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fesuvious

Problem? Or Not?

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Hello! Have I got a boost issue?

Maybe you have read my other posts? Maybe not..?

I have an Esprit S4S, which I bought @4 weeks ago. Since then I have fitted a 2.5" straight through exhaust (after the cat), I have also replaced;

Elbow at MAP (cracked)

Wastegate Solenoid (suspected knackered)

IAC (again, suspected knackered due to idle prob - idle is fixed)

TPS - due to jerky throttle (fixed)

Have checked most vacumn lines for leaks.

Removed throttle jack and EBPV solenoid (left connected electrically) - pump now directly to HVAC system.

Also fitted Blitz turbo timer, which is showing .85bar boost, NOT over .9 which I believe is where it should be? The car drives beautifully but seemingly isn't providing all the bost it should be.

Last night I removed the wastegate actuator and turned the rod in two turns. I could swear the boost is now more 'solid' and consistant but still only .85bar on the readout.

Any ideas? Should I turn the rod in some more? I had 10 'threads' showing, and now have 7/8 is it worth going some more?

Or is there somewhere, or something I havn't looked at yet? I did rebuild the lines with 5mm fuel hose, those being the lines from, and to the wastegate solenoid. The fit is all nice and tight and sealed but could the hose be too big? The internal bore looked about the same size as what came off.

Help, I want to get the car right before going to PUK for a chip!

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Upgrade today to remove Google ads and support TLF.

You can turn it up as much as you want ..............whether the motor will handle it is another story.

I f you want it to last , stick to the manufacturers spec .......This engine has been tried and tested since the early eighties and has shown over time that it is strong but to mess with it ????

richard

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What does Freescan show???

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Help, I want to get the car right before going to PUK for a chip!

There is no chip from PUK which is an improvement on the S4s code as far as I'm aware, spend your money on something which will improve the car instead.

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Thanks

Firstly, I am not looking to 'up the boost' from the actuator. Right now I am merely trying to get the car to perform as Lotus intended, which according to what is written on is 0.97BAR boost < ?

That is the problem I am trying to sort right now.

Guv'nor ; From what is written on here number3 chip with the high torque code is an improvement. If this is not the case then I am happy to read others opinions. However, this is 'down the line'. For now I wanted to get the car 'spot on' and then worry about improving performance in terms of lb/ft and BHP.

Actually, next on the list is brakes, but thats for another time and another topic.

Can anyone confirm that the standard boost shoulod be 0.97, and, if so, where else I might look for my lost boost?

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The waste gate solenoid is key to getting the maximum standard boost out of the car. First simple thing to do is make sure the wastegate actuator is set per factory spec by simply by-passing the solenoid valve. Take the boost pressure line from the manifold that connects to the solenoid and connect it direct to the waste gate acutator capsule (by-passing the soleniod). You should now get sustain boost at the maximum rating of the spring in the capsule, which the factory spec says should be 0.65 bar. Adjusting the length of the actuator arm will cause maximum boost earlier in the rev range or later.

If your achieving this then reconnect the boost solenoid. A freescan log is really important at this stage as you can clearly see how much work the boost solenoid is work working by looking at the wastegate D/C (Duty Cycle). This value is a percentage and should be no more than between 50/60 on full overboost. The maximum stock over boost the ECU will generate is around 0.8 bar.

The upgrade chips you are refering to can increase this maximum over boost by bleeading more boost pressure away from the wastegate. In effect, venting the boost pressure rather than allowing it to pass to the wastegate actuature and so opening the wastegate.

Your 0.85 sounds good to me for stock setup.

The higher # upgrade chips use the latest S4s code as a base but have modifed parameters to increase performance. The LEW Upgrade chip guides give a good summary.

Edited by CarlC

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Seems that you have my same problems: Im not sure if my car is ok or no!! maybe I have other problems but the common: "the car is ok or no?", thats my doubt!

Im Alessandro from Italy and nice to see you here "fesuvious"

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I tried connecting directly and she seemed to peak at 0.62 but no higher. However, when I say 'peak' I really do mean 'peak'. She seemed more to sit at the late fifties.

Am I answering my own question here? Is the wastegate actuator shot? Would further shortening the rod mask this? Or is this pointless?

Also, could someone explain (CarlC thanks) how would adjusting the length 'move' the peak boost? Surely it just means the gate will stay shut for longer and increase the overall boost pressure?

Could my boost level be caused by a knackered jubilee clip on the hose into the chargecooler? It 'tightened' up but felt 'iffy' - just a thought (cars at home so will get cracking on her later this eve)

Oh, thanks Alessandro, pleasure to meet you

Edited by fesuvious

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Never understood turbo timers myself but keep in mind - is the turbo timer even correct ?

