C270CDi: EGR disconnected; could Limp Mode be useful?

slottler

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Hi All

Although I've been reading these forums for about 2 years, this is my first post. (I have another in mind: to put together ALL the info I've gathered on using the 5g gearbox. Because I wish I could have found all the info in one place). I've learned so much!!! Thanks, guys. eg: I experienced a battery drain and was able to diagnose a faulty outside temp sensor, thanks to the forums.

I have been wanting to do the EGR shunt (a-la Dieselman and Alex Crow's postings) on my 2001 C270 CDi for a while now. Wanting to make a start, I identified the EGR vacuum relay and disconnected it. I knew that the MAF would cause errors and cause limp mode, but I took the car for a spin "just to see" how it felt. Actually, I quite liked the sound and feel, but let me explain...

1) On starting, I immediately noticed a change in the sound of the engine. Then I realised that the turbo wasn't working.... what was missing was the turbo whine. Actually, I don't like the whine of the turbo during low rpm town-driving... so the engine actually sounded better! :)

2) I had plenty of torque at pullaway... but the engine would not rev beyond 2000rpm. And was gutless when I put my foot down. But perfectly adequate for driving around my local village... my CDi felt like my dad's old W202 250D (non turbo)... not a fast car, but adequate. My gearbox seemed to work fine... I counted changes up to 4th gear at approx 70km/h.

3) My fuel economy appeared unaffected... or perhaps even better! The computer said that I used approx 8l/100km for this short (1.5km) journey to the shops and back. The engine didn't even have a chance to warm up.

So I started to think: this could be great!! I could fit a switch to disable my turbo just by disconnecting the EGR. Why? Well I could think of a few reasons:
a) For short journeys in my village, I hate to think of excess wear on my turbo as a result of running while still cold... or clogging with soot and deposits. So... wouldn't it be nice to be able to preserve my turbo by not using it when I don't need it?
b) A C270 is quite a quick car; quicker than most people realise. So I hate loaning my car out... because once people realise she's quick, they want to find out how quick. I would love to be able to "tame" the performance when I take the car to eg a valet or loan it to a friend. It really goes fine without a turbo... just not fast! :)
c) I would imagine that a non-turbo car might be more economical than a same turbo-car (at low engine loads and speeds). Anybody care to comment? I haven't noticed increased consumption as mentioned by some others.

BTW... this "limp mode" (no Turbo) is different to the "gearbox limp mode" (symptom: stuck in 2nd gear) which I have also experienced. My gearbox works OK.

I thought that all this was quite cool, but decided to reconnect my EGR until I get the parts to make my shunt. I did so, but my turbo did not return. Anybody have any ideas why? The obvious thought would be that I damaged a hose or wire while disconnecting the EGR wire... but I was careful.

So here are a couple of questions. I'd welcome comments and answers!
i) Is it possible that a code has been stored which needs to be reset.... before my turbo will work again?
ii) Can any harm be caused by driving the car like this? I wouldn't think so!
iii) Does anybody else think that this might be desireable sometimes? To disable the turbo!!!?

Cheers!
 

turbopete

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the turbo 'runs' all the time when the engine is on, so no saving there. all the limp mode does is stop it from boosting so, in the case of these variable geometry turbos, the vanes on the impellers sit at a slightly different angle, preventing boost and therefore not 'whining' in the air/exhaust gases driving the turbo

more economical? unlikely. the only way it would be is if you are keen to use the available performance regularly.

can it harm it? well its possible the vanes can stick in a position meaning low or overboost situations could occur.

the turbo should return after switching off the ignition and restarting it. if it doesnt then it will need codes reset.

i can think of no reason whatsoever where it would be desirable to disable the turbo, personally.
 

oigle

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Wonder if you disconnected the wrong transducer? It are the same unit as the one controlling the turbo boost.
I can see where you are coming from re the ability to "turn off" the turbo when required and can see no problems in doing so in the short term. Wouldn't make a practice of it though as the engine is being forced to run in a non-efficient mode which could have undesired side effects.
 
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slottler

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Hmm.. Thanx!

Hi

Thanks for the prompt replies!

Turbopete - you're not the same Turbopete from the Ssangyong Musso forums are you? :) So you're saying that limp mode doesn't disable the turbo... hmm, OK.

But do you really think that I now need to get my codes reset after temporarily disconnecting the EGR cable? I can't afford to take it to a stealer, maybe I need to disconnect the battery... :-(

Oigle... I'm fairly sure that I found the correct transducer. It took me a while, but I found photos on these forums which helped me to identify it.

Pity we can't "disable" the turbo so easily. I like the idea of being able to do so.

I may be forced to do complete the EGR shunt now, which may not be a bad thing. I don't have resistors and a diode handy, but I have some old circuit boards... maybe I'll scrounge secondhand bits!!!

Cheers!
 

turbopete

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Hi

Thanks for the prompt replies!

Turbopete - you're not the same Turbopete from the Ssangyong Musso forums are you? :) So you're saying that limp mode doesn't disable the turbo... hmm, OK.

