Start with the basics. An engine needs fuel (gas and air) and spark. If the engine starts, there must be some fuel and spark.
Are you sure the engine is getting too much gas? (Is there gas in your oil?) If so, possibly a large intake vacuum leak, when switching to the cold air intake, now engine getting too much air? If you have a large vacuum leak, the O2 sensors are reading lean and the engine control is adding more gas. Maybe the spark plugs are not correct and the spark is not working on all cylinders? High pressure fuel pump or pressure sensor issues pumping too much gas? (Dealer said, "fuel injectors are stuck open")
Do the cheapest repair first. Maybe put the air box and old spark plugs back (or confirm new OEM plugs). Check for disconnected vacuum lines/hoses.
In another Veloster thread on fuel,
"Hello all, new to the forum and seeking help if any one can. Here is the run down 2016 VT rspec, the car keeps breaking the FPS I have replaced it twice and also replaced the pump in the tank and the PCV valve. My question is does anyone know what can keep making these sensors faulty. My car starts to idle real low and missfire after that the car will just stall at idle. Check the codes I get a 0087 or bad FPS. ANY help would be great as this is my only car and im moving in 2 months."
"I think there was a recall for the turbos fuel lines collapsing, or kinking, something like that. That might explain why it starts then slowly dies, as it starts to starve for fuel."
Some high pressure pump issues or fuel pressure sensor failures result in too much gas. Do you have alot of gas in your crank case, contaminated oil?
The codes P0302 P0300 P0304 P0301 are random (PO300) and cylinder specific (1,2,4) misfires. Some people report misfires when there are fuel pressure issues.
Conduct a cylinder compression check.
Warm up the engine then
- remove and unplug coil packs
- remove all 4 spark plugs
- Unplug Fuel pump and fuel pump relay/Fuse
- connect compression tool to spark plug opening hand tight.
- Crank engine (Press start button) with foot on brake and with throttle all the way open (foot down on pedal). Not sure if this does anything on fly by wire cars but other places said to do it.
Specs are 180-200 psi, but more important is that the readings should be pretty even between the cylinders. A single or two adjacent low readings may indicate a bad head gasket or bad sealing from bent valves or failed piston rings. Contanimated oil from gas could cause piston rings to not seal properly and set misfire codes. A bad head gasket might include white exhaust smoke due to burning engine coolant. This engine uses a timing chain, so unlikley a skipped timing issue. ( I just repaired a Honda Pilot with skipped timing belt, off by one tooth, and giving random P0300 and P0305 and P0306 codes.)
Get an ODB 2 scanner and read what the engine control is doing and what the senros are reading. You'll need to read up on what the ODB scanner can tell you. It can tell you if the Mass Air Flow sensor is working, what the O2 sensors are reading (lean or rich fuel), ignition timing events (is the crank rotating the proper amount of degrees at ignition event) and which cylinder is misfiring, catalytic temp and much more.
Try to pinpoint the actual issue before buying and replacing parts (firing the parts cannon).
Bad Mass Air Flow sensor. MAP Sensor Replacement is
between $177 and $206
- Lean or Rich Fuel Mixture. ...
- Difficulty Starting Your Car. ...
- Engine Stalls After Starting or When Idling. ...
- Engine Hesitation and Dragging. ...
- Engine Hesitation and Jerking. ...
- Engine Hiccups.
Bad fuel pump. In tank pump part $60, High Pressure Pump part $460 to $650.
- Difficult Starts. ...
- Sputtering Engine. ...
- The Actual Stall. ...
- Power Loss. ...
- Surging Power. ...
- Lower Fuel Efficiency. ...
- Dead Engine.
Fuel high pressure sensor $106.
Good luck!
