Loss of power under load

[a5gcd]

I am looking for ideas regarding an obscure ill that has befallen my once trusty Elan.

Under heavy but not extreme acceleration at medium revs there was instant power loss (but not like you get when the ECU cuts the fuel), backing off the throttle restored the usual sweet running. Checking found that code 33 (MAP sensor) was set.

After this occured I limped home with the car running rough even at lowish revs when under load especially up hills. Running on a light throttle was OK and I could even accelerate gently.

After clearing Code 33 it has not re-occured.
I have checked everywhere for air leaks and the waste gate for sticking.
I have changed the plugs and removed the Everest chip just in case.

All of this has been to no Avail, the problem is still there.

I will do a run tomorrow with elanscan and post the log.

Meanwhile,any ideas??

[Doug]

leak thru bypass valve (if you have one) ?

check ElanScan MAP and TPS readings and see if there's flat spots = sensor is dodgy

or one of those funky CAS things

[Monty]

Maybe that was an old code did u get the engine light when u had the got the problem?

I had a similar problem and it was the coils (no code), which got covered with water when the header tank over flowed Luckly i had a spare set of coils

Now if it nothing to do with the code 33 and u get no engine light it could be:

Spark Plugs
leads
coils
wire conections
earthing
HALL (Hall effect sensor) in the CAS

[a5gcd]

leak thru bypass valve (if you have one) ?

check ElanScan MAP and TPS readings and see if there's flat spots = sensor is dodgy

or one of those funky CAS things

Thanks Doug

I don't think I have a bypass valve?? I will do a scan tomorrow and post it.

Monty

Maybe that was an old code did u get the engine light when u had the got the problem?

I think you are right, I didn't get a light when it happened and it hasn't come back since.

leads
coils
wire conections
earthing
HALL (Hall effect sensor) in the CAS?

Would these affect it only under load??

Geoff

[John_W]

Geoff,
Under load is where these problems would first show up, because the system is , well, under load.

If it's just ticking over, all could still work fine even with some degradation to leads, coils, wire connections, earthing connections or the Hall effect sensor. But like everything, it's when you put things to the test that they fail.

John

[dans]

I had a similar problem, and as monty said above, coils were the problem.

Found this after i'd replaced plugs and leads as part of the process.

DAN

[WillB]

I'd go with the coil(s) as well, had similar fault on an S2 I had a couple of years ago

[a5gcd]

Thanks everybody, I have changed the coil pack and it has completely cured it. I am assuming one coil was breaking down under load.

I got an Esprit coil pack from the Lotus spares sale, it is exactly the same as the one I took off. Part No A910E6940F

Geoff

[bobface]

I'm having very similar problems, did you get any turbo boost at all whilst you were having issues? did the gauge blip at all?

S

[dans]

When I was having similar coil problems, it would occasionally work and would get the usual turbo. But when it wasn't working I think I saw very little on the boost gauge, and just as you'd expect to get boost the car would feel like it was stuttering, still accelerating, but a lot slower then you'd expect (bit like an na I expect!! )

Dan

[a5gcd]

I'm having very similar problems, did you get any turbo boost at all whilst you were having issues? did the gauge blip at all?

S

The car would run normally until the boost came on then the power would drop significally (it was running on 2 cylinders). If I backed the throttle it would return to running smoothly.

Sometimes when I was pulling up a steep hill the power would drop and it would spit and splutter. When this happened the gauge needle would flick up and down.

I hope this helps.

Geoff

ps non of these problems showed up on ElanScan except the obvious loss of power under acceleration and no fault codes were set.

[John_W]

non of these problems showed up on ElanScan except the obvious loss of power under acceleration and no fault codes were set.

It's not really the sort of thing ElanScan would pick up. Elanscan just lets you see what the ECU sees via its sensors. There's no sensor that tells you how fat a spark you're getting.

When the turbo starts its job, you get a denser charge in the cylinders, which means you need a good healthy spark to be able to jump the gap and ignite the denser mixture. That's why some problems show up when the turbo comes on song (eg wrong plug gaps, coil packs on the way out, or wires shorting) whereas you don't notice them if you're just pootling about. But ElanScan isn't going to sshow it.

John