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Lotus in the Peak
28th - 30th June 2024

Lotus Elise S (Toyota 1zz) startup issue - need help or advice


McQuack[BE]

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Hi all,

I am the happy owner of the Lotus a Lotus Elise S, the one equipped with the Toyota 1ZZ engine. Since some time I got issues when starting up the car in very hot conditions or with warm engine. The car has high and irregular idle revs and it will not react properly to throttle. If I apply a little throttle the revs will drop... however if I apply full throttle the engine will first hesitate then settle around 3000 rpm. As you can imagine it is impossible to drive it properly... When this happens I also get the 'Check Engine' light on (MIL?). The only solution is then to wait for the car to cool down and it would then function again in a normal way.

Since a few days I had that issue again and decided to get rid of it so I went to Lotus (Belgium - Antwerpen) last week. The tech in the workshop did something to the ECU  (clear codes maybe) so the MIL disapeared and the car worked properly again. I got back home and, the day after I took the car to do some shopping. When I got back to the car after the shopping it started agin to have that same issue and now that issue doesn't seem to disappear when I let it cool down :-( The check engine light is staying on permanently and I am unable to use the car...

Would anyone here now what I should do to improve this situation ?

 

I am adding some pictures of the car.

 

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My money would be on a faulty throttle position sensor (TPS). This determines the position of the throttle and sends that information to the ECU. Any fault here could cause idle speed problems. Rapid movement of the throttle is also detected by the TPS to correct for the lag from the manifold pressure sensor and a fault would cause hesitation on harsh throttle application. It is further complicated as the ECU will likely have a TPS calibration mode which could get very confused by a faulty TPS.

Personally I would do these things in this order:

1. I would connect an OBD2 sensor to check first for error codes (I use a £3.95 bluetooth sender from eBay). 

2. Locate the TPS and give it a wiggle and a gentle tap in case you have a dodgy earth, common on Elises.

3. Attempt to recalibrate the TPS, sorry I don't know how on a ZZ Elise.

4. Remove and test the TPS with a resistance meter or perhaps a scope if you have access.

Nice car by the way.

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Might need to revise my comment ^^^, I'm a bit S1 centric. Turns out the 1ZZ Toyota is way more complicated. Seems there is a pedal position sensor, some complicated throttle bodies and throttle position sensors on the side of the throttle bodies. I would still suspect one of these three but probably need to bow out quietly until a series II chap comes along. In the meantime if you want to rule out the TPS here's the testing data:

 

Screen Shot 2017-08-16 at 21.49.01.png

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Ok i will do that and let you know the feedback. In the meantime I ordered an OBD2 Bluetooth dongle (this one here http://www.lemurmonitors.com/)
It should be delivered early next week. Anyway, now I am off to a Toyota to get the exact codes and maybe some advice from the techs there.
I will keep you posted...

When I comeback I will try to locate the TPS and perform the test.

Cheers

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Ok, these are today's new. 

In the morning I visited a Toyota dealer who refused to diagnose the car (despite having told me yesterday to come by on the phone). The good news is that I went there without trouble: no rough idle whatsoever and normal power delivery/throttle reaction.

After that I found a small mechanic shop who agreed to diagnose Elise tomorrow morning, their agenda was fully packed for today... The guy had a nice Testarossa in the garage :cool

I did all that without stopping the car but eventually I had to do actual shopping so I needed to leave the car on the parking lot and, to be able to close the doors I had to turn off the engine... I bought a multimeter (to test the TPS) and when I came back to the car, it again had the issue on start up (expected).

Finally, we craweled back home pretty slowly (10 or 20mph).

So, if all goes well, tomorrow i'll be able to share the error codes with you guys ! (fingers crossed)

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Ok, I just came back from that independant workshop where I had the car connected to an ODB reader (it cost me 25€...). Here is the codes I got on the car:

- P0638 : Throttle Actuator Control Range/Performance B1
       detazils here => https://www.obd-codes.com/p0638


- P2104 : Throttle Actuator Control System - Throttle actuator control system is in FMEM mode of forced idle
      Possible causes - List of elements that might trigger the appearance of this code
           PCM damaged
           Multiple ETC system faults
           Bad APP sensor
      Diagnostic help - Some tricks to help us for the diagnosis of the failure
           DTC indicates FMEM condition, and can be set in combination with DTCS P2121, P2126, or P2131 and P2111 or P2112. When P2104 is set in combination with P2121, 
           P2126, or P2131 repair Accelerator Pedal Position Sensor faults first (pinpoint test DK), when the P2104 is set in combination with P2111 or P2112 repair the Electronic 
           Throttle Body faults first (pinpoint test DV).

Any thoughts ?

