New 1999.5(?). Bought not running w/ no spark. OBD codes?

[TheRadBaron]

Hey guys. I just took a gamble on a 1999 Pathfinder that I bought non-running for $500. It's a 3.3, AT, 4x4 with 196,000 miles. It looks like it was a pretty well maintained machine for most of its life and it's overall in good shape. The previous owner told me that it's a 1999.5 and that it's kind of odd because it takes some 1999 parts and some 2000 parts. I don't think he really knew a lot about it, though. He bought it and drove it for 6 months or so until it suddenly started running really bad. He and some friends just started to throw parts at it without doing any real diagnostics or troubleshooting until he got discouraged and sold it...to me.

My preliminary testing shows that it has no spark. I haven't gotten much farther than that. I checked all the fuses and pulled the distributor cap to look underneath. Everything looks alright.

I have an '87 WD21 that I love dearly and I've gotten pretty good at working on it. Being able to pull the codes off the ECU by using the diagnostic switch has been really handy and helped me fix it a few times. This 1999 is the first R50 I've owned so I don't know a lot about it. I tried searching around a bit for some answers but I'm not having much luck. I'm working crazy hours and trying to get this thing on the road as quickly as possible.

I guess what I really need to know is

(1), where is the ECU located? It doesn't seem to be under the passenger seat like my '87

and (2), can someone link or describe how to pull the codes from the ECU using the diagnostic switch or dial?

I've come across a few descriptions of the process but they haven't been very clear to me. A while back I found a really good description of the process but now I can't find it.

 

Those are the main things that I need to know, but while I'm asking; Are there any common problems with the 3.3 that cause a "no spark" condition? Thanks a lot.

[Remus92]

Unfortunately this is a post 1996 vehicle. In 96 due to federal regulations obd ports are now required. You need to use a scan tool.

 

I ended up buying a cheap scan tool off of amazon for less than 20 bucks. You may be able to go to some parts stores and ask them to read it. The port is under the drivers side dash. Right where your knees sit.

[cntryboy_88]

The ecu is under the drivers side dash and it's obd2 because of the post 96 so you need to buy an obd2 scanner tool...if you have a Droid then you can get one on ebay for like $20 and buy the tourqe app ($4) and your good to go will tell you everything you need to know...have you checked any of the relays under the hood when you checked the fuses...there are certain relays like the anti theft and if it's not working the car will not even turn over to accerories working i had that problem took me like 2 weeks to figure out...also you're going to have a fuel pump relay you want to check as well

 

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[XPLORx4]

How did you determine that the issue is due to no spark? Are the plugs wet with fuel? Fuel odor out the tailpipe? If you're certain it's not getting a spark, it could simply be the ignition coil. The ignition coil is embedded inside the distributor, so you basically would need a new distributor. But it could potentially be any number of sensors, too. The crankshaft position sensor will also cause a crank-no-start condition.

 

Unfortunately if the engine won't run, you won't be able to tell if the check engine light is on, and whether it's worth the expense to get a code reader.

 

On the other hand, if you intend to do most repairs yourself on any 1996 or newer vehicle, an OBDII code reader is a must for a DIYer's toolbox. If the PCM is throwing a code, the code reader will tell you what it is, so you can figure out where to look.

 

If the previous owner indicated it was running OK and then started running poorly, do you know which parts they replaced in an attempt to fix it?

[hawairish]

You don't need a scanner. The procedure is in the FSM; in your case, see EC-59 for 1999 models.

 

If you've pulled codes from another Nissan before (particularly an older one), this won't be much different. The MIL blinks any/all codes at Diagnostic Mode II (EC-60). It's a very simple pattern of long flashes and short flashes to make a 4-digit DTC code, which then needs to be translated to the more-common P-code (EC-2). If you get a 0505 code (5 long flashes and 5 short flashes), then the system didn't detect anything...but of course, that doesn't mean you don't still have a problem.

 

If the gauge cluster responds in the On position, then the ECU can throw some codes. Turning it to Start and not getting a start-up response is also enough to trigger codes.

