Full Version: Another Fuel Issue
So after the IM gaskets were done my car was running great for a month or so. Then I started to get a hard start condition and if I primed the fuel pump a few times it would crank right over. If I didn't prime it, it would crank and crank and turn over after maybe 8-10 seconds of cranking. A couple weeks after that if I didn't prime the fuel pump I would have a slight misfire on cyl 4 (the same cylinder that was misfiring because of the gasket originally), but it would go away after a few seconds. Now even if I prime it I still get a slight misfire for a few seconds and the CEL goes on and off for it, IE: it will stay on for a few driving cycles and then turn off for a few and then back on, but it still turns over faster then if I hadn't primed it. I know for a fact I'm running pig rich because I just changed the plugs yesterday and they were black, but as you go from right to left they get less black. I should note that I have full power throughout the entire RPM band in neutral and in gear, when the CEL my timing is retarded but that's the ECU doing it's thing. At idle it will bounce every so often and when going from neutral to reverse it has stalled a couple times over the past week or so. The distributor is 2 months old, wires are new as of last summer, and plugs as of yesterday so I know it is not a spark issue, and there are no vacuum leaks that I know of however I will spray it down again tomorrow and see if I can find anything. So what's left is fuel and I know I have fuel because I can smell it when it finally turns over, just ask Ed, he was standing behind my car the other night when I turned it on. The question then becomes do I have enough pressure? And if I don't is it the regulator going bad or the pump itself? I should also note that the fuel filter is 4 months old. The car has 141k on it and the pump and regulator are both original. Here is a pic of the plugs that were pulled yesterday in order from cylinder 1-4 left to right.
is the fuel system a return style system? If it is the port for checking fuel pressure is usually before the regulator so a low pressure reading would most likely be a fuel pump issue. I'm not possitive on how the fuel rail is setup on those Nissan's though.
Just for shit's, hows your coolant level?
Just for shit's, hows your coolant level?
from what i see plug #4 is WAY more burnt than the rest. is it possible the #4 injector is sticking open?
regulator is likely to be cheaper than the pump, but both should be pretty affordable. You may as well do it.
regulator is likely to be cheaper than the pump, but both should be pretty affordable. You may as well do it.
QUOTE (Zack @ May 27 2010, 11:22 PM) 
is the fuel system a return style system? If it is the port for checking fuel pressure is usually before the regulator so a low pressure reading would most likely be a fuel pump issue. I'm not possitive on how the fuel rail is setup on those Nissan's though.
Just for shit's, hows your coolant level?
Just for shit's, hows your coolant level?
I believe it's a return system, but to be honest I'm not 100% sure. Coolant level was topped off after the IM gaskets, I'll check it in the morning though.
QUOTE (jcat @ May 27 2010, 11:37 PM)
from what i see plug #4 is WAY more burnt than the rest. is it possible the #4 injector is sticking open?
regulator is likely to be cheaper than the pump, but both should be pretty affordable. You may as well do it.
regulator is likely to be cheaper than the pump, but both should be pretty affordable. You may as well do it.
I think plug #4 is the worst because that's where the fuel rail starts which is also why I think this is a pressure issue, as you can see they get less and less burnt as you go down.
As far as prices, I just checked NAPA's website and depending on my MFG date the regulator is either $88.89 or $102.79 and the pump ranges from $118.99-$293.19 depending on which pump I go with.
QUOTE (Fstrsn @ May 27 2010, 11:46 PM)
I think plug #4 is the worst because that's where the fuel rail starts which is also why I think this is a pressure issue, as you can see they get less and less burnt as you go down.
As far as prices, I just checked NAPA's website and depending on my MFG date the regulator is either $88.89 or $102.79 and the pump ranges from $118.99-$293.19 depending on which pump I go with.
As far as prices, I just checked NAPA's website and depending on my MFG date the regulator is either $88.89 or $102.79 and the pump ranges from $118.99-$293.19 depending on which pump I go with.
if it's a return system, you'd see a return line coming off the fuel rail.
whats the chance something's clogging the fuel rail? Obviously fuel is getting all the way TO the rail...if you weren't getting ENOUGH pressure, idk if it'd kick over, and that would point to pump. If you were getting TOO MUCH fuel, as it seems like it's getting dumped into cyl4, i'd be inclined to think it was pump or a sticky injector.
