Nissan Repair Questions? Ask a Mechanic for Answers ASAP
are you referring to the engine temperature or the external temperature outside?
let me know plesae.
I am referring to the engine temperature
Thank you, XXXXX XXXXX your cold start enrichment is loading you up on fuel.
Do you have a misfire or anything? have you ever changed the plugs in this car?
No misfire and I haven't changed the plugs as it had new plugs when I bought it about a year ago. I did have to replace two fuel injectors about 3 weeks apart approximately 6 months ago
If pumping the gas pedal makes it easier to start then you can assues its flooded.
Hopefully the previous owner used NGK plugs. I see alot of people use bosch plugs which causes problems.
At this point I'd mainly check the fuel pressure regulator vacuum hose to verify theres no fuel leaking past the diaphragm. It's not likely a leaky injector or anything like that as that would be more consistant.
where do i find the fuel pressure regulator ?
thanks will get back to you when I've checked that
I've had a quick look but need to look properly in the daylight, the pipes are actually front and back but I presume the vacuum pipe is the smaller pipe which is connected between the regulator and the inlet manifold ?
I have found it and it is fitted horizontally with the pipes front and back not top and bottom I just wanted to verify that the vacuum pipe is the one which goes to the inlet manifold
pulled vacuum hose on fuel pressure regulator and there is no fuel leaking past the diaphragm. Hose is in poor condition lots of little cracks. Going to get some new hose and replace it and will get back to you with result.
I have now replaced the vacuum hose and it has made no difference. Earlier when it had difficulty starting my check engine light came on and when I flashed the codes it had just one code 143 fourteen long flashes followed by three short flashes, I let it cycle through a few times to be sure and that is the only code it flashed out.
I have also done a little experiment which may or may not be of use to you and found that if I leave the car sitting for about 15 minutes after it has reached working temp and then try to start it I find that it is difficult to start, but if I leave it for about an hour it will start no problem
Absolutely sure, I even let it repeat several times to be sure and it was the only code in it
On the subject of fault codes, this car has been giving this starting problem now for about 2 months and that is the only time the engine management light has come on. I checked the error memory again today just to be sure I had read it correctly and it now only gives me code 55 which is "all components working correctly"
To have the codes properly pulled means going to a Nissan dealer which will be expensive, too expensive given the likely value of the car.
I have checked the spark and it is sparking immediately but still turns over for 6 - 8 seconds before it fires. Another bit of info which may or may not be of use, I have checked and found that when it is hard to start but eventually fires, if I switch it off immediately it fires without letting it warm up and then try to start it again it will start instantly.
OK, so the main factor that makes it hard to start is letting it sit.
sounds like your losing your fuel pressure prime, or your leaking fluid into the cylinder.
Yes letting it sit for 10 or 15 minutes like when in a shop means it doesn't start easily but if sitting for a couple of hours or overnight it starts immediately, would cold starting not be affected also ?
Yea that's peculiar indeed. This can be tricky over the net.
You may have a leaky injector bleeding off rail pressure when it sits and flooding one of the cylinders. Granted without being there and having a gauge and pinching off the line it's impossible to tell without inspecting the cylinder.
OK so where does that leave me, do I simply have a choice between putting up with it or taking it to a dealer ??
You need at least a fuel pressure gauge here to continue.
that or your left puling the plugs and looking in the cylinders after its been sitting for a bit.
Honestly your symptoms are really peculiar because of their inconsistancy.
OK, well I can pull the plugs to look into the cylinders although with it being OHC the cylinders are a long way down from the top of the engine. I will have to wait for daylight to do this as I don't have a garage or anywhere indoors to work on it.
I could also try to borrow a fuel pressure gauge.
I wouldn't agree that the symptoms are inconsistent as it always behaves in exactly the same way when in any given state.
