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A little cough...

9318 Views 87 Replies 18 Participants Last post by  smhaze
Dear all,

Not a huge problem this, it certainly doesn't happen all the time, and it's mostly out of curiosity that I'm enquiring.

I find, occasionally, in 2nd and 3rd gears when accelerating slowly (such as when coming off a roundabout and getting back up to speed), that the 159 gives a little cough. It tends to happen at just over 2000 rpm. It's almost as if briefly the engine loses fuel or air supply.

It's a diesel, a 1.9 JTDm.

The EGR and throttle body have recently been removed and cleaned, as I thought this could have caused some of it. I have not had the EGR blanking plate / remap done.

Another thing that may valuable to know is that the acceleration profile in first gear (only) is not smooth. Up to around 3000rpm it is as smooth, but after this there is a giant kick up to 4000. I was thinking that perhaps the lumpy acceleration profile and the cough are related.

Has anyone else experienced anything similar, or have any ideas about what may be causing this?

All the best,

(Apart from this a very happy 159 owner)
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But still....noone has tried to put in a blankingplate & drive with that alone before mounting the "simulator"?
You mean compare the the simulator with no simulator? Plenty have had just the blanking plate.
I'm testing this for you as we speak.

So I had the `little cough problem` since +- 10 days. Especially when the engine is cold, around 1800 - 2000 rpm, and pushing the pedal just a few mm down. Resulting in the boostpressure to drop to zero. When giving a little more gas, there is a delay followed by a hikkup, afterwards things are normal again.

I had no issues starting though. What I did see was a 13% milage increasement over these days. I keep track of my fuelings:

First I thought it had something to do with my new tires (the milage increasement), but I couldn't ignore those `coughs`, so it had to be EGR related.

I've ordered the EGR simulator/cheater from ebay, and it's still on its way. However I couldn't stand my car being suffocated while waiting for the device. So I made my own EGR blanking plate out of 4mm RVS and as predicted after three runs the engine light came on. I've driven 200KM so far. No noticable power inprovement, but hey, I just had the problem for 10 days so thats different than having the problem for over a year.

The milages did improve and it's back to normal I guess, maybe a little better than normal. Atleast thats what the ECU is telling me, and it has proven to be quite accurate over time. I know for sure in 3 days when my tank is empty again.

I will leave the blanking plate on until next weekend, then i'm going to add the EGR simulator/cheater and see if that makes any difference in milage or power.
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Did the coughing disappear after you installed the plate? Loooking forward to hear if the simulator makes any diff. Beside turning of EML-light :)
Forgot to mention it did cure the cough as expected. I would expect that the simulator makes a difference, it changes the data generated by the MAF. I think the MAF sensor produces more sensative and accurate data than the MAP sensor does.

I even got an regen this morning, the current avg between regens is 404KM. When I notice the next regen, I will see what the new distance is and see if that's also improved.
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So I fitted the simulator/cheater today. I will post those results next week.

The results of the blanking plate with a check engine light:

The fuel econemy is back to old values: 15.41 km/l || 36.25MPG However this was incl 3 regenerations, so i'm certain it improved a little bit more than normal.

The strang thing though that was that it looked like my car switched between maps (if that is even possible). Perhaps because it doens't really know which sensor to trust, depending on the reading it switches map? I drive the same 200km highway everyday, since I live in the very flat netherlands I know this road very well. On specific points on the road it could do 14.5km/l || 34.11MPG while driving 120km/h 75Mph the next day, on the same part of the road with the same outside conditions (wind speed/wind direction) while driving the same speed, it could do 17.5km/l || 41.16mpg. Encouter this phenomena multiple times. Could be just an coincidence.

Anyway I fitted the simulator and did some ECU readings to see if it makes any affect on any of the sensor readings. Attached you will find 4 files (csv extension) This you can open with multiecuscan and check or uncheck some of the parameters to get a better view.

2 of the files are before I fitted the simulator/cheater. 1, in neutral gear with some various engine speeds. The other one is a short ride around the block. Same goes for the 2 files with the EGR simulater/cheater in place.

It seems that my turbo overboosts, do not really know if that's because of the EGR blanking plate, haven't noticed this overboost before.

Anyway, enough talk time for some attachments.

EGR simulator/cheater FiatMultiEcoScan graphs


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Might be worth your while putting some fuel readings onto a graph, your air figures seem to be all over the place. How is it driving in general now, with blanking, and then with simulator ?
Below is a link with a graph with a bunch of parameters. Don't know if I got all the rights ones though.

Driving is just normal, no difference with the simulator. I deliberately drove around without the simulator for a week, to see if it made any drivability changes.

As I descriped earlier in this thread, the fuel economy changes from time to time on the same road & conditions. However I don't feel any differences, just seeing a lower economy than normal. I also have the feeling the turbo pressure is just a bit higher than it would normaly be. For example, driving 120/kmph - 74 mph (flat road) the turbo gauge pressure would be around +- 0.5 and my fuel econemy would be 17kml/ 40mpg. The other case on the same road same speed ect.... would result in +- 14kml 32mpg and the turbo gauge would read +-0.7

Any of the other members using the cheater/simulator experiencing the same thing?

MES graph download link (Import the file with MultiEcoScan)
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Finally I got a remap done, so the EGR is now deleted in the ECU. Thus I have a simulator which I don't use anymore.

PM if anyone is interested.
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