Help! Car sat in the rain and now has idling/speedo issues.

[6i9]

Those of you in the southern california region know its been raining like piss for the past couple days. During the day I left my car parked on the street while the downpour was going on. Tonight I went to out to go get dinner and on the highway there was some trffic so I coasted in neutral to a stop. As I did this I noticed the idle ws jumping up and down between 1000 and 3000 rpm without any throttle inputs. This was making me burn the clutch and causing me to stumble in 1st gear starts.

Soon after this, the speedo began going crazy jumping from 0-40mph frantically. I pulled off the hwy and parked. Turning the car off and on seems to fix the problem for a short while. But as I set off again the same idle problem shows up.

Any ideas why this is happening? Iveread some people have identified the ac relay switch as the culprit (i did defrost my windshield with the ac). Another search showed someone mentioning water accumulation somewhere in the engine bay.

Please help, any responses are greatly appreciated

UPDATE: Now there is a CEL that has just come on. Joy of joys. No OBD scanner so I cannot read it either, and Autozone no longer rents them out

[jtrealty]

What year and Model? Sounds like a typical Lucas system to me! Imagine that, a car that can't take the rain, built in a country where it rains a lot!
David Teitelbaum

[lotuselise7]

Damn Chris, that sucks to hear. Hopefully its an easy fix!

[6i9]

Yeah thanks David, this rain is starting to piss me off. Very unwelcome weather

Originally Posted by jtrealty

What year and Model? Sounds like a typical Lucas system to me! Imagine that, a car that can't take the rain, built in a country where it rains a lot!
David Teitelbaum

2005 Elise. What Lucas system are you referring to?

[tesprit]

He is joking by referring to the old Lucas (Prince of darkness) electrical systems found on vintage British cars of which your car has none.

I would suspect you are having a problem with the wiring harness connection at your ECU. It is possible water got in there from the soaking rain and is screwing up the CAN bus which is why you are getting the weird instrument cluster activity as well as the poor engine running. Do you have a dry place you can put the car to allow it to dry out? If you do, let it sit for a day and then see what happens when you drive it again after the engine compartment has dried out. In the meantime, you might want to try to get a hold of a code reader and see what codes the ECU is throwing. Having the codes read might allow you to pinpoint the problem faster. Good luck!

[6i9]

Thanks for the insight. I am going to park my car in a dry area away from the rain tonight. Hopefully in the morning itll have dried out. Where can I check the harness connection (where is the ECU located in the engine bay?)

[muskaroxs]

Originally Posted by 6i9

Thanks for the insight. I am going to park my car in a dry area away from the rain tonight. Hopefully in the morning itll have dried out. Where can I check the harness connection (where is the ECU located in the engine bay?)

Open the Hatch and look straight at the firewall now look left and there it is! Has a lotus logo on it and is behind the intake rubber tube.

[Stale_Hotdog]

what area are you in I have an ob2 scanner if you want to read the code.

[6i9]

I live in Santa Monica. I'll send you a PM

[jtrealty]

If the car is throwing codes because of moisture in the wiring, knowing the exact codes will not help. Drying out the car is probably the best advice. I would go a little further and say you should remove the ECU plug and blow out any moisture you find, let things dry and then reconnect the plug. If you are lucky and it "fixes" things all it will take is a little dielectric grease in the ECU plug to prevent this from happening again. The Lucas reference in your case is just a joke. On older cars it is more than a joke. It is a reality that owners with older Lotus's have to live with. For instance the company motto of Lucas is "Get home before dark". There are a whole lot more, you can look them up on Google. BTW be careful with the plug.
David Teitelbaum

[6i9]

I let the car dry out overnight, and for a few minutes in the morning, the idle seemed normal. However, the problem came back soon afterwards.

