[smj999smj]

Thanks so much for your prompt response, smj
!
The truck is at my Nissan dealership right now, but they lost their service manual and OBD tools for this model year/engine, hence why I am researching and soliciting opinions. Their first thought was fuel delivery, but it tested fine (at my cost). My first thought was distributor/ignition coil intermittent - so it is good to receive your second opinion. I will run the diagnostics and see what sorts of error codes appear. I downloaded the service manual and found the ignition coil tests you mentioned - thanks for the specifics. Here in Canada it can be hard to source old parts. Do you have any idea what I should expect to pay for a new ignition coil assembly? I will follow your recommendation for a genuine Nissan part - thanks for that. Regards -Trevor

They don't need an OBD tool for this vehicle. All the OBD tool does is allow them to remotely do what they can do at the ECM using the red and green LED lights in it and the mode selector screw. If they need a factory service manual, tell them to go online:

https://www.********.com/nissan-service-manuals

(replace "*" with "nico club" minus space)

And for manually checking codes:

Nissan OBD / OBD2 Codes – TroubleCodes.net

www.troublecodes.net

 

[tmoat]

Thanks again smj. The diagnostics look straight forward to me. Can you tell me where I can find the replacement part numbers in the service manual? I am wondering whether the distributor, optical sensor, shaft bearings, etc. that you mentioned are sold individually or as an assembly. I will ask the dealership about ordering Nissan re-manufactured parts, but I might end up having to source these parts myself. By the way, if you are looking for an easy place to download the entire service manual as a compressed file, try this: Nissan Hardbody D21 Truck Service Repair Manuals. Thanks - Trevor

 

[smj999smj]

Thanks again smj. The diagnostics look straight forward to me. Can you tell me where I can find the replacement part numbers in the service manual? I am wondering whether the distributor, optical sensor, shaft bearings, etc. that you mentioned are sold individually or as an assembly. I will ask the dealership about ordering Nissan re-manufactured parts, but I might end up having to source these parts myself. By the way, if you are looking for an easy place to download the entire service manual as a compressed file, try this: Nissan Hardbody D21 Truck Service Repair Manuals. Thanks - Trevor

The service manual doesn't provide part numbers. You can look up part numbers at NissanPartsDeal.com. Nissan doesn't sell shaft bearings for their distributors, but if you search the web...and possibly this site...you can find people that have replaced the bearing and provide part numbers. It looks like the Nissan reman for the Hardbody V6, # 22100-88G01RE, is no longer available, so the only option is aftermarket for distributor replacement options.

 

[tmoat]

Hi again smj - thanks again for your advice. I have the truck at home again and will look at the ECM tomorrow. Is the ECM under the passenger seat or driver seat? Dealership says driver side, all the video tutorials show passenger side. Maybe it's different as I have a 4x4 SE V6. I can feel boxes under both.

According to the dealership, in addition to the lurching fix, I need the following, in order of importance: Rear Propeller Shaft centre bearing support assembly; both front lower ball joints, both front calipers, right front wheel bearings (possibly). Yikes. They are quoting $3200 to do all that work, plus the lurching fix (which I will diagnose via ECM tomorrow). The truck has 170k gentle miles on it, west coast only (no salt, no off-road, mild winters). Dealership recommends I abandon it; I only use it for ~4k miles/year (minor house renovation work) so I am loathe to invest thousands more into a monster truck that I don't know, need, nor want. I love the 4x4 SE V6 I have. Do you think it is worth salvaging?

I can afford the work - but I don't want to sink money into a hole if I can avoid it. Parts availability looks like a serious issue. My goal would be to squeeze another ten years and 50,000 city miles out of it. I replaced timing belt and clutch plates at 160k. Ideally, it would retire the same week I do... If I were to buy new, I would much prefer BEV (I own a Leaf already) but no viable options are yet available. Thanks again - Trevor

 

[BRubble]

Hi again smj - thanks again for your advice. I have the truck at home again and will look at the ECM tomorrow. Is the ECM under the passenger seat or driver seat? Dealership says driver side, all the video tutorials show passenger side. Maybe it's different as I have a 4x4 SE V6. I can feel boxes under both.

According to the dealership, in addition to the lurching fix, I need the following, in order of importance: Rear Propeller Shaft centre bearing support assembly; both front lower ball joints, both front calipers, right front wheel bearings (possibly). Yikes. They are quoting $3200 to do all that work, plus the lurching fix (which I will diagnose via ECM tomorrow). The truck has 170k gentle miles on it, west coast only (no salt, no off-road, mild winters). Dealership recommends I abandon it; I only use it for ~4k miles/year (minor house renovation work) so I am loathe to invest thousands more into a monster truck that I don't know, need, nor want. I love the 4x4 SE V6 I have. Do you think it is worth salvaging?

I can afford the work - but I don't want to sink money into a hole if I can avoid it. Parts availability looks like a serious issue. My goal would be to squeeze another ten years and 50,000 city miles out of it. I replaced timing belt and clutch plates at 160k. Ideally, it would retire the same week I do... If I were to buy new, I would much prefer BEV (I own a Leaf already) but no viable options are yet available. Thanks again - Trevor

Trevor,
"Suggestions would be much appreciated - I am the second owner of this truck (we are both Engineers and good friends, and I want to keep it in the family so to speak). "

It sound's to me like you Inherited - Whether you paid for it or Given to you that you Really didn't much want or Really NEED.

