suddenly - a lack of power

[Quicker 2]

folks - looking for some insight. I have been reading a lot of old threads...

about a month ago, my Esprit suddenly 'began' having a lack of power in the middle of a drive home. the engine will rev through the rpm range but a little 'slowly'. It will not make more than a 1/4 of the normal boost levels. Getting going from a dead stop is a little 'tricky'....

then - next time I start it - all good. Then two drives later - half-way on the drive home - bang, same issue.

I havenot been able to catch it near the garage - so I have not had a look at it on the lift or run Freescan on it while the problem was there.

Here is what I know:

- although it feel the same as driving with the EBPV - athough part of my troubleshooting I wired it open

- I though I my have an issue with the small vacuum line running to the manifold (where I t-d it for the dump valve) but I have replaced it

- it's not clutch related since it will stall if I can't give it enough beans

- it's got colder in Austin lately - so may/maynot be linked

I'll hit it with freescan - any thing to specifically look at?

[Vulcan Grey 257]

Spark, fuel pressure, and compression.

Ive had the same symptoms from bad spark plugs, and another time from 2 bad injectors. Last time it was a blown head gasket.

[Greenfort 0]

Had the same happen to me... need to figure it out myself, but according to Kim, it´s prob something to do with the sparkplugs - sounds plausible to me. Something about the wires popping out of their sockets. think it happens right below the carbs (yours has carbs too right?).

@Vulcan - does a blown HG rly produce such symptoms? Wasn´t aware... getting me all nervous here :-)

[Bibs 11,728]

Blocked cat? Blowing MAP sensor pipe/leaking elbow?

Freescan (or ideally Espritmon) will tell you

[Rich H 4]

If it's not making boost how about the turbo?

A sticking turbo would restrict the exhaust like the EBPV, blocked cat would do the same.

Head gasket would normally manifest itself as a loss of coolant, mayo in the oil and/or coolant, steam from the exhaust or one steam cleaned spark plug.

Can the Esprit run with a MAP sender pipe off? The S1 Elise switches to TPS only.

[Bibs 11,728]

Runs like there's a hole in a piston!!

You can build rpm very slowly up the range but any kind of demand sees it die.

[Quicker 2]

I have the laptop with me today - so I'll freescan it on the drive home (hopefully).

Some days it runs perfectly - so I don't think it's a mechanical issue like hole in piston.

The coolant is fine - no loss and no oil.

I have a hollowed cat. - maybe map?

Fuel pressure and spark are the path I guess.... (same as always)

I checked the waste gate - with the car off and it seems aligned appropriately (used the manual)

It's almost like the wastgate get stuck open - but that would be unusual - right? (stuck closed I would get - however it seems to move freely and the diagram appears to be working)

Edited February 14, 2012 by Quicker

[cjtpb13 12]

Lou,

If you recall my dealership fiasco I had what seemed like similar symptoms. Ultimately what is was that the flapper valve at the waste gate was not closed. From the outside view and operational check of the wastegate all seemed fine. It was not until I undid the exhaust downpipe and ran a videoscope into the turbo did I see the wastegate flapper valve stuck open slightly. Eve after removing the FOD I still had an issue due to the flapper rivet retaining washer had been broken off and the flapper was misaligned. Causing a intermittent boost, or lack thereof, issue

[Rich H 4]

My waste gate was not closing fully either and was 'jingling' on the seat, leaking boost, at all RPMs, a quick tweak of the waste gate actautor arm sorted it out. This assumes your car has an integral WG.

Given the above I'd first check all your vac lines and elbows are on OK. My vac line elbows were all split but it was only obvious if you flexed them. They were all leaking to some extent. I replaced all the vac lines with black silicone vac pipe with no elbow.

Edited February 14, 2012 by Rich H

[Quicker 2]

Chris - yep - they kinda does sound like it - and there is a different 'tone' from the exhaust when the situation occurs.

were they able to repair it - or was it a new turbo?

Edited February 14, 2012 by Quicker

[esp88 55]

Do you check O2 sensor ?

Yasuo

[Quicker 2]

I thought the O2 sensor wouldn't be used in a WOT (open loop) situation - right?

Edited February 14, 2012 by Quicker

[cjtpb13 12]

Lou,

Yes they repaired it. Actually because of the defective manifold Lotus paid to have the complete turbo rebuilt.

Also if you use ErikS4's Espritmon programme you can actually check the operation of the O2 sensor. In general when the O2 sensor fails most ECU's are designed to follow a preprogrammed map for AFR. Hence why you seem to get a richer burn when an O2 sensor fails.

[Quicker 2]

I thought at WOT - open loop - the ECU went to a map for AFR values and did not use the readings from the O2 sensor - no?

[Quicker 2]

here my Freescan file from the drive home...

I get RPM, speed, bat V and coolant temp - but nothing else...

what am I doing wrong?

02-14-12-log.zip

[Artie 6]

That's odd Lou, not sure why you'd only get certain values unless your interface cable is faulty. Also, did you pressurize your wastegate actuator to see if it holds pressure and opens properly? When I first got my Esprit I ran it hard from a stop sign once and the wastegate got jarred open and stuck partially open. It behaved as you describe. Very low boost and poor acceleration. I pulled the downpipe off and saw that the flapper was cocked back and jammed open somehow. I stuffed rags into the turbine opening to prevent damage to the blades and I pryed the flapper back in place. I then staked the little post that holds the flapper to prevent it from coming loose again. This solved my problem. Worth a try.

Artie