- This topic has 14 replies, 4 voices, and was last updated 6 years, 9 months ago by
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I’d clean the throttle body.
Carefully follow ETCG’s instructions to avoid problems.You will either need a helper or some other way to fully depress the accelerator pedal for cleaning, as detailed here:
https://www.ericthecarguy.com/faq/solving-automotive-idle-problems/cleaning-throttle-bodies
I went to local auto zone to rent fuel pressure tester. Only problem is it takes a special adapter to hook to Nissan fuel manifold. Where do I find such an adapter.
Have you removed and inspected all the spark plugs for condition and gap?
The spark plugs may be worn out.
Also inspect and replace the air filter.
Look for any vacuum leaks by checking all the vacuum hoses for cracks
Next, get the computer scanned for codes–often a free service at places like Autozone but others charge a fee.If these are all good, then look on Amazon or Rockauto for fuel pressure tester kits with the adapter you need.
It may cost the same for the set as it would for a single adapter.
https://smile.amazon.com/Bang4buck-Pieces-Injection-Pressure-Gasoline-driven/dp/B01MDUZ6VG/ref=pd_ybh_a_1?_encoding=UTF8&psc=1&refRID=ZTCYKAS5SFRH21CTAQ98 is cheap enoughi have an actron 9180 – not seeing any codes. no mil light ever. i changed plugs at 100k i now have 175k. This is an intermittent problem which to me means electrical. Probably a sensor. May even be the cvt. Lotta people having problems with tranny on these cars. Checked hoses they seem good. I actually found an adapter on snap on tools however without a picture not sure it will work with autozone fuel pressure tester. Not looking to buy a fuel pressure kit from snap on. Here is something weird I dont understand. Before I realized I needed an adapter. I followed the procedure to remove fuel pressure. I removed the fuse, then i ran the car until it was out of gas, tried to crank it a few times. I did not disconnect battery though although this is a safety feature. When i went to pull fuel line , gas sprayed out like it was never drained of gas. Wonder how that is possible
[quote=”ferd” post=189962]. i changed plugs at 100k i now have 175k. [/quote]
Might be time for plugs again. I’d at least check them.
[quote=”ferd” post=189962] This is an intermittent problem which to me means electrical. Probably a sensor. May even be the cvt. Lotta people having problems with tranny on these cars. [/quote]
Intermittent problems are not always electrical.
Does your scan tool check for transmission codes? Not all of them do.[quote=”ferd” post=189962]I actually found an adapter on snap on tools however without a picture not sure it will work with autozone fuel pressure tester. Not looking to buy a fuel pressure kit from snap on. [/quote]
As I said, it may cost the same to buy an adapter as to buy the entire kit.
I sent you a link for a complete kit for under $40.
There’s no way for anyone to know what adapters do or don’t fit AutoZone’s Fuel Pressure Tester without any information about who made their test kit.[quote=”ferd” post=189962] I followed the procedure to remove fuel pressure. I removed the fuse, then i ran the car until it was out of gas, tried to crank it a few times. I did not disconnect battery though although this is a safety feature. When i went to pull fuel line , gas sprayed out like it was never drained of gas. Wonder how that is possible [/quote]
Just because the car stalled , doesn’t mean there is no fuel pressure.
It means there is insufficient fuel pressure to run the engine.Your throttle motor also contains a throttle position sensor.
No. I don’t think you can rebuild it yourself.
No parts available to do so—and no instructions.At the very least, with the key on, engine off, you can see if the throttle position voltage changes smoothly from no throttle to WOT.
Civvy asked you,”What do your fuel trims look like at idle and under load (2000-3000 RPM)?”
Fuel trims are not fuel pressure.
Your scanner should show you STFT and LTFT (short term fuel trim and long term fuel trim).
When testing fuel trims at higher RPMs, you hold the RPMs high for 20 seconds or so and use those readings.i didnt see that post earlier for pressure tester kit. It looks like the one at auto zone. however if you notice the tee fitting in that picture it looks the same as the one at auto zone. The problem with auto zone and possibly that one is it is knurled on the end and wont go into the quick disconnect. I guess i could cut the knurl off with hacksaw and then it would fit I hope. I believe my scanner does have an stft and Ltft reading. I will get that and post it. Do these readings check out the throttle body. The symptoms I am having does act like a TPS sensor. A component that I have changed out in several other cars. Thanks for the info I didnt know that it was built into this throttle body, good to know.
i setup my scanner. Here are readings.
tps keyon engine off 0
tps -idle .7
STFT -idle- (.7&0) fluctuates
LTFT-idle (-1) steady
STFT – 2k rpm (1.5- 0) fluctuates
LTFT- 2k rpm (-3.4) steady
STFT-3k rpm (1.5- 2.3 ) fluctuates
LTFT-3k rpm (0.0) steady once it gets over 2k it drops to zeroIf one end of the adapter does fit the quick connect fitting on the fuel line, you can probably use the flex hose and clamps to attach it to the fuel rail.
If you consider buying a kit, I’d first email the manufacturer or seller to be sure there’s a fitting included for your car.
The fuel trims look fine.
IDK what the at idle throttle reading is supposed to be.
The real test is to see if the readings smoothly change, rather than jump.I was able to make my own adapter. I used a fuel filter and plugged it into the quick disconnect then with rubber hoses I was able to hook up the fuel pressure gauge. I had to go to auto zone disconnect fuel line and find a fuel filter that would work. I ran the pressure test the pressure was right at 51 . When iu accelerated it dropped a pound. When I turned car off prresure dropped 2 pounds however after 30 minutes it dropped to 25 pounds. I also noticed when i started car after releasing pressure it took a few seconds to get to 51 lbs. whether that matters or not. Wasnt able to do more testing wife needed car.
It’s concerning are that fuel pressure dropped when you increased the rpms.
Normally, there’s an increase in fuel pressure when accelerating.
I’d repeat the testing .
Makes me wonder if the fuel pump is weak or there’s enough gunk accumulated in the non-replaceable fuel pump filter to restrict flow.
Rather odd is that the fuel trims look normal.Though you seem to not want to, I’d pull the plugs and see if they’ve worn out enough for the gap to have widened.
Just because plugs are supposed to last 100K miles doesn’t mean they actually will.
I’d use NGK plugs if they do need to be replaced.Another thing to check is the battery/cable terminals.
Anything that lowers available voltage can cause the ECM to do all sorts of weird things.I PMed you, also.
As for CVT issues, they’re so common that Nissan doubled the warranty, as detailed here:
http://www.nissanassist.com/ProgramDetails.php?menu=2
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