01 Sentra 2.0 fuel issues?

[nametakennow]

As in title, this is a 2001 Sentra SE (SR20DE). 70k miles, 5spd

I've posted about these issues a few times with little success, but the symptoms seem more acute and identifiable now, so I'll try again.

1. Fill up with gas, go to start car, starts fine but then won't hold idle unless I give it a little gas.

2. If I get on and off the throttle repeatedly, as when in a traffic jam, the car often will try to stall the next time it goes to idle (say when I pull off the freeway and clutch in/throw it in neutral as I come to a stop at a light, that sort of thing). I can keep it alive by blipping the throttle, sometimes it takes a few blips. If it stalls, it almost always starts right back up, but once in a blue moon it will not turn over for a few tries.

3. Intermittent Evap codes for small leak and large leak. SES will sometimes turn off if I drive for awhile and don't have problems or manage them by blipping the throttle.

4. Water temp gauge bombs to the bottom when I have the throttle depressed at all. Sometimes it bounces around a bit even when not on the throttle.

5. Car bucks a bit when rolling at idle speeds in 1st, 2nd, and 3rd (not that I practically ever do this in 3rd) gears. I think this may be clutch related as I'm still on the original clutch and did have it turbo'd for awhile, so it's probably pretty worn.

I've replaced the following in the past ~10k miles - some of these are probably completely unrelated to the issues:PCVEvap canisterEvap purge valveWater temp sensor (twice)MAFECU foam recall IS doneECU and harness were replaced at ~50k after removing the turbo kitSpark plugs also at about 50k

I'm thinking this is related to fuel feed, as if the fuel pump can't maintain proper pressure. Would it be the pump itself, the relay, or what? I'm pretty certain the injectors are clean. I'm thinking I may have burned up the pump trying to feed the 360cc injectors I had when I had the turbo installed. I'd planned on replacing it with a Walbro 255, but was waiting on the cash to do so.

If you have any ideas at all, go ahead and post up. I'd really like to have this car run like it did before the turbo fiasco and should actually have the cash to fix it within the next few weeks. I'd also like to NOT have to play the throttle blipping game every time I fill up or happen to piss off whatever gremlins are in my car.

TIA

[SteveTheTech]

To start I want to ensure the basics are covered, more for anyone that may read this.

1) Make sure that the following parts are in good order.- Battery- Ignition system- Engine oil and coolant levels- Fuses- ECM harness connector-Done- Vacuum hoses- Air intake system(Oil filler cap, oil level gauge, etc.)- Fuel pressure- Engine compression- EGR valve operation- Throttle valve- EVAP system-Done

In doing a little brainstorming using the book and your description, I would lean towards an idle control valve input signal (CTS signal). This could either be caused by a problem within the gauge cluster. Something like a loose pin on the back of the meter or an internal failure.

I want you to try the test located on page EL-94. I am curious what the results are when you press the button (during the test) if the gauges do not respond in a smooth fairly quick motion once the button is pressed and stays that way until you release the button.

If you have another combination meter lying around I would swap it and see if that happens again. My thinking for this is the fact that although these things are not really related (for this symptoms, but are all inputs to the ECM) but the Combination Meter control unit perceives these signals. However I do not know if this would cause the engine to want to stall.

After the combination meter check depending on your results we may have to break out the multimeter and roll up our sleeves.

Sorry for the delayed response.

[nametakennow]

Battery - new within the last 6 monthsCoolant and oil - both within rangeFuses - will double checkVac - no leaks from what I can tellIntake - has a homemade vibration mount, but is otherwise great, filter is cleaned every ~10kFuel press - unsure, do we know of an easy test?Comp - pulls as hard as it ever has and doesn't really exhibit any compression symptomsEGR - should be fine, hasn't thrown any EGR codesThrottle valve - Seems to operate fine, pedal modulation results in quick responses (throttle cable instead of the QR's fly-by-wire FTW)

Going to give this test on EL-94 a shot and will check back in afterward. Thanks again, Steve.

[nametakennow]

Gauges look just about like the picture in the manual. Fuel was a little lower and water temp was a little higher, but around the middle. Responded quickly and smoothly.

Fuses look fine.

Tried an idle relearn. Couldn't get it to stall afterwards, but I think that was coincidence. We'll see when I fill up next (probably later today).

Talked to a Tech at the stealership today. He thinks they're unrelated - air bubble in the coolant, which is possible, and some other issue to cause the stalling. They said they could hook it up to the Consult and give it a shot - with the $95 diagnostic fee, of course. I told them I'd be in touch. Figured I'd report back here before I give up and open my wallet (possibly for nothing).

[SteveTheTech]

If there were indeed a coolant bubble the vent temperature would be suspect, but since this has been going on for a while and not changed. An air bubble should work it's way out. In most cases (the 2002 Altima QR will never bleed out) the air will works it's way out. I highly suspect something more complex than an air bubble, and a MAF. I would be skeptical taking it in to them unless you can clue them in on what has been done, the effects of the replacement of parts and the exactly how the issue goes on.