When referring to it's inconsistancy I am referring to this:
Car starts fine when cold, yet after letting it sit for a bit after running it has a long cranking duration, yet turning off and immediately back on nullifies the symptom when warm. It's not consistant with a hard start when cold or warm.
After the car has been sitting it's temporarily flooding out when left sitting for a short period of time it sounds like, but the flood is clearing overnight.
So it's highly unlikely it's headgasket related and more likely coming from the fuel system.
I understand it is difficult for you to diagnose via the web, by profession I am a transmission repair and rebuild engineer and also provide service support & diagnostic assistance for our products so I do have a good sense of where you're coming from but I know very little about engines.
I will try to get my hands on a gauge to test the pressure. My technical brain may also require slightly more in-depth explanations on occasion just so I know why I am checking certain things. On that note please correct me on these points if I am mistaken but if it is losing fuel pressure when sitting for 15 minutes will it not lose pressure also if left overnight or is hot and cold starting different in terms of fuel pressure and also if I have fuel leaking in to flood a cylinder or cylinders where does that fuel go overnight ?
My concern is more on the basis of seeing if you have an injector leak thats bleeding off pressure. Hence your possible confusion.
An injector leaking fuel into a cylinder will bleed off pressure, if you have a pressure gauge you can punch the feed line behind the gauge and see if it still drops off. If it does then you have a leaking injector allowing it to bleed off.
This same scenario if left overnight, would allow the fuel to wash down the cylinder or slowly evaporate. Therefore rectifying the issue overnight.
If it was just the pump losing prime, you could turn the key to the the ON positiong like 3 times and back off, then start the car just fine most likely. It's not the pump prime I am worried about per-say.
I hadn't thought of that, I will try cycling the ignition a few times and then starting to see if that makes any difference.
sorry to be a pain in the butt I accept that fuel in the cylinder could wash down or evaporate overnight but wouldn't the pressure drop regardless of how it is caused still exist and also cause the same problem when starting from cold the following morning ??
No, because thats assuming the hard starting is because it's flooded. not because of fuel pressure. The pressure gauge is to determine an injector leak not determine fuel pressure itself.
AH so the system will be pressurised on switching on and therefore we are possibly looking at a flooding problem rather than a pressure problem in terms of the starting difficulty and of course when I start it briefly the leaked fuel will be burnt off and it will then start normally ?? I do catch on eventually
OK I will start by attempting to check if I have fuel in any of the cylinders and get back to you once I've done that
Took a quick look at the spark plugs and found I have 1 plug on No.3 cylinder which appears quite wet on the insulator tip at the electrode and when I look into the cylinder the top of the piston also looks quite wet. I was just thinking I can't check the pressure at each injector individually as it is a common rail system so could only check the pressure before the regulator.
I was thinking that maybe my next step should be to get an injector and replace No.3 and see what happens
Either way would work, but you don't need to check pressure at each injector.
You SHOULD NOT lose pressure, if you pinch the feed/return lines. So pressure bleeding off would indicate a leak, you then would know which ones leaking since you took a visual.
Hi Jake,as soon as I am 100% happy that you have helped me identify my problem I will rate you
Sounds good, the site automatically will send you a reminder daily to rate the expert if oyu haven't already. I don't send those so you know.
since were on the subject though, rating your expert does not close the question it just ensures the expert gets compensated for their time is all. So you can rate now or when were done, makes no difference to me.
Just let me know if you need anything else ok.
I have not managed to get my hands on a fuel pressure gauge but decided this evening to try something. I switched off on arriving home and left it for the usual 15 minutes and had decided to remove No.3 plug, dry it, replace it and attempt starting immediately to see what happened. I removed No. 3 plug and it was completely dry as was No. 3 cylinder so I checked all plugs and cylinders which were all completely dry. I replaced all plugs and attempted starting and it turned over for a full 8 seconds before firing, so what does this do to the flooding theory ???
Not likely flooding if the cylinders were dry.
So I presume that means we are back to checking the fuel pressure if I can get a gauge ?