QuestionQUESTION: 2004 Sante Fe w/3.5L 58,000 miles. Had 60000 service. New dealer,opened less than 1 month replaced plugs, timing belt, and cleaned fuel injectors. Since the service I have the following issues. Idle is rough when warm and in gear. Engine torque is off. I will now downshift just going over a overpass. the 3.5 was very sensitive on initial acceleration. This is no longer true. Fuel mileage is down to 16 mpg from 21. Check engine light is off. There is no engine roughness other than idle.
On a separate note. How do you change the EGR valve. Do I need to remove the intake to get the exhaust pipe off or is there a easier solution?
Thank you for your advice.
ANSWER: All the symptoms you describe are consistent with one (or more) of the camshafts being timed incorrectly. The timing belt on this engine is particularly difficult to replace, and the limited visibility and access in this vehicle further compound those difficulties.
In regard to the EGR valve, if you have the proper size crow's foot, you can probably do it without removing the intake. Otherwise, once the intake is removed, you should be able to get a normal wrench on the EGR valve.
If I may ask, why are you replacing the EGR valve? This is an uncommon failure.
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QUESTION: I have had issues in the past with a EGR causing a rough idle and affecting the mileage. The cost of the EGR valve is only $45 and I looked easy until I could not get the exhaust fitting loose. I did not have a crows foot the right size. If this did not work I was planning on pushing the dealer to pull the timing cover and checking it. Has the 3.5 had issues with the EGR silonoid?
Do you what size of the crow foot is needed to get the pipe loose?
Thanks for your help.
AnswerThe 3.5 has had issues with the EGR solenoid as well as a component Hyundai calls a vacuum switch. It's purpose is to control the amount and rate of vacuum application to the EGR valve. Any problem with the EGR system should trigger a check engine lamp. Since you've been driving long enough to see a reduction in fuel economy, it's a reasonable assumption that the check engine lamp would already be on if there were an EGR issue.
The EGR system on your vehicle works as follows:
-- Vacuum is applied through the green-striped hose
-- The green-striped hose tees to go to the EGR valve as well as the solenoid
-- Vacuum returns through the yellow striped hose to the throttle body
-- During normal operation, the EGR solenoid remains open, allowing vacuum to bleed off back into the throttle body
-- During EGR operation, the EGR solenoid closes, directing vacuum through the switch to the EGR valve.
A simple check is to pinch off the yellow-striped hose while the engine is idling. If the engine acts like it's trying to stall, you've just verified the following:
-- The EGR passages are clear
-- The EGR valve is opening and closing normally
-- The vacuum hoses are not leaking
-- The solenoid is not stuck closed