It may actually be cheaper and easier for you to scrounge up a used combination meter from ebay and give that a shot for a little while to see if that has an effect. Although the gauge sweep came up with nothing that is only a very basic inspection.

I would hate to see you blow a hundred bucks and all your left with is a guess, I'm sure they'll recommend something to you but I cannot assure you that it will be the end of this problem. You need to have a shop foreman or specialist look at what you have. I really like the 01 Sentra with the SR and 5speed, it's a great little car before Nissan went with cheaper interior refinements.

[nametakennow]

The car itself is a blast, no doubt, and my issues aren't typical - which is part of the reason I can't seem to fix them.

When I filled up it stuttered but didn't quite stall. That happens from time to time. Then again, I may not have done the relearn properly. I tried the pedal procedure and it didn't seem to go correctly. I'd read that you could run it for 10 sec with the MAF disconnected then shut it down and plug the MAF back in and that would work too. Is that procedure correct?

I had a couple of other little tasks for them (things that are a pain for me to do and, therefore, I pay too much to have done) anyway, so the fee is somewhat unavoidable. In that case, what little insight they may have may give me an idea, though it may be simpler to just have someone else do the couple of other things for cheaper and keep trying on my own.

I'll start looking for that meter.

[nametakennow]

Went ahead and had it checked out while I was having a few other minor things taken care of. I was told that there's a MAF code popping up, and that it's supposedly a function of the CAI. I've had it for years and never sucked up anything, so I didn't buy that explanation, but I have had a ghetto-rigged vibration mount for awhile, so I converted it to a short ram and am trying it out for awhile to see if maybe that was throwing the MAF out of wack to cause the jerking and stalling.

They had no clue why the large and small leak were popping up.

As for the gauge, I was told there's a short in the dash, so when the load on the circuit rose under throttle, the gauge flipped out. Since they cleared the codes when I picked it up, the gauge has been rock solid. Could the extra load on the circuit caused by the SES being on be enough to make a short cause that sort of thing?

Regardless, the short, if it exists, is a $500 repair for no functional reason, so I held off. I haven't bought a MAF yet either while I try out this short ram thing.

[SteveTheTech]

I don't know if I completely buy their story although I cannot offer my own version of it without getting my hands into it. I have a sneeking suspision that some if not all of these things have some type of relation.

The $500 would be for a new combination meter yes?

A CAI should not throw a MAF code. The only MAF codes stored in these are related to circuit integrity not output performance. Without looking at CAL/LD numbers and referencing that with the gm/s MAF readings anyone who replaces a MAF is merely guessing.

[nametakennow]

No clue what the $500 was for, they seemed to indicate it would be for the whole gauge/dash wiring assembly. Combo meter makes sense though, since that's the only spot I could imagine there'd be a short to cause the water temp gauge issue.

Could excessive vibration caused by a loose intake mount cause MAF failure? That's what I was guessing at by converting to short-ram.

That said, the car stumbled a bit today in traffic. Tach bounced off zero a couple of times and then it went back to normal. SES popped up shortly thereafter. This is with the short-ram conversion, so if it was vibration then either there's still too much (which is possible, I suppose), the MAF is already shot such that it doesn't matter how it's set up now, or they're entirely wrong to begin with.

With the SES on so far, the water temp gauge seems to be holding up, but it was only a couple of minutes before I got home after it came on.

[SteveTheTech]

No clue what the $500 was for, they seemed to indicate it would be for the whole gauge/dash wiring assembly. Combo meter makes sense though, since that's the only spot I could imagine there'd be a short to cause the water temp gauge issue.

That was the reason I suggested getting a junk yard combination meter for testing purposes only and you will need to replace that at some point with the correct mileage. It makes sense as an issue, given the amount of critical signals that pass through the combination meter so many seemingly unrelated symptoms may all route back to the same issue.

Could excessive vibration caused by a loose intake mount cause MAF failure? That's what I was guessing at by converting to short-ram.

That said, the car stumbled a bit today in traffic. Tach bounced off zero a couple of times and then it went back to normal. SES popped up shortly thereafter. This is with the short-ram conversion, so if it was vibration then either there's still too much (which is possible, I suppose), the MAF is already shot such that it doesn't matter how it's set up now, or they're entirely wrong to begin with.

That may cause a hesitation, no start, missfire under load, or extended cranking. MAF and the control circuit has a tremendous role in all functions of engine management. I doubt that is the root cause of your problems. The most common product of a failing MAF is driveability before a DTC, this is due to the fact that the engine will run within a wide range of voltages. There are some advanced numbers that need to be looked at to confirm an out of spec voltage. If the DTC was for a circuit fault I would start looking toward the ECM circuit. Reasoning for this is the MAF is an input and does not have anything to do with the combination meter. It is possible to have more than one issue compounding or as a byproduct of one repair.

With the SES on so far, the water temp gauge seems to be holding up, but it was only a couple of minutes before I got home after it came on.

Let me know what the code is this time, number please.

Knowing what DTC it is will give me the information I need to hunt through the FSM and see if I can find something that jumps out. (Potential harness commonality or ground issue) You would be surprised how often things like power supply, ground and signal wire integrity especially when it comes to intermittent issues like this.