 | |
Re: Throttle position discrepancy
Cars Maintenance General car maintenance (uk.rec.cars.maintenance)
 |
| | Thread Tools | Search this Thread | Display Modes |
#1
 
| |||
| |||
|
Re: Throttle position discrepancy -
05-07-2007
, 05:29 AM
|
I have an 03 2.0 dti Signum, and the engine management light keeps coming on (3 times in the last week), and the engine switching to limp home mode (until I turn the ignition off and on again). I took it to the local garage to get the codes read, and they said it gave a throttle position discrepancy code. He said their kit did not go into detail or carry out any kind of testing, and a VX dealer would be able to. There are several things it could be, and his only way of diagnosing would be to throw expensive parts at it one at a time. Is there a common fault on these engines? I have noticed a distinct lag (like turbo lag) recently, and am thinking it is either the actuator becoming weak, or the throttle being sticky/gummed up, just like my old favourite the idle control valve off my R reg veccy. Is stickyness usually the case, or is it a replacement job (I know VX replace ICV rather than clean them out). Bob I don't know about Vauxhalls, but VW/Audi etc cars with drive-by-wire |
position) sensor. If one track reads much different to the other, then
you get this error. Clean or replace the sensor would be my suggestion.
#2
| |||
| |||
|
|
I have an 03 2.0 dti Signum, and the engine management light keeps coming on (3 times in the last week), and the engine switching to limp home mode (until I turn the ignition off and on again). I took it to the local garage to get the codes read, and they said it gave a throttle position discrepancy code. He said their kit did not go into detail or carry out any kind of testing, and a VX dealer would be able to. There are several things it could be, and his only way of diagnosing would be to throw expensive parts at it one at a time. Is there a common fault on these engines? I have noticed a distinct lag (like turbo lag) recently, and am thinking it is either the actuator becoming weak, or the throttle being sticky/gummed up, just like my old favourite the idle control valve off my R reg veccy. Is stickyness usually the case, or is it a replacement job (I know VX replace ICV rather than clean them out). |
often get gummed up / partially seized because of the dreadful way the EGR
system works! Dismantle the pipework check and clean this first. Also check
the diaphragm is not split. Check all the vacuum pipes to it, and to the
control valves.
Also check the oil level- the vacuum pump is the first to knacker from poor
lubrication. (also infrequent oil changes- the 20k intervals are a joke)
If it is no better at all, have the codes re-read, and and if they are the
same as before, replace the PPS.
Tim..
#3
| |||
| |||
|
|
"Bob Smith" <bobsmith65 (AT) spoo (DOT) Usenet-News.net> wrote in message news  2C%h.318558$6P2.6361 (AT) newsfe16 (DOT) phx...I have an 03 2.0 dti Signum, and the engine management light keeps coming on (3 times in the last week), and the engine switching to limp home mode (until I turn the ignition off and on again). I took it to the local garage to get the codes read, and they said it gave a throttle position discrepancy code. He said their kit did not go into detail or carry out any kind of testing, and a VX dealer would be able to. There are several things it could be, and his only way of diagnosing would be to throw expensive parts at it one at a time. Is there a common fault on these engines? I have noticed a distinct lag (like turbo lag) recently, and am thinking it is either the actuator becoming weak, or the throttle being sticky/gummed up, just like my old favourite the idle control valve off my R reg veccy. Is stickyness usually the case, or is it a replacement job (I know VX replace ICV rather than clean them out). On these, there is a vacuum operated butterfly in the inlet manfold, these often get gummed up / partially seized because of the dreadful way the EGR system works! Dismantle the pipework check and clean this first. Also check the diaphragm is not split. Check all the vacuum pipes to it, and to the control valves. Also check the oil level- the vacuum pump is the first to knacker from poor lubrication. (also infrequent oil changes- the 20k intervals are a joke) If it is no better at all, have the codes re-read, and and if they are the same as before, replace the PPS. |
Do you know what codes were stored?
Throttle Discrepency sounds like the actual pedal being faulty, but I'm sure
that should cause the engine not to rev.
The Vacuum pipe spliting is very common on these, and the usual culprit is
the joining peice going to the solenoid control valve that's attached to the
bonnet landing panel. Easiest way to check is with a vacuum gauge. You
should get at least 0.7bar of vacuum at the supply to all the solenoid
valves (should be done with the engine hot, as that's when a weak vacuum
pump will show up the most). Any less, and the turbo wastegate doesn't hold
shut properly under full boost (it's vacuum controlled on these), leading to
Critical System Malfunction codes being stored, and the ECU then goes into
limp home mode.
