Need Help Diagnosing Misfire :( (1 Viewer)

[2001LC]

I'd also, check compression and use a borescope, while plug out.

 

[GTV]

I did confirm that #3 plug is firing, so that's good news. I did not do a compression test yet as I believe I gave that tool away before I moved last summer. Who knew I'd need it. Looks like I'll be buying a new one.

Interesting if the #3 injector decided to leave the chat at this specific time. I see that these injectors have been rebuilt here, approximately 96k miles ago. Which makes me wonder, do I have this rebuilt or replace with new? All 8 or just this one? I'm scared to investigate the cost of 8 new injectors...

 

[suprarx7nut]

I did confirm that #3 plug is firing, so that's good news. I did not do a compression test yet as I believe I gave that tool away before I moved last summer. Who knew I'd need it. Looks like I'll be buying a new one.

Interesting if the #3 injector decided to leave the chat at this specific time. I see that these injectors have been rebuilt here, approximately 96k miles ago. Which makes me wonder, do I have this rebuilt or replace with new? All 8 or just this one? I'm scared to investigate the cost of 8 new injectors...

I'd just consider the one. They can last nearly forever so I wouldn't expect any other time-related failures.

That said it is nice when you know they all match flow rates. I was concerned about that with high performance engines with turbos 15 years ago. A 2UZ though? It's probably fine.

 

[2001LC]

I did confirm that #3 plug is firing, so that's good news. I did not do a compression test yet as I believe I gave that tool away before I moved last summer. Who knew I'd need it. Looks like I'll be buying a new one.

I would for sure check compression, before R&R of any fuel injector (FI). Why:

• Misfire just after T-belt service, where crank was spun while T-belt off. You may have had an "interference" event. If just one valve stem slightly bent. Valve will not seal, and fuel/air mix can not combust since air pressure escapes.
• No clues indicating this could be, but. Compression test reveals head gasket or ring issue also
• Alternative to compression test, is a leak down test. This, usually done when compression issue found. But can be done on it's own. This requires compressed air. When a leak detected, we then want to know from where. With compressed air blowing into cylinder, via attached leak down test tool. We listen for air escaping: at open throttle body (intake valve leak), oil fill port (rings leak) and exhaust pipe (exhaust valve leak).

Both leak down and compression testers. Are often free use, from parts stores.

No RPM change when Fuel Injector disconnected, spark AND compression confirmed good.
Most cases, is no fuel to combust. Which is either:

Issue with signal to FI (short). The FSM has test to make sure signal/power (no short) getting to FI.

Or

Dead Fuel Injector. Replacing one fuel injector, requires removing that banks fuel rail.


I just had a #3 misfire, which all indications were, dead #3 FI. Which is was!

• Good spark.
• Good compression.
• Borescope, no issues seen in cylinder.
• No change in RPM, FI wire block disconnected.

1. I pulled, the fuel rail on that bank only. After cleaning area so no sand could drop into intake ports.
2. I replaced FI with used, that test good, and all FI seals of bK1.
3. Replaced all gasket (washers) on fuel rail at unions.

Misfire gone.

Notes:

• All gaskets (washer) on fuel rail are the same. Except 1, the (upper) under the fuel dampener device.
• In the 2000 w/250k I just did. I sent 4 used injectors to FSI, to test, clean and rebuild. Then just install all 4 rebuilt FI on bank 1. We'll do BK2, some other time.

Interesting if the #3 injector decided to leave the chat at this specific time. I see that these injectors have been rebuilt here, approximately 96k miles ago. Which makes me wonder,

Not likely related to being rebuilt 96K miles ago.
I just saw one go, at ~250K miles. Factory installed FI, that had never been touched.

do I have this rebuilt or replace with new? All 8 or just this one? I'm scared to investigate the cost of 8 new injectors...

If buying new, I'd just buy one. OEM injector VVti list today at $252. $164 to $174 wholesale. For next 2 weeks, 25% off wholesale $142.
You can get used FI. But must be tested, best to also have cleaned and rebuilt and tested.

One of the issues with any brand of fuel injectors and fuel pressure regulators. If they sit and dry out, needles may rust. They then, have spray and flow issues.
The exception is Denso new in the box. They can sit on the shelf for years, and work perfectly fine.
I keep my collection of used FI, in jar of ATF. When I need one or more, I take my used to chuck at FIS for, servicing.

 

[FxFormat]

I have a few injectors from a stock 3UZ FE out of my LS430, not sure if it's interchangeable but might be. If you need it, i can send to you, car had 136K miles on it when some mouth breather botched a timing belt job and blew the engine. I bought it as a parts car.

I didn't know timing belt kit for a 470 would also fit a 430, and water pump too.

 

[Mauser]

I've got noid lights if you want to borrow them. I also have a few used injectors that I have cleaned. You are welcome to one of them if you want it.

 

[2001LC]

I've got noid lights if you want to borrow them. I also have a few used injectors that I have cleaned. You are welcome to one of them if you want it.

That is so nice of you. Can I ask, which make & model number? Would you buy them again, or some other?

 

[GTV]

Thank you for the offers @FxFormat and @Mauser
I had to look up what a noid light even was! I came from the land of carbs and distributors, never heard of them before.

I thought that the VVTi injectors had a different part number and looking up the vehicle fitment here it isn't all that clear. That pn that is correct for 05-07 LC but not earlier LC's, and it also claims to be correct for 01-07 Sequoia's and 04-09 4R's. Clear as mud. They're probably all the same but I'd like to confirm.

I would for sure check compression, before R&R of any fuel injector (FI). Why:

• Misfire just after T-belt service, where crank was spun while T-belt off. You may have had an "interference" event. If just one valve stem slightly bent. Valve will not seal, and fuel/air mix can not combust since air pressure escapes.
• Both leak down and compression testers. Are often free use, from parts stores.

