I am driving a '99 Sonata GLS V6 that I have had since 125,000 miles and now has another 50k on it. It works hard for me everyday but sometimes it's hard to start, or idles rough or idles high or.. All the basics are good. Plugs, wires, etc. What do you guys think contributes to these slight problems as the car ages? Mechanically it's great, but obviously there are some fuel and or ignition problems creeping up. Specific to the Delta V6, I wonder if there are some engine management parts that I can start replacing that might return it to factory driveablility.



Your thoughts? Thanks.

 

Have you done a compression test on it lately? That will give you an idea of how healthy the internals are.

 

My E-diagnosis.. fuel filter -> coils -> sensor of some sort..

 

I haven't done any diagnosis because it really runs great, just small problems occasionaly on startup. Have thought about coils too, might just get new ones as preventive maintenance.



Sometimes it seems like the fuel pump runs too long (you know, turn the ignition on and listen..) before it pressurizes and stops the pump motor. Maybe the fuel system is bleeding down. What is the item that causes the system to lose pressure?

 

Does your engine oil smell like gasoline?

 

I checked and it does not. What would that indicate other than internal wear/bad rings?

 

If the injectors are leaking the residual fuel pressure into the cylinders, that's not great. It would make your oil smell like gas if it happened overnight all the time. I guess it could cause funky starting if you had extra gas in the cylinders that hadn't leaked past the ring pack yet. I want to say loss of fuel pressure could also be a fuel system check valve somewhere no longer checking as well as it should.

 

Okay..makes good sense. The hard starting is the worst of my problems now. Just did an 1800 mile round trip and developed significant trans. prob. As in at 70 mph in O/D it just faults out to third with a big bang/jerk and sets the check engine light. Need to get it read again. Something about internal solenoids.

 

Ugh. Did you ever use anything but the specified Hyundai transmission fluid?

 

Only used SPIII from the Kia dealer. Haven't been using the car lately, not real driveable. The code it's showing is trans output sensor failure. It's a simple swap, accessible from the top of the trans. I think I'll start with replacing that.