Keep chasing misfiring...

[Myka]

Hey guys, I've been here for a long time and my old account has an email that is no longer in use so I can't get my password reset so on with a new account!

Anyways,

2000 with 157,000ish miles...

I've been chasing misfiring for a few months now. At this point spark plugs have been replaced, ignition coils have been replaced, I changed out the fuel injectors in the driver side and I still have cylinders 3,5,6 missing... I'm at a loss and looking for some advice on where to look next.

Thanks in advance!

Micah

 

[NE Snowman]

Did you replace coils with denso/Toyota oem? folks had short success with cheaper coil like only 2 months in some cases.

Did you move coils around to see if the misfire moved?

Is it missing randomly, at idle, or under load, or random misses under load?

If coils/spark plugs check out. Fuel pump could not be delivering enough fuel?

 

[Kamran Khan]

Before you spend more money on more parts, do a compression test on all cylinders.

 

[3_puppies]

lightly spray starting fluid around intake manifold, see if idle changes, could have bad intake gaskets.

 

[Myka]

Thanks for the replies... I don't have Denso coils.

It seems like it's always missing. Idle and accelerating. There seems to be a point in the rpms where it'll get smooth again.

Let me ask this question because it might help me pinpoint,

What at the cylinder numbers? I've looked and can't seem to find anything conclusive....

Thanks Guys.

the issue.

 

[2001LC]

You have the cylinders numbering correct!

How do know you've "misfire's"
Did you see misfire in tech stream on 3, 5 & 6?
Or
Is this a call on your part, by some test?

You changed BK 1 Fuel injectors. Where you get the injectors? Were they tested?
Did you clean the top of engine and injector area, before R&R injectors. Pictures says Nope! Last think you want is cylinder damage from dust/sand dropping in.
Did you replace the injector seals.

FWIW:
Cheap aftermarket or Denso or Toyota/Denso coils from ebay, are all junk. Same goes for spark plugs.

 

[Myka]

You have the cylinders numbering correct!

How do know you've "misfire's"
Did you see misfire in tech stream on 3, 5 & 6?
Or
Is this a call on your part, by some test?

You changed BK 1 Fuel injectors. Where you get the injectors? Were they tested?
Did you clean the top of engine and injector area, before R&R injectors. Pictures says Nope! Last think you want is cylinder damage from dust/sand dropping in.
Did you replace the injector seals.

FWIW:
Cheap aftermarket or Denso or Toyota/Denso coils from ebay, are all junk. Same goes for spark plugs.

I have a code reader and that is how I know those are the cylinders misfiring. I new at working on 100 series so I could just be way off. So glad I have this forum to help me.

What's the correct ordering?

So is the best place to get plugs and coils directly from Toyota?

 

[Eyedaho]

FWIW, I replaced all of my 20 year old cracked coils with YEC/Flamma from Partsouq three years ago based on positive feedback, and I haven't had a single issue. I couldn't justify ~$700 for Toyota OEM. Partsouq has YEC/Flamma for $25/ea right now.

 

[Myka]

FWIW, I replaced all of my 20 year old cracked coils with YEC/Flamma from Partsouq three years ago based on positive feedback, and I haven't had a single issue. I couldn't justify ~$700 for Toyota OEM. Partsouq has YEC/Flamma for $25/ea right now.

Thank you for that heads-up.

Can someone tell me the correct order of the cylinders?

 

[2001LC]

I have a code reader and that is how I know those are the cylinders misfiring. I new at working on 100 series so I could just be way off. So glad I have this forum to help me.

What's the correct ordering?

So is the best place to get plugs and coils directly from Toyota?

As I sated above. Your picture shows you have cylinder numbering correct. LHD (USA model): DS (LH) is Bk1 which has the odd numbers. BK2 is on PS (RH) has even number cylinders.

Toyota (made by Denso) is best source for coils, insuring they're not bootleg.
I use mostly Denso (w/Toyota name on them), which coils have the name Toyota, ground off. I get all my coils & plugs from Denso authorized distributors or Toyota.
Denso support has told me; Toyota's name ground off coil, means Toyota gave permission to sell in 2ndary market.
Do not waste your money buying coils or spark plugs off eBay, 99% are bootleg and will not last.
I don't even buy these from parts store anymore. To much garbage making it's way into the parts store like Advance Auto.

By moving a coil from a cylinder you're not getting a DTC (code), to one you are (good to bad). The DTC will move with bad coil. If DTC does not move, check spark plug. If coil and plug good, check wires. If all three good, check compression.

