bullstarz
Full Member
I don't believe in miracles, divine intervention or good luck............. I rely on them.
Posts: 135
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Post by bullstarz on Aug 15, 2020 17:23:04 GMT
I’ve been away from my car for about 10 weeks, it’s not been started and left outside but well covered and will sheltered. Well back to the car obviously it wouldn’t start, the battery is just that little bit too low, a few hours on the charger and it’s fine. However, I noticed that the tickover was quite high, where when I left it all those weeks ago it was about right. I did have an idle control valve which would raise the tickover when the engine is cold, lowering it to 850 to 900 rpm once warmed up. It can also increase for when other things cause a load on the engine, which to stops it stalling. First thing I did was to remove the control valve, as I thought this may be sticking, so blank the pipe off but it made no difference whatsoever. But I checked all the pipes coming off the inlet manifold to make sure they weren’t leaking, everything seemed fine. Then today I took off the main pipe to the throttlebody, Just to make sure that the actual throttle was closing correctly. It’s also gave me a chance to adjust it so it was fully closed when the foot is off the throttle.
However having done all this it’s still ticking over at about 1750 rpm, far too quickly. The air fuel ratios was slightly rich, which would indicate that there wasn’t a leak, making the engine rev. But for some reason it still revving high and I can’t find the fault.
It may be just the warmer temperature than it was three months ago, making the engine run quicker at tickover, but have really no idea. next step will be to plug the laptop in and just change the fuelling and try and bring the tickover down that way.
I have got his niggling thing at the back of my mind, somewhere, that I’ve ever looked something or missed something very simple. This is normally the case when you stare at something and you just can’t see the wood for the trees.
Other than just altering the fuel and try and bring the tick over down to a reasonable level has anyone got any ideas what could cause this to change. |
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Sapphirestag
Full Member
Letting your tyres down at the moment. I was also a target of the Fiefdom controlling the SOC forum
Posts: 129
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Post by Sapphirestag on Aug 15, 2020 18:52:05 GMT
Difficult to know where to start with what you have done to the car? my initial thought is its' possibly defaulting to fast idle due to incorrect inputs from coolant / air temperature sensors ? It thinks its starting from cold ? Just trying to chuck ideas your way.
Another thought is are you still running Cat's on it, if not what did you do with the closed loop, could there be a problem there.
I once also found, after a lot of hard work, corrupted software in an ECU. A re flash cured that.
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bullstarz
Full Member
I don't believe in miracles, divine intervention or good luck............. I rely on them.
Posts: 135
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Post by bullstarz on Aug 15, 2020 19:42:53 GMT
Thanks.
I never had the cats fitted but it’s running a Link G4 xtreme ECU. I have new Link G4X xtreme ECU to put in but there is a lot to sort out before I put it in, as it fly by wire.
I was hoping to iron out all the small issues with this ECU before fitting the new one, just to limit the amount of problem that I will have. Which I know will be of epic proportions.
I’ll plug the laptop in next week, hopefully that will shine some light on what’s going wrong. More than likely a human error, like you said coolant sensor unplugged.
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Post by Flying Farmer on Aug 16, 2020 19:47:58 GMT
Is it running off a throttle position sensor or an air flow meter?
The engine needs air to run and that can't get down a wire.
When plugged in the TPS should read zero percent with the throttle shut, if it isn't then something has changed although you say you have physically checked the throttle is shutting.
I have no experience of air flow meters (apart from the old flapper type Rover systems) but provided leaking air is being pulled through the meter it will correct the mixture for the airflow involved and hence it won't go weak.
Just wonder if you have some sort of crankcase ventilation system that has a stuck open valve and it is drawing the extra air in that way?
Neil
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Post by richardthestag on Aug 16, 2020 20:00:44 GMT
the hotwire lucas system is pretty bullet proof too
Bullstarz issue is why I just do not do modern cars
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bullstarz
Full Member
I don't believe in miracles, divine intervention or good luck............. I rely on them.
Posts: 135
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Post by bullstarz on Aug 16, 2020 20:55:23 GMT
The engine takes most of its data off the map sensor but it also uses the TPS as a reference. I’ve not plugged it into the laptop yet but everything was fine and the TPS were set up correctly. I know that if the TPS isn’t giving a correct signal, then the ECU goes into default mode, for that it is max fuel. I did check this on Saturday by unplugging the TPS and the engine stopped due to over fuelling . yes the throttle is physically closing, you can feel the suction. Also I didn’t hear it drawing air in from anywhere else, such as the inlet manifold gasket sort of area.
As for the crankcase ventilation have no idea on that one, I can’t recall that there is any valve or anything, but both rocker covers have a breather that goes into a catch tank. There was nothing being sucked or blown out of those hoses.
The new ECU’s are very complexed and to throw up Loads of issues where the old style of things either ran or didn’t. But the link ECU’s are extremely good. I think the only time they haven’t worked correctly, it’s been due to one of my many errors.
Hopefully tomorrow I’ll get my laptop on it, with a bit of luck It will show something glaringly obvious that’s causing the issue. Otherwise it will be another day of achieving absolutely fuck all.
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bullstarz
Full Member
I don't believe in miracles, divine intervention or good luck............. I rely on them.
Posts: 135
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Post by bullstarz on Aug 20, 2020 21:19:52 GMT
I plugged the laptop into the ECU and all seemed fine. So once again I checked all the hoses for any leaks and there is nothing. But I did notice, as I switch the engine off, you could hear a sort of suction noise. But the noise seemed to be coming from underneath the inlet manifold. I knew there was a bit of Lexus magic lurking underneath, that I thought this may have gone wrong. So I took the Inlet manifold off, which isn’t the easiest of jobs, although it is a lot easier than the original stag inlet manifold. Once everything was off I couldn’t see nothing at all wrong, however there is a small air solenoid , this is controlled by the ECU to do some magic in the inlet manifold. This seems to be stuck open, so all of the stuff was removed and the hose blanked off. All back together and the tickover was very very low, a quick adjustment and this seems to cured the problem. A long winded affair just to replace electrical solenoid or isolate it. One that wasn’t even wired into the ECU, another few days wasted on something which shouldn’t have gone wrong.    |
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