I'm planning on doing a compression test on #3 and also #1 to compare.

It is possible that I had an interference event (anything is possible) but it's hard for me to imagine that is the case. The contact would have to be light enough for me to continue turning the engine by hand but also hard enough to bend a valve. That is an incredibly narrow window. I've felt piston/valve contact before and it's a hard stop.

 

[2001LC]

I do hope your right. If just bad FI, it's an easy repair.

 

[GTV]

Very bad news. Zero compression on #3.

 

[Trunk Monkey]

That sucks, sorry to hear. Wonder if the timing was off and hit the valves. I'd throw a borescope in that cylinder and see if you can see marks.

 

[FxFormat]

Omg dude

What are you planning to do? Pull the head off and replace the valve once you confirm it is indeed a bent valve.

 

[GTV]

I should do a proper (all 8) compression test to make sure that is the only cylinder with an issue. I confirmed that 1&2 are pumping up. I could do a leak down test to tell me where the air is going. Boroscope would give me visual proof I suppose.

Maybe pulling the valve cover will tell me something, might be able to see a stuck valve.

Seems like the head will have to come off. I don’t have access to that kind of space right now and I don’t have the money want to pay someone to do it. I will fix it myself but I’m not sure logistically how that’s going to happen.

 

[2001LC]

I feared as much! Believe me when I say, I'm very sorry to hear!

So now we know. Cams Timing Marks on the "I" in VVTi. "I" is for interference. Question I still have, is the "T" safe or also interference.

Study and prep for the job. Plan on 4 days minimum. Take your time!

Make sure to study and follow FSM. Very import step, is to lock off cam sprocket with 10mm bolt before pulling cam caps.
All cams, cam caps, spring, bucket shims, valves must return to same spot.
You'll need to reset cam lobe to bucket/valve gaps.
Be very organized and clean.

Good luck.

 

[MountaineerLC]

I feared as much! Believe me when I say, I'm very sorry to here!

So now we know. Cams Timing Marks on the "I" in VVTi. "I" is for interference. Question I still have, is the "T" safe or also interference.

Study and prep for the job. Plan on 4 days minimum. Take your time!

Make sure to study and follow FSM. Very import step, is to lock off cam sprocket with 10mm bolt before pulling cam caps.
All cams, cam caps, spring, bucket shims, valves must return to same spot.
You'll need to reset cam lobe to bucket/valve gaps.
Be very organized and clean.

Good luck.

Oh my, I’ve never been that deep into a 2UZ. Definitely sounds way more in depth than pulling my the heads on the old pushrod Rover V8!

 

[2001LC]

It is and there's a few instances in mud. Where DIYers, did not study the FSM first. They just started tearing down and pulling head. Ended up, with bad heads.

A rather well know Denver Land Cruiser machine, Robbie. Told me ~8 years ago, he charge ~$2,500. He was $90 per/rate. So that's ~28 hr job. Today, $200 hr is average.

A machine shop can restore a head, and set gap. Tick is, finding a good one. If valve seats and valve guides good. Heads can be done DIY. With a few extra tools.

In this case. I'd more than likely service the heads. But I'd be further delineating this engine first. If lower end all good. Head job, if not engine R&R

Some would rather R&R engine, than heads.

But finding a good engine, isn't that easy. Which this engine took me months to find and only had 98K miles. It was a fresh kill, rear side impact and never out in the weather. With a perfect Lexus service history. Cost ~$2,500 to my door IIRC. It was from a GX470, adding labor to the swap.

Replacement 4.7L VVti, takes time and more money in most cases, then DIY heads. I say most cases; Since I know a guy, picked-up what he said was a good Japanese (100 series) 4.7L VVti, for $600. He drove through the night, on the days listed for sale. To pick-up, from 900 miles away.
USA made 4.7L VVti are cheaper, at ~$1,500.

 

[GTV]

If you’re implying that I rushed through the job (5 days), that I don’t have an FSM (got the complete set) or that it was my first time doing the job (3rd) you would be incorrect on all accounts.

Even though I’ve been working on cars since I was able to hold a flashlight for my dad I am not a professional mechanic so I take things slow and methodically. If this is indeed what I/we think it is, I second guessed myself when checking the timing. I removed the belt and rotated the engine by hand, I did not feel any interference in the slightest, so reinstalled the belt. Apparently I f*cked something up and I own that. Now I have to fix it.

 

[Trunk Monkey]

I think (hope) 2001 is talking in generalities, not about you specifically. While I love to do my own work, I hate the feeling when I know the only person to blame for a mistake is myself. Hope the damage is minimal, you can get a cheap borescope camera off Amazon that has surprisingly good image quality if you don't have one, I just picked one up myself.

 

[2001LC]

If you’re implying that I rushed through the job (5 days), that I don’t have an FSM (got the complete set) or that it was my first time doing the job (3rd) you would be incorrect on all accounts.

Even though I’ve been working on cars since I was able to hold a flashlight for my dad I am not a professional mechanic so I take things slow and methodically. If this is indeed what I/we think it is, I second guessed myself when checking the timing. I removed the belt and rotated the engine by hand, I did not feel any interference in the slightest, so reinstalled the belt. Apparently I f*cked something up and I own that. Now I have to fix it.

No, S**t happens! You're the OP, but it's not just about you. Many people will read this thread for years to come. I'm, as TM suggest, speaking in general to the forum.

I was not trying to shame you. But trying to warn you and those after you. Head R&R is one of the more technical services of the 4.7L. Most mess up during disassembly. By just digging in and taking apart. Search mud, you find them.

I'll stay out, so not to offend you.

Good luck.

 

[AARONTLC]

How are you progressing? Sorry to hear about the low compression.