Car shocks when coming off the throttle after ETM Clean

[erik]

I have a 01XC model ( november 2000 one) with 272.000KM on the clock with a 2nd ETM for about 120.000km. It started to show irregular idle and needed a service (at 270.500) so I took the ETM out and cleaned it this fixed the irregular idle. Also at the same time cleaned the MAF about 80.000km old 4th clean ( clean it every 3 services or so), did a drain and fill with mobil 3309 on the the gearbox, new oil filter and oil and new spark plugs (all orginal volvo with new ETM gasket). After all this it ran fine for about 1 week then it started to misbehave, when coming off the throttle slowly it give a big jolt or shock even the passengers notice it like the engine dies, then picks up again. I double checked all the hoses and intake pipes I can not see any obvious leaks or disconnected hoses. other then the shock the cars runs ok no error codes or check engine light either, fuel consumption stayed the same ( car always runs the same road to and from work with the same driver). I also think it might be slightly down on power too, like it does not build enough turbo pressure. It burns about a liter of oil avery 2000km it has done so for 160.000 km and oil consumptions stays stable.

I am thinking maybe the TCV ( turbo control valve) or the boost pressure sensor might be the cullprit. My ETM is a yellow sticker one which after reading a lot of posts is the volvo improved version one, this could be also the root cause but before spending the 400-500dollar xedomex ETM rebuilt I want to make sure that the ETM is causing the issue.

Any suggestions are welcome. I would love to keep it going for another 30-50k or so till 2nd Timingbelt replacement. but if this repair goes about 1000bucks the car is doomed for the scrapper. Don't get me wrong she did us very well and gave all here live to us and am very happy with here but it comes to the point that a repair is not worth the value of the car........which I hope is not the case.....

I do not have the dice tool just a standard obd2 reader which did not see any codes.

[howardc64]

When I had random short throttle cut offs, I had no code on VIDA/DiCE and it was MAF. I finally found it by swapping the MAF with another car.

When my throttle was unresponsive, I didn't get a jolt when it became unresponsive. Just a sudden lost of power. However, then the throttle became responsive again a few second later, there would be a slight jolt as the power came on.

Eventually, the engine would die randomly coming to a stop.

120km on an ETM could obviously be another culprit. Best to do an ETM test on a VIDA/DiCE tool.

[erik]

Hi Howard

thanks for the feedback, I swapped the MAF also already but same symptoms on both MAF. I now also did this Xemodex test:

http://www.xemodex.com/technologyimp...ow%20Chart.pdf


The ETM seems to do the 6 second thing but ever since I lost the cruise control it does no longer turns on, I will try the 20-30 minute battery disconnect to see if that brings the cruise back.
I also have notice when driving arround 20 km/h just on the idle I think it is in 2nd gear the RPM starts moving around by about 300-400 RPM you can feel the car go faster slower faster slower about 3 times then it sticks at 1100 rpm. Tonight I will try to do the break cleaner stall thing they mention in the Xemodex sheet to see if there are not leaks in anywhere


Also checked the boot pressure sensor in the intake tube to the etm to see if any debry was clogging it it was clean. Also for the 4th time rechecked all the hose clamps and pipe for signs of leaks again.

[howardc64]

VIDA/DiCE ETM test is described in page 3 and 4 in this link

https://www.box.com/shared/cjh7pkl0cs

The 6s whin+click is probably some kind of calibration step. When I fixed my ETM's TPS, I had the ETM out but plugged in. I when I turn on power, I can see the butterfly vibrate and finally clicks into the default position. Anyhow, I think it is an indication ETM internal electronics is functioning properly (But it doesn't mean the TPS sensors are not worn)

Before you disconnect the battery, read this to avoid damaging your CCM

http://howardsvolvos.webs.com/miscissues.htm#207347288

Running okay for 1 week would suggest your reassembly was good with no loose connections.

At 120km, I would do an ETM test with VIDA/DiCE just to know what you are dealing with there.

Not sure if you had the codes read by generic code reader or VIDA/DiCE. VIDA/DiCE would give you all Volvo specific codes. Next best step is probably to get full info on ETM test and any codes with VIDA/DiCE.

[erik]

problem found I think

The intake pipe between the intercooler and etm has disintegrated on the etm side. I noticed whan cleaning the etm that the pipe was not that flexible at that side. today on the way home I got the check engine light with P1238 and p0121 which means it can not build presure the turbo has to work more due to either a PCv broken or a leak. in my case a leak the pipe cracked and split all around on the connection to the etm.

So I am pretty sure it was leaking causing the issues I have seen the last week I be off to volvo tomorrow for such a new pipe. I hope they do not cost a arm and a leg......

[erik]

She is fixed!!!! that made my day today, new pipe installed and she runs as new again. Thanks Howard for all tips and tricks, I do not post a lot on this forum but I do read a lot on it and without all the mentioned fixes I never would have found the problem.

Just FYI the new pipe was 183 Canadian Quebec tax included.

[howardc64]

Congrats. I should have mentioned assembling that hose onto the ETM is a little tricky. Many people have messed up part of the fitting without getting a good feel on how to push it back on. On the first one I did, I eventually discovered I have folded about 1/8" of the lip inwards but caused no leaks.

Anyway, good work finding it and congrats on a fully healthy car again