Slow start and fuel smell

[fooldall1]

I let the LC get pretty low recently on a drive and now after a refill of fuel, I get a slow start and smell fuel from the outside. I admit I’m at a loss, I can’t see fuel puddling or leaking. Where can I start troubleshooting here? TIA!!

 

[fooldall1]

I should also note that once started, or if the truck has been running for some time- it'll start right up. From cold, it seems that the "priming" does take longer than I would expect. it IS time to replace that fuel filter, but does that account for the fuel smell?

 

[BnvS]

So I would get a make shift fuel pressure gauge which should be easy to make and check the pressure from your fuel pump. If it's sending enough and if it holds pressure. Cause that's sounds like your fuel pump is going.

Sorry I cannot help you with the fuel smell. Not idea why that would happen.

 

[Dirt J]

For the fuel smell, I would see if you can track it down to the charcoal canister under the hood or maybe the gas cap. CC may be full of gas or worn out (charcoal saturated).

 

[diego355]

For the fuel smell, I would see if you can track it down to the charcoal canister under the hood or maybe the gas cap. CC may be full of gas or worn out (charcoal saturated).

Also, the fuel filler neck is known to develop cracks

 

[2001LC]

Toyota vehicle OM, warns, do not run fuel tank low; As may damage CATs. I don't really see this happen, by just running low. Running out of fuel is different. I've taken my fuel level down to only 1 or 2 gallons remaining for 20 years in 100 series, without issue. But note: running tank low exposes fuel pump to air, removing from cooling effective of fuel in tank.

Fuel smell when engine has been off and cooled for hours. May be a leak. Leaks are dangerous as we're smell vapor, which is highly combustible. Do not park in garage. With leaks, we can usually determine area of leak point/area, where smell the strongest.

Some have issue with fuel boiling, which fuel comes out gas cap. It's normal to build pressure in fuel tank on a hot day. We'll hear a short hiss as we open fuel cap. fuel coming from cap area is not normal. In these we typically see gunk (dirty mucky) in fuel cap area.

Gas tank building excessive pressure & fuel smell. Dangerous for sure! Why does this happen?

DANGEROUS GAS PRESSURE BUILD UP IN GAS TANK! Why? What's going on? How can we fix this? Edited 3/15/25: Since first posting this thread. I've corrected many boiling fuel. By working in this order: Coolant system if first on the list, must be operating as designed. Which radiator fins cleaning...

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When I hear cold start issues. I first look at charging system:
Weak battery we'll get slow cranking speed. Most notable on cold start. Toyota group 27 battery is used in colder climates. Which I feel best for even warmer regions. Yields a faster stronger starting crank on cold mornings.

If battery and all points down stream of battery post, show the same at 12.4 volts or greater. And, we also get a nice fast cranking speed. We then look at fuel:

Long crank to start. Is most often associated with; excessive fuel injector (FI) leak down. This is when, fuel leaks out of fuel injectors when engine off. FSM has a leak down test, testing the entire fuel rail (all 8 FI) at same time. Excessive leak down, is mostly associated with engine not run for prolong periods. How long engine off, before noticeable long crank. Depends on how bad leak down. Note: fuel pressure regulator (FPR), must also working within spec.

Weak fuel flow due to clogged fuel filter or weak fuel pump. Typically result in engine running lean, cold or warmed-up engine. But can have more noticeable effect during cold engine start up. Gets back to fuel available & pressure in FI, for start up.

Fuel smell from exhaust:
CATs need to be brought up to operating temp. If once at operating temp (hot), we still get fuel smell form exhaust. This is most often associated with engine running to rich a fuel mixture.

I've found when I've a well tuned engine (all FI tested and rebuilt, new Denso or NGK spark plugs (not China bootleg junk), no vacuum leaks, good air filtration, perfect MAF (new OEM or cleaned), etc..)). Yet I get a fuel smell from exhaust after warm up. I do a driving test: Getting on HWY ramp I floor it. Keeping floored up to very high speeds. If I feel any hesitation through power curve, even the smallest. I replace all 8 coils (COP). Hesitation goes away as does fuel smell.

If no hesitation in above driving test. I'm finding benefits in replacing MAF sensor with OEM only. A bad, weak or even aftermarket MAF is a CAT killer.

Note: A bad charcoal canisters. We'll have a smell like old stall gas. One person describe it well "like 10 year old gas in a lawnmower"

 

[fooldall1]

Toyota vehicle OM, warns, do not run fuel tank low; As may damage CATs. I don't really see this happen, by just running low. Running out of fuel is different. I've taken my fuel level down to only 1 or 2 gallons remaining for 20 years in 100 series, without issue. But note: running tank low exposes fuel pump to air, removing from cooling effective of fuel in tank.

Fuel smell when engine has been off and cooled for hours. May be a leak. Leaks are dangerous as we're smell vapor, which is highly combustible. Do not park in garage. With leaks, we can usually determine area of leak point/area, where smell the strongest.

