Occassional boost to 0.75 bar

[Pete_8lan]

Since returning from holiday (and totally flat battery) my Elan boosts to .75 bar for a few seconds under hard acceleration in 2,3,4th gear. After about 1 to 2 seconds it drops back to normal max of about .5 bar.

Could this be a faulty earth or something more?

I was away 3 weeks and when I returned the battery was very flat, I know when I had an elise if the battery went flat you had to leave the car running for a minute for the ecu to remap, could this be the problem.

Was out today (in glorious weather) for a long run still doing it, but not so much when realy warm

Thanks in anticipation for useful suggestions.

[Doug]

well, it is possible that you are witnessing the transient overboost allowed by the ECU -- otherwise it could just be a slightly less than perfect ground wire from the boost transducer instrument . . .

keep your eyes on the road

[Doc Fizzix]

Just a thought. I know this sounds crazy but I always like to check the bearings on the turbo when ever I feel there is a problem in the system. Just for fun, pull the intake and feel for play on the turbo's shaft.

I had a car years ago that would boost real high but could not hold the boost very long. I found out the bearings had given way on the turbo, it would spin up and then become unstable (out of balance) and then the boost would fall back down.

I am in no way saying that is your problem but from experiance I always like to check it and rule it out.

[Nige]

Slightly sticky wastegate perhaps, particularly if the car has been unused for a little while?

[Pete_8lan]

Will have a better look at the week end.

It seems to be running well enough - so hopefully sitting in a garage for 4 weeks is the culprit.

Good idea to keep my eyes on the road.

Also got Friday off so will give it a decent run down to the coast and see if that blows away the cobwebs.

Thanks