Code P0305 Help! (1 Viewer)

[FT4WD80S]

Ok! Before I give up on my 96 and see the shop...got this code P0305, and engine runs rough, loss a little bit of power. I've search the forum and it seems like I'm the only one with this particular code.

Misfire #4 cylinder, right? So I replaced all my Plugs, wires and distrib. it was due anyway. Fired it up...went for a test drive after clearing the code and bam CEL flashed a few times, engine started to vibrate (hesitate) as I depress on the gas pedal starting at about 1200 rpm. now CEL is on again, scan code = P0305 is back. At idle it seems like it skips a beat.

I have checked spark plug wire resistance and it is within specs...what else could it be??? Please advice.

Parked in my garage Thanks in advance.

 

[corsair23]

Short in the wire to the injector? Had a similar issue on a non-Toyota vehicle and it was a short (scathed wire) leading to the fuel injector. Just a thought...

 

[Beowulf]

I've search the forum and it seems like I'm the only one with this particular code.

Not exactly. The P030x codes are for cylinder misfires where x gives the failing cylinder number, with another code to indicate multiple cylinder misfires.

Given that you've replaced the dizzy cap, rotor, plugs, and checked/replaced the plug wires, the most likely candidate for failure is the wiring harness. Typical places to look are where the harness runs by the EGR valve and where the harness runs through the firewall to the ECM behind the glove box.

In the future, please give us the year and engine that you are working on. In this case we know it is a '96 or '97 because it has OBD-II and we know it is the 1FZ-FE because it has spark plugs. Instead of requiring us to guess or ask, it is good forum etiquette to give us this information in advance. Adding this information to your sig line is suggested so that you don't forget to post it.

-B-

 

[FT4WD80S]

sorry guys, was such in a hurry. I do have a 96 TLC (US) 4.5L 1FZ-FE Gas of course. This baby has about 196,000 miles on the clock. Unfortunately I can't read or there's no other code other than p0305. I am now trying to see if there's any broken insulation on the wires leading to #4 injector ...hard to access. guess I'm gonna need to take the intake stuff off. Any sugestion. I'm waiting for the engine to cool down a bit for a closer look.

 

[kai38]

Sounds like the same thing my '95 FZJ80 was doing. I dont know what the code was showing though.
Mine ran rough after heavy rains and flooding out here, I dried the cap out replaced the plugs,caps & wires. Same problem.
I took it to the shop where they could not even start the cruiser. They at 1st traced it to a burnt fuseable link wire off the battery. Of course it cant be something simple.
They found the FI wireing harness melted through right behind the EGR at the firewall.
The fix after talking to a Toyota repair shop in town was to splice each burnt wire, rewrap, and cover w/ a split section of heater hose held on w/ hose clamps on each end.
I was able to buy a used harness instead and replaced the whole harness. We wraped the area on the new/used one with some header exhaust wrap and electric tape and pulled it as far from the EGR as possble and secured to the fire wall.
I have heard this is a common problem on some year FZJ80s
Kirk

 

[97fortieth4me]

Uhh, ohhh!!!

Why does this sound so familiar?!!

 

[Beowulf]

sorry guys, was such in a hurry. I do have a 96 TLC (US) 4.5L 1FZ-FE Gas of course. This baby has about 196,000 miles on the clock. Unfortunately I can't read or there's no other code other than p0305. I am now trying to see if there's any broken insulation on the wires leading to #4 injector ...hard to access. guess I'm gonna need to take the intake stuff off. Any sugestion. I'm waiting for the engine to cool down a bit for a closer look.

P0305 is a misfire on cylinder #5.
Typically, you are not looking for a problem at the #5 injector; you are looking for a problem in the wiring harness that will involve the wire going to the #5 injector.
You do not need to remove the intake.
You need to inspect the wiring harness at the EGR valve. If this is OK, then inspect the wiring harness at the ECM. (Please reread Post #3)
This is a problem common to all years with the 1FZ-FE engine.

-B-

 

[CJF]

sorry guys, was such in a hurry. I do have a 96 TLC (US) 4.5L 1FZ-FE Gas of course. This baby has about 196,000 miles on the clock. Unfortunately I can't read or there's no other code other than p0305. I am now trying to see if there's any broken insulation on the wires leading to #4 injector ...hard to access. guess I'm gonna need to take the intake stuff off. Any sugestion. I'm waiting for the engine to cool down a bit for a closer look.