I'd say either replace or get injector number 4 professionally cleaned. Something tells me that's your problem.
I'm not a pro on fuel and ignition systems... but some of your first symptoms (hard starts and misfire) sound like it could be a crankshaft position sensor. I only say that because I recently had to replace mine after I threw a random misfire and my car started to die out from time to time. When I was researching it, people also said their car would take a long time to crank.
QUOTE (bmrabb @ May 28 2010, 09:52 AM)
I'm not a pro on fuel and ignition systems... but some of your first symptoms (hard starts and misfire) sound like it could be a crankshaft position sensor. I only say that because I recently had to replace mine after I threw a random misfire and my car started to die out from time to time. When I was researching it, people also said their car would take a long time to crank.
i was thinking this too, back when you had the misfire for the first time. either that or a cam sensor.
QUOTE (jcat @ May 28 2010, 10:14 AM)
i was thinking this too, back when you had the misfire for the first time. either that or a cam sensor.
Yep, I replaced both the camshaft and crankshaft position sensor on my car. It's been fine since then.
QUOTE (bmrabb @ May 28 2010, 10:17 AM)
Yep, I replaced both the camshaft and crankshaft position sensor on my car. It's been fine since then.
When I was diagnosing the IM gasket leak I ended up replacing both of those.
I also posted this over on http://www.nissanclub.com to try and get another point of view on this and this is what I've gotten for replies so far. . .
To which I replied. . .
Then I got this. . .
And this. . .
To which I replied. . .
So if anyone local has a timing light and wouldn't mind checking my timing before Monday can you let me know?
QUOTE (JSerrano)
Carbon is a good electric conductor. You see them used as brushes in electric motors and in the distributor caps. So every spark plug that gets very carbonized will eventually reach a point where it will begin to misfire.
A couple of things can cause a rich condition; a bad front O2, MAF, ignition timing, FPR, engine cooling issues, ECT, etc.
I think you need to work this problem as a hard starting issue. Is the problem occurring during a warm start, cold start, or both? The reason you want to fix the hard start condition first is because it worsen things that could appear to many as a problem during an engine running condition.
Let me illustrate, let's suppose the MAF sensing element is very dirty. Well when the engine is running is will actually be running in a leaner-than-normal state, not rich. So the spark plugs insulator would be white or blistered in extreme conditions. But during starting, a dirty MAF will not be feeding the correct air coming in so the mixture will not burn properly. Luckily during an engine start all injectors are firing simultaneously so the cylinders will eventually get quite wet. And at some point the engine will be able to start once a good amount of fuel has built up inside the cylinders. But a lot of that fuel has also attached to the cold spark plug and has carbonized, causing the second state - fouled plugs with a potential misfire in the works.
Lastly, a warm hard starting or stalling condition is typical of a bad distributor, which we've all been very aware of.
Get the idea? Fix engine starting issues first before engine running issues.
On a cold start if I do not prime the fuel pump it will take approx 8-10 seconds to turn over and when it does it stumbles for a few seconds, then the idle raises, and then it is fine.
A couple of things can cause a rich condition; a bad front O2, MAF, ignition timing, FPR, engine cooling issues, ECT, etc.
I think you need to work this problem as a hard starting issue. Is the problem occurring during a warm start, cold start, or both? The reason you want to fix the hard start condition first is because it worsen things that could appear to many as a problem during an engine running condition.
Let me illustrate, let's suppose the MAF sensing element is very dirty. Well when the engine is running is will actually be running in a leaner-than-normal state, not rich. So the spark plugs insulator would be white or blistered in extreme conditions. But during starting, a dirty MAF will not be feeding the correct air coming in so the mixture will not burn properly. Luckily during an engine start all injectors are firing simultaneously so the cylinders will eventually get quite wet. And at some point the engine will be able to start once a good amount of fuel has built up inside the cylinders. But a lot of that fuel has also attached to the cold spark plug and has carbonized, causing the second state - fouled plugs with a potential misfire in the works.