I inspected the engine bay as charliex mentioned here Diagnosing a vacuum leak

I checked the connections and found that if I apply pressure to this particular connection area, the idle calmed down. Not sure if it's coincidence. But, the problem comes back after I start driving again. Can someone tell me what I am pressing on in the video? I cannot identify the part in my owners manual

http://www.youtube.com/watch?v=FzGp_goCvz0

[stinkyonion]

cant really remember what everything looked like before the supercharger install, but im guessing that is the air flow sensor. Common source of air leak, perhaps when you are pressing on it the leak goes away and idle improves. People have caulked around it with silicone and the like. There is a thread here for building a pressure tester for the intake side which would show a leak with hissing sound. Of course, this would not cause your cluster to go haywire. Im still agreeing with the electrical issue somewhere.

[6i9]

Thanks for the input. That makes sense if that is the MAF sensor, as there are a number of threads that point to a dirty MAF as causing high idle. Is there any particular way to disconnect the sensor to clean the contacts with some brake/parts cleaner? I dont want to break the plastic tabs, they seem pretty flimsy.

The speedo issue I haven't a clue on though. I wouldn't say they are separate issues, since the speedo only goes out of whack when the idle acts up...

[Doghouse]

For those not familiar with South East Texas weather, we get very heavy rain from the combination of cold fronts off the Plains mixing with tropical moisture coming off the Gulf of Mexico. Rain of 2-3 inches per hour is not uncommon, so we know about rain.

The electrical connections in the Elise / Exige between the ECU, the dash and other engine sensors are prone to moisture issues when it rains hard. When that happens the car begins to 'freak out' just as you have described.

Solution: Dry out the car as has been already suggested. Unplug the ECU connectors. While they are drying out, go to the local auto parts store and get some di-electric grease (a little pack should cost you like $2). CAREFULLY apply some dielectric grease to both the male and female connectors. I have found that a piece of stiff paper is a great way to apply thin layers of di-electric grease to the male connectors. Re-plug in the harness and this should solve any moisture problems.

Knowing the engine code will help you figure out which sensor needs to be treated (i.e. disconnected, dielectric grease, re-connected). In my own experience, the connectors to the MAF and the throttle position sensor are subject to getting soaked and this treatment magically fixed the engine code problem.

If you can afford it, buy an OBD-II code reader. It will save you many hours of saying "WTF, my car is dead." and will pay for itself very quickly. Also allows you to check emissions and the overall status of your car before you take it into the smog check place. Knowing before you go can save you serious money because you don't have to pay someone to tell you "Sorry you don't pass. You have 10 days to get it fixed and retested."

Good luck.

[6i9]

Thanks Doghouse. Is there any particular care I should take before disconnecting the ECU or the MAF sensor? Also, where is the TPS located?

In addition to the di-electric grease, do you recommend spraying some brake cleaner on the connections? I believe a search said this help clean the contacts.

I am meeting Stale_hotdog tonight to read the code and reset it. I will definitely invest in an OBD scanner though.

Thanks for all the input so far. Any other comments/thoughts are welcome

EDIT: I have identified the part I was applying pressure to in the video above. It is not the MAF sensor, it is the VSV (airbox flap valve vacuum switch). Info via http://www.sandsmuseum.com/cars/elis...ake/index.html

[6i9]

After borrowing stale_hotdog's (thanks again man) OBD scanner, the following codes were read:

P0508 - idle control system circuit low
P0500 - vehicle speed sensor A malfunction

Codes were cleared. During the drive to meet with him, the idle issue did not come back. Crossing fingers

[Monsi]

when my car got really wet a month back it developed a dash squeak that was louder than any other noise the car made... after about 45 minutes sitting in the sun it went away

[Doghouse]

Originally Posted by 6i9

Thanks Doghouse. Is there any particular care I should take before disconnecting the ECU or the MAF sensor? Also, where is the TPS located?

In addition to the di-electric grease, do you recommend spraying some brake cleaner on the connections? I believe a search said this help clean the contacts.