Go for the wiring harness first...

Edit: Or Beo's gonna get pissed off!

 

[Beowulf]

Go for the wiring harness first...

Edit: Or Beo's gonna get pissed off!

Too late.

-B-

 

[FT4WD80S]

Runnin' back and forth-garage to computer room. I see what you guys are saying.

I don't think mine got wet it never rains here in SoCal. My engine is dry as far as I can tell, one thing I noticed though it seems like it get pretty hot in the engine compartment. Rubber, plastic and other non-metallic parts starting to look brittle. I won't be surprised if my harness/wires starts to laminate to each other, that's scary. I have to wait until the engine get's a little cooler for me to touch those wires looms, insulation for closer inspection. I hope I can find the culprit tonight. I don't see any visible proof that the harness behind the EGR is melted yet dunno about inside the wireloom. But just in case, Kirk where did you get your harness and how much did it cost you?

One more time I tried starting the engine to see if CEL will come on and it did again P0305. I'm gonna wait till it completely cools off so I can take a closer look at those wire harness. -> thanks Beo It's hard to get to #4 fuel injector . Is there an easy way to tackle this?

Please keep posting your comments, experience or expert advice. I will trywhile I try to cool off a little myself.

Engine problem troubleshooting GODS help !

 

[Beowulf]

Is there an easy way to tackle this?

Please keep posting your comments, experience or expert advice.
Engine problem troubleshooting GODS help !

This isn't rocket science and you don't need more advice until you can eliminate the wiring harness as the culprit. Read this thread while you are drinking your beer and waiting for the engine to cool off. There are some pictures in that thread including a picture of the repaired section of harness.

You should take notice that Fax was a little stubborn about doing what needed to be done and he did just about everything to avoid checking the wiring harness. He even told us he checked it and it was fine. This "fact" threw us off the track for a while, then Fax took his truck to a mechanic who found bare wires exactly where we told him to look... at the engine wiring harness as it passes by the EGR valve.

Kirk's symptoms were exacerbated when his harness would get wet. This "wet harness" is somewhat unrelated to the actual problem as it doesn't make any difference if water is thrown into the fray or not. Once those wires start shorting, any number of symptoms will surface. Most of the time it is an injector that fails to fire but we've seen various symptoms from this problem.

-B-

 

[97fortieth4me]

Runnin' back and forth-garage to computer room. I see what you guys are saying.

I don't think mine got wet it never rains here in SoCal. My engine is dry as far as I can tell, one thing I noticed though it seems like it get pretty hot in the engine compartment. Rubber, plastic and other non-metallic parts starting to look brittle. I won't be surprised if my harness/wires starts to laminate to each other, that's scary. I have to wait until the engine get's a little cooler for me to touch those wires looms, insulation for closer inspection. I hope I can find the culprit tonight. I don't see any visible proof that the harness behind the EGR is melted yet dunno about inside the wireloom. But just in case, Kirk where did you get your harness and how much did it cost you?

One more time I tried starting the engine to see if CEL will come on and it did again P0305. I'm gonna wait till it completely cools off so I can take a closer look at those wire harness. -> thanks Beo It's hard to get to #4 fuel injector . Is there an easy way to tackle this?

Please keep posting your comments, experience or expert advice. I will trywhile I try to cool off a little myself.

Engine problem troubleshooting GODS help !

Try this link. Might help you a little in getting to that harness.

https://forum.ih8mud.com/showthread.php?t=110359&page=2

 

[Beowulf]

Borrowing an image from the thread that 97fortieth4me posted:

The section of harness that you want to inspect is the part with the silver wrap. This picture makes it easy to see because the EGR valve was removed. You can see that the wiring harness is right next to the very hot pipe going to the EGR valve. The protective wrap disintegrates over time and then you start melting wires.

If you are reluctant to open the wrap then wiggle the harness and see if the problem changes or improves. This isn't a great test but it might confirm for you that there is a problem inside before you open it. If the problem persists while you are moving the harness then you can't draw any conclusions.