By the way the car is from 2007, this may help. I also found an interesting post here from a guy with similar issue: http://www.lotustalk.com/forums/f101/p0638-p2104-cel-unable-move-421321/

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If I've read those codes correctly then:

P2014 - This is just status from the ECU telling you that's it's gone into the limp mode due to some other fault. 

P0638 - I think this is the root problem.

I'm guessing the toyota model has a fly by wire accelerator in which case there is a stepper motor driving the throttle opening rather than a cable. The 638 error is complaining that the ECU has set the throttle position but the TPS is reporting back a different position. So either the throttle isn't being set correctly by the stepper motor or the TPS is reporting the wrong value. Think I'd test that TPS to narrow it down a little and then (assuming it's OK which it probably is) I'd check the price of a new throttle body before taking the old one off and having a bit of a clean and spruce up anything obviously gummed up.

If you do get the throttle body off or it's easy to photograph post a picture as I'm kind of curious now which one it is.

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Reminds me of something very similar that happened to my daily a few years ago, it got so bad in the end that the car would stall then refuse to start.. 

The fix for me was to remove and thoroughly clean the engines throttle body valve (this car was a drive by wire, there was no mechanical cable between the accel pedal and TB).

These valves don't appear to close completely under normal conditions - they always allow a small amount of air to pass on idle and start-up. Now, if the small air gap is gunked up (as was in my case), even by a small amount, then the ECU ends up pulsing the valve to prevent the engine from stalling at tick over. 

However, if yours is cable driven then the TPS/wiring is definitely the likely candidate and first thing to replace - do they cost very much to try??

Ol  

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6 hours ago, Digimap2k said:

Keep us posted. If all else fails you can always swap it for a whole new level of problems and buy the Testarossa.

I think that is out of reach for the time being :-D

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7 minutes ago, themightylad said:

Reminds me of something very similar that happened to my daily a few years ago, it got so bad in the end that the car would stall then refuse to start.. 

The fix for me was to remove and thoroughly clean the engines throttle body valve (this car was a drive by wire, there was no mechanical cable between the accel pedal and TB).

These valves don't appear to close completely under normal conditions - they always allow a small amount of air to pass on idle and start-up. Now, if the small air gap is gunked up (as was in my case), even by a small amount, then the ECU ends up pulsing the valve to prevent the engine from stalling at tick over. 

However, if yours is cable driven then the TPS/wiring is definitely the likely candidate and first thing to replace - do they cost very much to try??

Ol  

Mine is a drive by wire. I think I saw some posts from another guy who had the Throttle Body changed and it was north of 1000€ if I recall well ...

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Those throttle bodies are confusing, there are K-Series parts which seem to be up around 800UKP as I think they might be custom jobs with four bodies, trumpets and shiny bits. The toyota part looks a lot less exotic as it's the same as fitted to many 1ZZ's, problem seems to be that even within the 1ZZ-FE there are lots of different configurations around the same throttle body based on some cars being cable, some wire and lots of different shapes for all the toyota variants. Trick will be to work out which one Lotus used, surprisingly little information on this even over on the seloc tech wikies. 

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Hello guys, I have some news for you.
As already mentionned, I bought an ODB Reader and I must say it's working quite well. I'll attach some screen shots. 

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Besides this, with the help of a friend, I removed the throttle body and cleaned it with wd40 (couldn't find carburetor cleaner). There was some black dirt in it but not much. It was pretty clean. We also tried to test the actuator/sensor with a multimeter but this wasn't succesful. The only explanations I found (one of the earlier post from Digimap2k) on the ohms open & closed is for a different type of Elise throttle body so it could not be applied. We also cleaned the mass air sensor in the air box (also with wd40, not sure that's a good idea).

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After putting everything carefully back together in the engine bay, and adding some coolant fluid lost in the operation (throttle body is watercooled whatthahell.gif) we started the car succesfully. The MIL was gone! We then decided to go for a quick ride, get the car to temp, make sure all is ok the stop the car and start it again while hot. No problem , everything fine.

A bit later, my friend who actually is the co-owner of the car, needed to go fetch someone at the tube station and he decided to use Elise (who could resist?). When he trie to start it, MIL was on and the erratic idle was there again. facepalm.gif Disapointed, I decided to open the engine bay and disconnect the throttle body connector, wait for a few seconds on connect it back. This manipulation made the idle normal again ! 

Conclusion, I definitively have an issue with the electronic part of the throttle body. Do you agree with that statement ?
This doen't seem to be repairable: the electronic box is riveted so I suppose that opening the thing would cause damage to the internals and prevent any future usage...

I will try to source a second-hand throttle body from a 1ZZ. THere are some available on ebay (from uk) at around 60€ but i'll try first to find it in Belgium (easier for warranty).

Does that sound like a good idea to you ?

Cheers

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