Knock Sensor code 52, variation on a theme (4 Viewers)

[Mighty Mouse]

I've not been able to drive my 94 Land Cruiser for over three months now. Like so many other posts on here where it appears chasing an electrical issue nothing has worked.

In short, the cruiser 1FZ-FE engine, will start fine, idle fine, but as soon as you start to drive, it stumbles and won't drive forward, unless I can get RPM over 3000.

Every posible part, and the list is long, has been replaced.

When I was trying to replace the ECT sensor, both the plug for the ECT and Knock Sensor broke off as they were dry and brittle. Before this, I had no CEL codes at all. just wouldn't drive.

I have replaced both the ECT and the $250 OEM knock sensor because it started throwing code 52 after I got my grubby hands under the intake manifold and broke those connectors.

this is already too long, currently I'm still working on the code 52 and today I tried a continuity test between knock sensor plug, and ECU plug. No beeps so no continuity.

I disconnected the WHITE plug as it had the white wire at pin 4 that I was looking for, and on the other side of the plug, that turned into a Red with silver trace pin. no continuity. even on every pin in that ECU plug.

Was that the right plug?

If not: what plug should I be probing?
If so: then what's next, tracing the entire loom and how to do that? What's my next move?

After three months of almost daily work, I'm exhausted and frustrated beyond capacity. I can't sell the dang thing because it isn't running. My options seem very limited.

Just looking for ideas or suggestions for now. Thanks

Mike
Wyoming
1994 LC80 1FZ-FE engine

 

[NeverFinis]

Air intake leak? Sounds like your engine is running lean due to unmetered air.

 

[NeverFinis]

You should also inspect the engine harness, especially near the EGR valve.

 

[landtank]

Fuel pump relay especially if it seems to clear up over 2000 RPMs

 

[60 toy ota]

Dumb question but are you using the EWD to identify the connectors to test against?
And I dig the thread title.

 

[Mighty Mouse]

Air intake leak? Sounds like your engine is running lean due to unmetered air.

I’ve sprayed carb cleaner around looking for vacuum or air leaks. I also replaced the large 4” hose between MAF and Throttle body.

I’m inclined to say I have that covered, but the stuttering and slight backfires definitely indicate lean.

I put an ohm meter in the MAF pins and all checks were within specs.

 

[Mighty Mouse]

You should also inspect the engine harness, especially near the EGR valve.

I was trying to do a wire tracer on the knock sensor wire, but as soon as I tested downstream on the knock sensor wire plug, I got no beeps. Assuming it’s because the wire is shielded?

I wasn’t able to inspect the wire harness myself, but a more agile friend opened it up and said it looked good.

I also did an EGR delete to keep any further damage limited to that area.

It’s killing me not being able to drive it. No logic to any of this in my mind.

 

[Mighty Mouse]

Fuel pump relay especially if it seems to clear up over 2000 RPMs

That’s one item I didn’t replace. I did replace fuel pump and filter.

I’ll get a relay ordered ASAP. Thanks for the suggestion/tip.

 

[Mighty Mouse]

Dumb question but are you using the EWD to identify the connectors to test against?
And I dig the thread title.

Not sure what EWD is, but I have two manuals I’m using as reference, neither of which is the factory service manual, if that answers your question?

 

[NeverFinis]

I was trying to do a wire tracer on the knock sensor wire, but as soon as I tested downstream on the knock sensor wire plug, I got no beeps. Assuming it’s because the wire is shielded?

Yes, they are shielded.

Not sure what EWD is, but I have two manuals I’m using as reference, neither of which is the factory service manual, if that answers your question?

Electrical Wiring Diagram (EWD). They are in the resource section here and are extremely valuable in diagnosing electrical problems.

 

[Mighty Mouse]

That’s one item I didn’t replace. I did replace fuel pump and filter.

I’ll get a relay ordered ASAP. Thanks for the suggestion/tip.

Fuel pump relay especially if it seems to clear up over 2000 RPMs

Landtank I am at a point where I either sell the Land Cruiser for a huge loss, as it’s not running, or start throwing money at it. Not my preference, but lacking any other options, that’s my choice now.

Went down to the dealer, and ordered that fuse, which quite unexpectedly, was $250. Ouch.

However, I really want this vehicle to be my long term camping, fishing, wheeling vehicle so for me, I’ll spend that money.

Part comes in Friday. I have other things I’m still working on and will try to finish that first.

Thanks all.

 

[NeverFinis]

I mean, I would bypass the fuel pump relay as a test before paying $250.

Check this post from the V8 Swap thread: Registry - 8x Series V8 Swaps - https://forum.ih8mud.com/threads/8x-series-v8-swaps.948869/post-15968855

 

[Mighty Mouse]

After 3 1/2 months I’m just going to give up. Today I installed the fuel pump relay, new Toyota battery with all new cables and tore out all the PO’s electrical savagery and returned it to stock. Replaced the fusible link they butchered up badly with a new one.

To refresh the issue, I can start the cruiser and it idles fine. I can rev the engine smoothly. As soon as I put it in drive and press the accelerator it stumbles. After a few minutes it throws a Knock sensor code 52. OBD1.

I replaced the knock sensor with $250 OEM part and spliced in a shielded pigtail. Continuity from sensor plug to ECU confirmed.

It’s a damn nice cruiser, but I’m done with it.

Ideas how to Sell/trade it in this condition? I need a running vehicle. Soon.

Mike

 

[ppc]

Leave the keys in it parked in a dark alley and hope it gets stolen.