#4
| |||
| |||
|
|
"Tim.." <the.farm.no (AT) spam (DOT) btinternet.com> wrote in message news:vtCdnVl4muD2jqLbnZ2dnUVZ8vmdnZ2d (AT) bt (DOT) com... "Bob Smith" <bobsmith65 (AT) spoo (DOT) Usenet-News.net> wrote in message news 2C%h.318558$6P2.6361 (AT) newsfe16 (DOT) phx...I have an 03 2.0 dti Signum, and the engine management light keeps coming on (3 times in the last week), and the engine switching to limp home mode (until I turn the ignition off and on again). I took it to the local garage to get the codes read, and they said it gave a throttle position discrepancy code. He said their kit did not go into detail or carry out any kind of testing, and a VX dealer would be able to. There are several things it could be, and his only way of diagnosing would be to throw expensive parts at it one at a time. Is there a common fault on these engines? I have noticed a distinct lag (like turbo lag) recently, and am thinking it is either the actuator becoming weak, or the throttle being sticky/gummed up, just like my old favourite the idle control valve off my R reg veccy. Is stickyness usually the case, or is it a replacement job (I know VX replace ICV rather than clean them out). On these, there is a vacuum operated butterfly in the inlet manfold, these often get gummed up / partially seized because of the dreadful way the EGR system works! Dismantle the pipework check and clean this first. Also check the diaphragm is not split. Check all the vacuum pipes to it, and to the control valves. Also check the oil level- the vacuum pump is the first to knacker from poor lubrication. (also infrequent oil changes- the 20k intervals are a joke) If it is no better at all, have the codes re-read, and and if they are the same as before, replace the PPS. I took it back to the garage that read the codes - I asked them to check all the pipes etc while it was in for an oil change, and they found nothing wrong. I wanted to book it in for them to strip it down to clean out the throttle assembly. He seems to think it is something electronic? He says he will strip it down and clean it if I insist, but does not think it is gummed up. Is gumming up the most common problem? If the EGR comes in the flow before the throttle, then I would go with this (from my ICV / crank gas gumming up / fitting oil trap fixing it experience), but he thinks it is unlikely. Symptoms other than engine light/limp home include slow acceleration / seems like wrong gear selected all the time, no acceleration until 2000 revs. It feels like turbo lag, and on a couple of occasions the engine light came on just as the engine started picking up (I assume the ECU gave up waiting for the throttle to move just as it started moving). Does this point to any common problem? |
anyway.
What Tim is talking about, is the swirl control valves, but they generally
don't cause the symptoms you're having.
Sounds very much like a vacuum problem, or a MAF (mass air flow) sensor
problem.
Lack of vacuum will give those exact problems, and so could a faulty MAF
sensor.
#5
| |||
| |||
|
|
"Bob Smith" <bobsmith65 (AT) spoo (DOT) Usenet-News.net> wrote in message news:HH71i.229666$ZA5.120241 (AT) newsfe15 (DOT) phx... "Tim.." <the.farm.no (AT) spam (DOT) btinternet.com> wrote in message news:vtCdnVl4muD2jqLbnZ2dnUVZ8vmdnZ2d (AT) bt (DOT) com... "Bob Smith" <bobsmith65 (AT) spoo (DOT) Usenet-News.net> wrote in message news 2C%h.318558$6P2.6361 (AT) newsfe16 (DOT) phx...I have an 03 2.0 dti Signum, and the engine management light keeps coming on (3 times in the last week), and the engine switching to limp home mode (until I turn the ignition off and on again). I took it to the local garage to get the codes read, and they said it gave a throttle position discrepancy code. He said their kit did not go into detail or carry out any kind of testing, and a VX dealer would be able to. There are several things it could be, and his only way of diagnosing would be to throw expensive parts at it one at a time. Is there a common fault on these engines? I have noticed a distinct lag (like turbo lag) recently, and am thinking it is either the actuator becoming weak, or the throttle being sticky/gummed up, just like my old favourite the idle control valve off my R reg veccy. Is stickyness usually the case, or is it a replacement job (I know VX replace ICV rather than clean them out). On these, there is a vacuum operated butterfly in the inlet manfold, these often get gummed up / partially seized because of the dreadful way the EGR system works! Dismantle the pipework check and clean this first. Also check the diaphragm is not split. Check all the vacuum pipes to it, and to the control valves. Also check the oil level- the vacuum pump is the first to knacker from poor lubrication. (also infrequent oil changes- the 20k intervals are a joke) If it is no better at all, have the codes re-read, and and if they are the same as before, replace the PPS. I took it back to the garage that read the codes - I asked them to check all the pipes etc while it was in for an oil change, and they found nothing wrong. I wanted to book it in for them to strip it down to clean out the throttle assembly. He seems to think it is something electronic? He says he will strip it down and clean it if I insist, but does not think it is gummed up. Is gumming up the most common problem? If the EGR comes in the flow before the throttle, then I would go with this (from my ICV / crank gas gumming up / fitting oil trap fixing it experience), but