Missfire (#2 cyl) (1 Viewer)

[98 SNAKE EATER]

Last week I got a random missfire code for cyl #2

Stumbled at idle, but cleared up when driving

Pulled the spark plug wire at the distributor as a quick test while on the road and it stumbled some more, then smoothed out when I held it against the cap.....

Pulled the #1 and #2 plugs and they had a bit of ash on them, but not saturated with oil, fuel or coolant (I've been putting off replacing valve seals for a while, so I was expecting worse)

Decided to swap the plug positions, clear the code and drive until it comes back while I wait for new plugs in the mail.....

Code came back about 50 miles later for #2 missfire again, so the plugs wasn't the issue....

Fast forward to today....I replaced the plugs (OEM of course), but still had a stumble at idle.

Pulled the #2 cable again and the cylinder was definitely dead

Did a quick resistance check on the plug wire and it passed (wire set is only a couple years old....OEM as well)

Grabbed my stethoscope and both #1 and #2 injectors sound like they're ticking as they should.

Tapped on them, but it made no difference.

Pulled the injector plugs, grabbed my meter and both injectors test out at ~14.4-14.6ohms

That's about as far as I got as it gets dark way too early nowadays

Plan on pulling the spark plug again to see if it's fuel soaked (doubt it), but right now I'm just assuming a clogged injector

Before I pull the rail, is there anything else I should look into?

 

[baldilocks]

I think the resistance range is 12-14 ohms. In that case those would be outside spec. I know you have a lot of miles so your injectors are probably in need of service/overhai anyway. Guess this would be a good time to do the valve seals and clean everything up too. How many miles does your cruiser have on it now?

 

[The Eradicator]

94 FSM:

96 FSM:

 

[98 SNAKE EATER]

Crap

I was actually thinking of the old FSM specs when I checked them

That means that #1 is also out, but doesn't have an issue

I guess I should just replace them all (not gunna be cheap)

405,xxx miles

The High Mile Club

 

[retrofive]

Crap

I was actually thinking of the old FSM specs when I checked them

That means that #1 is also out, but doesn't have an issue

I guess I should just replace them all (not gunna be cheap)

405,xxx miles

The High Mile Club

LOL! I don't have a answer but was going to say doesn't your truck have over 400k on it

 

[98 SNAKE EATER]

Just curious, but aren't the injectors the same from 93-97

If so, why the difference in specs?

 

[george_tlc]

To get an ACCURATE resistance measurement on low resistance items (e.g. our injectors) you need:

a) to CLEAN the contacts and the meter probe tip REALLY WELL.
b) Touch the meter probe tips together and subtract that reading from your resistance measurement, since that reading is the probes & test leads.

b) can easily be 0.5 to 1 ohm for cheap/nasty/abused test leads/probes...

When my #6 injector failed it went open circuit 100%. Totally dead. I doubt 14 ohms or 15 ohms makes any real difference to injector performance...

When were they last cleaned?

Did you keep the old spark plug leads??

cheers,
george.

 

[98 SNAKE EATER]

To get an ACCURATE resistance measurement on low resistance items (e.g. our injectors) you need:

a) to CLEAN the contacts and the meter probe tip REALLY WELL.
b) Touch the meter probe tips together and subtract that reading from your resistance measurement, since that reading is the probes & test leads.

b) can easily be 0.5 to 1 ohm for cheap/nasty/abused test leads/probes...

When my #6 injector failed it went open circuit 100%. Totally dead. I doubt 14 ohms or 15 ohms makes any real difference to injector performance...

When were they last cleaned?

Did you keep the old spark plug leads??

cheers,
george.

a) Meter probes are new, but I'll try one of my other meters as well as cleaning the injector contacts tomorrow.
b) It zero'd out as always.

Other than a bottle of Techron in the tank every few months, the injectors have never been serviced.

I always keep my old wire sets, but they won't do me much good at my shop 1200 miles away

I'll pull the plug wire at the spark plug and see if it zaps against ground tomorrow just to rule it out

 

[george_tlc]

Well, if 1 and 2 are similar length, you may be able to swap them (just leave the plastic top 'cap' off to give a bit more 'slack')...

I'd say your injectors are well an truly ready for a pressure clean/test and new seals etc. When our #6 injector failed, I ordered a new one and sent the other 5 in to be cleaned etc. It was very noticeable when everything was reinstalled how much smoother the engine was running/idling.

What kind of meter are you using? Fluke with decent silicone insulated high strand count leads or some 'cheapo'?

Gone south to FL for the winter eh?

cheers,
george.

 

[shadowsixniner]

I would recommend a compression test and see what the results are before taking out all of the injectors.

 

[98 SNAKE EATER]

Well, if 1 and 2 are similar length, you may be able to swap them (just leave the plastic top 'cap' off to give a bit more 'slack')...

I'd say your injectors are well an truly ready for a pressure clean/test and new seals etc. When our #6 injector failed, I ordered a new one and sent the other 5 in to be cleaned etc. It was very noticeable when everything was reinstalled how much smoother the engine was running/idling.

