Spark plug reading (1 Viewer)

[ARFCOM15]

Hi all, hope your Friday is good!

Anyone want to try and interpret the spark plugs below? Been chasing a code 26 "lean" condition on my '94 for months. Erratic idle and poor, sluggish acceleration.

Hopefully someone is bored enough to indulge me

I'll post up the other two next.

 

[BILT4ME]

Yes, they are all very light and white indicating a lean condition.

What codes is it throwing?

 

[jbee]

02 sensors?

 

[ARFCOM15]

Before new injectors a few weeks ago it was bouncing between 25 and 26. Now I get an on off again 26. I'm working on it tonight so I'll check stored codes again.

 

[ARFCOM15]

02 sensors?

Brand new NTK installed after PAIR and EGR delete. Relocated in PAIR ports.
Good call though.

 

[BILT4ME]

Year, make, model?

I'm guessing 94 based on your description of codes.

 

[Irish Reiver]

I'm also guessing '93 or '94. My '94 had the exact same symptoms. Took me a while to isolate the cause but it was the harness from the O2 sensor that runs over the transmission.. A quick rewire direct from the O2 to the ECU fixed that problem.

 

[ARFCOM15]

Year, make, model?

I'm guessing 94 based on your description of codes.

1994 FZJ80 OBD1 with 310K

 

[ARFCOM15]

I'm also guessing '93 or '94. My '94 had the exact same symptoms. Took me a while to isolate the cause but it was the harness from the O2 sensor that runs over the transmission.. A quick rewire direct from the O2 to the ECU fixed that problem.

Correct. 1994 model with OBD1. I chased that harness as far as I could but could not find its beginning, I got to the top of the tranny and then lost it. Where does it start on DS of the block?

 

[ARFCOM15]

Here is #5 and #6.

 

[Irish Reiver]

It comes over the tyranny in a corrugated cable shield that will likely crumble when you touch it. I recall there is a disconnect near the starter before it joins the main engine harness that runs along the bulkhead. I opened the main harness were it goes through the firewall to the ECU and unwrapped enough cable to give me the 30 cms or so of the blue shielded O2 cable that I needed to eliminate the route over the tyranny. It is quite a simple job especially since you have the O2s in the manifold.

 

[ARFCOM15]

It comes over the tyranny in a corrugated cable shield that will likely crumble when you touch it. I recall there is a disconnect near the starter before it joins the main engine harness that runs along the bulkhead. I opened the main harness were it goes through the firewall to the ECU and unwrapped enough cable to give me the 30 cms or so of the blue shielded O2 cable that I needed to eliminate the route over the tyranny. It is quite a simple job especially since you have the O2s in the manifold.

Got it. I'll dig in fresh light tomorrow. Did you get specific O2 trouble codes? And just a rub through, shorted to ground?

 

[Irish Reiver]

I started off with a code 21 (O2 Sensor) . Then it would jump to Code 24 (rich) then code 26 (lean). It was all over the place for weeks which made it hard to troubleshoot. Eventually it settled to code 26. I'm not entirely sure what the fundamental cause was but shortening the cable by 80% resolved the issue. I imagine there was some damage in the part of the cable I could not see.

 

[jbee]

Got it. I'll dig in fresh light tomorrow. Did you get specific O2 trouble codes? And just a rub through, shorted to ground?

This was the trouble with mine, the O2 sensor wire had rubbed on the driveshaft after some medium wheeling and everything went sideways until I fixed that wire.

 

[ARFCOM15]

This was the trouble with mine, the O2 sensor wire had rubbed on the driveshaft after some medium wheeling and everything went sideways until I fixed that wire.

I just can't work up the courage to snip the connector and pull it out to inspect. Did you test for continuity while intact?

 

[Rifleman]

ARFCOM15, Below you'll find a link to a thread i wrote on how i troubleshot my code 26 problem on my 94. I've also included a link to a web site that'll tell you how to check the voltage on you're O 2 sensor's to make sure they are working when in closed loop.

Vf1 voltage

Vf voltage information about Oxygen Sensor

alflash.com.ua

How i fixed my 94 L.C. check engine light Code 26

I Went to the store the other day, and as i was pulling out of the parking lot i noticed my engine RPM's floating up and down. Next, i noticed as i pulled up to the stop light the motor wanted to die, and got worse with the AC turned on. When i turned the AC off, it seemed to make the motor...

forum.ih8mud.com

 

[ARFCOM15]

ARFCOM15, Below you'll find a link to a thread i wrote on how i troubleshot my code 26 problem on my 94. I've also included a link to a web site that'll tell you how to check the voltage on you're O 2 sensor's to make sure they are working when in closed loop.

Vf1 voltage

Vf voltage information about Oxygen Sensor

alflash.com.ua

How i fixed my 94 L.C. check engine light Code 26

I Went to the store the other day, and as i was pulling out of the parking lot i noticed my engine RPM's floating up and down. Next, i noticed as i pulled up to the stop light the motor wanted to die, and got worse with the AC turned on. When i turned the AC off, it seemed to make the motor...

forum.ih8mud.com

Thanks man!

 

[Rifleman]

ARFCOM1, Here is another location i found that can cause code 25 and code 26 problems along with ruff idle problems. While checking the Ohm's readings on each O2 sensor i found the right (passengers side) O2 sensor connector was full of water.

I'm sure all that water would cause all kinds of conflicting signals to be sent to the computer. After blowing all the water out of both connectors, plus cleaning off all corrosion i reconnected them, started the truck up, both O2 sensors were now working right, and the idle was rock steady at 650.

What i found, my truck is a 94 so I'm sure this will effect the 93 too, is the right side O2 sensor connector where it connects to the wiring harness connector is held in a vertical position. The problem with this position, even though the connector is supposed to be a weather tight connector, the bottom part of the connector is shaped just like a cup.

So any water that gets inside the connector will be held there, causing corrosion and never being able to drain out. What I've done to hopefully prevent this from happening again, I've turned the connector horizontally and tied it in place. This should allow any water that may get inside the ability to drain and dry out.