he thinks it is unlikely. Symptoms other than engine light/limp home include slow acceleration / seems like wrong gear selected all the time, no acceleration until 2000 revs. It feels like turbo lag, and on a couple of occasions the engine light came on just as the engine started picking up (I assume the ECU gave up waiting for the throttle to move just as it started moving). Does this point to any common problem? Diesels generally don't have throttle assemblies, and certainly not this one anyway. What Tim is talking about, is the swirl control valves, but they generally don't cause the symptoms you're having. Sounds very much like a vacuum problem, or a MAF (mass air flow) sensor problem. Lack of vacuum will give those exact problems, and so could a faulty MAF sensor. Would it cause the throttle position discrepancy engine code? I would |
Bob
--
Posted via a free Usenet account from http://www.teranews.com
#6
| |||
| |||
|
|
"moray" <mtb_hyphen_rules (AT) hotmail (DOT) co.uk> wrote in message news:f24vjm$4kg$1$8302bc10 (AT) news (DOT) demon.co.uk... "Bob Smith" <bobsmith65 (AT) spoo (DOT) Usenet-News.net> wrote in message news:HH71i.229666$ZA5.120241 (AT) newsfe15 (DOT) phx... "Tim.." <the.farm.no (AT) spam (DOT) btinternet.com> wrote in message news:vtCdnVl4muD2jqLbnZ2dnUVZ8vmdnZ2d (AT) bt (DOT) com... "Bob Smith" <bobsmith65 (AT) spoo (DOT) Usenet-News.net> wrote in message news 2C%h.318558$6P2.6361 (AT) newsfe16 (DOT) phx...I have an 03 2.0 dti Signum, and the engine management light keeps coming on (3 times in the last week), and the engine switching to limp home mode (until I turn the ignition off and on again). I took it to the local garage to get the codes read, and they said it gave a throttle position discrepancy code. He said their kit did not go into detail or carry out any kind of testing, and a VX dealer would be able to. There are several things it could be, and his only way of diagnosing would be to throw expensive parts at it one at a time. Is there a common fault on these engines? I have noticed a distinct lag (like turbo lag) recently, and am thinking it is either the actuator becoming weak, or the throttle being sticky/gummed up, just like my old favourite the idle control valve off my R reg veccy. Is stickyness usually the case, or is it a replacement job (I know VX replace ICV rather than clean them out). On these, there is a vacuum operated butterfly in the inlet manfold, these often get gummed up / partially seized because of the dreadful way the EGR system works! Dismantle the pipework check and clean this first. Also check the diaphragm is not split. Check all the vacuum pipes to it, and to the control valves. Also check the oil level- the vacuum pump is the first to knacker from poor lubrication. (also infrequent oil changes- the 20k intervals are a joke) If it is no better at all, have the codes re-read, and and if they are the same as before, replace the PPS. I took it back to the garage that read the codes - I asked them to check all the pipes etc while it was in for an oil change, and they found nothing wrong. I wanted to book it in for them to strip it down to clean out the throttle assembly. He seems to think it is something electronic? He says he will strip it down and clean it if I insist, but does not think it is gummed up. Is gumming up the most common problem? If the EGR comes in the flow before the throttle, then I would go with this (from my ICV / crank gas gumming up / fitting oil trap fixing it experience), but he thinks it is unlikely. Symptoms other than engine light/limp home include slow acceleration / seems like wrong gear selected all the time, no acceleration until 2000 revs. It feels like turbo lag, and on a couple of occasions the engine light came on just as the engine started picking up (I assume the ECU gave up waiting for the throttle to move just as it started moving). Does this point to any common problem? Diesels generally don't have throttle assemblies, and certainly not this one anyway. What Tim is talking about, is the swirl control valves, but they generally don't cause the symptoms you're having. Sounds very much like a vacuum problem, or a MAF (mass air flow) sensor problem. Lack of vacuum will give those exact problems, and so could a faulty MAF sensor. Would it cause the throttle position discrepancy engine code? I would expect it to be actuated by a stepper motor rather than vacuum. |
not critical, as the sole purpose of them is to partially restrict the flow
in through one inlet port on each cylinder to create a swirl effect and
improve combustion under set conditions. They are held open by spring
pressure, and closed by the vacuum. If they get gunked up, they can stick
shut or open, which usually causes some loss of power (more so at high revs
due to restricted airflow), and smoking.
Personally, I think you've been given the wrong description of the fault
codes. I'd suspect it's more likely to be a Boost Pressure Discrepency
fault, but the garage is using diagnostic kit that doesn't supply the
correct description for the code (and the garage doesn't have a clue about
diesels). Can you get the garage to supply the actual fault code numbers?
I'd guess it's a P0101, or P1101 code that's stored...
|
« Previous Thread
|
Next Thread »
| Thread Tools | Search this Thread |
| Display Modes | |
Linear Mode
| |
Powered by vBulletin Version 3.5.4
Copyright ©2000 - 2008, Jelsoft Enterprises Ltd.
Copyright ©2000 - 2008, Jelsoft Enterprises Ltd.