Real Denso

We don't know why the Denso (real deal) has a stick over stick, but they all do.

"Buy cheap get cheap junk"

 

[Eyedaho]

As I sated above. Your picture shows you have cylinder numbering correct. LHD (USA model): DS (LH) is Bk1 which has the odd numbers. BK2 is on PS (RH) has even number cylinders.

Toyota (made by Denso) is best source for coils, insuring they're not bootleg.
I use mostly Denso (w/Toyota name on them), which coils have the name Toyota, ground off. I get all my coils & plugs from Denso authorized distributors or Toyota.
Denso support has told me; Toyota's name ground off coil, means Toyota gave permission to sell in 2ndary market.
Do not waste your money buying coils or spark plugs off eBay, 99% are bootleg and will not last.
I don't even buy these from parts store anymore. To much garbage making it's way into the parts store like Advance Auto.

By moving a coil from a cylinder you're not getting a DTC (code), to one you are (good to bad). The DTC will move with bad coil. If DTC does not move, check spark plug. If coil and plug good, check wires. If all three good, check compression.

View attachment 3441386




View attachment 3441387
Real Denso

View attachment 3441392
We don't know why the Denso (real deal) has a stick over stick, but they all do.
View attachment 3441391
View attachment 3441394


"Buy cheap get cheap junk"

How much are you paying on average for the Denso coils? The cheapest I'm seeing them for through a Denso authorized seller is $58/ea.

 

[2001LC]

How much are you paying on average for the Denso coils? The cheapest I'm seeing them for through a Denso authorized seller is $58/ea.

I've not check or bough in 2023, but sound right. Plus shipping, tax and fee for Paypal.

 

[SteveH]

$54 - Rock Auto. More Information for DENSO 6731303 - https://www.rockauto.com/en/moreinfo.php?pk=2140934&cc=1356094&pt=7060&jsn=359

 

[3_puppies]

just for laughs, try my suggestion in post #4
when running, lightly spray starting fluid or similar around intake gasket area and see if the gaskets are bad, engine will rev up if sucking air thru the gasket

I went thru similar last year on a rig

here was the thread:

intake manifold gasket failure

working on a customer's rig, random misfires, P0300 codes, rough idle but smooths out above idle. nothing I'm coming up with is helping. BIG Thanks to Paul @2001LC for some guidance, sounding like a vacumn leak. start spraying ether trying to pinpoint a location. seems #5 and #8 intake are...

forum.ih8mud.com

 

[2001LC]

just for laughs, try my suggestion in post #4
when running lightly spray starting fluid or similar around intake gasket area and see if the gaskets are bad, engine will rev up if sucking air thru the gasket

I went thru similar last year on a rig

here was the thread:

intake manifold gasket failure

working on a customer's rig, random misfires, P0300 codes, rough idle but smooths out above idle. nothing I'm coming up with is helping. BIG Thanks to Paul @2001LC for some guidance, sounding like a vacumn leak. start spraying ether trying to pinpoint a location. seems #5 and #8 intake are...

forum.ih8mud.com

Good idea. I found one went so long with loose intake manifold bolts. The compression test failed from dust sucking in past the gaskets. Killed the engine and the CATs

 

[Myka]

Thank you all for the advice. I will start trying these things out as soon as I can. Ill pick up some starter fluid tomorrow as thats easy to try.

 

[suprarx7nut]

$54 - Rock Auto. More Information for DENSO 6731303 - https://www.rockauto.com/en/moreinfo.php?pk=2140934&cc=1356094&pt=7060&jsn=359

Beware, I've had multiple Denso parts DOA from Rock Auto. With Rock Auto's lovely return policy, I ate the cost of those faulty parts each time. I'm not salty about it, though...

 

[Eyedaho]

Beware, I've had multiple Denso parts DOA from Rock Auto. With Rock Auto's lovely return policy, I ate the cost of those faulty parts each time. I'm not salty about it, though...

When I looked on the Denso site, Rockauto was not listed as an authorized seller. I'm not sure how that supply chain works, but it's something to consider.

 

[suprarx7nut]

When I looked on the Denso site, Rockauto was not listed as an authorized seller. I'm not sure how that supply chain works, but it's something to consider.

Yeah, I suspect some sort of foul play. I've had other orders from Rock Auto go south with non-Denso parts as well. Side windows that should have been clear, but were heavily tinted, incomplete kits, etc... All non-refundable because I was past the brief return window every time.

One of my least favorite dealers of auto parts. I'd much prefer to buy elsewhere.