The wastegate capsule is regulated at 0.65 bar, the wastegate solenoid bleeds air away from this to achieve higher boost controlled by the ECU

Playing with the rod will end up with a 4 grand repair bill if you just keep tunring it without knowing what you're really doing.

The way to set it up is to put a compressor on the wastegate capsule and set it to 0.65 bar, it has to move X mm at that pressure (not sure what the movement is, sure its on LEW) - I can find out or you can call Lotus. The ECU controlls the rest.

Possible there is a blockage on the wastegate solenoid so it is not bleeding the air so well. A freescan would show this very easuily - under high RPM and high throttle the wastegate duty cycle should be ~75/90 % - if it is saturated at 100% then you know the system is blocked or not working. You'll also work out what the ECU thinks the boost is...thats the most important thing, you might read 9 bar on an external gauage but it is the ECU that governs.

By adjusting the rod length you're messing with the way the ECU adjusts the wastegate solenoid as well, take it back to standard and work through it methodicly or you're gonna pop something.

Of course you might have something as simple as an air leak !

Trying to solving the issue with a £400 chip also will probably bring more missery, btw all those chip data facts are not dyno backed up - they are just figures plucked out of the air.

Do you have any freescan data ?

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The specifications for the setting of the wastegate actuator are that for an initial 0.4mm of rod movement there needs to be 0.58 +/- 0.02 bar (8.5 +/- 0.25 psi) of pressure applied.

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Freescan log sorted !

Wastegate duty cycle shows a big fat ZERO throught, from cold through hot and from part to full throttle and indeed all through the rev range. Is this right?

Secondry injectors seem to operate through 1 and 2 as they should.

Closed loop shows a value of '1' all the way through, no matter temp or revs.

Once again max boost is 0.85 BAR.

Any other values I should list? The freescan file is over 600kb and the site won't let me upload it.

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Wastegate DC not right, it shows percentage of operation so zero is not operating....dunno whats wrong there, usually means it's broken or disconnected but it should flag a Code26

Is your check engine warning light working ? It's not unknown for funny buggers to take the bulb out when there is a problem with a car - key to pos 2 the warning lights should light up inc the yellow engine light so you can check it's working.

Possible 'Closed loop' wont goto 0 whilst there is an issue with the wastegate solenoid

Mine hardly ever goes to 0 unless I goto almost absolute max rpm, infact I was gob smacked when it went to 0 when I last done a checkup on the car !

How are you measuring boost ?

Ignore the turbo timer, what does freescan's MAP value say pref under full chat and idle.

Its possibe the wastegate dc sees the car naturally overboosting and stays off becuase it doesn't need to go in, I mean mechanically this is possible to wind the rod so far as to achieve 0.85bar

However the ECU limits boost until's warmed up to about ~70-75c then enables the overboost - so it's possible the car is not getting to temperature ?

Check the coolant temp value on freescan (Not on the dash).

I think sorting the wastegate actuator out is your main and urgent priority - once you know that is right you can diagnose the remainder.

Try and cut the freescan log down, import it into excell or open office and then delete the boring lines and leave the ones that are of interest, or zip the file ?

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Map at 5950rpm is 1.65

at idle (warm) is 0.49

Thats all from the freescan file

Ignition key to position two - NO check engine light - hhmmmmm

Temp on freescan all looks a-ok, mid eighties

Car does throw a code 26, which is what prompted me to start this mission !

Took the actuator off last night and it felt ok, need a fair amount of force with my muscles to pull the rod out, and when id did so it moved @1/2 to 3/4 inch and sucked back in just fine.....???

Just checked again, and yes, wastegate duty cycle shows ZERO all the way through

p.s thanks, I was hoping you'd show up!

Edited by fesuvious

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I personally do not believe that Freescan's "closed loop" flag is actually showing the fuelling mode. It might be showing that conditions for closed loop fuelling have been met but not that the ecu is running this mode.

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Lotus were curious about the closed/open loop as well - I just ignore it now.

----

Right easy fix then (everything else sounds OK - inc the boost, you're just getting extra umph from a dodgy'd wastegate actuator, btw the car will cut fuel if it overboosts so hopefuly its all ok)

Sort the actuator rod back to factory settings,

Sort the bulb in the binacle - probably been disconnected cus the PO couldn't find the fault - code 26's are hard graft sometimes,

Sort the code 26 (likely to be the wastegate solenoid either up the spout or one of the wires / connectors are broken,

Re-test

Should have that fixed by....mid day tomorrow ? :thumbsup:

Some late night reading :

http://www.lotusespritworld.com/EGuides/ETechnical/turbo.html

http://www.lotusespritworld.com/EGuides/ETechnical/Wastegate.html

Main thing to do is to stop guessing with the wastegate and use an air source to set it up - you can use the turbo timer's pressure reading to analyse this as well by re-piping.

