Elysium and won't boost as expected

[Alan_C]

Hmm, the SE is now running Elysium V5.3, K&N filter in standard dustbin, Piper 2 1/4 exhaust, timing is spot on, but boost won't go above 0.79 BAR. Checked most things, can't find a fault. I've attached a short ElanScan in case I've missed anything, if someone could have a look?

[Alan_C]

Looking closer, I notice that the wastegate duty cycle is very high when on boost, at about 80%, other cars seems to be about 40%? Looking at my previous ElanScan results http://forum.lotuselancentral.com/viewtopic.php?f=34&t=15816 when running standard PROM it's also high at 80%, but with standard boost. I can't get my head round what this means, does a higher wastegate duty cycle mean the ECU is trying to reduce the boost and for some reason it can't? If so, why would it be trying to reduce the boost when it hadn't reached the max limit?

[Alan_C]

Still can't get boost above 0.79 BAR. Checked all hoses, taken off boost control solenoid and checked it's operation, working fine. Ran the car without any boost control (with the boost control actuator pipe disconneted), so in theory it should have boosted to the moon, nope, still only get 0.79 BAR. Ran with open air filter box, still same. Any ideas? Doesen't look like there's any high presure leaks, the intercooler seems fine, though without fully dismantelling the inner wheel arch/removing front bumper it's not that easy to check, but eye exam doesn't show any leaks (usually fairly easy to spot as over time they become oil stained and black).

At least I don't get boost creep I guess!

So, what to do?

Alan C

[Monty]

I`m not up on the ES and haven`t got it installed.

Just wonder if your wastegate is slightly stuck open give it a wiggle

[Alan_C]

Done the wastegate wiggle, against spring presure of the actuator, it moves freely and can be felt to close.

[rip]

Have you got a dump valve which needs adjustment?

[Alan_C]

Nope, not got one fitted. Still mistifying me, gonna remove the turbo, manifold and downpipe for examination. Got a spare lot on their way including a stiffie to replace the exhaust dustbin. If I have a spare lot at least I won't get stuck when all the studs sheer off! Mind you, bet the problem is still there when the replacement turbo is bolted on, assuming I can't see any faults with the old bits

[Elanlover]

Is it possible you've got a leak in the intake system somewhere? Perhaps a loose clamp or the like where by, once a certain pressure is reached, ai escapes?

[Alan_C]

I thought I did, well, yes, I did. The outlet hose from the turbo had a lose hoseclip, there was evidence of air escaping as a greasy mark, similar to a soot mark on a blowing exhaust. Aha thinks I, found it! Replaced the clip, and.......... no difference. Boll0x As I can't see any leaks in the high pressure side of the plumbing, it must be the turbo, manifold or blocked exhaust? Only pipe I haven't checked is the 90° elbow on the outlet of the intercooler as the wheel liner has to come off for access. Doubt it's a blocked exhaust, it's a fairly new Peco, unless the down pipe dustbin has something in it, I presume on non-cat SE Elans this is empty? Cracked exhaust manifold would make noise, and not much to go wrong with a turbo, pressure wise, unless the exhaust turbine is damaged or the waste gate is not fully closing. The compressor looks fine when intake pipe is removed, no end play and rotates smoothly. Either way, it's all got to come off for examination, and I wanted to fit a stiffy anyway, that 'orrible cast iron dustbin looks, well, 'orrible and has the flow characteristics of a big trashcan wiv an 'ole in the bottom!

[GeoffSmith]

Check for leaks!

[Elanlover]

What he said.

Also, are you sure the onboard switch is set on the proper setting? If you have the remote switcher the board needs to be set to position "0". If not, then whatever number is for the Elysium program.

[Alan_C]

By blowing into the turbo inlet pipe? Never done that before! If a cylinder is on the transition then both valves could be open, but guess that'll be obvious. Well, I'll give it a try!

[Alan_C]

Board is def on position 0 and switcher is on closed loop Elysium, I've even checked the PROM ID in Elanscan to be double sure. Don't forget, I've also run the car with no boost control what so ever, so should have had massive boost, but didn't. There's no escaping boost noise suggesting a leak either, they're usually obvious, a loud whoosh while on boost?

[Alan_C]

I'm all embarrassed

Followed Geoff's advice and blew into the turbo. Bit more advanced than just blowing into the turbo, I stuck a drilled bung into the turbo inlet and put my compressor hose on it, the rubber pipes swelled out a bit then at 11.5 psi air hissed out at the union with the metal pipe and the long elbow that connects onto the plenum. Could have sworn the joint was fine, but the hose clip was kinked underneath where I couldn't see and so wouldn't clamp tight. 11.5 psi, 0.79 BAR. Would explain why I couldn't get any higher boost, the leak was acting like a blow off valve! Sorted the leak, now to check what boost I can get, but too tired to go for a drive tonight and hook up Elanscan.

[Elanlover]

Never underestimate the power of Geoff

[GeoffSmith]

WhatHeSays.gif

Glad you found the problem. Maybe a Wiki-top-tip?

[Alan_C]

I know it's been a while since I posted, but that didn't cure the problem, still couldn't get boost above 0.79 BAR. As I suspected the turbo waste gate, only way to really check was to take it off. I bought a spare turbo, complete with manifold and stiffy as I knew I'd snap all the studs taking mine apart. Anyway, took the original turbo off, and removed the exhaust elbow (snapping all 4 studs as expected). The wastegate was not closing! Closer examination reveiled that the turbo has been removed previously and dropped, landing on the wastegate actuator, bending it, it's bracket and the actuator rod, thus holding the waste gate open about 2mm, hence I couldn't get expected boost, would also explain the high waste gate duty cycle seen in ElanScan. The compressor housing is also damaged, the thread has been stripped for the air presure take off adaptor and glued back on with epoxy, plus the cast exhaust manifold was cracked in 2 places, I'm glad I got a replacemnt assembly! New turbo all bolted up, but can't yet test as also noticed the RH CV boot has split and there's grease everywhere.

[Alan_C]

Update - Tested and can get full boost, gauge showing just shy of 1 bar boost, I'm now getting the boost I expected. Also get overboost as I found out, 5th gear, throttle held to floor
So how do I cure overboost when the turbo has been ported already? Make the wastegate hole a bit bigger still I guess.

[tigerdog]

You could always fit a nice, restrictive exhaust.

[rip]

Advancing my ignition timing cured many sins, including overboost at 4000rpm.
I now get overboost at much higher revs in cold weather only & my wastegate is un-ported.