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Discussion Starter #1 (Edited)
On my 00 Esprit V8 TT,sometimes while downshifting/coming to a stop, the engine cuts off, there is also a delay in power when pushing down the gas pedal (usually when the car is cold). I read that the ECM on these cars tends to that but i'm not a 100% sure. There isnt a Lotus dealer locally but i called the closest dealer which is a 4 hour drive away and they told me there is a software update available but the service adviser didn't know if that update covers this issue, he simply said the software is for improved performance. Has anyone else been in the same position? I did reset the ECU by resetting the IACS and it didnt help. The issue happens only sometimes but it gets annoying though.
 

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you should try other culprit before pointing to the ECU. It will leave you no choice to troubleshoot once you zero in the ECU.

Could be dirty air idle valve - idle learning process - cracked vacuum hose - dirty throttle bodies (carbon deposit in the butterfly) - dirty fuel injector - bad tps - dirty fuel filter - bad fuel regulator........& more
 

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Discussion Starter #3
ok i'm gonna drive it a bit more and see if its the learning process. I barely drive the car, the other day when i finally got into the mood to drive it, battery was close to complete dead
 

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Always a good idea to drive it more. ;)

In case you want a great battery tender: [ame]http://www.amazon.com/Battery-Tender-021-0128-Plus-Charger/dp/B00068XCQU/ref=sr_1_1?ie=UTF8&qid=1345831585&sr=8-1&keywords=Battery+tender+plus[/ame]
 

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You need to keep a fully charged battery all the time. If the headlight pods move while you are starting the motor the battery is too weak and you are probably resetting the computer. If you do not drive the car you MUST keep a Battery Tender on it for at least 1 day every other week. It takes a few driving cycles for the ECU to relearn the idle trim tables. A shop with a Tech 1 can input a manual trim # to bump up the idle till the table is relearned. The upgrade you refer to is the HTU (High Torque Upgrade) and an '00 should have it already. It won't fix this problem anyway. If the stalling persists you may need a service with new spark plugs and maybe injectors. You can also have a bad idle motor or air leaks in the idle system. If you don't have a check engine light the computer is not seeing a problem. You may also need to adjust the throttle linkage. Most likely you just need to drive the car enough to rebuild the idle trim table and keep the battery fully charged so you don't lose it. If the battery is over 5 years old, replace it.
David Teitelbaum
 

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Discussion Starter #7 (Edited)
ok i drove it a good 40-50 miles today. runs MUCH better and no stalling. I got a check engine light though, ran the scanner on it and it gave a P0171 code (oxygen sensor bank 1 detects lean condition), going to clean the MAF, do i have to reset ECU after cleaning MAF?
 

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because you are doing some testing, I will clear the code now and keep testing - hoping the code will not come back. u r not out of the loop yet.
 

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Discussion Starter #9
because you are doing some testing, I will clear the code now and keep testing - hoping the code will not come back. u r not out of the loop yet.
should i do the full ecu reset again or just clear with scanner (I dont believe the scanner does a full trim reset)
 

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I would clear the code and see if it comes back. Possible causes include:
Fuel pressure problem
Air leakage
Bad injectors
O2 sensor poisoned
EGR stuck
This could also contribute to a bad idle so the idle may only be a symptom, not a problem. Next step would be to switch the post O2 sensors left to right and right to left and see if the trouble moves. That will tell you if it is a sensor problem or a system problem. If you have more than 40K miles consider replacing the primary injectors. The OEM injectors are known to fail by 50K miles. While you have the plenum off you can check for air leaks and see if the EGR is OK.
David Teitelbaum
 

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Discussion Starter #12
ok drove a bit more the light was off but came back on after a while.
Bank 1 is the passenger side correct? also where is the MAF located on these cars?
Car is only at around 30K miles.
 

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Oh, I thought you cleaned the maf? When you open the hatch and the engine cover, its located at the middle edge top of the plenum. The black rectangular plastic near the accelerator cable & the black plastic fuel lines.

Now, do what Jrealty said...switch the o2 sensor. I'm sure when you parked this car and not driven for so long there was no cel. Esprit is like a piano, it needs to be played or it will be out of tuned. Maybe the 02 sensor is contaminated.
 

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Discussion Starter #14
cleaned and switched the o2 sensors pre-cat.
I couldnt locate the MAF though, what does lotus call it?, i couldnt locate the part in the manual unless its called something else.
Also check engine light was off when i started the car, i'll take it for another drive :D
 

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The MAP was OK because if it wasn't you would have seen a code on it. Try not to touch things which you don't have to, if you mess up it will only add to the confusion. I suggested switching the O2 sensors because it is the easiest thing to do. Preferably you should scan them and see what is going on without touching them but that requires test equipment. Just your act of touching things could affect it, all it may be is just a bad connection in a plug and by moving the sensor you may fix it.
David Teitelbaum
 

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Discussion Starter #18
thanks for the help. I cleaned the o2 sensors and swapped them, hopefully its just an o2 sensor.
The engine light is off though and i didnt clear it before i started the car so i'll drive it for a few days and see. I was also reading that it could also be the gas, i was reading on another forum where some esprit owners were getting the P0171 code when running on Shell gas with ethanol, not sure if there is any truth to that
 

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What kind of scanner are you using?

I downloaded the free V8 software called ODBII + Lotus Esprit V8, and you can see all sorts of things with it. You would be able to see the exact voltages coming off of the O2 sensors in real time while driving if you wanted.

Regular $50 scanners are no where near as useful as this software.

http://www.lotustalk.com/forums/f164/odbii-reader-best-option-117581/
 

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Discussion Starter #20
sorry forgot to end this. Everything worked out fine, the car just needed to be driven (the drained battery kep resetting the computer and the car had to relearn everything all over again)
 
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