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So you are thinking a dodgy connection or broken wire is causing the DC to read zero?

And this could be the code 26? If so, could a relay be in this circuit?

Is there an equation for MAP to boost?

Oh, and THANKS !

p.s

It aint pretty (although it is prettier now) but heres the exhaust I made, prior to cleaning up, finishing off and fitting

post-9573-127351986745.jpg

Edited by fesuvious

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MAP is Mass Air Pressure reading inside the inlet manifold - it is related to boost and relative to BARO.

BARO is usually 0.85 at sea level and only a value, again not a pressure reading - anything below BARO on the MAP scale is a vacuum, anything above is positive pressure (turbo pressure)

on freescan it is represented as a value not a pressure reading, in order to get a clue what it means refer to my excellent graph :

http://www.flickr.com/photos/jonhimself/3698222359/in/set-72157623278905153/

That was done using a known compressor - 2 gauges to confirm plumbed into my GT3's MAP sensor to get a real world idea of what freescan is telling you - it is accurate.

Keep in mind the MAP can goto zero (usually from medium-high revs and you come off the throttle) - pistons are still moving but the throttle is cloed = vacuum

Map is usually 0.55 or there abouts at sea level

On boost the MAP value represents the air prssure being generated by the turbo.

The wastegate solenoid is driven from the ECU, when the ECU wants to 'fire' it an internal quad driver in the ECU grounds the wire Green/Yellow wire from the solenoid to earth - there are no relays involved with the wastegate solenoid.

CODE 26 are notoriously difficult to find if you're not 100% clear with the fault - I'm guessing its the problem but it can be one of a few issues - see freescan's fault code page.

My guess is, it doesn't seem to be working, there is a code 26 and the wastegate will cuase a code 26 so its probably a duck to me.

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Ahh, I see, that graph is excellent.

So, first step is replace the wastegate actuator? I presume that is what you mean by the 'wastegate' being able to throw a code 26? Not surprising afterall the one on the car looks past its sell by date and is @15 years old.

Or should I be tracing the wiring from the solenoid first? I don't have the tools to test the actuator by hand, only by plumbing it direct, which seemed to show 0.62 on the boost guage (blitz-digital).

So the wiring goes straight to the ECU then?

I have used my 'upload quota' otherwise I have a reduced in size freescan file I could have posted up

RIGHT - the coffee has kicked in! Using your graph and my freescan log; The MAP reading virtually never gets over 1.6. And so is not boosting beyond a real time 0.6BAR. Now, allied to the data showing zero on the wastegate duty cycle I have to presume that the solenoid is passing the gas straight through. So, correct me if I am wrong

I have a wastegate that is opening early and so the actuator may be shagged?

I have a solenoid that sin't working?

The 0.85 on the guage is just a spike, and so isn't to be trusted for this diagnosis?

All of the above?

Edited by fesuvious

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Going back to basic here Matt, didn't you buy this car about a month ago from Matty's? In this case, if I were you, I'd ensure the car was returned and these problems fixed under their warranty which I understand is always very good and well honoured.

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A blown or missing check engine light bulb will give a code 26 & reduce boost to .85 bar so get that bulb replaced first.

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...And I had lods of problems not getting anywhere near full boost without ever seeing an error code logged. My boost problems were largely cured by a new wastegate actuator (circa £100) and a new wastegate solenoid valve (circa £30). If the wastegate capsule has never been replaced, its well worth getting it replaced to help ensure you consistently get the most out of the car.

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No, 1st step is to start from where you know the car is good.

See my steps from last post and true enlightenment will be yours :construction:

Wastegate DC is the percentage of which the ECU switches the solenoid ON to bleed air from the wastegate capsule in a given time (lets call it wastegate frequency as the ECU pulses the valve on and off, pulse modulation).

So at 0 (zero) the ECU is not switching the solenoid and the valve is closed, this means the 100% turbo pressure is reaching the wastegate actuator which is why you're not getting a lot of boost (wastegate is set to 0.65 Bar)

If the Wastegate solenoid DC was 75% it would be opening the valve, bleeding the air off from the wastegate at a rate of 3 in every 4 (ie open for 0.75 seconds and closed for 0.25 seconds). If it was 100% then the wastegate solenoid would be bleeding air constantly (this is not likely unless special circumstances arrise, or in chipped cars which do this to fake you into thinking the car has more HP than it actually has becuase it allows the car to enter overboost with no restrictions !).

You need to clear that ECU fault / bulb, you need to ensure the wastegate it set correctly BEFORE attempting anything else and you'll end up chasing your tail around for hours trying to fix the car and could end up buggering it up and causing an overboost.

Ignore that blitz controller - use freescan, use the chart, and you can now tell exactly what the pressure is in the manifold - you dont need anything else to help.

