2.5 crd 2002 idling rough when hot - possible causes?

Hello all

I have a 2002/3 Chrysler Voyager 2.5 CRD manual, 130,000km/85,000miles/12 years on the clock.

Up until recently it was running great, but during the last couple of months, the engine has started idling roughly, but only when hot. As soon as I place a load like the AC or put some throttle, it's fine.

I had the garage check for error codes and only the thermostat showed a problem, so it has been replaced - it needed replacing anyway, as the temp needle had been slowly creeping close to 1000 hrs and the normal operating temp is more like 0830 to 0900.

So here's my thinking:

1. it's not the EGR valve, EGR solenoid or EGR cooler as when idling, that is switched off after 60 seconds

2. it fires up immediately when hot or cold, so it's not the glow plugs or ignition related

3. It runs fine when cold or when hot with load (not idling). In this situation, I assume it would have a higher fuel and air pressure so that seems to balance out any irregularity.

4. The engine oil is fine. Dipstick level is 80% but I can't remember if I filled it up to 100% when I did the oil change. Smells ok and is black (after about 12k miles) so I don't think it's burning and or mixing with any coolant. This would imply that seals are ok. On the other hand if I have lost engine oil... it's could be that I am burning oil - but exhaust smells fine and at high idling revs, there is no smoke.

5. the tail pipe is black and the inside of the tail pipe is carbon rich, but dry - I think this is normal for a diesel. It feels as though there is more smoke, then usual in the exhaust when I accelerate. So I'm thinking that I may have an incomplete burn in one or more pistons. Acceleration is not bad although it feels as though it has gone down, but only by a small amount. This again suggests power loss in one or more cylinders.

Tomorrow, I will check the glow plugs. I replaced them last autumn and I'm wondering if one or more are slightly loose, allowing lower burn pressure and incomplete burn.

My worst case scenario is failing injectors - fingers crossed. How does one check for these. Wouldn't faulty injectors throw an error code?

The other possibility is one or more faulty sensors leading the computer to incorrectly manage fuel/air mix and timing. What sensors would I have to check for this to be the case?

Are there any other possibilities?

Thank you, kkc.

 

2.8Td Grand Voyager
Hi guys/girls.
Ive been having problems with different things at different times. It was driving me nuts. I was told to clean the contacts under the fuse box, which I did I even cleaned the ECU contacts and the contacts on the injectors, fuel pressure sensor and the cam position sensor. Basically if it has a connector I cleaned it with contact cleaner and a cotton buds. Wow what a difference. so far not a bit of trouble. it mite worth a try. don't cost a lot.

 

Your car is only rough when idling, so fuel metering/injection via sensors when accelerating, coasting is ok. Like a voltage glitch here somewhere.
You've done the IPM fuse box contact clean have you. I'm keeping getting someone hitting me on head saying Mass Air Flow meter needs cleaned.

 

Bee and goggs... excellent idea to clean all contacts, will do so today. goggs, the MAFF is a ceramic disc that based on air temperature changes electrical resistance. So even if it is dirty, it should work. That being said, I will clean it. In fact I have ordered some EGR spray cleaner - spray it into any air passages (just before MAF, just before turbo and just before EGR) and it is supposed to flush some of the dirt and carbon off.

I'll also be running some diesel additif to clean the injectors etc.

And there will be an oil change coming up in a month or so, so I'll flush the engine too with some engin cleaner.

Fingers crossed...!

 

I've got a 2002 2.5 CRD too and experienced something similar.
The engine runs perfectly well but every now and then (when hot) the car rocked a little waiting for a traffic light like running irregular or on 3 cylinders or something
And also sometimes not always..
Strange..
I suspected some obstruction in the fuel system or dirty injectors so I added a "CRD cleaning additive" (although people told me it wouldnt work ) to a full tank and finished the tank riding from France back to Holland, next tank I filled up with the more expensive Vpower diesel from Shell and finished that tank on a long drive. too
Since then I did not experience that "rocking" any more.
So it seems it solved it for me.

 

Vmaxxer has illustrated one of the characteristics of clogged injectors, a VERY long high-speed run in the order of hundreds of miles is probably as good as actual injector cleaner, the throughput of diesel in the injectors is much heavier than normal, and the pulsing frequency is much higher due to the high speed of motorway/highway driving. The clogging shows up when the throughput is at its minimum as when idling.

I can tell you with BP "ultimate" cleaner-diesel that it costs 40pence extra per gallonUK as of my calculation about 2years ago.

Unclogging the injectors will make a significant improvement in MPG, one of the reasons to keep a permanent eye on fuel consumption. Example:-- My daughter has a 1.9ltr. diesel Vauxhall Vectra-matic which was doing around town about 25mpgUK. After a long trip from Yorkshire to Wales, it's now almost 30mpgUK on the same local motoring here in Leeds.

Leedsman.

 

I can not compare my "test" with a run without additives or "doped" fuel, but Leedsman is probably right.
The German ADAC concluded after an extensive test with Aral Ultimate and Shell Vpower that they could measure an improvement in fuel consumption en cleaner emissions with both fuels, but Vpower was winner.
However the advantage was so small that they doubted that the effect was justifying the extra costs.

 

Interesting...!!! I am relieved to hear that it's not just my car that "rocks" when idling. This morning I added some Bardahl diesel additive to clean out the fuels system.

Perhaps this is why in the user manual, Chrysler specifically recommends occasionally or normally pushing/hard accelerating the car whilst driving.

I also noticed that the EGR solenoid makes quite a bit of a noise when it's operating... almost as though the solenoid is pulsing up and down rather than staying in a steady position based on the sigral from the PCM via the relay. I'll test the vacuum and electricals when I get a moment and post results back.

BTW, my economy on this car is 7li/100km. This equates to 40mi/gallon (UK), 33mi/gal (US). These are summer values (summer tires and temperatures). Consumption is higher in winter (winter tires + lower temperatures). These kinds of numbers for me seem to be excellent, given the extra soot and rough idling I am experiencing.

 

My 2001 2.5 CRD does the same, i have only had the vehicle a few weeks, i have managed to reduce the rough idling by changing the air filter and cleaning the MAF sensor with electrical contact cleaner as this had oil deposits on it, i also put a diesel additive in the fuel to clean the injectors etc. next i am to change the fuel filter, clean out the EGR valve and do a engine flush.

 

It must be an amazing coincidence, but this morning I started my Mercedes 190 2.3E for the first time in weeks and he was rocking when idling although he had never done that before.
I took the car for a testrun on the highway and drove it for a good hour on highspeed (~130 km/h). Stopping on a parking lot it was still running a little rough when idling and rocking a little like not running well on 4 cylinders.
I visited the carshop and bought a bottle of Wynns injector cleaner and went of for another testrun on the highway.
After a few miles speeding I noticed a definite increase in engine power and a more regular rev while running 130-140 km/h.
Back from the highway, stopping on a parking lot the car was idling perfectly smooth. And it stayed that way.
I cooled down the car and tested again:
Still running perfect

So either it took 2 runs on the highway to clean out the injectors or the bottle of Wynns did its job.
Another possibility could be that I did get some "moisture" in my electric system which took some time to evaporate, but the fact that the car got running better quickly after adding the bottle of Wynns seems no coincidence..
Anyway I am happy, both cars run fine now.