I am meeting Stale_hotdog tonight to read the code and reset it. I will definitely invest in an OBD scanner though.

Thanks for all the input so far. Any other comments/thoughts are welcome

EDIT: I have identified the part I was applying pressure to in the video above. It is not the MAF sensor, it is the VSV (airbox flap valve vacuum switch). Info via Lotus Elise Modification, Cold Air Intake Install

IMHO, and perhaps CharlieX is the best person to answer, I use a can of spray terminal cleaner designed for electronics. Not that expensive compared to brake cleaner and presumably the fluids are cleaner / designed to not screw up sensitive electronics. I have no idea what they might use in a brake cleaner, especially some of the citrus based (bio-degradable) versions, and how it might impact your electronics. You are on your own with that decision.

But really all that is needed is some time for things to dry out and a little di-electric grease. If it is you DD, I really feel for you. It sucks when you DD is non-op and yet it looks like it should be going 100 mph!

BTW if you don't know which sensors are where, spend the $25 dollars and download the Lotus emission manual. It has LOTS of useful information on things other than emissions and is very useful if you plan to do any self-help on these cars.

Lastly, know your limits as to what you can do no problem, what you probably can do with the help of reference materials, and when you need to call in professional help. Don't be too intimidated by the fancy fiberglass shell and aluminum frame, under the skin this is a Toyota motor and trans and LOTS of people work on those.

Good luck and stay dry...

[theveganporkchop]

I drove my car in that same LA downpour and my car won't start at all now. I went out and bought a OBD scanner and my car read a P0508 as well as a few others codes. Is that a common problem for a rain soaked Elise?

[TimMullen]

Originally Posted by theveganporkchop

I drove my car in that same LA downpour and my car won't start at all now. I went out and bought a OBD scanner and my car read a P0508 as well as a few others codes. Is that a common problem for a rain soaked Elise?

Not common that I know of. From the Factory Service Manaual (everyone should download a copy for $25 from LCU):

Idle Speed Control
P0506 Idle Air Control System RPM Lower Than Expected
P0507 Idle Air Control System RPM Higher Than Expected
P0508 Idle Air Control System Circuit Low (prior '06 M.Y.)
P0509 Idle Air Control System Circuit High (prior '06 M.Y.)

Description
Prior to '06 M.Y. the ECU controls the air entering the engine with an idle air control (IAC) valve. To increase the idle the ECU commands the IAC to open up. This allows more air to bypass the throttle blades. To decrease the idle speed the ECU commands the IAC to close up. This will reduce the amount of air bypassing the throttle body. The ECU performs low and high circuit checks when it is activating the component.
For '06 M.Y. onwards, the electronically controlled throttle needs no IAC, as the ECU commands the throttle valve itself to control idle speed.

Component connections (prior to '06 M.Y.)
Connector Description ECU Pin ECU Connector
1 Idle air control value 35 52 Way
2 Battery Voltage - -
3 Ground - -

Malfunction Criteria
P0506 – This code is set if the engine fails to achieve the desired idle speed by more than 100 rpm.
P0507 – This code is set if the engine fails to achieve the desired idle speed by more than 200 rpm.
P0508 – This is set when the ECU does not get the expected feedback (prior to '06 M.Y.).
P0509 – This is set when the ECU does not get the expected feedback (prior to '06 M.Y.).

Enable Criteria:
• Engine at idle speed
• Battery Voltage between 10 – 16 V
• Idle speed learn limit ± 15%
• Timer expired 5 seconds

Monitor: Continuous

Potential failure modes:
• Throttle body sticking (not fully closing) (prior to '06 M.Y.)
• Connector / wiring corroded or loose connections (prior to '06 M.Y.)
• Throttle linkage / cable binding (prior to '06 M.Y.)
• Induction system air leak
• Excessive engine load from front end accessory drive system, e.g. water pump seizing

Notes:
The MIL will be illuminated if the fault is present for 2 consecutive trips.