Intermittent power loss?

SAM PAULEY

MEMBER
1994 NISSAN HARDBODY
2.4L
4 CYL
2WD
MANUAL
165,000 MILES

Truck starts up and drives just fine. Then randomly it will start to not accelerate. If the clutch is in, then you can rev the engine but if it’s not it won’t. It feels almost like if you shift into too high of a gear and try and accelerate. If you gently give a little bit of throttle it will pull a little bit, but anything more than a hair it bogs down and will die on you. It’ll start right back up and go and then it’ll happen again. No check engine light or anything.

5 Replies

JACOBANDNICKOLAS

MECHANIC
109,645 POSTS

Hi,

It sounds like you may have a fuel pump failing. If the pressure drops off, this is what can happen. You can rev it, but when the engine is under a load and needs more fuel, it's not there.

This is my first suspect, so here is what I suggest. We need to check the fuel pump pressure to make sure it is within the manufacturer's specifications.

Here is a link that explains in general how it's done:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

I attached the directions below specific to your vehicle. Note: You will need a fuel pressure gauge, but most parts stores will lend one to you.

Also, since this vehicle has an OBD1 system, I would recommend checking for codes simply because the light doesn't always turn on when there is a problem. You don't need a scan tool.

Here is a link that explains how it's done:

https://www.2carpros.com/articles/nissan-obd1-diagnostic-trouble-codes-and-retrieval-procedure-1984-to-1994

Let me know what you find or if you have questions.

Take care,

Joe

See pics below.

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Thursday, July 13th, 2023 AT 9:16 PM

SAM PAULEY

MEMBER
3 POSTS

Thank you for your response. I had already replaced the fuel pump, which said the one that said it was correct part wasn’t, so I had to splice it in and make it work. I will check fuel pressure though. That said as I was driving it today it would drive fine for a while then do the same thing. I turned the truck off and restarted it and the problem went away. Had to do it one additional time, maybe 20 minutes or so afterwards and it was just fine again.

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Friday, July 14th, 2023 AT 5:53 AM

JACOBANDNICKOLAS

MECHANIC
109,645 POSTS

Keep in mind, fuel pumps are made differently and produce different pressures. If they sold you the wrong one, confirm the pressure is correct.

Also, there are other things that can cause this. For example, if the internal portion of a catalytic converter has come loose, it can move and restrict airflow. That will cause a power loss as well. Also, a failing sensor can as well.

Is the check engine light on when the engine is running? Also, did you try to retrieve diagnostic codes?

Is there any gray or black smoke from the exhaust or odd odors?

Let me know.

Joe

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Friday, July 14th, 2023 AT 8:06 PM

SAM PAULEY

MEMBER
3 POSTS

Hey guys, sorry for the late reply, didn’t get any codes, I already had parts on order, so I ended up redoing the fuel system, changed out the tank, pump, sending unit, filter and constant pressure regulator. The tank was kind of gross on the inside, which is to be expected on a 30-year-old truck. But when I changed out the fuel filter it rattled like the filter media came apart from the inside, I’m pretty sure that was the culprit or the pressure regulator was gummed up from sitting for a while, starts and runs just fine now thanks!

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Wednesday, July 26th, 2023 AT 2:41 PM

JACOBANDNICKOLAS

MECHANIC
109,645 POSTS

Hi,

Thanks for the update and I'm glad you resolved the issue. As far as the fuel filter goes, I don't think it should do that. LOL

It was great to see the truck (part of it) in the one pic. I always liked that body style. I nearly bought a new one in 1989 with 4wd, but because I was driving 35K miles a year, I went with something smaller. Well, I guess I just gave away my age. LOL

Take care of yourself and feel free to come back anytime in the future.

Joe