Car shuts off when doing donuts

CAHNOR

MEMBER
2005 KIA OPTIMA
2.7L
6 CYL
2WD
AUTOMATIC
70,240 MILES

I have upgraded this car. Suspension, brakes, wheels, struts, and everything else underneath the car. I have had some issues recently with it though. I have been experiencing some bad acceleration and extremely horrible gas mileage. My car has trouble starting sometimes, but other than that it runs great. But if I go do a u turn quick or turn a corner quickly my car drops rpms and sometimes will completely shut off (engine only, check engine light, airbag, battery, oil lights all come on as if I just have the battery on. I pull over and start it and it's right back up and sometimes traffic is coming, so I will accelerate out quickly and nothing! Do you think maybe it has something to do with my transmission? When the car has trouble starting the RPMs needle goes to 1 then slowly drops halfway then jumps to one and back down then to one then completely down like its off. (Picture it is jumping from 500 RPMs-1k then back down.) Then will shut off and has trouble starting up. I have only had this issue when the gas is at a certain level. It is just a gallon or so bellow the last quarter of gas. I took it in for some other opinions and was told the coolant sensor was broken and maybe that could be it. I fixed that myself and no codes pop up anymore. Still had the issue. I thought it could be the camshaft sensor (even though I had no error codes for it or a check engine light) I decided to replace it and at first seemed great but the problems came right back. Gas mileage is a bit better it seems, but the poor acceleration is definitely there still with the car stalling during a you turn. The fuel filter and other filters all were good. No codes. Fuel injection was good too. Battery at 79% alternator and starter both passed tests. Car also got a smog recently which it passed. There is a drive belt chirping sound from time to time and gets faster and a tiny bit louder if I rev the engine or if driving accelerate. I would love to hear back from you.

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

Sounds like we have some larger issues but let's address the stalling on U-turns first.

I would suggest we start with checking the fuel pressure when this happens because I suspect we are losing prime on the fuel pump due to the fuel sloshing to one side of the tank and it sucks air, stalls the engine and then it restarts when the fuel is back in the bottom of the tank.

Here is a guide that will help with this:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Let's just start by checking the pressure when this stalls in a tight turn and go from there.

However, other issues such as poor fuel mileage and poor starting may be caused by aggressive driving so we will need to ensure the base engine operation is okay, such as compression.

https://www.2carpros.com/articles/how-to-test-engine-compression

However, the hard starting at certain fuel levels may be related to the fuel pressure so we need to start with this and fix that issue and then we can get a post started just for the issues that are left.