What kind of meter are you using? Fluke with decent silicone insulated high strand count leads or some 'cheapo'?

Gone south to FL for the winter eh?

cheers,
george.

All my Fluke stuff is back at the shop

I have this el-cheapo that I travel with, but it's decent with good leads.

I have a couple more that I'll pick up at work tomorrow

I would recommend a compression test and see what the results are before taking out all of the injectors.

They'll be no talk of that, sir

Don't you know this is Mud, where whatever problem you talk about happens soon after

Why do you think I keep my ass out of the HG threads

It's the injector and that's that

 

[george_tlc]

Well, it's a cheapo meter, but not total garbage

Specs say +/1.2% and 2 digits, so that means it could read up to 0.4 ohms high/low of the 'correct' reading.

Anyhow, I seriously doubt the injector resistance you are seeing indicates any fault in the injector. You're pretty close to the spec and it does vary some with temperature. Good enough for the bush.

With a dead #6 on ours t was of course worse at idle than at 2000rpm (not that it was good at 2000rpm...). Presumably at idle since the motor is turning pretty slowly, any misfire has a 'rougher' feel to it.

Anyhow, make sure spark is good (swap leads). Have a look in the dizzy cap and make sure the contacts for #2 are 'clean' and look like the others.

Get the injectors pressure cleaned and flow tested. I'll not mention any other 'engine related things'...

cheers,
george.

 

[shadowsixniner]

All my Fluke stuff is back at the shop



They'll be no talk of that, sir

Don't you know this is Mud, where whatever problem you talk about happens soon after

Why do you think I keep my ass out of the HG threads

It's the injector and that's that

Touche good sir, touche

 

[WhosDannyGeorge]

Just bought my rig with 250k on it. Had a cel for cyl 6 misfire.. Looked here and saw a few people with the same issue and mentioned to check the big bundle of wire harness going along the firewall and down next to the egr pipe. Sure enough my harness was resting on it. Cut it open to inspect and sure enough 6 wires were melted a bit. Spread them apart and put some heat shrink on each and re wrapped and misfire and cel are gone! Might be something to look at since no one has mentioned it above.

 

[BlueCruiser84]

Also, under the dash behind the glovebox. Wires from the back of the ecu chafe against brackets and the firewall.

 

[98 SNAKE EATER]

Yeah, I had tied up the one by the EGR a while ago and it still looks good.

Update:

Swapped the #2 cable with the #1 cylinder and it works fine (engine stumbles more when I pull the lead from the distributor)

The #1 lead couldn't reach the #2 cylinder, but I pretty much ruled out the #2 lead since it worked on #1.

Pulled #2 plug and it was definitely saturated with fuel

Put one of the old plugs back in, set all of the wires back in place, started it for 30 seconds, pulled #2 plug and again, it was fuel soaked.

Both #1 and #2 injectors are still ticking as they should

Gotta get to work, so I'll be pulling the dizzy cap tomorrow

 

[98 SNAKE EATER]

BTW, what do you guys think of the injector set on FleaBay?

-Warranty- (6) OEM Reman Fuel Injector SET Lexus Toyota Land Cruiser 23250-74080

 

[george_tlc]

BTW, what do you guys think of the injector set on FleaBay?

-Warranty- (6) OEM Reman Fuel Injector SET Lexus Toyota Land Cruiser 23250-74080

I returned my dead one to Rockauto and for about $25 got a re-manufactured one (after $10 core). I've kept it as a 'spare' and have one new OEM and 5 cleaned units. The ebay price is great, but no idea on the quality etc...

The problem of course is that it's a bunch of work to remove/replace the injectors (due to the fuel rail etc), so not something you want to be 'experimenting' with....

With the wet #2 it would appear you've located the misfire cause (flooded cylinder). So, either #2 injector is badly leaking/stuck on or something is keeping it on or no spark. The +12V is common to all 6 injectors and the ECU grounds (via the 6 output drivers) each injector to 0V to activate the injector at the appropriate time. A scope could show you the injector waveform and you could compare #1 to #2 just to verify that the harness/ecu connection is all healthy and at that point the culprit would definitely be injector #2 (or no spark).

All comes down to time, got lots and you could pull all 6 injectors and send them in for pressure cleaning and testing and wait for the response back. For $$ you could overnight them to one of the many injector services and they will turn them around in one day and send back overnight (again on your dime).

choices, choices....

cheers,
george.

 

[98 SNAKE EATER]

Don't have my scope with me, but I can take it to my uncle's shop up here on my next RDO

Thing is, I'd rather get the diagnosis sorted out before I get there so I can have the parts on hand cause I hate having to tie up a bay

Once I know for sure what it is, I'll order up a set of valve seals and tackle everything at once

With Winter approaching, I need my baby ready for the white stuff

 

[98 SNAKE EATER]

Touche good sir, touche

Unfortunately, you were on the right track with the compression test

~155 across the board on all but #2

Did a leak down test and it was pissing out the tailpipe

Pulled the head yesterday and found a burnt exhaust valve

I had put off doing the valve seals for far too long and it bit me in the ass

Dropping the head off at the machine shop in the morning to have it thoroughly checked out