Not making expected boost?

[JonT]

Your scan looks like a perfectly normal stock 1499 closed loop.
What's bugging me is the consistent behaviour of .58 Bar boost which is exactly the stock setting. It is almost as if you had a stock 1499 installed instead of a 1499 Everest.
What does the white writing on the main SST chip on the Moates board say ?

Pretty sure it said 1499 Everest, but I'll have a look in the car later and check. I thought the boost control valve duty cycle still implied a leak as a healthy reading would be nearer 40% than 80%?

All good thoughts and things to check though!

[saska]

I thought the boost control valve duty cycle still implied a leak as a healthy reading would be nearer 40% than 80%?

If you mean Wastegate Duty Cycle then 80% is a healthy reading -- just looked at a couple of other normal scans.
Think I recall Senor Smith saying around 80% is max value for WDC.

[trig]

Your scan looks like a perfectly normal stock 1499 closed loop.
What's bugging me is the consistent behaviour of .58 Bar boost which is exactly the stock setting. It is almost as if you had a stock 1499 installed instead of a 1499 Everest.
What does the white writing on the main SST chip on the Moates board say ?

Pretty sure it said 1499 Everest, but I'll have a look in the car later and check. I thought the boost control valve duty cycle still implied a leak as a healthy reading would be nearer 40% than 80%?

All good thoughts and things to check though!

Jon , I'm running an Everest so simple enough to plug in my ecu go for a run and compare

[PECKHS]

Sorry to hijack this thread. But ididd an elanscan recently and it showed 0.35bar when I'm quite sure the boost gauge read close to 0.5bar. The max power logged was 80hp, and highest speed was 60.( however the speedo did read close to 90kmh).
I have a 3bar MAP ( for some reasons unknown the MAP I ordered from sjsports did not arrive).
Will the 3bar MAP affect the readings for boost pressure, as well as speed and power?
And how do we change the value for the .ini file ?
Thanks

Peck

[JonT]

The plot thickens. Inspired by a post on SELOC about pressurising header tanks to look for HGF, I adapted a bike inner tube to allow me to easily pressurise the turbo system:


Once pressurised, it was easy enough to hear a leak from behind the intake plenum, but no idea where it was coming from. I used a gas fitters trick of a squeezy bottle of fairy liquid and water sprayed over the pipes to look for bubbles indicating a leak. The 'L' pipe Geoff had problems with I've already replaced with some small diameter silicon hose, but this appeared to have a pinhole in it, so I swapped that out. However there's still a slight hiss, and I just can't work out where it's coming from. Should there be a slight leak into the vacuum system? The diagram Saska posted above indicates there are some links into this system. Or should it hold pressure once set up? (according to SWMBO sat in the drivers seat, the dash gauge was getting up to about 0.25 bar). I haven't had a chance to go out for a drive and check yet - only just put it all back together. I'm out again tomorrow so I guess I'll see if there's any improvement then, but otherwise if anyones got ideas about what pipes might be leaking, that would be very useful!

Oh, while I'm at it, I pulled the map sensor and it's badged GM (446? IIRC) so I think that's standard, and checked for leaks while it was pulled out so it's definitely not that hose.

cheers,

Jon

[DeanG]

I can't help you out however I do like your test rig. Very inexpensive and creative.

[JonT]

Still not fixed Possibly marginally better but only going by the dash gauge as I wasn't out with ElanScan yesterday. Certainly didn't feel any faster.

[saska]

Still not fixed Possibly marginally better but only going by the dash gauge as I wasn't out with ElanScan yesterday. Certainly didn't feel any faster.

A way to narrow down where the leak is located would be to use a piece of flexible pipe / rubber tubing. Put a plastic funnel over one end to fit over your ear and an earplug in the other ear.
Then pump up the ingenious test rig and see if you can locate the leak by moving the end of the tubing around. If it is behind / below the plenum then it is likely somewhere in the secondary throttle pipework marked A B C in the vacuum hose diagram. I don't have a very good photo but this one may help you, the secondary throttle bits are at top of picture slightly left of centre. I'll try to get a better photo next time I over there. Good luck.