Lastly, a warm hard starting or stalling condition is typical of a bad distributor, which we've all been very aware of.
Get the idea? Fix engine starting issues first before engine running issues.
On a cold start if I do not prime the fuel pump it will take approx 8-10 seconds to turn over and when it does it stumbles for a few seconds, then the idle raises, and then it is fine.
To which I replied. . .
QUOTE (StanzaDescendant)
On a cold start if I do prime the fuel pump it will turn over within a couple seconds, stumble ever so slightly for a couple seconds and then be fine.
On a warm start if I do not prime the fuel pump it will take approx4-6 seconds to turn over and like with the cold start it will stumble and then be fine.
On a warm start if I do prime the fuel pump it will turn over in a couple of seconds and then be perfectly fine.
I should also note that after starting under all 4 conditions I can smell gas. I smell it the most under a cold start with no priming and the least on a warm start with priming. The plugs are brand new, wires are a year ago, distributor/cam sensor are a couple months old and it is an OEM Nissan unit, and the crank sensor was replaced at the same time as the distributor. The front O2 was changed last year when I bought your HS header and was replaced with a Bosch unit. When I go out now I'll check for any vac leaks and for shits and giggles the coolant level.
On a warm start if I do not prime the fuel pump it will take approx4-6 seconds to turn over and like with the cold start it will stumble and then be fine.
On a warm start if I do prime the fuel pump it will turn over in a couple of seconds and then be perfectly fine.
I should also note that after starting under all 4 conditions I can smell gas. I smell it the most under a cold start with no priming and the least on a warm start with priming. The plugs are brand new, wires are a year ago, distributor/cam sensor are a couple months old and it is an OEM Nissan unit, and the crank sensor was replaced at the same time as the distributor. The front O2 was changed last year when I bought your HS header and was replaced with a Bosch unit. When I go out now I'll check for any vac leaks and for shits and giggles the coolant level.
Then I got this. . .
QUOTE (JSerrano)
After that full detailed description, that there sounds to me like a MAF or IACV related issue. Most likely MAF though. If you get me a data log capture of the engine speed, airflow, injector pulsewidth, and coolant temp I could probably tell you what's going on. If you don't have a scan tool then get me a video showing the MAF voltage when ignition key is set to ON, then when the engine is cranking, and finally when the engine has started and is running. That might help me see what's going on.
And this. . .
QUOTE (blackalti)
did you remove your fuel rail when you replaced your img? i found the source of my gas smell and the idle fluctuation....needs new rubber grommet's/o-ring's
To which I replied. . .
QUOTE (StanzaDescendant)
just talked to my buddy who's the one that actually pulled the IM originally and he said he didn't pull the rail. However the #4 injector and o-ring were replaced back in December when we thought it was a bad injector. But after talking to another mechanic friend of mine he thinks all this may just be a timing issue, so on Monday I'm gonna take it down there and see if he can check/adjust the timing.
So if anyone local has a timing light and wouldn't mind checking my timing before Monday can you let me know?
UPDATE: So on Tuesday I was coming home from work and it was popping and backfiring the whole way home, which to me is very very embarassing. When I got it home I went to turn around so I could park on the right side of the street and it semi-died on me, and when I got it parked it flat out died. So I tried cranking it over and got nothing, not a starters click, not a fuel pump priming, nothing. So I popped the hood and lo and behold the positive terminal that I replaced while Tap and I were doing my fog light install had managed to loosen itself right up and off the battery which none of us noticed because of the insulators on top of the terminals. So I rushed to get it back on and tight before the storm hit and checked the negative while I was at it. Now it starts up just fine, albeit it takes a couple seconds to turn over, but it is back to running the way it was after the IM gaskets were done. 
Just when I thought I had ruled out all the obvious possibilities it comes back and bites me in the ass. Thankfully I caught this before I dumped any money into new parts. This also explains why I thought was my key FOB dying.
Just when I thought I had ruled out all the obvious possibilities it comes back and bites me in the ass. Thankfully I caught this before I dumped any money into new parts. This also explains why I thought was my key FOB dying.
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