Puurplex
New Member
- Joined
- December 7, 2023
- Messages
- 4
- Reaction score
- 0
- City, State
- Clinton Twp, MI
- Year, Model & Trim Level
- 2014 Police 3.5l
Hi all, new member here. My wife has a 2014 PIU with the 3.5l Duratec, 120k-ish miles. Shortly after she got it, the vehicle started having either surges or chokes (I can't tell) under low or moderate acceleration. Idle is nice and consistent, and WOT is pretty smooth. So at no load, or high load, the issue disappears. Also, the car has began having a really tough time with cold starts. It doesn't fail to start often, but the starter will turn the engine over for a good 5-7 seconds before she comes alive. I've been hunting this ghost for around a year now, and I refuse to accept defeat. I'm hoping someone may have experienced or heard of this issue and can maybe help shed some light on it.
What I have done: Starter, Battery, Injectors, Fuel Pump.
I graphed some of the engine data to help provide insight, hoping to find a sensor that didnt act congruently with all the other signals. I found exactly what I had expected. Fuel pressure on the fritz, AFR in tandem. I've watched the AFR spike to 29.38, over double the norm. So it seemed that the engine was being fuel starved. Ok, great, replace all fuel related components. Well, did that. No dice. The issue does seem better in certain aspects, but is still present.
The vehicle threw absolutely no codes until I started replacing things. Finally, I got a CEL (for once I was actually happy to see it). It was P0430 - Catalytic Converter. Huh. Strange, I know the exhaust system is integral to the engine, and yes technically a plugged cat could cause surging and rough starts, but I would imagine that would indicate AFR running rich, not lean. So I'm very doubtful the cats are the issue. Anyways, I checked the temps, and they run around 1600-1700 degrees, under moderate, normal driving conditions. I drive an Infiniti G37, and my cats are around 900 normal. So yeah, they definitely seem bad. Still doubtful. Anyhow, Cats are going in next week when I have time. The reason I haven't changed any sensors out is because monitoring them doesn't seem to indicate that they are faulty. That is my next angle of attack, because after that I don't know what avenues are even left to explore (see what I did there?)
A car savvy family member suggested possibly a bad camshaft position sensor, or carbon buildup on the valves because these vehicles spend most of their lives idling.
Oil changes at regular intervals, around 5-8k, I personally keep all maintenence up to date. There's nothing I can't do on that car, so if anyone has any suggestions, please, let em fly. I want to exhaust (hehe) all options before venturing into the motor itself - but if I have to, I'll drop a god damn new engine in this mf.
Oh, also, I very briefly got a code for cylinder 5 misfire. Which I already know, I can feel the engine stumble. Hasn't shown up since.
So, anyone?
What I have done: Starter, Battery, Injectors, Fuel Pump.
I graphed some of the engine data to help provide insight, hoping to find a sensor that didnt act congruently with all the other signals. I found exactly what I had expected. Fuel pressure on the fritz, AFR in tandem. I've watched the AFR spike to 29.38, over double the norm. So it seemed that the engine was being fuel starved. Ok, great, replace all fuel related components. Well, did that. No dice. The issue does seem better in certain aspects, but is still present.
The vehicle threw absolutely no codes until I started replacing things. Finally, I got a CEL (for once I was actually happy to see it). It was P0430 - Catalytic Converter. Huh. Strange, I know the exhaust system is integral to the engine, and yes technically a plugged cat could cause surging and rough starts, but I would imagine that would indicate AFR running rich, not lean. So I'm very doubtful the cats are the issue. Anyways, I checked the temps, and they run around 1600-1700 degrees, under moderate, normal driving conditions. I drive an Infiniti G37, and my cats are around 900 normal. So yeah, they definitely seem bad. Still doubtful. Anyhow, Cats are going in next week when I have time. The reason I haven't changed any sensors out is because monitoring them doesn't seem to indicate that they are faulty. That is my next angle of attack, because after that I don't know what avenues are even left to explore (see what I did there?)
A car savvy family member suggested possibly a bad camshaft position sensor, or carbon buildup on the valves because these vehicles spend most of their lives idling.
Oil changes at regular intervals, around 5-8k, I personally keep all maintenence up to date. There's nothing I can't do on that car, so if anyone has any suggestions, please, let em fly. I want to exhaust (hehe) all options before venturing into the motor itself - but if I have to, I'll drop a god damn new engine in this mf.
Oh, also, I very briefly got a code for cylinder 5 misfire. Which I already know, I can feel the engine stumble. Hasn't shown up since.
So, anyone?
