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ultimass
Original Poster
53 posts
28 months
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The idle is playing up on my LS7. Recently at no particular time (it has never done it until the engine is properly warm) it 'sticks' at various levels - around 1500, 2000, 3000 rpm. After a while it will go back to normal(1000rpm)and then 'stick' again as it did this evening.
Even if you blip the throttle, it makes no difference.
When it is not idling properly, the engine is not as smooth and the pickup is poor.
I have checked the linkage and butterfly's to see if it is sticking anywhere, but all is ok.
The ECU is Motec.
Any ideas on what could be causing the problem?
Martin.
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Steve_D
8,661 posts
127 months
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What throttle body is it and is it electric fly-by-wire?
Steve
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Storer
1,995 posts
84 months
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Lots of things to check.
Things that spring to mind are(in no particular order):
Inlet manifold bolts all correct torque.
Engine loom earths all good.
Plugs all tight (a bit of connector spray may help too).
Check your engine loom wiring and make sure none has got too close to something hot.
If it is heat related then it suggests that something, like a sensor or it's wiring, is breaking down when hot. Probably a process of elimination.
Good luck.
Paul
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738 driver
1,187 posts
62 months
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Air leak......... vac pipe (or bung) loose, split, missing ???
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F.C.
2,565 posts
77 months
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738 driver said: Air leak......... vac pipe (or bung) loose, split, missing ??? +1
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Steve_D
8,661 posts
127 months
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If it were an air leak you would expect it to be there all the time not random. Nore would you expect it to pick different revs to run at.
Temp related I could understand particularly with the plastic intake.
More likely a failing sensor. A data log from the ECU should find that.
Steve
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macgtech
607 posts
28 months
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Steve_D said: If it were an air leak you would expect it to be there all the time not random. Nore would you expect it to pick different revs to run at.
Temp related I could understand particularly with the plastic intake.
More likely a failing sensor. A data log from the ECU should find that.
Steve All of the above, but I would guess an air leak somewhere. Are you running lambdas, and if so in what mode? The other one that we have found is next to useless on the LS7's is the MAP sensor. I think the other sensors would simply throw up errors constantly on the ECU - are you able to read any fault codes?
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andygtt
6,394 posts
133 months
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do you have logging enabled in the Motec? its 195 plus vat and will allow you to review what the ecu is seeing rather than trying to find it while its running and thus changing constantly.
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ultimass
Original Poster
53 posts
28 months
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Thanks for all the info.
I have checked as far as i can for leaks and hot spots etc. and everything seems fine.
not had the problem for a while then on Sunday it happened again twice.
spoke to the guy who mapped the car for me and he thinks it may be the throttle position sensor and advised me to replace it. i have taken it off but there is very little identification only a 'c' symbol in a circle (like a copyright symbol) and the numbers 1107. Can anyone identify it and where i can buy one from in the uk?
Thanks,
Martin.
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Storer
1,995 posts
84 months
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ROWDYRENAULT
717 posts
83 months
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Martin: When the system goes into this fault mode again try the following: Go to the sensors page on the motec, look at throtle posistion on the screen as you move the throtle if it is not indicating a steady movement, or if you see no change in throttle posistion your Throtle posistion switch is at fault. It is a snap to change the TPS but you will need to reset the motec. If you need instructions on how to do that E mail me and I will send you my file. Lee
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