Engine seems to have lost power. Acceleration is very poor. Also I cannot get it to go much over 90kmh/60mph.

This is a 1999 Hyundai H-1 (Starex) van, 2.5L Regular diesel engine, no turbo, no rails, manual trans.

When I am driving quietly, you would not know there is a problem at all. But as soon as I press the gas pedal a little too much, the engine seems to give up.

It idles perfectly. However, when the engine is idling and I press the gas pedal hard, the RPM increases for a second and then goes back to normal idling. Also, when I do this, the "check engine" lamp lights up after a few seconds and remains lit until I let go of the gas pedal. Is this possible to diagnose?

The "check engine" lamp aslo flashes a second or so before engine startup, but it has always done that. Think this is normal?

I have done the basic stuff like changed the diesel and air filter and have run diesel cleaning stuff through the fuel. Do dice.

Thought diesel engines were simlpe, but now I am kind of out of ideas. Is there a gauge or something like the gasoline lambda sondes for diesel engines as well, or is the engine computer controlled or something?

Ideas please...?

Brgds Karsten

This post has been edited by karsteb: Feb 13 2008, 05:32 PM

a few basic things come to mind for starters, is the air filter dirty? have you got your fuel contaminated with water? is the exhaust silencer and/or cat. blocked?

Hi Montego.

Thanks for the ideas.

- Tried removing the air filter to rule out a dirty filter, but that did not change anything.

- I do not believe the fuel is contaminated, as I have run through several diesel tanks with the same problems. I usually run the tank empty and then refill it completely, so that should not be the problem eiter.

- Being a diesel engine, there is no catalyser. The engine runs fine on high RPM's so I do not believe the silencer is blocked either.

Would anyone know if there is an air-flow sensor in the enigne regulating air intake?

Or is there perhaps a solenoid of some sort sensing RPM's or something?

- k

Hi, I saw your post on the thread I started a while ago.

I took my van to a diesel mechanic who hooked it up to a little device that checked the engine for fault codes and errors. It was showing 2 errors, one being an air intake temperature error, where the reading was at -40 which was apparently a default but could be a faulty temp guarge. Another error was also present that I forget what it was related to.

The guy cleared the errors, drove it about a bit and only the air temp intake one came back. Its VERY strange now as since then, my van has not chugged or had any problems at all, and done 1000 miles since then.

I recommend finding a local dealer who can hook up a Hyundai ECU reader to check for fault codes. I noticed it was a proper Hyundai fault finding tool he was using.

The one I used was near Wolverhampton / Walsall way. If thats just happens to be close to you I'll give you the details of him. He charged £30 an hour and spent an hour with us talking about possible problems it could be.

Hi Karsten, you changed the air filter ok, but what about the fuel filter?
If this is blocked or filthy, you could easily lose power under high revs.
Dave