ETM Theory
#1
09-24-2005, 02:51 AM
ETM Theory
Hi,
With reference to the Electronic Throttle Module issue discussed elsewhere on this site.
I have just obtained a 1999 V70. It's at the workshop at present undergoing diagnosis as to why its beeen stalling. Whilst discussing the V70 in general terms with Greg the mecahnic, I asked him about the reliabilty of ETMs. He has replaced 1, and the Volvo dealer 3. He finds cleaning them usually solves
issues. I asked him where the oil breather pipe was as this was cleaned before the car was delivered. He pointed out its location: A rubber pipe runs from the fuel rail (probably to help keep the fumes cool) and then it is plumbed into - would you believe the ETM. So in essence greasy fumes enter and fowl the ETM. Such a stupid setup.
I am now looking to re-route the hose and plumb it into the base of the air filter, so the fumes can be filtered by the filter not the ETM. I have also ordred a K&N filter to replace the Volvo one.
I look forward to your views.
Cheers .... Nick
With reference to the Electronic Throttle Module issue discussed elsewhere on this site.
I have just obtained a 1999 V70. It's at the workshop at present undergoing diagnosis as to why its beeen stalling. Whilst discussing the V70 in general terms with Greg the mecahnic, I asked him about the reliabilty of ETMs. He has replaced 1, and the Volvo dealer 3. He finds cleaning them usually solves
issues. I asked him where the oil breather pipe was as this was cleaned before the car was delivered. He pointed out its location: A rubber pipe runs from the fuel rail (probably to help keep the fumes cool) and then it is plumbed into - would you believe the ETM. So in essence greasy fumes enter and fowl the ETM. Such a stupid setup.I am now looking to re-route the hose and plumb it into the base of the air filter, so the fumes can be filtered by the filter not the ETM. I have also ordred a K&N filter to replace the Volvo one.
I look forward to your views.
Cheers .... Nick
#2
09-27-2005, 01:06 PM
RE: ETM Theory
Nick, since you have perused the forum and found postings re: throttle body...........you undoubtedly have found many postings by me as I am, or course, interested in the class action that was filed. At any rate, I can understand your theory but, Volvo spent a lot of time developing over the years, the etm and it seems to work well.................with the exception that it was manufactured in Italy and it is not a German quality Bosch part. I wonder if re-routing "the hose" would defeat another purpose of plumbing it into the etm in the first place. I hope Tech responds to your posting as it is indeed interesting. At any rate, I have found that running a can of Ventil Sauber and a can of Jectron on a periodic basis in conjunction with having the etm removed and cleaned by the dealer does wonders with the mileage and performance of the 2.3 turbo.
R.
R.
#3
09-27-2005, 09:20 PM
RE: ETM Theory
Out of all the hundreds of throttle body's I have cleaned I haven't seen much oil in them.
It is a carbon build up just like on all other cars.
If the throttle body is cleaned regularly then it lasts alot longer.
I have seen cars that had it cleaned and the car has 120,000 miles on the original throttle body.
It is a carbon build up just like on all other cars.
If the throttle body is cleaned regularly then it lasts alot longer.
I have seen cars that had it cleaned and the car has 120,000 miles on the original throttle body.
#4
09-28-2005, 08:03 AM
RE: ETM Theory, Breather & Fuel Pump
Hi Tech and Reg,
Concerning the engine breather. I will probably go ahead with my conversion as I think the current arrangement has wiskers on it. However here is the reply from Don Wilson below: Incidently our V70 went into stalling mode last Friday. Greg my Volvo engineer checked for codes - none - he said the fuel pump had seen better days. Now the previous owner sold the V70; because every few months over the past 2 years it would loose power and stall, restarting would solve the issue. At any rate he went to his Volvo dealer who replaced the crank angle sensor, oxygen sensor, mass airflow sensor - twice, but the problem would re-occur. Hence he traded on a newer V70. It seems that the fuel pump is not recognised by the onboard computer, and a fault would not be recorded. A fuel pressure test would not necessarily pick up the problem which is ususlly intermittent. With the new pump in place the V70 is now OK. The previous owners spent a lot of money for nothing. Maybe the newer Volvo mechanics only rely on diagnostic computer technology and common sense has done a "Bill Gates" and gone out the window.
Hi Nick,
I have company today but I thought this quick reply to Gorgi might be of interest.
Don
Gorgii's message and my reply
Mr.. Wilson, I just want to call attention to a perceived contradiction in the dealer information section on your website. On the "For the Dealer" page, it says that to your knowledge, Volvo has never informed the dealerships of the real cause of the ETM problems. At the same time, your site refers readers to a URL for an attorney's website which contains the following statement (my emphasis):
The key phrase is "the real cause".
