Loss of rpm above 3000

[mas]

Something new, it has happened twice in the past week, while going through the gears, the acceleration seems to slow down once it hits 3000 rpm.  At slow speeds, I can hear the turbo in the background.  So far twice, both times the next time I drove, the engine when through the gears normally.  What gives?

[Nigel]

Sounds like the car went into limp mode but it doesn’t always set a check engine light. When it happens if you can easily pull over, stop and shut engine off for about twenty seconds you will hear a click from the Sam by your knees then you are good to go until it happens again.  When mine goes into limp it’s all I can do to maintain highway speed on the flats.  You need to scan for codes to see what is happening.

 

Nigel

[smart142]

After the click wait for at least 5 seconds to reset the computer.

More often than not a malfunctioning EGR is the cause of the problem.

[mas]

would poor fuel mileage be associated with this situation?

[mas]

Since it looks like I am going down the EGR road, research has led me to installing an egr blocking plate and/or removing the solenoid and turning the cartridge 180 degrees.  

My question is, which one do I do?  No CEL on the dash but at times the car goes into limp mode (is it just a matter of time?) If I go blanking plate, would I still remove the EGR valve and give it a clean? And since I am there, do the 180 thing and not bother with the blanking plate. Is one easier than the other or is it the case of 'since I am already up to my elbows may as well..."

[Getfuzzy]

I went with a blocking plate as I could not get the egr to even move. The SS plate I got had ears so I loosed the bolts and slid it on (only 7 or 8 bucks at the time, hard to find now). Exceeding the boost limit could also set off limp mode. My limp mode and cel was caused by a poor connection from the egr, unplugged it, cleaned the contacts and alls good. The code was for the egr but having blocked it almost as soon as I got the car, I was pretty sure it couldn't be a plugged up egr.

[mas]

It was gone into limp mode about 3-4 times now and what I noticed on the last one was that the engine was cold and I gave it a hard acceleration in first.  Therefore the over boost mentioned above fits this situation.

[Willys]

3 minutes ago, mas said:

It was gone into limp mode about 3-4 times now and what I noticed on the last one was that the engine was cold and I gave it a hard acceleration in first.  Therefore the over boost mentioned above fits this situation.

IF you can afford buy yourself something like a ScangageII scanner that runs as you are driving, it shows you plenty of information as you drive such as boost levels RPM, speed, fuel consumption etc etc. I have mine set so I can always watch boost pressure, RPMs and fuel consumption both actual and over trip time. It's how I usually control my driving...lol.

Any way......IMHO...I suggest that you research boost pressure adjustment as in turning the boost locking adjustment nuts on the waste gate rod to the left a few turns which if I remember correctly reduces the boost available so you do not over boost as easily. It only takes 5 seconds at over 16 psi or so of boost to trigger the ECU to sygnal a limp mode.   Next I would be removing your EGR soaking it in gasoline for a while and cleaning it as best you can, hopefully to near new condition. Now you can decide what to do with it next. Either turning it 180 degree and reinstalling it back on to the engine OR blocking off the EGR and installing a emulator or simply running the cleaned up EGR hanging and grounded to the engine bay somewhere. It will run perfectly well as long as it's plugged into original wiring harness and the EGR is grounded to the engine using a wire.  BUT you have taken it out of the dirty operational system so it'll never get gummed up again. I ran my beater this way for years. I have also run the emulator for years in my good car.
IF you want to open up your engine bay for more space ......if you do remove the EGR out of the system you can now remove the heater hoses that run to the exhaust manifold to the thermostat location. There will be about 4 feet of heater hose removed, it makes a difference when getting your hands etc into the engine bay to work on things. 
IF, you can cut a piece of metal and drill two holes into it you can make your own plate to block off the EGR and use silicon or gasket material to seal it. 

Again, it's all time and an easyish job except the dirty part cleaning the EGR. Gasoline I have found desolves the carbon gunk the best of all chemicals I have tried that you can buy.   OR you can clean it and simply reinstall it and carry on, adjust the wastegate rod nuts and be on your way. BUT, the problem will be back sooner than later.

Do your research and IF you want to afford one, buy a ScangageII.

IF you have use of one and see the boost levels try to keep them lower than 15.4 psi so it never trips the ECU into limp mode again.

[Awesys]

This exact experience happened to me on my way to work today. The check engine light was on, but usually it has't impacted performance in the past.

 

I immediately knew something was wrong once I got onto a main street as I felt the power drop at high revs, but I was able to keep up with the higher speeds and the 50 minute commute. I also was able to make it up the parkade ramps - phew! It was fine on the way home and operating normally. I let it stay in the high rpm range for a while and even let the Automatic transmission take it for a while. About 166,000kms on ours.

[MikeT]

Check the codes - do you have a ScanGauge?

[mas]

When it does go into limp mode, there is no CEL. However this morning ( first cold start of Fall, I turned the key right away without waiting and it turned over 8X (instead of the normal 3X) before starting and sure enough I got a CEL.  I have a univerval OBD-2 reader and it gave me the P0405 and my scanner will not allow me to delete.

[stickman007]

I regularly go past 16psi. It’s closer to 18psi for 5s before the overboost limp mode kicks in. It doesn’t alway have a CEL.

 

As Willy’s pointed out, basically the 2 main thing that will cause limp mode is EGR and overboost.

 

Pulling the FC will tell you which is the culprit. P0405 will be a EGR circuit code - potentially shorted coil as voltage is low. An active code will not allow you to delete.

[Awesys]

On 10/8/2024 at 8:30 AM, MikeT said:

Check the codes - do you have a ScanGauge?

I sure do, thanks to this community! But unfortunately it's at the other end of town.  Will pick it up tonight and see what the codes are.

[slipperyslope]

On 10/8/2024 at 5:41 PM, stickman007 said:

I regularly go past 16psi. It’s closer to 18psi for 5s before the overboost limp mode kicks in. It doesn’t alway have a CEL.

 

As Willy’s pointed out, basically the 2 main thing that will cause limp mode is EGR and overboost.

 

Pulling the FC will tell you which is the culprit. P0405 will be a EGR circuit code - potentially shorted coil as voltage is low. An active code will not allow you to delete.

computer trips at 18.3......i have my waste gate set at 17.9    and have zero issues