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david craig
david craig, Auto Mechanic
Category: Kia
Satisfied Customers: 3317
Experience:  owner/mechanic at 3D Automotive
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04 rio rebuilt entire engine new maf tps knock sensor iat

Customer Question

04 rio rebuilt entire engine new maf tps knock sensor iat when running with no load it's fine with lost engine timing goes 9 degrees negative Po 325 code can't find any bad wires tried known good ecu same results
Submitted: 10 months ago.
Category: Kia
Expert:  david craig replied 10 months ago.

Hi Im David, so under load the engine runs rough?

Expert:  david craig replied 10 months ago.

P0325 is a code for the knock sensor. A faulty knock sensor will not leave the car disabled but is required for correct fuel delivery to the engine in higher load situations. It is located on the engine block in the rear under the intake manifold.

Expert:  david craig replied 10 months ago.

It's usually a faulty sensor. The knock sensor senses vibrations in the engine block and relays that to the computer to adjust fuel delivery.

Customer: replied 10 months ago.
The engine runs great with no load as soon as you put a load on it the car has zero power because the ecu will not advance the timing. I double checked the timing marks on the belt I'm ready to abandon this project the knock sensor is an own brand new
Customer: replied 10 months ago.
With the car jacked up in gear the timing goes to full advance apply some brake to simulate a load and it immediately goes roar pun 9 degrees retarded
Customer: replied 10 months ago.
Sorry oem ks
Customer: replied 10 months ago.
With my reader hooked up the load is increasing its just the ignition timing that's the issue
Expert:  david craig replied 10 months ago.

the ecu will not advance the timing because of the knock sensor fault.

Expert:  david craig replied 10 months ago.

do you realize how a knock sensor works?

Expert:  david craig replied 10 months ago.

When the knocking or pinging is detected, the sensor sends a signal to the ECM, and this in turn retards the engine spark timing at two degree intervals until it has corrected the issue

Expert:  david craig replied 10 months ago.

The symptoms of a bad knock sensor usually show up at highway speeds or under a load. Be clear that this sensor affects the ignition timing of an engine. The vehicle will have a loss in fuel mileage and acceleration especially at highway speeds.

Customer: replied 10 months ago.
I fm a mechanic and know how the system works the car acts like it has a bad map sensor but this car has no map sensor do you know what the values should be at the connector? The car won't barely go 10 mph compression is perfect etc the only thing I haven't checked is fuel pressure but that shouldn't have any effect on the timing
Customer: replied 10 months ago.
Still haven't heard anything
Expert:  david craig replied 10 months ago.

Im suggesting to replace the knock sensor. if you are not willing to follow my suggestion then I cant help you.

Customer: replied 10 months ago.
I replaced it with a brand new oem one already same exact symptoms
Customer: replied 10 months ago.
I even tried moving the knock sensor from the engine to firewall and made sure it was grounded just to see if there was some engine noise that it was picking up that I couldn't hear, same results
Expert:  david craig replied 10 months ago.

this is quite head scratching...... let me see if i can poll my resources a little more.

Expert:  david craig replied 10 months ago.

check the grounds. five grounds. Really four but one has two ends that go from the engine to the body. You should disconnect, clean, load with contact lube/goop and reconnect. Bad grounds can cause issues because they create an under voltage situation on the ECM which is really worse than overvoltage because the computer operates on voltage levels and it doesn't properly interpret any inputs.
1st grnd - Negative battery terminal
2nd grnd - On rear of transmission just in front of where the driver sits.
3rd/4th grnd - Up just under the Coils. or near the coils.
5th grnd - Runs from the top left Timing belt cover bolt to the Passenger side strut tower.

Customer: replied 10 months ago.
I'm thinking of replacing the three wires directly from the knock sensor to the ecu and bypassing the harness
Expert:  david craig replied 10 months ago.

check those grounds first. did you do a continuity check on those 3 wires? did you check for a high resistance short to ground also?

Customer: replied 10 months ago.
I cleaned all grounds and used dielectric grease even added an extra one
Expert:  david craig replied 10 months ago.

what about the continuity on those 3 wires?

Customer: replied 10 months ago.
They aren't shorted but I don't know if it should have 5 volts from the ecu do you know where I can get a diagram of the three wires that feed it
Expert:  david craig replied 10 months ago.

sure ill get you one

Customer: replied 10 months ago.
Thank you
Expert:  david craig replied 10 months ago.

i believe this is the correct one

Customer: replied 10 months ago.
Thanks but that's the wrong diagram 04 rio 1.6 with automatic
Customer: replied 10 months ago.
I removed the entire wiring harness that contains the knock sensor circuit stripped all covering checked continuity and found where the wires go into the connector at the the knock sensor plug were not making good contact with the male pins, I cut and spliced a new one and walla runs like brand new thanks
Expert:  david craig replied 10 months ago.
Im very sorry ...im on vacation and cant get the mobile app to work right. It
Expert:  david craig replied 10 months ago.
Im very sorry im on vacation. And the sites mobile app will not allow me to see anything except you are waiting on a reply. Please request another expert so you wont need to wait until i get home. Thank you