During the course of the litigation, we obtained internal documents from Volvo that showed the ETM problem was much larger in scope than we had initially believed. These documents reveal that the
defect exists not only in the 1999 through 2001 model years (as the technical service bulletins Volvo distributed to its dealer network indicate), but in later model year vehicles as well.
The original lawsuit only addressed the 'secret' part of the TSB and I think they had no knowledge of how the ETM was built and what was the real cause of the failure.
The Dealer page on your website also states: "In some cases it seemed that excessive black gunk built up was causing a 'sticky' throttle that responded to cleaning of the throttle bore. The reason this seems to work is that in the early stages the failure is very intermittent and the fact that cleaning is helpful is purely coincidental. (my emphasis)" I ask you, because you are an expert engineer familiar with this problem, whether the black gunk which seemed to be causing the "sticky" throttle could be the result of the plastic being scraped off by the "wipers" on the ETM.
No, the two are completely different.
The 'black gunk' is something that is often associated with throttle bores in all types of gas engines. There is a system on cars called the exhaust gas recirculation system. It is a hose that sucks air out of the crankcase of the engine and traps any 'blow by' that little bit of combustion products that get past the piston rings and the intake and exhaust valve seals. Years ago this was just vented to the atmosphere, but now it is carried by a hose to the intake system, after the air filter but before the turbo (if present) and the throttle. As the intake air, now carrying the contaminant loaded crankcase air, passes though the throttle plate it is now swirling around and heavier particles of oil and other 'gunk' are slung outward and some stick to the throttle bore. On the ETMs I have seen the deposit is only a smear, with no obvious thickness. None of the ETMs I have seen had enough 'gunk' to cause sticking.
The thick film resistor material is in the end caps and separated from the bore by a ball bearings with double oil and dust seals and an 'O' ring under the bearing. The amount of the thick film resistor is probably less than one pass of fingernail polish with the 'in-the-cap brush'.
Does this help?
If cleaning is helpful, might it be because the sensors can operate better with the black gunk removed (there is none there) (and, as such, no longer interfering), therefore making the cleaning NOT just coincidentally helpful? If this is the case (if cleaning is more than just coincidentally helpful), then it would make sense that Volvo had suggested throttle bore cleaning as a way to improve performance and, at the same time, extend the use of the part until the expiration of the warranty. Maybe I am not interpreting your remark correctly. I am asking about the cleaning of the throttle bore being referred to as only coincidentally helpful. It seems that the cleaning is more than just coincidentally helpful because my car has seemed to accelerate more smoothly after it has been serviced. Maybe what you mean by coincidental is that the cleaning helps, but doesn't actually fix the real problem. Obviously, I am confused by what you mean there.
I cannot explain the improved performance. The dealer might have uploaded some revised software that made a difference. He might have tightened some hose clamps that were allowing un metered air to enter the engine. It could also be that in moving the throttle plate by hand while cleaning it, the throttle shaft was shifted a slight amount so the wiper was on a fresh surface of the thick film resistor.
Even after servicing, when the engine seemed to run more smoothly again, the problem persisted concerning the cruise control working intermittently. I was told yesterday that the cruise control operates off a vacuum, and when it senses loss of pressure, it will cut off.
I will check on this but I think one of the primary reasons to go to fly-by-wire is to eliminate the vacuum system used in cars since the 1950s. Now it only requires some lines of computer code to integrate the digital speedometer (monitor the speed), the master computer (to compute the error signal), the steering wheel switches (start, faster, slower and off), the brake light switch (to cancel the cruise control) and the electronic throttle (to control the air flow to the engine).
I think your website is a wonderful resource and offers very professional information. As such, it is really a public service. I truly appreciate your sharing your expertise, and your providing readers with links to other helpful sites..
Thanks for your kind words and taking the time to read and try to understand the what is going on. I appreciate the critique.
Don
Concerning the engine breather. I will probably go ahead with my conversion as I think the current arrangement has wiskers on it. However here is the reply from Don Wilson below: Incidently our V70 went into stalling mode last Friday. Greg my Volvo engineer checked for codes - none - he said the fuel pump had seen better days. Now the previous owner sold the V70; because every few months over the past 2 years it would loose power and stall, restarting would solve the issue. At any rate he went to his Volvo dealer who replaced the crank angle sensor, oxygen sensor, mass airflow sensor - twice, but the problem would re-occur. Hence he traded on a newer V70. It seems that the fuel pump is not recognised by the onboard computer, and a fault would not be recorded. A fuel pressure test would not necessarily pick up the problem which is ususlly intermittent. With the new pump in place the V70 is now OK. The previous owners spent a lot of money for nothing. Maybe the newer Volvo mechanics only rely on diagnostic computer technology and common sense has done a "Bill Gates" and gone out the window.
Hi Nick,
I have company today but I thought this quick reply to Gorgi might be of interest.
