out.
Wondered if it might be a coolant sensor making the car think it was always hot, and stopping enough fuel getting through for a cold start, but I can't see why it would start no bother on the 2nd time of asking if it were that.
Wondered if it might be a coolant sensor making the car think it was always hot, and stopping enough fuel getting through for a cold start, but I can't see why it would start no bother on the 2nd time of asking if it were that.
Its easy to check if the fuel system is priming, crack open the fuel rail "in" banjo it should prime with ign on for about 5secs. (obviously this will generate a bit of fuel leaking out!)
These really are quite a simple system & pretty much infallable, my thoughts are has somebody re-wired the car for a stereo or similar & used a wire that goes to to the COR relay or FP relay.
Pull the relays in the engine bay & check for corrosion. I am aware of some older gen cars where a well worn ign switch did similar things, again that will show up by the relays not doing their thing. Could be something as simple as a bad earth but there are several on these to-from the engine to each section & to each part of the loom.
It would be an easy test with a power probe & a wiring diagram. Anyone local familiar with these 2JZ engines could help. Have a look on the Supra forums, I'm sure its an easy find.
These really are quite a simple system & pretty much infallable, my thoughts are has somebody re-wired the car for a stereo or similar & used a wire that goes to to the COR relay or FP relay.
Pull the relays in the engine bay & check for corrosion. I am aware of some older gen cars where a well worn ign switch did similar things, again that will show up by the relays not doing their thing. Could be something as simple as a bad earth but there are several on these to-from the engine to each section & to each part of the loom.
It would be an easy test with a power probe & a wiring diagram. Anyone local familiar with these 2JZ engines could help. Have a look on the Supra forums, I'm sure its an easy find.
cptsideways said:
Its easy to check if the fuel system is priming, crack open the fuel rail "in" banjo it should prime with ign on for about 5secs. (obviously this will generate a bit of fuel leaking out!)
These really are quite a simple system & pretty much infallable, my thoughts are has somebody re-wired the car for a stereo or similar & used a wire that goes to to the COR relay or FP relay.
Pull the relays in the engine bay & check for corrosion. I am aware of some older gen cars where a well worn ign switch did similar things, again that will show up by the relays not doing their thing. Could be something as simple as a bad earth but there are several on these to-from the engine to each section & to each part of the loom.
It would be an easy test with a power probe & a wiring diagram. Anyone local familiar with these 2JZ engines could help. Have a look on the Supra forums, I'm sure its an easy find.
Thanks for the replies.........it had a stereo replaced about 2-3 years ago, as they all do, the standard one always breaks! The new one came with a connector block that was wired wrongly, in that the perm live and ignition live were the wrong way around. However that was an easy fix, and so long ago that I can't realistically see any connection to this.These really are quite a simple system & pretty much infallable, my thoughts are has somebody re-wired the car for a stereo or similar & used a wire that goes to to the COR relay or FP relay.
Pull the relays in the engine bay & check for corrosion. I am aware of some older gen cars where a well worn ign switch did similar things, again that will show up by the relays not doing their thing. Could be something as simple as a bad earth but there are several on these to-from the engine to each section & to each part of the loom.
It would be an easy test with a power probe & a wiring diagram. Anyone local familiar with these 2JZ engines could help. Have a look on the Supra forums, I'm sure its an easy find.
I remember the ignition switch thing on the early cars, as far as I was aware they simply collapsed and wouldn't allow the key in rather than caused issues like this, but I might not be correct there? Also, I thought they had resolved it by the time the 2004 cars were about, but again, I may be wrong.
There are an awful lot of posts on various forums about this, it seems strange that people still seem to find a definitive reason for it to be so elusive. Thanks for your suggestions, I'll pull the relays after checking the fuel pressure, that still seems likely from the symptoms.
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