Fuel Issue

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VastOcean

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Good morning,

New SHO owner and new to the forums, so here's what's going on. I just picked up this 2010 SHO from a family friend and it's been having issues. The car puffs white smoke out of the exhaust and even drips fuel from the tailpipe, so I thought it would be an injector issue. Three different cylinders are misfiring and there was a CEL on for the misfires as well as P00C6-Low fuel pressure cranking. When I pulled the spark plug out of cylinder 4 it was super clean, the spark plugs aren't very old but only the #4 plug looked like there was no carbon or anything on it. I tore apart the intake and inspected the injectors and I noticed one of them was missing a piece of the gasket under the top O-ring so I cycled the key on to prime the fuel pump and pressurize the rails with the injectors in them. All the injectors were dry, except one that was spraying. I replaced the leaking injector and put everything back together but it made no difference. I suspect the fuel pump, fuel pressure regulator, or another injector is faulty. I do plan on getting all six injectors changed out but I wanted to see what you guys thought it could be before I tear it apart again.
 

Texas Marauder

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You don't mention mileage. I doubt it's actually fuel dripping from the exhaust. Fuel would have to make it past the catalytic converter which should burn any raw fuel. Raw fuel in the catalytic converter will destroy a catalytic converter. You would likely have a flashing check engine light warning of potential damage to the cat. P00C6-Low fuel pressure cranking could be from a weak low pressure pump(in tank) or a weak high pressure pump(on valve cover). You need a scan tool that can monitor PIDs low pressure fuel desired, low pressure fuel actual, high pressure fuel desired and high pressure fuel actual.
 

VastOcean

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Just over 202k on the odometer, the family member who sold me the car said he was driving it when the CEL light flashed and then stayed on while he was driving it. It definitely seemed like fuel from the exhaust when I smelled it but I could be wrong. I don't want to run the engine for too long because of hydrolocking, I drained the oil and there was fuel mixed in too.
 

kryptto

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Just over 202k on the odometer, the family member who sold me the car said he was driving it when the CEL light flashed and then stayed on while he was driving it. It definitely seemed like fuel from the exhaust when I smelled it but I could be wrong. I don't want to run the engine for too long because of hydrolocking, I drained the oil and there was fuel mixed in too.
Off-topic to the issue, did the replace the water pump, timing chain, and oil pump? Was the recall items addressed when he received them? With 200k+ miles what was his maintenance schedule?
 

VastOcean

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Yes all of those were addressed early on when he owned the car. From my knowledge just preventative maintenance like brakes, oil, transmission filter/fluid, tires etc was done aside from the recalled parts. Unfortunately my scan tool can't read specifics like fuel pressure desired/actual. I've been doing some research but its just led me back to thinking its an injector or fuel pump issue. Maybe the FPR, would that cause a fuel leak like that of a leaky injector?
 

Texas Marauder

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There is no fuel pressure regulator, per se. It's all electronically controlled. An injector stuck open may prevent the HPFP from building enough pressure. You can use FORScan to monitor hundreds of PIDs. You'll need a USB adapter and a laptop. You may be able to read them with the free version, or you may have to get a free 2 month license or a $12 yearly license. Cheap for a full function scan tool. It is not necessarily intuitive to use.


 

VastOcean

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So I guess the plan of action is to find out what the fuel pressure desired vs actual is. If I see the pressure way off of what is desired then ideally what would that rule out or what would it lead me to suspect?
 

Texas Marauder

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Possibly a weak fuel pump, possibly a clogged fuel filter. The filter is a permanent filter inside the fuel tank.

Here is a screenshot of the Android FORScan app showing the PIDs and readings from my car. These numbers are at idle.
 

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VastOcean

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Okay, I'll try that out. I'm just curious though, would a weak fuel pump in these engines cause symptoms like fuel in the oil, white smoke from exhaust, heavy fuel smell, etc? Also, could the high-pressure pump be the culprit, the one that sits on the valve cover? I've heard that these cars have two fuel pumps, one main and one to transfer.
 

Texas Marauder

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These engines create a lot of blowby. This makes the oil smell like fuel, more so than other engines. To me, my oil always smells of gasoline. It doesn't use any oil, or gain any oil, in 5000 mile change intervals. It runs perfectly.

White smoke is usually coolant. That could be another problem.

Yes, two fuel pumps, one low pressure in the tank, one high pressure on the valve cover. That's why you need to get readings on the fuel pressure PIDs.

I could tell you the story about an F150 with the same code as you. The only code. The engine would turn over but, wouldn't start or run. HP fuel was 1250 desired and >100 cranking. Turned out to be a broken crankshaft. The camshafts weren't turning.
 

VastOcean

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The smoke does not smell sweet like coolant though,I've seen it in cars with blown head gaskets but it smells like straight fuel. The car does start and runs, its just like crap, I'll update this post after I run the PID's and see what comes of it. I still will probably replace the injectors with ones off a wrecked SHO
 

SHOdded

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was the misfire code a general misfire code or did it indicate which cylinders are at fault?

a super clean plug would worry me. that is almost surely a coolant leak.

gen 4 SHOs are known for having problems with the valve cover gaskets but most often bank 1. that could be the source of the misfires esp if you see oil on the plugs.

pcv issues can create white smoke, and of course overnight condensation will too. consider replacing the pcv elements located on the bank 1 valve cover.

 

VastOcean

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Will do, thank you guys for the replies. This is my first time toying with these engines, it had a misfire code specifically for 4,5, a random, and I believe 6 but I'll have to double check. There didn't seem to be any oil residue on the plugs and #4 was very clean. Even after changing out the plugs and running the engine for a short time, #4 was squeaky clean while the others had somewhat carbon on them
 

SHOdded

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did #4 at least smell like fuel? if its dry you definitely have a problem besides just a possible vc gasket.

def need to verify injectors ... you may be in for a full replacement job there. if one goes ...

another possibility is the fuel rail is clogged on that side but i have not seen that yet, its usually the injector letting loose.

if the pcv system is creating a heavy mix of oil water and fuel and its blowing into the intake, clean out the intercooler and possibly get a catchcan going. would also move to heavier weight oil, 5w30 or even 10w30 eventually.
 
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VastOcean

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I'll try to take a video later today of it, #4 didn't exactly smell like fuel but when I pulled it out the plug itself was smoking lol. When I originally pulled the injectors and tested them only one was visibily leaking with the fuel pump on so I replaced it but that didn't seem to fix it. I'm definitely getting a catchcan since my srt is the same way
 

kryptto

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What're the chances of more then one going bad and can they fail in other ways? When I replaced the one injector I put them in the rails before reinstalling and they didn't leak and seemed to hold low pressure.
Ok well I work in technology and managed servers for fortune 50 company for 5 years.... mechanical hard drives back then had mtbf - or mean time before failure. So does every mechanical item ever sold - the way the manuf plans for part replacements and can estimate stock and qty. Injectors should be replaced at the same time - once you have access just do it.
 
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