-B-

 

[FT4WD80S]

Sorry guys, I haven't forgotten to reply. I'm just too busy, yes I have started to take a close look at all the suggested problem area and it is a work in progress. You guys are right, Mr. Beowulf that picture you borrowed from 97fortieth4me is exactly where it melted (on the bottom part) not too obvious at first glance. But I am slowly and carefully taking it apart. It is tight in there and hard to reach, I placed a piece of plywood on top of my engine and lots of towel and hard foam to minimize scratches on paint and damage to vacuum hoses and other delicate parts if you know what I mean.

I must warn all owners of the 80 Series to take a good look at this possible problem. You don't want to wait until you suffer what I have now. The insulating material that the manufacturer used seems to be inadequate cloth like (fiberglass??) material has disentegrated due to the very close proximity to the EGR pipe (Bad routing, design) my infrared thermometer indicates about the same temp as the exhaust manifold at the EGR piping.

After I have individually (painfully, one by one) inspected all wires in the harness for insulation breakdown I will wrap it with electrical tape (using 1.5 mil 3m elect. tape), then I will wrap the whole harness in that area with Design Engineering Inc. Heat screen Radiant matting then wrapping it with their cool-it tape. Supposedly it is designed to protect or shield up to 1000 deg F of direct heat. There maybe some other products better than this but this is what I have available at my local Kr*g*n store, Maybe it's overkill but now I'm even thinking about wrapping the egr tube at least near the wire harness with Heat screen Radiant matting. I don't know if that will have any negative effect on the engines EGR feedback(?) function but I want to keep this rig for a while (actually my wife prefers to drive it over the 2002 Tundra). Please feel free to chime in...

Maybe we should have this on the list of preventive maintenance FAQ as it can save us some grief if you haven't suffered this one yet. 97fortieth4me has an awesome writeup on this area. I will try to post pic, later. for now if you're harness is Ok Go wrap it with Heat screen Radiant matting and cool-it tape or something better to protect it from meltdown due to EGR heat.

Before I forget thanks Mr. Beowulf, 97fortieth4me, CJF, corsair23, Kai38....Not done yet

 

[fj40fax]

Just take the hood off, it is way easier. And yes, I am stubborn.

 

[RichElliott]

Bump for update?

Sorry guys, I haven't forgotten to reply. I'm just too busy, yes I have started to take a close look at all the suggested problem area and it is a work in progress. You guys are right, Mr. Beowulf that picture you borrowed from 97fortieth4me is exactly where it melted (on the bottom part) not too obvious at first glance. But I am slowly and carefully taking it apart. It is tight in there and hard to reach, I placed a piece of plywood on top of my engine and lots of towel and hard foam to minimize scratches on paint and damage to vacuum hoses and other delicate parts if you know what I mean.

I must warn all owners of the 80 Series to take a good look at this possible problem. You don't want to wait until you suffer what I have now. The insulating material that the manufacturer used seems to be inadequate cloth like (fiberglass??) material has disentegrated due to the very close proximity to the EGR pipe (Bad routing, design) my infrared thermometer indicates about the same temp as the exhaust manifold at the EGR piping.

After I have individually (painfully, one by one) inspected all wires in the harness for insulation breakdown I will wrap it with electrical tape (using 1.5 mil 3m elect. tape), then I will wrap the whole harness in that area with Design Engineering Inc. Heat screen Radiant matting then wrapping it with their cool-it tape. Supposedly it is designed to protect or shield up to 1000 deg F of direct heat. There maybe some other products better than this but this is what I have available at my local Kr*g*n store, Maybe it's overkill but now I'm even thinking about wrapping the egr tube at least near the wire harness with Heat screen Radiant matting. I don't know if that will have any negative effect on the engines EGR feedback(?) function but I want to keep this rig for a while (actually my wife prefers to drive it over the 2002 Tundra). Please feel free to chime in...

Maybe we should have this on the list of preventive maintenance FAQ as it can save us some grief if you haven't suffered this one yet. 97fortieth4me has an awesome writeup on this area. I will try to post pic, later. for now if you're harness is Ok Go wrap it with Heat screen Radiant matting and cool-it tape or something better to protect it from meltdown due to EGR heat.

Before I forget thanks Mr. Beowulf, 97fortieth4me, CJF, corsair23, Kai38....Not done yet