[JonT]

Thanks for the pic Saska - that along with the workshop manual pic for the back of the engine should help, although the priority for this weekend is tightening up the a/c and PAS belt as it's started to slip.

I've added a slightly more detailed write up of the bike tube trick to the wiki for future posterity:
http://wikilec.9600.org/index.php/Boost_leak

[JonT]

So I think it's the EGR valve. I blanked off the secondary throttle pipes - no change. Having a fiddle around (and poke with a funnel to help listen), I found the "hiss" changed as I moved my hand under the back of the EGR. How easy are these to take off (at least to have a better look at it)? A search suggests they aren't available any more - anyone got a spare or know if they are repairable?

cheers,

Jon

[surfboardfiller]

So I think it's the EGR valve. I blanked off the secondary throttle pipes - no change. Having a fiddle around (and poke with a funnel to help listen), I found the "hiss" changed as I moved my hand under the back of the EGR. How easy are these to take off (at least to have a better look at it)? A search suggests they aren't available any more - anyone got a spare or know if they are repairable?

cheers,

Jon

Very easy to take off Jon, 4 bolts. I doubt it will be a problem, just take it off clean the faces and seal it before bolting it back on.
I have some liquid Exhaust gasket/seal if you can wait for CC, maybe we can all have a look then.

Feel free to PM me if you get any other problems/questions.

PS
I don't see how the turbo induction leak can be EGR?

[JonT]

Got the EGR off this morning. Pics below which may or may not help identifying it. Mine seems to be different from some of the pics posted elsewhere in that it has an electrical sensor in it (possibly temp sensor)? 2 wire and connected to the loom in the same place as the other temp sensor that's directly into the inlet manifold.

I wonder if in my case the gasket between the "Top hat" like portion and the cast portion is leaking - there's 3 short cross head screws holding the halves together but I can't see how to get at those non-destructively. The top half of the top hat must be placed over the lower half then crimped in place all around. The actual rubber diaphragm appears fine and if I block the small high pressure inlet with it displaced, it stays there so I think it's airtight.

Was very coked up, so used a lot of carb cleaner to try and decoke it.

Assuming it was the valve leaking, I see two possible mechanism. Firstly the piston seal between the inlet/exhaust isn't sealing properly - hopefully decoking this will help there. Secondly if the gasket I mentioned above is blowing slightly or the seal around the small piston no-longer airtight, again the inlet manifold could leak to atmosphere.

Anyway, all back together so will go for a drive shortly and see what happens.

Pics (in no particular order). Sorry, forgot to take one of the electrical sensor, but it looked very like a small o2 sensor.

[JonT]

Well, after all that, no improvement

Test rig still shows a hiss, and a drive with elanscan shows no improvement. Initial boost quickly up to ~0.6bar, but over a couple of seconds drops slightly to 0.55 and holds there with 80% duty cycle on the wastegate and 100% throttle.

Just about ready to throw it at someone and ask them to sort it - running out of ideas and patience I'd throw it at Andy at QMech, but I'm not sure he knows the Elan well enough.

[JonT]

Another look this morning, and I'm back to suspecting the EGR again. When the system is pressurised, lifting the EGR diaphragm, the hiss drops to a deeper tone as the intake can now drop pressure into the exhaust system (ie backwards to how the EGR is meant to work). The piston from the diaphragm is surrounded with a rubber bung - I'm wondering if this has perished and is leaking

In the absence of being able to find a replacement, has anyone fitted a blanking plate? (I'm thinking a thin plate between the inlet manifold and the EGR valve). The sensor there would misread as there wouldn't be any flow from the exhaust but I don't even know if it's used by the ECU as most of the pictures from other peoples EGR valves don't seem to show one (to complicate things, my car had a replacement engine fitted in 1995 but it is a non-cat engine).

Does anyone fancy putting together a test rig like mine and trying on their (known-good) car to see if I'm chasing a red-herring and this is an expected leak?

[tigerdog]

From my research, the EGR valve with sensor is only applicable to cars with California emissions ratings. The sensor provides temperature feedback to the ECU, essentially telling the ECU exhaust is entering the intake when it should.

