Runs badly at 2,000 rpm's

Hi and thanks for using 2CarPros.com.

What you described can be the result of many things. Things such as low fuel pressure, need of tune up, engine vacuum leaks, partially plugged catalytic converter, can all cause issues.

What I suggest is to check for diagnostic trouble codes. Here is a link that shows hot to check on an OBD1 system as your vehicle has:

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

Do this first and let me know what you find. If I try to just give you all the things it could be, it will become confusing.

Let me know if you have trouble or have other questions.

Joe

Thank you but still acting up. Now my number five spark plug wire is not giving any spark. I check distributor cap , and rotor still good unless its the whole distributor? I also rotate it little bit but still no spark on number five wire. I bought spark plugs and wires just three months ago and it was running fine . I have my old ones try to replace it to spark plug wire number five still the same problem no spark . Any advise?

When I start my truck it will idle up and down and shuts off after a few seconds.

Welcome back.

The idle issue sounds like it could be related to the idle air control valve (IAC) or an engine vacuum leak. However, that is not related to the no spark to only one plug.

Have you checked for trouble codes?

Do you know what is a good scanner for this ? Not to expensive though. Truck is 1994 Nissan hard-body v6 3.0 automatic. I searched online there is different plug in and I am not sure.

Welcome back.

Honestly, OBD1 scanners are getting more difficult to find. If you follow the link I sent, you should not need a scanner. The computer will communicate via the engine light.

Let me know if I can help.

Joe

I checked trouble codes giving me 55 ( No malfunction recorded ). I have no clue.

Welcome back.

That does not help. lol Since there is no spark on the one cylinder, we need to check the ignition control module/power transistor. It it near the coil. Remove it and follow these test directions.


1. Disconnect power transistor harness connector.

Picture 1 shows the connector on the component as well as what leads to test.

2. Check continuity between power transistor terminals with a digital meter.

Picture 2

Note: Set tester in lower range.

Confirm the readings correlate with the specs in pic 2.

Picture 3 shows component location.

The only other things I question are the distributor itself or the cam sensor, which is responsible for ignition timing and injection timing. However, I feel it should have set a code.

Let me know if you have questions or need help.

Joe

Where is my crank position sensor?

Hello, I am Danny

Just to help. It is located inside the distributor in your engine. I have attached a picture. Hope this helps and thanks for using 2CarPros.
Danny

Thank you and also do you know any scanner for 1994 Nissan Hard body v6?

Hello again.

That will be hard to find, however Snap-On brand has the MT26000 for your vehicle but has to have the Import Cartridge for your vehicle as it is OBD1. I am attaching a tutorial for you. Scroll to see Nissan. Hope this helps.
Danny-

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

I have a question. Do you know the order of the spark plugs wires. On the left side passenger it goes 135 and right side is 264. Is that the correct?

Welcome back

I attached a picture of the firing order. Let me know if it helps.

Joe

My truck is 1994 v6 3.0l the way I was looking at it right now the wires is going 264 not 246 .

The firing order is 1 2 3 4 5 6. So, starting with the number 1 which is in white, and the distributor turning counter clockwise, that is the order the plug wires need installed. Basically, at 10 oclock on the distributor is cyl 1, at 8 oclock would be the wire going to cylinder 2, at 6 oclock that is where the wire to cylinder 3 would go and so on.

I apologize, but I'm not sure what you mean with going 264 and not 246. Can you explain?

Okay, on the left side passenger of the engine its goes 1,3,5 in order odd number and right side of driver of the engine it goes 2,6,4 in order even number .

That sounds correct. Did it make any difference?

Okay, just checking. Okay, now my truck starts when I adjust the distributor but its still idling and it will shut off. There is spark and fuel and compression is good starter is good battery is good. Could it be my ignition lock cylinder? Because when I start it it is hard for me to turn it on like I have to force it. So I took out the panel to take a look and found out harness was loose or it is not connecting or whatever. Could that be it too?

If it shuts itself off after starting, the switch could be bad. Do a spark test and see if spark stops when the engine shuts off. If it does, then you may have a switch problem. It could also be the ignition control power transistor. The ignition signal from the ECM is amplified by the power transistor, which turns the ignition coil primary circuit on and off, inducing the proper high voltage in the secondary circuit. Test that next. Follow the following directions and the two attached pictures.

1. Disconnect power transistor harness connector.




2. Check continuity between power transistor terminals with a digital meter.


Note: Set tester in lower range.

Does any body know where my MAP sensor located?? Nissan hard body v6 3.0l.

