Please Help! T4R shaking and loss of power

[1985taylor1925]

If you're looking at it from the front, facing the truck:
(windshield)
5-6
3-4
1-2
(Front Grille)

^^This is the cylinder number order. This is not to be confused with the wiring or the firing order which are different. The coils sit on top of Cyls #1, 3, and 5. Each coil has a boot (like I mentioned before) that goes directly to the plug underneath it and also a wire going to another cylinder on the driver's side. So each coil pack fires 2 plugs. The wiring/coil order is:
-The coil on top of #1 also (has a wire going to and) fires #4
-The coil on top of #3 also fires #6
-The coil on top of #5 also fires #2
Make sure your plug wires are routed this way, if not the engine will run like crap and not fire in the correct order.

Got it. Thanks a ton. Im gonna work on it tomorrow morning

 

[zcruiser]

Which cylinder is which? Like if sitting in my vehicle, three cylinders on my side and three on the passenger side, how would they be numbered?

Not to duplicate Brian, but I kinda like this diagram...

 

[dave_mcmillan]

Not to duplicate Brian, but I kinda like this diagram...

This is awesome...:cheers:

 

[cordrayj1]

Where can i get the coil boots?

i went to parks for plugs, wires, and coil packs. be sure to get anti-seize.

 

[1985taylor1925]

Not to duplicate Brian, but I kinda like this diagram...

Sweet! That makes it easy. Thanks

 

[1985taylor1925]

I just finished changing the plugs. They were actually all double pronged, and all in pretty good shape (installed about a year ago). I actually changed them to 4 prong bosh plugs. I didnt notice anything wrong with the coils. But I switched 3 and 5 as a check. The engine light didnt come on when i drove it right after doing the work, but time will tell. If it moves to 5 then ill know that boot needs replaced. Also, one of the plugs was covered in oil. Makes me wonder if the shop that changed the plugs less than a year ago just ignored it. I called autozone and they said the leak is probably coming from the metal boot that the plug sits in. Is that a diffictult fix?

 

[zcruiser]

Also, one of the plugs was covered in oil. Makes me wonder if the shop that changed the plugs less than a year ago just ignored it. I called autozone and they said the leak is probably coming from the metal boot that the plug sits in. Is that a diffictult fix?

Good luck on the Bosch plugs... I think the 'boot' and the coil pack go together. More likely you need new plug wires. One technique is to fire up the truck at night, and use a spray bottle with water to mist the plug wires and check for visible arcing. If you see arcing, then your plug wires need to be replaced.

Oil in your plug well is due to a leak in the top valve cover gasket. I've never replaced one myself but I've seen several go bad on OHC engines. Sounds like you need to replace your valve gaskets, which is not a hard job just lots of disassembly/reassembly.

 

[NickF]

I just finished changing the plugs. They were actually all double pronged, and all in pretty good shape (installed about a year ago). I actually changed them to 4 prong bosh plugs. I didnt notice anything wrong with the coils. But I switched 3 and 5 as a check. The engine light didnt come on when i drove it right after doing the work, but time will tell. If it moves to 5 then ill know that boot needs replaced. Also, one of the plugs was covered in oil. Makes me wonder if the shop that changed the plugs less than a year ago just ignored it. I called autozone and they said the leak is probably coming from the metal boot that the plug sits in. Is that a diffictult fix?

Bosch 4 prong? Did they come pre gapped? If not, what did you gap them to?
Also, yeah Its more likely to be the valve cover gasket than anything else.

 

[brian2sun]

You can get just boots and not the whole coil pack. They are much cheaper to so if you're not sure if it's the boot or the coil, I would buy the boot first. It's worth taking the chance of loosing $14 if it might save you $70 IMO. Plus you'll usually get a miss in both of the cylinders that the coil fires, just one cyl indicates a bad connection to just that plug (that is if it's an ignition problem at all and not a valve train issue or something else). I really don't think it's the wires since his miss was on the coil side of the engine.

 

[1985taylor1925]

Good luck on the Bosch plugs... I think the 'boot' and the coil pack go together. More likely you need new plug wires. One technique is to fire up the truck at night, and use a spray bottle with water to mist the plug wires and check for visible arcing. If you see arcing, then your plug wires need to be replaced.

Oil in your plug well is due to a leak in the top valve cover gasket. I've never replaced one myself but I've seen several go bad on OHC engines. Sounds like you need to replace your valve gaskets, which is not a hard job just lots of disassembly/reassembly.