[JonT]

Bit more of a play. Took the EGR off and fitted a blanking plate on the inlet manifold hole. Also disconnected the temp sensor in the EGR. Used the test rig again, and no perceptible leak. So I think that's pretty conclusive - the problem is the EGR.

Put it all back together with the blank still in and did a brief elanscan on the drive (let it warm up to ~60C). No problems logged, so I'll go for a drive in a bit and log again and see what happens.

If I need the EGR to work come MoT time it's not that much of a faff to remove the plate now I've had the EGR off a couple of times.

[saska]

In the absence of being able to find a replacement, has anyone fitted a blanking plate? (I'm thinking a thin plate between the inlet manifold and the EGR valve).

As a diagnostic method to see if this is the cause of your 'not making expected boost' then I'd go along with fitting a thin blanking plate between inlet manifold and EGR. GeoffSmith (not a numpty) also suggested it earlier on.

The sensor there would misread as there wouldn't be any flow from the exhaust but I don't even know if it's used by the ECU as most of the pictures from other peoples EGR valves don't seem to show one (to complicate things, my car had a replacement engine fitted in 1995 but it is a non-cat engine).

I'm only speculating with what follows but here goes:
The sensor on the EGR is only used with California spec cars AND with Ca spec ECUs. Lotus used the same loom and parts on lots of different spec/destination cars.
The EGR valve is operated via a solenoid identical to the boost control solenoid. So a vacuum take-off from below the plenum intake goes to the EGR solenoid and another vacuum pipe then goes from the solenoid to the top-hat diaphragm on the EGR valve. When the coolant temp is >30C, MAP says the engine is under load, RPMs are > 1000, acceleration mode is On, then the solenoid switch opens and allows the vacuum from the plenum intake to pass to the EGR diaphragm and open the EGR valve. On non Ca. spec cars the ECU doesn't know, or care, about the sensor on the EGR -- it only knows, or cares, about whether the EGR control solenoid is open or closed. It reports its position (On/Off) to the ECU and Elanscan (Flag 12 Bit 5)
So I don't think it will do any harm to blank it off but additionally you shouldn't get a fault code or CEL because the solenoid is still reporting its position correctly even though the EGR isn't actually passing gas to the intake.
My only concern in the longer term is the EGR pipe is taking exhaust from the exhaust manifold (before the turbo) and if this is leaking to atmosphere via the leaky EGR valve then this may reduce the turbo spooling (loosing exhaust pressure to atmosphere). If the blank plate works, I'd be very tempted to remove the EGR pipe and blank plug the EGR pipe at the exhaust manifold.
All the above is my opinion, do at your own risk, worth what you paid for it, etc.

[JonT]

In the absence of being able to find a replacement, has anyone fitted a blanking plate? (I'm thinking a thin plate between the inlet manifold and the EGR valve).

As a diagnostic method to see if this is the cause of your 'not making expected boost' then I'd go along with fitting a thin blanking plate between inlet manifold and EGR. GeoffSmith (not a numpty) also suggested it earlier on.

As mentioned above, I have now tried this. Having been for a testdrive, it's not actually any better - possibly even slightly worse according to ElanScan (peak boost 0.05bar down) - but it is a much hotter day. I'm now really confused. I'll have to try the test rig again once everything has cooled down. Out of paranoia I removed the Everest chip and went for another quick run, but unsurprisingly that made no appreciable difference.

[wayne]

Out of paranoia I removed the Everest chip and went for another quick run, but unsurprisingly that made no appreciable difference.

Could it be a problem with the Everest? Anyone else near you have one that you could try?

Sorry I know it could be a silly question but it looks like youve tried just about everything else.

[JonT]

Out of paranoia I removed the Everest chip and went for another quick run, but unsurprisingly that made no appreciable difference.

Could it be a problem with the Everest? Anyone else near you have one that you could try?

No, I don't think it's the everest - I went for a quick run having removed the everest chip from the ECU so it was running as standard and still showed the same symptoms.