Don
Gorgii's message and my reply
Mr.. Wilson, I just want to call attention to a perceived contradiction in the dealer information section on your website. On the "For the Dealer" page, it says that to your knowledge, Volvo has never informed the dealerships of the real cause of the ETM problems. At the same time, your site refers readers to a URL for an attorney's website which contains the following statement (my emphasis):
The key phrase is "the real cause".
During the course of the litigation, we obtained internal documents from Volvo that showed the ETM problem was much larger in scope than we had initially believed. These documents reveal that the
defect exists not only in the 1999 through 2001 model years (as the technical service bulletins Volvo distributed to its dealer network indicate), but in later model year vehicles as well.
The original lawsuit only addressed the 'secret' part of the TSB and I think they had no knowledge of how the ETM was built and what was the real cause of the failure.
The Dealer page on your website also states: "In some cases it seemed that excessive black gunk built up was causing a 'sticky' throttle that responded to cleaning of the throttle bore. The reason this seems to work is that in the early stages the failure is very intermittent and the fact that cleaning is helpful is purely coincidental. (my emphasis)" I ask you, because you are an expert engineer familiar with this problem, whether the black gunk which seemed to be causing the "sticky" throttle could be the result of the plastic being scraped off by the "wipers" on the ETM.
No, the two are completely different.
The 'black gunk' is something that is often associated with throttle bores in all types of gas engines. There is a system on cars called the exhaust gas recirculation system. It is a hose that sucks air out of the crankcase of the engine and traps any 'blow by' that little bit of combustion products that get past the piston rings and the intake and exhaust valve seals. Years ago this was just vented to the atmosphere, but now it is carried by a hose to the intake system, after the air filter but before the turbo (if present) and the throttle. As the intake air, now carrying the contaminant loaded crankcase air, passes though the throttle plate it is now swirling around and heavier particles of oil and other 'gunk' are slung outward and some stick to the throttle bore. On the ETMs I have seen the deposit is only a smear, with no obvious thickness. None of the ETMs I have seen had enough 'gunk' to cause sticking.
The thick film resistor material is in the end caps and separated from the bore by a ball bearings with double oil and dust seals and an 'O' ring under the bearing. The amount of the thick film resistor is probably less than one pass of fingernail polish with the 'in-the-cap brush'.
Does this help?
If cleaning is helpful, might it be because the sensors can operate better with the black gunk removed (there is none there) (and, as such, no longer interfering), therefore making the cleaning NOT just coincidentally helpful? If this is the case (if cleaning is more than just coincidentally helpful), then it would make sense that Volvo had suggested throttle bore cleaning as a way to improve performance and, at the same time, extend the use of the part until the expiration of the warranty. Maybe I am not interpreting your remark correctly. I am asking about the cleaning of the throttle bore being referred to as only coincidentally helpful. It seems that the cleaning is more than just coincidentally helpful because my car has seemed to accelerate more smoothly after it has been serviced. Maybe what you mean by coincidental is that the cleaning helps, but doesn't actually fix the real problem. Obviously, I am confused by what you mean there.
I cannot explain the improved performance. The dealer might have uploaded some revised software that made a difference. He might have tightened some hose clamps that were allowing un metered air to enter the engine. It could also be that in moving the throttle plate by hand while cleaning it, the throttle shaft was shifted a slight amount so the wiper was on a fresh surface of the thick film resistor.
Even after servicing, when the engine seemed to run more smoothly again, the problem persisted concerning the cruise control working intermittently. I was told yesterday that the cruise control operates off a vacuum, and when it senses loss of pressure, it will cut off.
I will check on this but I think one of the primary reasons to go to fly-by-wire is to eliminate the vacuum system used in cars since the 1950s. Now it only requires some lines of computer code to integrate the digital speedometer (monitor the speed), the master computer (to compute the error signal), the steering wheel switches (start, faster, slower and off), the brake light switch (to cancel the cruise control) and the electronic throttle (to control the air flow to the engine).
I think your website is a wonderful resource and offers very professional information. As such, it is really a public service. I truly appreciate your sharing your expertise, and your providing readers with links to other helpful sites..
Thanks for your kind words and taking the time to read and try to understand the what is going on. I appreciate the critique.
Don
#5
09-28-2005, 01:31 PM
RE: ETM Theory, Breather & Fuel Pump
Good argument Nick, but the problem only seems to occur with Volvo. You must realize that many manufacturers now use an ETC, such as Mercedes, and I have yet to hear of an issue with them. All of the crank case breather hoses go into the combustion chamber 'ahead' of the ETC as the input has to be monitored by the 'computer'. At any rate, I acknowlege what you are proposing to do and give you plaudits for doing it. On the other hand, I still cannot fathom why the manufacturers did not plan this course rather than plumbing the system as they do? Let us know how your set up works with periodic up-dates.
R.
R.
#7
10-02-2005, 10:21 PM
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