But do you really think that I now need to get my codes reset after temporarily disconnecting the EGR cable? I can't afford to take it to a stealer, maybe I need to disconnect the battery... :-(

Oigle... I'm fairly sure that I found the correct transducer. It took me a while, but I found photos on these forums which helped me to identify it.

Pity we can't "disable" the turbo so easily. I like the idea of being able to do so.

I may be forced to do complete the EGR shunt now, which may not be a bad thing. I don't have resistors and a diode handy, but I have some old circuit boards... maybe I'll scrounge secondhand bits!!!

Cheers!

no im not on any ssangyong forums. in fact i thought i was a bit of a 1 off, but theres obviously another lurking around out there!
 
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slottler

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Hi all,

Well, after disconnecting my battery for half an hour, my turbo still doesn't work. So I must have damaged something when I disconnected/reconnected the EGR actuator. Actually, the electrical cables seemed quite brittle and perished, so I suspect that's the problem. So I'm hoping the EGR shunt will fix my problem... I'm just battling to find the resistors, without needing to go on a long drive!

Today I took another trip to the village... 2km there and 2km back. I know that the trip computer is not accurate over such short distances, but once again my fuel consumption was around 8l/100km (sorry, I don't speak mpg!) which I find quite good, considering that my engine didn't have time to warm up. I seem to recall consumption of around 11l/km for similar short journeys, with the turbo "working".

It does seem more economical with the turbo "disabled"!!!

Cheers!
 
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slottler

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Update

So I drove 50km in the end, to buy the parts to make my EGR shunt. The total cost was 38c, but as I had to buy packs of 10, it cost me R3.80. In Euros or dollars, that would be around 40c for ten of them! Expensive mod! :)

Although I have driven very few kms since losing my turbo, my car computer is reporting a remarkable 8l/100km with a cold engine for short journeys. It is remarkable because here are the official figures for this car:
Fuel consumption (economy) - urban 9.7 l/100 km
Fuel consumption (economy) - extra urban 5.1 l/100 km.

I'm tempted to go on a longer drive before I fit my shunt, to see whether the improved economy is for real. If it is, maybe I'll install a switch to "disable" my turbo after all...
 
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slottler

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Woot! My EGR shunt is installed and seems to be working... :)

I savaged an old modem because I wanted a switch... which I placed on the +12V supply to my shunt.

So now, depending on how the switch is set, I get either:
* EGR disabled, and hopefully more economy and grunt
* or voluntary Limp Mode ... which I think might be useful. I must still do a longer drive to confirm or refute my observation that the car seems much more economical without the turbo.

I finished the job at midnight, so I just went for a short drive to check that everything works. It does. :) I'm really looking forward to a proper drive tomorrow, to see whether I can notice a difference with the EGR disabled.

Cheers!
 
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Right... so I've been meaning to do my EGR shunt for months now, and I finally got it done. I feel better now that my engine breaths fresh air.

I've learned so much from reading these forums; thanks guys. So now I know that I should really remove and clean my inlet manifold and the EGR. And block the swirl flaps. But I'm lazy. So I'd like to ask for some opinions on how important that is.

Some history on the car:
- I bought her 10 years old from a granny, with 125k km on the clock. She had a FSH and was serviced every 10000km by a stealership. She was quite immaculate, although later I discovered that she had some problems...
- I live in a really small town. My daily commute is less than 2km each way. So she does a lot of short journeys, which isn't ideal for a diesel. I suspect that the previous granny-owner also did short journeys only.
- The engine is in great condition. My economy and power have always been great. She doesn't smoke (except for a tiny bit when I boot her ... normal for diesel, seeing as I normally drive her very gently). So I didn't do the EGR mod to solve a problem. I did it as preventative maintenance and hopefully to improve my grunt and economy.
- In the 2.5 years that I've had her, I've only done +- 15k km. Most of that is short journeys, but once or twice a year I drive 1000km journeys.

I'd appreciate some opinions. Just how gunked-up is my inlet manifold likely to be???? How important is it to clean the manifold? And perhaps more importantly... my swirl flaps seem fine. No leaks or anything. Hopefully they'll last longer with the EGR disabled. Do you guys really think that I need to blank-them-out?

Thanks!!!!

-
 

oigle

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Right... so I've been meaning to do my EGR shunt for months now, and I finally got it done. I feel better now that my engine breaths fresh air.

I've learned so much from reading these forums; thanks guys. So now I know that I should really remove and clean my inlet manifold and the EGR. And block the swirl flaps. But I'm lazy. So I'd like to ask for some opinions on how important that is.

Some history on the car:
- I bought her 10 years old from a granny, with 125k km on the clock. She had a FSH and was serviced every 10000km by a stealership. She was quite immaculate, although later I discovered that she had some problems...
- I live in a really small town. My daily commute is less than 2km each way. So she does a lot of short journeys, which isn't ideal for a diesel. I suspect that the previous granny-owner also did short journeys only.
- The engine is in great condition. My economy and power have always been great. She doesn't smoke (except for a tiny bit when I boot her ... normal for diesel, seeing as I normally drive her very gently). So I didn't do the EGR mod to solve a problem. I did it as preventative maintenance and hopefully to improve my grunt and economy.
- In the 2.5 years that I've had her, I've only done +- 15k km. Most of that is short journeys, but once or twice a year I drive 1000km journeys.

