Strange happenings whilst driving over speed humps

[dictys]

Strange happenings whilst driving over speed humps?

Last night stop the car to drop off a video at our local shops then proceeded to drive through a car park to exit. I drove over 5-6 large speed humps at about 2-5 mph and by the time I had finshed, my engine revs at idle were about 2000 rpm, they kept on going up and down then the "Engine Check" came on. I pulled over stopped the engine then restarted, no light everything checked out ok. Too make sure then I went for a hour long blast travelling at v.high and low speed down all sorts of roads, not a single problem, car went v.well no check light and no problems idleing.

Any views on this or is it a just a Lotus thing?

Rgds
Dictys

[lotusguy]

Hi,

There isn't necessarily any 'cause and effect' in what you describe. But, assuming that there is, I would be inclined to say that all that flexing caused some interupt to the ground (earth) wire connections, or that a positive lead somewhere in the wiring harness is frayed and shorting to earth when touching an earth source in the course of the body/chassis flexing. The real test would be to repeat the drive and see if the same things occur.

As a precaution, you might check all the ground connections, especially the engine block to ground for tightness and/or corrosion, worn insulation of other wiring which could have rubbed against an earth source causing a temporary short. Happy Motoring! Jim'85TE

[Trevyuk2002]

Definatley sounds like a connection issue, trick is finding where the offending little bugger is!
My SE turbo had been having these type of problems for ages, where i drive to work, i have to go over 5 completley non-lotus friendly speed 'mountains'.
The car would suddenly drive fine, then would feel like it had lost a cylinder, the car would stall at rest, the engine would rev high, then low, the check engine light boogied on down as if the saturday night fever soundtrack was playing.
Using freescan, the car kept on coming up with memcal errors, not a nice sight to see, and my wallet shivered at the thought of having to replace that!.
I know very little about the inner workings on these things, but i work in the computer industry and am fully aware that a connecter that looks connected, may not actually be, if you get my drift.
Last weekend, after d/loading Mikes vid of removing the ecu, i thought i would give that a go.
All connections looked ok when i started, i took the ecm chip out of the slot, blew on it, blew on the connectors, pushed it back in, redid all the bolts on the cover, re-mounted the ecu, reconnected the 4 coloured cables after making sure they looked clean, another good blow used there.....started the engine, and hey presto. Its been 4 days now since then, and she hasnt stalled once, the check engine light hasnt appeared once, she has been fine(touch wood).
So, do what i did, take it out, blow on it, reseat the chip and see if that helps.

[superdave]

Come on Dictys, surely this was a excuse you gave the missus just to have an hour long drive. I do this all the time with mine. It's the only way I can get to drive my baby, 'Just had to test the **** so took the car for a spin to make sure things were OK!'

LOL

Dave Walters
ps. just a silly suggestion but could it not be the ECU trying to adjust with the driving conditions? Depending how you dipped your clutch and applied your accelerator or if indeed you didn't and just released the clutch slightly on idle speed, the ECU may not be able to cope with this after a number of times. It sometimes happens with my other cars if Iam reversing up and down the drive applying the accelerator sometimes and sometimes not, just using the idle speed speed to move me, the idle jumps up then takes a while to resettle. Sorry can't offer any proper technical advise just hope you get to the bottom of your problem.

dictys said:

Strange happenings whilst driving over speed humps? Last night stop the car to drop off a video at our local shops then proceeded to drive through a car park to exit. I drove over 5-6 large speed humps at about 2-5 mph and by the time I had finshed, my engine revs at idle were about 2000 rpm, they kept on going up and down then the "Engine Check" came on. I pulled over stopped the engine then restarted, no light everything checked out ok. Too make sure then I went for a hour long blast travelling at v.high and low speed down all sorts of roads, not a single problem, car went v.well no check light and no problems idleing. Any views on this or is it a just a Lotus thing? Rgds Dictys

[dictys]

Well.... I had to take it out again last night just to make sure and the only problem is that everyone else seemed to drive so slow.

Really no problems, so seems a dodgy connection some where, I'll repeat the same series of bumps at the weekend and see what happens.

Thanks for the help guys.

Rgds
Dictys

[maigret]

Talking about Speed bumps, watch out for those in France.

We were on holiday passing through a small town. I saw the sign and slowed down to less than 30mph. Then, Oh shit.... on with the brakes. Crash, bang as the vehicle bottoms out the suspension then launches over the bump.

Note that this was in a VW Kombi!!!!

The Renault with rear suspension missing by the side of the road should have warned me...

There was a couple of old guys on a park bench set up to watch the bumps. They roared with laughter and toasted us with their wine glasses. Obviously a source of entertainment for them.