 

I recommend recording the MIL flashes with your cell and then resetting the codes. You can reset the codes by following the flow chart, or retain the codes by turning the ignition to Off after you've recorded all the DTC codes (they repeat endlessly until you take an action). Just be sure the screw is fully clockwise before going back into Diagnostic Modes.

 

I've been using this exact procedure on a 98 Frontier for the life of it (and we still have it). In fact, I never attached a scanner to it until a few months ago. A "fix" I made to the ECU long ago allows me to pull codes without a scanner or tools. But, the fix was out of necessity—I'll tell you first-hand that you don't want to break the screw off inside the ECU while in Diagnostic Mode II. (Hint: the screw is delicate.)

 

The procedure on late-model R50s is a bit more complex, but fortunately doesn't require ECU access. I did a few times before finally getting a wifi module. Like the others have suggested, I recommend it, too. It opens up the vehicle to a lot more information, including real time values.

 

Good luck, and report back any codes.

[TheRadBaron]

Thanks for all the information and responses. I didn't really have much time to fool with it last night so I just checked for spark by pulling off a plug wire, popping a new plug into it, and grounding the plug body to the motor while my daughter cranked it over. No spark present. I tried it on two different plug wires. I checked all the fuses and looked for any obvious problems with connectors under the hood and found nothing. I'll be back at it after work today and I plan to pull the codes as a starting point.

The PO told me that he changed the fuel filter, fuel pump, and crank position sensor. I didn't get the impression that he was a very experienced mechanic so hopefully those parts were replaced correctly.

I can hear the fuel pump run when the key is turned on but I haven't checked for fuel pressure.

[TheRadBaron]

Alright, I went out an got some information and symptoms. I'm thinking that there's more than one problem here. The first weird thing that it was doing is related to the fuel system. When I turned the ignition on to being getting the codes from the computer, I left it on for maybe 30 seconds while getting my phone ready to record the MIL flashes. After about 30 seconds with the ignition on, things started to happen under the hood. The fuel pump was cycling on and off, over and over again. On for a few seconds, then off for a few. Then on again, etc. I could hear a sort of "swishing" noise under the hood that sounded like maybe fuel rushing though the lines.

When this was happening it was making MIL act really strange so I couldn't get the codes. I took out the fuse for the fuel pump and that stopped the pump from cycling with the ignition on. But there were other relays or devices clicking and whirring and going crazy under the hood. I'm an electrician and it sure sounded like relays or contacts opening and closing very quickly. They sounded more like they were coming from around the motor and I couldn't feel any of the main relays in the two relay boxes actuating. The MIL was still going crazy, dimming when certain things under the hood were clicking and blinking nonsense patterns in time to the underhood noises. This went on for about 30 seconds, then suddenly stopped.

After everything stopped clicking and whirring the MIL stabilized and I was able to read the codes. Here's what I got:

-0101 MAF sensor

-0201 #1 fuel injector circuit open

-0304 Cylinder #4 misfire

 

None of these would seem to cause a "no spark" condition to me. Plus, there seems to be something weird going on with the fuel system. I don't see any leaks anywhere. What could cause the pump to cycle like that? Maybe a faulty fuel pressure regulator?

[hawairish]

Don't forget you need to translate the DTC codes you get from the ECU to the P-codes, so...

 

0101 = P0304, Camshaft position sensor

0201 = P1320, Ignition Signal - Primary

0304 = P0325, Knock sensor

 

These are a bit more suited to your situation.

 

Like XPLORx4 mentioned, the camshaft position sensor is likely the culprit. That'd be where I'd start. The other two codes will likely be addressed once the engine fires up.

[TheRadBaron]

No kidding. Sheesh. I guess that I missed that part about code translating. Thanks very much for the tip. I was just about to start looking for a "no spark" flowchart but now I have a better place to start. Wish me luck.

[hawairish]

No sweat, and good luck!

[TheRadBaron]

Alright! I went to the junkyard and pulled a $15 distributor today. Got home, put in in my truck, and it fired right up. I took it for a 10-mile test drive and it runs and drives great.

I still need to fine-tune the timing, reset the codes, etc., but I think it's safe to say at this point that the problem is solved. Not bad for $515.

Thanks everyone for the help. Cheers.

[hawairish]

Excellent!