diesel engine rough idling at cold start

**altec** · March 12th, 2009 09:15 AM

Mga gurus,

my kia sedona is experiencing rough idling at cold start. But after you rev the engine, in a few seconds the idling normalizes. Kia already replaced the injection pump. The pump was replaced for a different problem. This rough idling happened after the pump was replaced. I sent it back to them, they just bled the priming pump. But every morning, the problem is still there. What could be the cause of this rough idling?

**duskylim** · March 12th, 2009 09:50 AM

Dear Sir:

Are there any other symptoms aside from the rough idle? Did you lose power, does it emit white smoke, black smoke, lower idle speed or higher idle speed?

It would help diagnose the problem if we knew more.

Offhand, check the timing and idle speed. Also check to see if the nozzles are OK.

Give us a more complete description and its more likely we can find the problem.

Best Regards,

Dusky Lim

**altec** · March 12th, 2009 02:28 PM

no power loss noticed, no unusual white or black smoke observed. The only other observation is that when the aircon compressor switches on, the idling rpm drops. It only happens in the morning. But it shouldn't be the case.

**altec** · March 12th, 2009 04:23 PM

I also noticed that my sedona past 100kph, it crawls to accelerate beyond that, though it does reach 120 eventually. Previously, it could do 120 easy, and have done even 140kph before.

I told Kia that maybe there is something wrong (again) with the injection pump they supplied. Says they suspect maybe something else, maybe electrical. I really have my doubts. But will be bringing it back to them this saturday.

**duskylim** · March 12th, 2009 06:24 PM

Dear altec:

Injection pumps have a mechanism for increasing the idle speed when the engine is loaded with an auxiliary device like an air conditioner. If the idle speed drops when your aircon comes on, clearly that device is not set properly or not working.

The lack of power past 100 kph is interesting. That should not have happened especially with a new pump installed. It seems possible that they mis-timed the injection pump when they installed it.

If the pump timing is a little retarded it tends to lose power and if severely retarded will emit white smoke.

Over-advanced timing will cause the engine to run slightly rough and the knock tends to be more pronounced.

The safest thing for you to do is to return it to them under warranty. Tell us what happens after.

Regards,

Dusky Lim

**4JGtootsie** · March 13th, 2009 02:41 PM

There is air in the fuel system either from filter/lines or pump itself.
If you can bring it to Central Diesel if you are in the QC area, I will be happy to check it free of charge.

==========================
Central Diesel 4113711 to 13

**afrasay** · March 14th, 2009 08:55 PM

I recenlty have the same problem in my Patrol. It was a bad engine and tranny support. Had it replaced and it nows idles and drives smoothly

**Dieseldude** · March 15th, 2009 02:22 AM

Originally Posted by altec

Mga gurus,

my kia sedona is experiencing rough idling at cold start. But after you rev the engine, in a few seconds the idling normalizes. Kia already replaced the injection pump. The pump was replaced for a different problem. This rough idling happened after the pump was replaced. I sent it back to them, they just bled the priming pump. But every morning, the problem is still there. What could be the cause of this rough idling?

What type of fuel system is installed on your Sedonna? Common rail or rorary injection pump?

**altec** · March 15th, 2009 08:03 AM

Originally Posted by Dieseldude

What type of fuel system is installed on your Sedonna? Common rail or rorary injection pump?

Its not yet the crdi system, i am sure. I sent it back to Kia, since they installed the new injection pump, should still be with warranty. But I still have doubts with them if they really know what they are doing, as I sent it back before and they released it with the same issues.

**Dieseldude** · March 16th, 2009 02:33 AM

Originally Posted by altec

Its not yet the crdi system, i am sure. I sent it back to Kia, since they installed the new injection pump, should still be with warranty. But I still have doubts with them if they really know what they are doing, as I sent it back before and they released it with the same issues.

Talk to the service manager and explain your situation. They will honor the warranty.

We can help you though if they are not able to correct the problem.