I've read through this and to me it look's like this truck has been driven and NOT been given Regular Routine Preventative Maintenance. Now You've got it and have to decide whether Fixing what wasn't done over the Past 27 year's is worth it!

If YOU need a Truck look @ the Price's of New and Used Truck's NOW. 3200 $'s is a drop in the Bucket for a Good Running Used Truck Now.

You say You are an Engineer but started this without a Geniune Nissan Service Manual! If indeed you are a Working Engineer then get the Service Manual, Roll Up Your Sleeve's and GET To Work. If you do the work yourself, then it won't cost you near as much as the DealerShip quoted.

It really depend's on Whether You Want and NEED this Truck IMO.

Regards,

 

[smj999smj]

ECM is under the passenger seat; it's a lot easier if you remove the seat out of the way. You "may" just need to repack the wheel bearings (get new seals) rather than replace. They aren't sealed hub units like modern vehicles and do require periodic servicing. With the driveshaft center support, stick with the genuine Nissan part; if it's not something you feel comfortable with in replacing, you could remove the shaft and take it and the new part to a driveshaft shop or independent auto repair shop and have them replace the center support for you. Front calipers aren't hard to replace and you can get "loaded" calipers for $47 ea. at Rockauto.com that include the pads and mount bracket. I would also recommend new front brake hoses, with Rockauto carries at dirt cheap prices. I would go with Moog or Mevotech Supreme as far as the lower ball joints which is a bit harder to do and one needs to be careful. You could also always get a second opinion from a reputable independent repair shop.

 

[tmoat]

Hi again smj - Thanks again for your advice - I ran the diagnostics and here is what I have found so far:

• Switched accessories on, (i.e. left engine off)
• Error code 34 (Knock Sensor) was stored in ECM memory
• Started engine; Mode 3 Code 34 still active (and symptom present while idling)
• Entered Mode 4 to clear memory (I wanted to see if any other codes came up)
• Entered Mode 3 again and observed Code 55 (no fault detected) which seemed odd
• Shut engine off, re-started, let run (rough) for two minutes
• Entered Mode 3 and observed Code 34 again.
• Shut engine off.

Continuity confirmed between the KS connector pin E through the harness to the ECM connector pin 27. From the KS connector pin E on the engine side of the connector to ground (battery negative post) there is an open circuit. The manual page EF&EC-137 indicates continuity should be present here.

The harness seems fine. Suspect KS is faulty (or at least, not referenced to ground). I see no obvious damage to the wiring harness from the KS connector into the engine.

I can't find any further hints in the manual from here. Page EF&EC 15 indicates that the KS sensor is mounted directly in the block, under the intake manifold. Somewhere I read that removal/replacement of that is 4-6 hours of work.

I would not have though the KS would cause this problem; rather, I think it is measuring a symptom of the problem (engine knock, likely due to improper or untimely ignition). That said, I also read the the ECM retards the ignition signal if the KS signal is TRUE, and perhaps if the KS is dead then the ignition is too delayed.

Have you seen this situation before? Can you suggest any other diagnostics I should run before replacing the KS (assuming I can find one...)?

Many thanks - Trevor

 

[tmoat]

Hi again smj - I forgot to mention the ignition coil impedance - I measured 1.1 ohms between pins A-B on the LV connector side and 12.44 kohms between pin A and the HV output pin C. The manual calls for "approximately 10 kohms" from A to C; I'm 25% above that, which seems high to me. Inductors in my experience fail open; their resistance doesn't change over time. Perhaps it's different with ignition coils. Any thoughts here? The good news is that both the ignition coil and the knock sensor appear to be available from nissanpartsdeal.com. Thanks again - Trevor

 

[smj999smj]

The knock sensor generates a voltage when impacted, so a dead knock sensor wouldn't cause the ECM to retard the timing. Typically, they almost never cause a drivability or performance issue with the exception of the supercharged VG33ER engines. They do go bad and they are a pain to replace because they are bolted to the top of the engine block and the lower intake manifold must be removed. You may want to look into relocating the knock sensor, as many do. A knock sensor and subharness from a 95-99 Maxima is used. The one end of the subharness plugs onto the knock sensor and the other plug is cut off. The wires to the knock sensor are located within the EGI harness and cut and the new subharness w/ sensor is spliced in. The knock sensor is then bolted to the engine, often at an intake manifold bolt location. It's not a sensitive as a location as being directly on the block, but it saves a lot of work and some money in parts. There's a thread about how to do it at ClubFrontier.org and there is probably one or more YouTube vids on it available.
Some of the specs on the older Nissans can be a bit generic. 12.44 Kohms in a spec of "approx. 10 Kohms" is actually pretty close and "probably" okay.

 

[tmoat]

That is an interesting idea - I would be able to install a new knock sensor without doing anything to the intake manifold, and while doing so I would splice out any breakage in the KS harness too (since I am reading open circuit from the main harness connector to the KS). FYI smj - I started a new thread on this problem because I hijacked Crystal's old thread here and wandered off topic a bit. The new thread is here: 1994 VG30E 4x4 SE Truck - Severe Lurching/Lugging at...
I'll copy your notes over, and thanks again for your time and suggestions.