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Okay so I am a big rig diesel technician and would love to see some input on this one. This car has been a pain in my hind quarters. Simply put it has had a lot of work done to it. Mainly by me as I am someone that tends to be on the cautious side which as the owner put it is rare to find in a technician.
Repair History
The fact of the matter is it is an engine ripped from a different vehicle (not by me) same year and same engine size to my knowledge and inserted into a non damaged chassis. Previous owners girlfriend got pissed and lit the intake on fire on the body car and the engine was ripped from another. Engine has approx 66k miles on it. When I first looked at it it scared me so many things were wrong coolant lines were lacking clamps due to the heat cycling the clamps had lost there spring tension. All of them were fixed. There was 2 evap leaks that were fixed with epoxy and the fuel cap was leaking so was replaced with one that had a proper rubber o-ring. There was 2 different brake leak problems both of which were in both rear quarter fender area but, on the inside fixed them which was fun 2 universal joints a wobble extension and a flex head ratchet all on a crows foot. The engine runs powerful but, the owner decided against my advice to use fuel stabilizer and gummed up multiple injectors. Had multiple codes for varying cylinders on both banks. Ran a fuel injector cleaner through it and cleaned up all missfire codes except for cylinder number 3.
Latest repairs
I replaced the fuel filter as I was unsure of which vehicle it came out of the one with the engine with 66k miles on it or the body with 20k. Also with having just run the fuel cleaner through it, it seemed like a good idea. It was still misfiring on the cylinder number 3 after filter replacement. I then got 3 sets of o-rings and removed the rail on cylinder number 3 side. I then manually cleaned the injector by having the owner spray brake clean through both sides while I actuated it using a 9v battery by tapping the one lead never leaving it click on for more then a brief second. I then did it in reverse 3x per direction. When I had removed the fuel rail and had to remove each injector I inspected the o-rng screen only one of the three was partially blocked and that was cylinder number one and it was only blocked at roughly 8-10% once blowing out with brake clean it removed it. I then replaced all o-rings coating with a light film of the same oil the engine takes and reinstalled. Clean fuel was not readily available or I would have used that and I must stress a thin film just enough to make things easy to reassemble. During this process fuel had dumped out of the fuel rail into the intake runners. I had already purged the system as best I could using the service bolt on the recently replaced fuel filter.
After reassembly I had the owner key on key off approx 15-16 times. I then had him start the vehicle got misfires on cylinders 1 and 3 at startup and then had him clear those codes and then we took it for a long test drive. At which point we had no codes come back but, the engine was behaving like it had a vacuum leak. I had properly diagnosed the vacuum leak and found a vacuum leak on the fuel regulator on the bank for cylinders 1-3 and it has multiple cracks I am assuming from heat cycling. Upon looking for hoses of the proper proper inside diameter found that there were non readily available as it was sunday and no parts stores could equip me with 3.5mm Inside diameter hose. AKA it had to be from a dealer. So it was not repaired.
My thoughts on the fuel in the oil any input would be awesome.
We checked the oil at the end of all of this and it smelled of fuel. This has both me and the owner concerned as the only things I can come up with is the cylinder head, cylinder head gasket, valves, an over-pressurized fuel rail due to the faulty vacuum line on the fuel regulator, and/or rings could be leaking. I verified several days later that it was not due to all the fuel smells we had been smelling all day and with a clean paper towel there is now fuel in the oil. I have instructed him to do an oil change something he is capable of doing himself.
My issue is I do not see how it could be valves or it would not sound as good as it does. The engine is not behaving as one with bad rings though I ran out of time before I could do a compression test wet or dry. If it was a faulty head gasket where it had burnt its way into an oil passage I would expect to see a return of oil into the cylinder at shutdown due to the oil pressure in the passage and have oil filled smoke at start-up but, I do not see this. I also do not smell fuel in the exhaust after cleaning the injector. There is also no loss of power with the exception of hard acceleration at under 2k rpms due to the vacuum leak. My question is do you think it is due to the fuel being dumped into cylinders 1-3 from the fuel rail removal that it just bypassed the rings I must remind you that it was only 1 rail worth of fuel divided rather evenly across those 3 cylinders. Do I have a leaking injector my thoughts still cylinder number 3, is the fuel rail remaining overly pressurized due to the faulty vacuum line on the fuel regulator, or do I have a ring problem? I used a noid light and verified that the signal to injector number 3 was perfectly fine through all rpm ranges.
Regardless of this we are going to take it to a guy that specializes in NSX’s for repair in upstate NY as he is the closest viable option. I plan to patch the vacuum leak with electrical tape then wrapped with aluminum tape for DPF’s on big rigs which can take up to 1.5k degrees F as it is right next to the engine and I feel the heat would be enough to melt the electrical tape without a heat shield of sorts from the aluminum tape. It is roughly a 300mi trip and would be a lot less costly to drive the nsx with me in a separate car carrying tools for roadside repairs then to hire a proper knowledgeable person to load/unload and transport the NSX up to that mechanic’s shop. Any advice or input would be greatly appreciated. I would love to get as much resolved as possible before the trip as I do not want to be dumping fuel into the oil for that long a period of time.
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I’m not trying to sound like a stuck up elitist, but as someone who has spent alot of times on internet forums, no one will want to read that long line of text without SOME paragraphs. As it is, I’m way to tired to try reading it myself, will do so in the morning though.
Update
He did the oil change and ran it at idle and it is now missing more often. The speed hesitation that is from the vacuum leak he says is different then before. When the engine is not missing it is running much smoother after the oil change. After running it at idle and a short test drive he says it smells of fuel in the oil still but, it is greatly reduced.
I am just wondering if there is a common issue that a tech knows of with this car pertaining to my problem? Is there any other possible ways fuel could be getting into the oil? Does anyone know if that particular regulator increases or decreases fuel pressure? If the rings were that bad wouldn’t the oil also smell slightly burnt and/or smell of combustion gases? I really think the valves are fine as I can hear valve problems over the sound of diesel engines and I hear mine in my TDI slowly eating away at my cam every time I hard accelerate or go over 3k rpms. Just any input would be awesome even if it is far fetched and unlikely; Murphy Tends to like both me and the owner in that way.
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