Need Help. 97 1FZ, slight top end knock, no codes even when I disconnect O2 sensors.

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Jaysjammin

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I bought the truck from a mechanic back in April and it was pretty much straight piped so I never heard a knock if it was present. I haven't driven it since I bought it because I wanted to baseline it.

I've replaced full exhaust with cats and Denso O2 sensors, spark plugs, wires, valve cover gaskets/tube seals/TB gasket, distributor cap/rotor/o-ring/dust shield, crank pulley seal/oil pump seal, water pump/all cooling and heater hoses, fuel filter/fuel pump, PCV, vacuum modulator and lines, charcoal canister hoses, AC idler pulley and belts.

When I started it after these repairs, I heard the knock. It's not necessarily a rough idle but it's a bit lumpy. Tried checking for vacuum leaks using propane, checked the EGR, checked timing(set to 3), cleaned MAF, pulled EFI fuse for a few minutes, no check engine light comes on no matter what I do. The light works and can be seen in the ON position but no codes come up even if I disconnect the O2 sensors.

What am I missing? What should I look for? Additional note, Airbag light is on and no amount of Tc/AB grounding has turned it off. I don't see any dummy sensors or resistors for the O2 at the connectors. Need to order a belt gauge to make sure my belts are to spec.
 
Comet

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Sir, get in touch with Marshall at Troll Hole. He is a cruiser guy who knows his way around a rig. I believe he is close to a buddy of mine near Greer, SC. @Trollhole
 
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Jaysjammin

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Could be a damaged power steering pump gear. If you search there is a number of threads describing this.
Yea, I read through some of those posts. I've got a stethoscope on the way to try to figure it out.
Sir, get in touch with Marshall at Troll Hole. He is a cruiser guy who knows his way around a rig. I believe he is close to a buddy of mine near Greer, SC. @Trollhole
Yup, that's my move once I get the truck back together. I've never met him but I have heard of him.

I just figured I'd throw up a post since the CEL issue is non searchable. All of the posts are about how their CEL is on after removing the cat.
 
LINUS

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Airbag light:

It’s not as easy as the read in the FSM - I did kick mine too.
(brainfarted / totally my fault - hit the battery w/ 24v on 200a with our bumpbox that was still set to the dozer)

-I swear it took a good ~dzn times (no joke, maybe a few more) - you REALLY got to hit the marks / seems there were some timed gaps.

-Anyhow, make a decent jumper & keep trying it if you are sure you know the system is good.
It’s just really touchy IMO.
 
Ozark80

Ozark80

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Just a thought.. but have you checked to makes sure the exhaust you installed doesn't have a leak somewhere which might be causing a ticking or "knocking" sound.

Also, do you hear the knock at all RPMs, or just at idle?
 
Ozark80

Ozark80

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Another thought I had is that maybe some of the valve clearances are out of spec? I'm not sure if that would cause a sound like you're describing though..
 
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Jaysjammin

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Just a thought.. but have you checked to makes sure the exhaust you installed doesn't have a leak somewhere which might be causing a ticking or "knocking" sound.

Also, do you hear the knock at all RPMs, or just at idle?
It increases with RPM. I'm not ruling out an exhaust leak from the manifold, I added all new gaskets but it's an aftermarket exhaust and some manhandling was needed. It's one of the reasons I tried disconnecting the O2 sensors just to see if it made a difference. I'm really confused why it doesn't throw a CEL with them disconnected.
Another thought I had is that maybe some of the valve clearances are out of spec? I'm not sure if that would cause a sound like you're describing though..
That's a very real possibility, I just want to rule everything out before taking it to a professional to adjust the valves or diagnose the issue.

May end up pulling off the intake in case there's a leak coming from the manifold gasket or one of the hoses underneath the intake.
 
LandLocked93

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Could be a damaged power steering pump gear. If you search there is a number of threads describing this.
After preponderance of the evidence...and assuming you're OBD1, ^this^
I have a 'knock' too after replacing ps pump. I was careful af too removing the gear. Evidently, not careful enough.
 
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robnicko

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have you tried removing all the drive belts and running the motor for a few seconds to see if the knock is still there?
 
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Jaysjammin

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After preponderance of the evidence...and assuming you're OBD1, ^this^
I have a 'knock' too after replacing ps pump. I was careful af too removing the gear. Evidently, not careful enough.
Its a 97 OBDII, just curious how that makes a difference? I haven't replaced any PS components yet but it doesn't sound like it's coming from the front. It sounds like it's near the top and towards the back of the engine near the intake pipe.
have you tried removing all the drive belts and running the motor for a few seconds to see if the knock is still there?
I have not... that's a good idea though. I'm guessing the only downside is the water pump not running? By few seconds do you mean 2 or like maybe 15-30 seconds?
 
LINUS

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So when you twist the key to ‘on’ position prior to crank, does the ‘check engine’ LED work?

Have you tried to D/L any codes stored / OBD2 ?


-just covering basics before we deep dive.
 
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manofthewoods

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Its a 97 OBDII, just curious how that makes a difference? I haven't replaced any PS components yet but it doesn't sound like it's coming from the front. It sounds like it's near the top and towards the back of the engine near the intake pipe.

I have not... that's a good idea though. I'm guessing the only downside is the water pump not running? By few seconds do you mean 2 or like maybe 15-30 seconds?
30 seconds on engine that is cold or a little warm is fine. Hot? I wouldn't.

Also. If your valve clearance is off...
Adjustments aren't that tough - see Ottram video
 
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robnicko

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Its a 97 OBDII, just curious how that makes a difference? I haven't replaced any PS components yet but it doesn't sound like it's coming from the front. It sounds like it's near the top and towards the back of the engine near the intake pipe.

