KA24E PROBLEM.

jacksapple · Feb 18th, 2005, 11:14 PM

I have a 93 Nissan truck with a KA24E 4 cyl. engine. I have a rather strange problem with it that I can't figure out:

The truck has 180,000 + miles on it. I got up the other morning to go to work and when I started my truck, it had a hard time starting. It sounded like it was only hitting on 3 cylinders. I let it run for a while and it smoothed out. When I went to leave for work, my truck would not rev over 2500-3000 rpms. Once it would reach this rpm, the truck would die out. I thought I just had a clogged fuel filter, so I changed it. About a year ago I put new plugs in it, but I took them out anyway to check and clean them. Nothing helped, so I started digging a little deeper, thinking I had slipped a tooth on my timing chain. I threw a timing light on it and it was set at 10 degrees BTDC, which is what the specs calls for. Has anyone had this problem before? I would really like some help to figure this one out.

Thanks in advance,
jacksapple

**88pathoffroad** · Feb 20th, 2005, 07:04 AM

Plug wire crapping out on you, perhaps? Check your vaccuum lines. KISS!

jacksapple · Feb 20th, 2005, 02:39 PM

I thought of plug wires too, I've changed them, the plugs, distributor cap and rotor, checked for vacuum leaks, checked the timing, changed the fuel filter.... Nothing has helped so far. Thanks for the response though, I need the feedback. Any ideas that can be thrown at me I will investigate. I believe my truck is in "fail safe" mode for some reason. I'm not sure how to get it out of the mode though. I checked for error codes and get a 55 which is "No Problems".

Quote:

Originally Posted by 88pathoffroad

Plug wire crapping out on you, perhaps? Check your vaccuum lines. KISS!

Will · Feb 20th, 2005, 05:02 PM

It could be as simple as water in the tank. Water and gasoline do not mix. But if condensation builds up enough in the tank. It can get concentrated enough to get picked up by the the pump. It smooths out when the concentrations move away from the pump. A new fuel filter will be contaminated very quicky if this condidtion exsists in the tank. Try a couple containers of dry gas, in keeping with, the keeping it simple theory. Cost=maybe a couple of $.

jacksapple · Feb 20th, 2005, 08:23 PM

Thanks for the thought Will, but unfortunatelly I thought of that too. My truck was on about a quarter of a tank when this happened and I have filled it up since then. I will try putting some Heat in the tank to see if that helps. I can still drive my truck around town, but I'm lucky if I can get it up to 40 mph. It runs great below 2800 rpms.

Quote:

Originally Posted by Will

It could be as simple as water in the tank. Water and gasoline do not mix. But if condensation builds up enough in the tank. It can get concentrated enough to get picked up by the the pump. It smooths out when the concentrations move away from the pump. A new fuel filter will be contaminated very quicky if this condidtion exsists in the tank. Try a couple containers of dry gas, in keeping with, the keeping it simple theory. Cost=maybe a couple of $.

**88pathoffroad** · Feb 21st, 2005, 01:17 AM

The ECU's fail-safe system has been triggered by either fuel injector malfunction or mass airflow sensor malfunction. Under fail-safe mode, the engine RPM's are limited to 2800 RPM's to prevent damage to the engine due to an accidentally excessively lean mixture which could potentially cause detonation and a fairly serious condition commonly known as: "Holes In The Pistons".

Check your MAF wiring and make sure it's plugged in OK, as well as the wiring for the injectors. Physically unplug the MAF harness and visually inspect it from the front AND back to make sure nothing's corroded or barely making contact.

jacksapple · Feb 21st, 2005, 02:41 AM

Thanks for the advice. I'll check this out tomorrow. I'll have to figure out where the MAF is at on my truck. I have a Haynes book but haven't found the MAF yet. I'll post back and let you know what I've come up with. Thanks for the help!

Quote:

Originally Posted by 88pathoffroad

The ECU's fail-safe system has been triggered by either fuel injector malfunction or mass airflow sensor malfunction. Under fail-safe mode, the engine RPM's are limited to 2800 RPM's to prevent damage to the engine due to an accidentally excessively lean mixture which could potentially cause detonation and a fairly serious condition commonly known as: "Holes In The Pistons".

Check your MAF wiring and make sure it's plugged in OK, as well as the wiring for the injectors. Physically unplug the MAF harness and visually inspect it from the front AND back to make sure nothing's corroded or barely making contact.

SPEEDO · Feb 21st, 2005, 09:20 AM

the mass air flow is the little black box mounted at the top of the throttle body!

jacksapple · Feb 21st, 2005, 10:31 PM

Well, I unplugged the air flow meter and checked for a bad connection, checked my vacuum lines for leaks, and accessed my ECU to see how my fuel mixture was doing, to see if I was running lean. I got both red and green lights flashing when I went into mode 2 which tells me that my fuel mixture is just right. Hmmm... what a headache. Any other advice anyone could give me would be nice. Grimlins maybe?

**88pathoffroad** · Feb 22nd, 2005, 01:00 AM

Tried disconnecting your battery for five minutes and then re-connecting it? That'll reset the ECU and take it out of fail-safe mode.

jacksapple · Feb 22nd, 2005, 09:48 AM

Not a bad Idea 88pathoffroad. I'll unhook it tonight and leave it unhooked all night. I hope you're right about it resetting the ECU and taking it out of fail-safe mode. I'll let you know what happens in the morning.

Thanks for all of the input guys, please keep it coming!

Quote:

Originally Posted by 88pathoffroad

Tried disconnecting your battery for five minutes and then re-connecting it? That'll reset the ECU and take it out of fail-safe mode.

jacksapple · Feb 23rd, 2005, 09:42 AM

Update: I unhooked the battery overnight to try to clear the ECU out of fail safe mode with no results. The truck still will not rev over 2800 rpms. Any other ideas?

Quote:

Originally Posted by jacksapple

Not a bad Idea 88pathoffroad. I'll unhook it tonight and leave it unhooked all night. I hope you're right about it resetting the ECU and taking it out of fail-safe mode. I'll let you know what happens in the morning.

Thanks for all of the input guys, please keep it coming!

Myke · Feb 23rd, 2005, 01:51 PM

I went through a similar problem, mine turned out to be the wiring harness that runs parallel to the valve covers. It was shorting out on one of the brackets, causing the ECU to detect a temperature overheat problem. The temp sensor is right up front to the left of the vavle cover.

I know of another person that had the same symptom, his turned out to be the ECU. Do you have a code reader? Is anything stored in the memory?

The Nissan also has a level of diagnostic memory that only the stealer can access.
Myke

SPEEDO · Feb 23rd, 2005, 02:16 PM

have you checked/cleaned the injector connectors and or the head temp switch?

jacksapple · Feb 23rd, 2005, 03:13 PM

I have checked the injector connectors, but haven't thought about the head temp switch... I'll have to look that one up to see where it is located. I'll see if I can find it and check it. Thanks for the advice!

Quote:

Originally Posted by SPEEDO

have you checked/cleaned the injector connectors and or the head temp switch?