If you have no access to tools to check the wastegate capsule rod then you need someone with a compressor or a hand pump with a good gauge - check it with another gauge to ensure the readings are correct and set it up from there.

From the freescan data, it sounds perfectly to me like there is a straightforward wastegate solenoid fault, and the ECU is limiting boost by disabling the wastegate solenoid from operating.

As said above that could be to do with the bulb - very easy fix, but as a precaution I would also get the wastegate capsule/rod checked (even though it sounds as if it's nigh on correclty set as it is if you are only geting 1.6 MAP peak on freescan).

PS : when your car hit's max overboost you will know about it becuase it's like being in a time machine, you're actually missing out on about 70 horse power at present ! Be careful when testing as the difference in power will likley cause the car's rear tyres to spin

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holy sheet

binnacle removed, engine check light was butchered! bust, broken and bodged, now repaired.

Took car for run - no engine faults found - OH MY GOD. How fast !

Quickly came back to plumb wastegate direct to inlet and do a run with freescan which again showed no higher than 1.61 MAP, so, I am guessing the wastegate actuator is working as it should.

Car showed a maximum (on the blitz) 1.45BAR !!!!!!!!!! now thats 21psi, is that right! The car felt/feels monumentally quick, and believe me I have owned some quick cars in my time but this thing feels quicker than the 440BHP M5 I had.

Will do a run with the data logging on after its cooled enough for me to plumb her back properly.

Oh, and reset the actuator back to 10 threads showing

EDITED 21:30 TO ADD

some data, from the latest run with her all put together properly. < SCRAP THAT! data is useless, I trimmed the file to get it to upload and the data thats there doesn't show the very rev range I need it to!

This car is monumentally quick. I have attached a freescan log.

Sincerely hoping I might get some feedback

lotuspossfixed2130may11.csv

Edited by fesuvious

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Right, looking at the file now (all of that down to a little bulb, well i never)

Your Wastegate DC is working - good.

Your boost is going very high on low revs though and thats not good.

Your road speed and rpm dont really get up high enough to produce that demand and boost level so I am thinking that this is coming from the wastegate capsule and not the ECU commands even though the Wastegate DC sometimes hits 100%

Your car is acting more like a chipped car there is nothing limiting the build up of boost, the MAP actually hits 2.23 which saturates the sensor (ie it cannot read more than that) for a period of time and there seems to be no demand for the ECU to cut the fuel to stop the car blowing up. You're hitting about 1.25 bar of boost there (Blitz maybe right to 1.45 in which case this is serious damage territory) if you take into acount the over run, so something is wrong and I expect it is the wastegate rod thou hath been twidling about with. Fast though isn't it ? V8 fast.

If I were you I would seriously stop, and get the right equipment in to sort the wastegate or at least check for any leaks in that system as the car is overboosting significantly - fun but when you blow the engine up it wont be smiles :construction:

As standard you should not be seeing any more than 1.0 bar of boost OR much more than 2.1 MAP reading on freescan and this would be at about 5000 RPM with your foot to the floor.

Heed what I say, you might save yourself a £4,000 rebuild.

Finally for your info is a graph I just did from some freescan logs of the relationship between the wastegate solenoid, RPM and boost on my GT3 (yours will be a bit more spicey as you have a better turbo 200 more CC and a better flowed head). Was done on my own personal runway from 25mph to over 100mph in 5th gear and at 100% throttle to see how boost is built up and how the wastegate governs it.

Edited by Jonathan

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Good Morning.

The 2.23 spike appeared but then, according to the missus who was sat with the laptop watching the 'engine' tab on freescan held a solid 1.77 whilst on boost all the way through to the gearchange from 4th to 5th.

Matty's are getting me a new wastegate actuator. My plan would be (correct me if this doesn't sound right) to plumb gate to inlet and do a 4th gear run using freescan. Then, ensure that all is well and the car is holding @1.6 on the map reading throughout the range.

Assuming this is all correct; Have the rod wound out and do another run, adjust as ness with the target being @2-2.1 on the map reading as a maximum. I presume my target for the main part should be @2 on the MAP reading? (as it is an S4s)

What do you think? Oh, and thanks again, my knowlage of these cars has increased substantially over the last 48 hours.

Oh, prob should mention that the rod is now wound back out to 11 threads, from the original 10. It was on this setting when I did the run last night.

Also, the 'plumbing' I have re-done with 5mm fuel hose, brand new hose and brand new clips. I have also used clips on every join from the solenoid. I am pretty darn sure there is no leak! I'll certainly check again but...

Just had a thought - could the diaphram have gone stiff, causing the initial surge in boost and then once the resistance has been overcome thats why it holds 1.77?

Edited by fesuvious

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