2004 Elise - intermittent power loss

[steve_otolith]

Hi,

I've been chasing my tail with this issue for a while, I'm posting it here, where there are a lot more Toyota engined cars, in the hope that someone has seen this problem before.

I've a 2004 Elise 111R I've owned for three years. It has a 2bular exhaust and TRD induction. It has recently been suffering an intermittent loss of power at high revs. Sometimes it is fine, sometimes it isn't. This is with the engine properly warm, obviously.

I have just had the ECU reflashed to lower the cam change point. Since refitting the ECU, the problem has been continuous - the cam change happens (at 5700rpm in my car), the engine note changes, the car continues to accelerate briefly, but then bogs down and goes completely flat from 6000rpm to a little over 7000. It then picks up a bit and starts to accelerate up to the shift light. I was pretty confident that this was the result of the pre-existing problem and not caused by the reflash, but it was hard to be sure.

I had it in to my Lotus specialist yesterday. On the way, it threw a CEL while sitting in traffic. The diagnostics said misfire, but after clearing the code it didn't do it again. They have changed the plugs, looked at the cat, checked the fuses, checked over the sensors, problem persists.

I took it out today, warmed it through and - problem gone. Bit of hesitation the first time I took it over 6000rpm, but then perfect after that. Drove it for about 7 miles, all working properly, lowered cam change and all. Parked up. Came back ten minutes later. Problem is back. At least I know for sure it isn't the reflash, it's definitely the same issue it had before.

This is what it looks like:

111R High Lift Cam Problem - YouTube

111R High Lift Cam Problem - YouTube

I don't think it's a problem with the VVTLi mechanism - it sounds as if it engages and it revs right through to over 8000rpm.

I'm wondering about coils. They've been out, cleaned, greased. They're an expensive thing to try replacing as a diagnostic exercise, though.

Anyone seen this before?

[David Craig]

I had a loss of power problem on a Corolla that turned out to be a dirty fuel filter. The power loss was to the point that the car would almost stall out if I tried to accelerate quickly. The fuel filter had between 60,000 and 100,000 miles on it.

A new fuel filter was only 10 bucks and it solved the problem completely.

[steve_otolith]

It does feel a bit like that. I hope it isn't, because the fuel filter is integral to the pump, you have to drop the fuel tank to get at it!

[steve_otolith]

Just reading something which suggests that broken lift bolts can cause intermittent or partial loss of performance - anyone experienced this?

[Vulcan Grey]

The coils for the coil on plug are arcing into the tubes in the head.

Coil Pack Arcing
Di-Electric Grease on Spark Plug coils?

Or it could be the cam
Misfire @ cam-switchover + P1301 on '06 Elise
First Engine Light Code

[steve_otolith]

I thought coils, but my specialist reckons it would be recording error codes - after clearing that misfire code there have been no more codes logged.

If it was cam wear, would it not be constant? The problem sometimes clears and it runs perfectly for a while.