I'd appreciate some opinions. Just how gunked-up is my inlet manifold likely to be???? How important is it to clean the manifold? And perhaps more importantly... my swirl flaps seem fine. No leaks or anything. Hopefully they'll last longer with the EGR disabled. Do you guys really think that I need to blank-them-out?

Thanks!!!!

-

I cleaned out my manifold (sh1tty job) and inspected the flaps. Were in good order so I left them alone, knowing they wouldn't gunk up again. The egr particulates are quite abrasive and eventually damage the seals and they then leak - sometimes on to the swirl flap motor which then proceeds to fail.
If I was to do it again, I would probably delete the flaps and remove the swirl flap motor by using a resistor. I have had no issues since the cleanup - about 50K ago, so flaps are still working OK. However, they will fail eventually I guess, so removal would have been the better option. If you do remove the manifold to clean it up, I would suggest that you may as well do the flap removal at the same time. Not much more work. If you don't do the cleanup, leave well alone until it fails.
 
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slottler

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First day with no more EGR!

Hi!

Oigle, thanks for the comments. I've decided to do much as you suggested: and leave the inlet manifold, which isn't causing any trouble (yet!), well alone. Thanks. Hopefully my flaps will last longer sans EGR!

Of course, I couldn't wait to see whether my car performed better after the mod. Perhaps I shouldn't have read all the forum threads first, because I knew what to expect: More low-end grunt because the turbo spools-up quicker and the engine breaths pure fresh clean air. Some people commented on the "growl". Same top-end (foot-flat) as the EGR would be closed anyhow. Well, I was very frustrated to be stuck in traffic at 40km/h. I drove slowly to create a gap between me and the car ahead, then put foot briefly to hear the growl, then had to brake again. :-( I must go on a proper road soon!

Maybe I'm influenced by what I read, or maybe not. The change is subtle. But my motor sure does sound nice... like a V8 under load, as somebody suggested. And it does seem perkier. I gave her approx 1/4 throttle and just waited... and she pulled like a train. So nice.

But the best part for me, is the peace-of-mind. Once I learned about EGRs, I felt sinful knowing that my engine was getting gunked-up every time that I drove, and that I just had to do a small job to stop that. Now I've done the job, and it is like a weight off my shoulders. I did the right thing.

Even though the traffic limited me to puny speeds today, I'm sure that I drove harder than usual. I really wanted to hear the growl!!! (First the turbo whistles... it sounds a bit like a cop-siren and sometimes freaks me out!!! But if you keep your foot down, then comes the Growl... ;-) )

The point of the last paragraph is... and Turbopete is so gonna bliksem me for this... I drove harder than yesterday (with my turbo disabled) and now, with turbo-working and the EGR mod, she was even more economical than yesterday!

I know that our computers do lie to us, but normally only by 10%-or-so. Well, the official urban consumption for a C270CDi is 9.7l/100km. But I do such short journeys, that I am used-to-seeing around 11l/100km. Seems fair to me, and I've never been unhappy with her consumption. So I was excited yesterday to achieve around 8l/100km (according to the computer).

Well, today, the computer recorded 7.8l/100km for two trips down to the village. With my turbo working as it should, and the EGR shunt in place.

I really shouldn't complain. If the computer isn't an utter liar, those figures are wonderful!!! Gosh I love my car again.

It also suggests that Turbopete and Oigle might be right: that there is no benefit, economy-wise, to disabling the turbo via limp-mode. (But I still hope to do a better study!)

If anybody cares.. (well I like to read stuff like this!)... my computer recorded 5.5l/100km when I drove 900km two weeks ago. At normal highway speeds (120km/h) but slowing down each time I passed a town. The official extra-urban figure is 5.1l/100km, but I find that a bit optimistic (as expected).

Do the math... I do: a 60l tank should do over 1000km, at 5.5 or 5.1 l/100km. I just manage to do 900km on a tank... ie I can do the whole journey without refilling, but it is so tight that inevitably I land up putting in a few extra litres shortly before I get home. That says that my actual consumption is approx 6.67l/100km. Not as good as the official figures, but I still find that good.

I run fat 18" AMG mags on my car, so that would probably make her slightly less economical than official figures. (And at least she doesn't look like my granny's car anymore... those early W203 Elegance mags looked awful!) But I'm also keen to see whether the EGR mod helps economy at-all for the return 900km journey.

Ciao!
 

Parkgate

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Confused, I never hear the turbo in my 2.7CDI and I don't comprehend how it can be disconnected? Yes it sounds like a V8 when booted (a bit gruff and 'diesely' when not under load) thought that was normal for these engines...but hell the grin when you boot it and get that shove combined with the 'V8' noise...pity it runs out of steam around 40mph but hey ho its a diesel.
 

Parkgate

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Thinking about this a little more it sounds like you either have a MAF problem, or your filter filter need changing as it sounds like you keep dropping into 'engine limp mode' but without the warning lights on the dashboard...which happened to me, a dodgy MAF and fuel filter combined with a carboned up EGR valve.
 

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