I have not... that's a good idea though. I'm guessing the only downside is the water pump not running? By few seconds do you mean 2 or like maybe 15-30 seconds?
it wont hurt the engine at all to run it with no belts for 20 seconds or so, just enough time for you to hear if the knock is still evident or not

is it all the time or just when warm / cold etc?

that being said, if you hose down all the drive belts whilst the engine is running they go very quiet until they dry off again so that could be another option. just be careful if doing on a hot motor
 
Zjohnsonua

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It is ridiculously easy to make a PS gear deform enough to create a tick. If the belt delete doesn't show your culprit, pull the pump and look for gear teeth with ANY tooth deformation. A bright spot is a give-away. Gear pullers are necessary to pull the gear off during a pump replacement, and most designs put point loads in the gear that will do it in. Gotta be careful with those services.
 
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Jaysjammin

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Lots of helpful ideas guys, thank you.
So when you twist the key to ‘on’ position prior to crank, does the ‘check engine’ LED work?

Have you tried to D/L any codes stored / OBD2 ?


-just covering basics before we deep dive.
Yup, first thing I checked. Light turns on then goes away when started. No codes at all except for the airbag light. No CEL with O2 pulled, engine dies without MAF, no CEL if I pinch the EGR hose and kill the engine. Can't think of anything else that would make it throw a code. I guess I could pull one of the spark plug wires?
30 seconds on engine that is cold or a little warm is fine. Hot? I wouldn't.

Also. If your valve clearance is off...
Adjustments aren't that tough - see Ottram video
I just watched the video. I didn't see anything about adjustment but he does a good job of checking the clearances. I guess the adjustment is ordering a replacement a replacement shim. I just got a stethoscope so I'll start with that. Try some soapy water on the exhaust. Then try removing the belts. Then either power steering or valve clearance.
I had this. Was a bad brand new water pump. Sounded like a spun rod bearing
I really hope not. It was a shiny new Denso but I'll keep it in mind. It doesn't sound like a rod bearing to me just because the noise is from the top. If I get under the truck, the noise doesn't get louder. I guess removing the belts will let me know if that's the case. Fluid cycles well, no overheating after multiple flushes and leaving it on for 15-20 minutes at a time. I've got a paint bucket for a seat right now so I haven't been able to give it a good shake down.

it wont hurt the engine at all to run it with no belts for 20 seconds or so, just enough time for you to hear if the knock is still evident or not

is it all the time or just when warm / cold etc?

that being said, if you hose down all the drive belts whilst the engine is running they go very quiet until they dry off again so that could be another option. just be careful if doing on a hot motor
I've done a few coolant flushes and it is all of the time. It gets quieter between 1500 and 2000 RPM but that may be the fan being louder than the knock. I put half a quart of Marvel Mystery Oil in there and ran SeaFoam through the intake. It SEEMS quieter but it's more than likely a placebo. I'll remove the belts and see what happens.

It is ridiculously easy to make a PS gear deform enough to create a tick. If the belt delete doesn't show your culprit, pull the pump and look for gear teeth with ANY tooth deformation. A bright spot is a give-away. Gear pullers are necessary to pull the gear off during a pump replacement, and most designs put point loads in the gear that will do it in. Gotta be careful with those services.
I'm not ruling out PS because the previous owner likely put it through its paces. I'm planning on rebuilding it eventually just hadn't planned on it yet. If it is the gear, does Toyota sell the gear separately or does it come with a new assembly?
 
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manofthewoods

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Lots of helpful ideas guys, thank you.

Yup, first thing I checked. Light turns on then goes away when started. No codes at all except for the airbag light. No CEL with O2 pulled, engine dies without MAF, no CEL if I pinch the EGR hose and kill the engine. Can't think of anything else that would make it throw a code. I guess I could pull one of the spark plug wires?

I just watched the video. I didn't see anything about adjustment but he does a good job of checking the clearances. I guess the adjustment is ordering a replacement a replacement shim. I just got a stethoscope so I'll start with that. Try some soapy water on the exhaust. Then try removing the belts. Then either power steering or valve clearance.

I really hope not. It was a shiny new Denso but I'll keep it in mind. It doesn't sound like a rod bearing to me just because the noise is from the top. If I get under the truck, the noise doesn't get louder. I guess removing the belts will let me know if that's the case. Fluid cycles well, no overheating after multiple flushes and leaving it on for 15-20 minutes at a time. I've got a paint bucket for a seat right now so I haven't been able to give it a good shake down.


I've done a few coolant flushes and it is all of the time. It gets quieter between 1500 and 2000 RPM but that may be the fan being louder than the knock. I put half a quart of Marvel Mystery Oil in there and ran SeaFoam through the intake. It SEEMS quieter but it's more than likely a placebo. I'll remove the belts and see what happens.


I'm not ruling out PS because the previous owner likely put it through its paces. I'm planning on rebuilding it eventually just hadn't planned on it yet. If it is the gear, does Toyota sell the gear separately or does it come with a new assembly?
I just put a brand new PS Pump (along with everything else:bang:), I had to pull the gear off the old one. Worked out fine. they call it a pulley (weird). 44316-60020 it ain't cheap:cry:
 
zapatius

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I was just saying spun rod bearing to give you an idea of the sound and not the location.
 
LandLocked93

LandLocked93

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Its a 97 OBDII, just curious how that makes a difference? I haven't replaced any PS components yet
Because:
1) of all the things you touched (changed) w/o confirming net plus good between the touches - AND STILL have no CEL on OBDII..."trust the force, Luke." Trust the instrumentation until you have reason to believe otherwise.
2) Did you ask PO if he/she/they/it/them/one/we/our/woof changed any ps components prior to your ownership?

Loud pipes cover alot.
Refreshing so many things at once - w/o confirmation between - could yeild end results orphaned in a sea of new evidence.
 

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