To the best of my knowledge, in 94 they didn't have one. Are you getting a code or something that is making you question it?

I thought I had one because if I have a throttle position sensor, mass air flow sensor , idle air control valve sensor, oxygen sensor and crank shaft position sensor should I not have one? My truck can start but I have to keep tapping on the gas in order for it to start and my RPM even just a little tap RPM goes way to high to 5. I am not sure what is wrong with it. But I did order online MAF sensor, IACV sensor, throttle position sensor and ignition lock cylinder. Hopefully when I put in the new parts it works fine.

I checked both of my manuals because I thought it would have one, but neither list it. So, I checked online parts and nothing.

Do you know why my RPM is so high? When I just tap a bit on the gas pedal like way too high?

Your description sounds like a vacuum leak or the throttle body needs to be cleaned. Both can cause a higher idle. The vacuum leak because it allows unmetered air into the engine and the dirty throttle body because it will cause the throttle plate to bind up.

I bought ignition lock cylinder for my truck 1994 Nissan hard-body v6 automatic transmission. And I noticed just now that I see the white box that is pointed the color red arrow has a wire in the back and the one on my truck does not. It has like a black wire or cable that connects to the back of the white box.

I did not install it yet because I am not to sure. Unless I take it out the white box and replace it on the old one on my truck or maybe the one I bought with the wires will connect to the black or cable wire. Any advise?

Does anybody know where my PCV located on my truck 1994 v6 3.0l?

It screws into the intake manifold at the rear of the engine. Behind the throttle body.

Thank you.

Does anybody know why when I turn the key to on it cranks then in five second or ten seconds it will start. It cannot be my starter because it will start up and crank, battery is good, fuel is good. Nothing is clogged up. Right now I have parts for it bought a throttle position sensor, idle air control valve, mass air flow sensor and ignition lock cylinder. I hope these parts will work so I can be driving on the road. Also, my RPM just a little tap on the gas it goes up way to high to 4,000 RPM's then drops down below 1,000 RPM's in the middle.

So you turn the key and it turns over for five to ten seconds and then starts? What about if you start it, let it run a bit, then shut it off, does it start right back up like it used to?
If it starts and runs okay after that initial long crank the starting problem is not any of the parts you listed as having bought. It is a fuel check valve problem, it is not holding line pressure in the fuel system. To test that you need to T in a fuel pressure test gauge on the line. Crank it until it starts, then read the pressure. Now shut it off. You should see a minor drop in pressure and then it should hold steady for a long time. If you shut it off and the pressure drops rapidly to zero the check valve in the pump is bad.

Sorry, still learning about parts of my truck. Is that the fuel pump or any pictures of it?

Hi and welcome back:

The fuel pump is in the fuel tank. See picture 1

Here are directions in general showing how testing is done:

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

Here are the specific directions for your vehicle. Pressure specifications are included. All remaining pictures correlate with these directions.


FUEL PRESSURE TEST
NOTE:
- When reconnecting fuel line, always use new clamps.
- Make sure that clamp screw does not contact adjacent parts.
- Use a torque driver to tighten clamps.
- Do not perform fuel pressure check while fuel pressure regulator control system is operating; otherwise, fuel pressure gauge might indicate incorrect readings.

PROCEDURES
1. Release fuel pressure to zero.
2. Disconnect fuel hose between fuel filter and fuel tube (engine side). Then install pressure gauge.
3. Start engine and check for fuel leakage.

Fuel Pressure Gauge


4. Read the indication of fuel pressure gauge.


SPECIFICATION AT IDLING

5. Stop engine and disconnect fuel pressure regulator vacuum hose from intake manifold.
6. Plug intake manifold with a rubber cap.
7. Connect variable vacuum source to fuel pressure regulator.

Vacuum/fuel Pressure Test


8. Start engine and read indication of fuel pressure gauge as vacuum is changed.

Note: Fuel pressure should decrease as vacuum increases. If results are unsatisfactory, replace fuel pressure regulator.

Let me know if this helps.

Joe

Found out why or hopefully it is . That maybe my fuel tank wires one of the ground wire . I probably need to located where its located and check the bolt where its connected and just clean it could be dirty or corrosion.

The ground from the fuel pump is in the left kick panel. See the attached schematic. Let me know if this helps.

Joe

Having hard time looking for it. I found all five wires i am trying to follow it . It is leading me to the engine but it is tape with lots of wires now and i am kinda confuse . Any advise?

Did you remove the kick panel? There should be ground wires to the body behind the panel.

Joe

What kick panel ?