Valve cover gasket was changed less than a year ago

 

[1985taylor1925]

Bosch 4 prong? Did they come pre gapped? If not, what did you gap them to?
Also, yeah Its more likely to be the valve cover gasket than anything else.

I asked and they said 4 prong doesnt need to be gapped. So ya they come pre gapped I guess you could say.

 

[1985taylor1925]

You can get just boots and not the whole coil pack. They are much cheaper to so if you're not sure if it's the boot or the coil, I would buy the boot first. It's worth taking the chance of loosing $14 if it might save you $70 IMO. Plus you'll usually get a miss in both of the cylinders that the coil fires, just one cyl indicates a bad connection to just that plug (that is if it's an ignition problem at all and not a valve train issue or something else). I really don't think it's the wires since his miss was on the coil side of the engine.

The boots look good. No wear at all as far as I can see. And ya i dont think its the wires since they were replaced less than a year ago. This thing is really frusterating me though. It was pretty bad again today. I did switch two of the coils last night when i changed the plugs to see if thats the cause, but i cant run the diagnostic for three days anyway. The plug for cylinder 5 was covered in oil (apparently a seperate issue from the misfire which was on cylinder 3) when I pulled it out. The valve cover gasket was changed less than a year ago too. So ruleing that out, do you have an idea what might be causing that leak?

 

[1985taylor1925]

Is it possible the injector itself failed on cylinder #3?

 

[brian2sun]

I would either wait to read the code to see if the miss moved to another cylinder (and confirm or rule out the coil pack) or just test the coils now (Autozone, O'reilly's, etc.. should be able to do this for you for free). The injectors can be tested for electrical function, but if it's clogged it just has to be removed and inspected. Luckily, all your problems are on the pass. side so you won't have to remove the intake plenum to get to the injectors if that is the problem. Rule out one thing before you move on to the next. Coils 1st, then injectors.

 

[zcruiser]

On my 300ZX, you can quickly check the injectors by placing an ohmeter across the two injector connector pins. 11-13 ohms, the injector is still technically good. Open circuit and it's dead. Of course, a good injector can still be clogged, but at least there's a check for a failed solenoid inside the injector. I've had 3 go bad so far, but have never ohm'ed out my 5VZ injector to see what a normal impedance is.

 

[notrayray]

On my 300ZX, you can quickly check the injectors by placing an ohmeter across the two injector connector pins. 11-13 ohms, the injector is still technically good. Open circuit and it's dead. Of course, a good injector can still be clogged, but at least there's a check for a failed solenoid inside the injector. I've had 3 go bad so far, but have never ohm'ed out my 5VZ injector to see what a normal impedance is.

The wires can be checked by a resistence reading also.

 

[1985taylor1925]

I would either wait to read the code to see if the miss moved to another cylinder (and confirm or rule out the coil pack) or just test the coils now (Autozone, O'reilly's, etc.. should be able to do this for you for free). The injectors can be tested for electrical function, but if it's clogged it just has to be removed and inspected. Luckily, all your problems are on the pass. side so you won't have to remove the intake plenum to get to the injectors if that is the problem. Rule out one thing before you move on to the next. Coils 1st, then injectors.

Hey. I ruled out that coil pack today. Switched coils from 3 and 5 on saturday night, had it tested today. Its still misfiring #3. I know its not the plugs since i just changed them, and again the wires were replaced less than a year ago. So im really thinking the injector. Im waiting on my chilton manual to get here. Will that give instructions on how to get to the injectors? Obviously iv never done it before. Again thanks for the help

 

[notrayray]

Hey. I ruled out that coil pack today. Switched coils from 3 and 5 on saturday night, had it tested today. Its still misfiring #3. I know its not the plugs since i just changed them, and again the wires were replaced less than a year ago. So im really thinking the injector. Im waiting on my chilton manual to get here. Will that give instructions on how to get to the injectors? Obviously iv never done it before. Again thanks for the help

Here is the components layout
http://www.ncttora.com/fsm/1996/SIL.../02rmsour/2002/024runne/sf5vzfe/inje/comp.pdf

and here is the electrical testing procedure
http://www.ncttora.com/fsm/1996/SIL.../02rmsour/2002/024runne/sf5vzfe/inje/insp.pdf

 

[brian2sun]

Yes, I would move on to the injector now. Get the upper and lower o-rings for all 3 injectors on the pass side (total of 6). None of them should be re-used and all the injectors tend to come out when you pull on the fuel rail. Also, use a little vaseline on the new o-rings so they don't hang up and tear when you install them.

 

[1985taylor1925]

Do those o rings come with the valve cover gasket set?