Some have issue with fuel boiling, which fuel comes out gas cap. It's normal to build pressure in fuel tank on a hot day. We'll hear a short hiss as we open fuel cap. fuel coming from cap area is not normal. In these we typically see gunk (dirty mucky) in fuel cap area.

Gas tank building excessive pressure & fuel smell. Dangerous for sure! Why does this happen?

DANGEROUS GAS PRESSURE BUILD UP IN GAS TANK! Why? What's going on? How can we fix this? Edited 3/15/25: Since first posting this thread. I've corrected many boiling fuel. By working in this order: Coolant system if first on the list, must be operating as designed. Which radiator fins cleaning...

forum.ih8mud.com

When I hear cold start issues. I first look at charging system:
Weak battery we'll get slow cranking speed. Most notable on cold start. Toyota group 27 battery is used in colder climates. Which I feel best for even warmer regions. Yields a faster stronger starting crank on cold mornings.

If battery and all points down stream of battery post, show the same at 12.4 volts or greater. And, we also get a nice fast cranking speed. We then look at fuel:

Long crank to start. Is most often associated with; excessive fuel injector (FI) leak down. This is when, fuel leaks out of fuel injectors when engine off. FSM has a leak down test, testing the entire fuel rail (all 8 FI) at same time. Excessive leak down, is mostly associated with engine not run for prolong periods. How long engine off, before noticeable long crank. Depends on how bad leak down. Note: fuel pressure regulator (FPR), must also working within spec.

Weak fuel flow due to clogged fuel filter or weak fuel pump. Typically result in engine running lean, cold or warmed-up engine. But can have more noticeable effect during cold engine start up. Gets back to fuel available & pressure in FI, for start up.

Fuel smell from exhaust:
CATs need to be brought up to operating temp. If once at operating temp (hot), we still get fuel smell form exhaust. This is most often associated with engine running to rich a fuel mixture.

I've found when I've a well tuned engine (all FI tested and rebuilt, new Denso or NGK spark plugs (not China bootleg junk), no vacuum leaks, good air filtration, perfect MAF (new OEM or cleaned), etc..)). Yet I get a fuel smell from exhaust after warm up. I do a driving test: Getting on HWY ramp I floor it. Keeping floored up to very high speeds. If I feel any hesitation through power curve, even the smallest. I replace all 8 coils (COP). Hesitation goes away as does fuel smell.

If no hesitation in above driving test. I'm finding benefits in replacing MAF sensor with OEM only. A bad, weak or even aftermarket MAF is a CAT killer.

Note: A bad charcoal canisters. We'll have a smell like old stall gas. One person describe it well "like 10 year old gas in a lawnmower"

I cannot any leaks anywhere, I am going to start with the Canister and the Fuel Filter (Which needs replacing anyway). Fuel filter makes sense, too as I ran the possibility of grabbing tank sediment running it so low as I did.. Fuel Filter first, then canister. Any tips on replacing canister? Seems fairly complicated on the surface.

 

[fooldall1]

Update: So, the Driver's side, first Fuel injector or rail is dripping fuel. Never worked on this before, can anyone note on the difficulty or ease of replacing what probably is an o-ring leaking on the rail or the injector?

 

[fooldall1]

Found this, hope it helps someone else doing this...

 

[2001LC]

I cannot any leaks anywhere, I am going to start with the Canister and the Fuel Filter (Which needs replacing anyway). Fuel filter makes sense, too as I ran the possibility of grabbing tank sediment running it so low as I did.. Fuel Filter first, then canister. Any tips on replacing canister? Seems fairly complicated on the surface.

Running fuel tank low, doesn't suck anymore sediment. If sediment there, it's being pumped/sucked at all times.

CC in 98-02 easy. But NAL. Guys are using a sub, Tundra IIRC.

Fuel rail has band joe fittings and specific seals (washer). Damper has various type washer. Need torque wrench for the job, for sure. If pulling injectors from intake manifold. Do NOT drop dust into FI ports. Regardless, start the job by staring cold engine, wash while idling. Then blow off intake manifold fuel rail and fuel injectors with air pistol while wet. Then drive to dry. Hit with air pistol again at being of tear-down. O-ring and grommets vary be year. 06-07 (VVT) differ from that of non VVT

When to Clean or Replace fuel injectors

Please post your experiences and thoughts on the subject. I’ve been considering cleaning or even replacing all 8 fuel injectors, is this wasting time and money. I understand keeping fuel injector clean by adding a can of additive to the gas tank, now & then, is a good practice. This keeps them...

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[fooldall1]

MAN! I got the rail off and inspected the injectors... Each and every injector on that side needs new o-rings and seals. Ordered kits for each (driver's side) and not touching the others (passenger side) until they start leaking or having issues. Definitely not an easy job. Lots of brackets and such in the way. Not terrible, but not easy either.

 

[fooldall1]

For anyone who might have to do this job: it’s also recommended to change the fuel filter when rebuilding or replacing injectors.

 

[fooldall1]

Success. Thanks all.

 

[Les Summer]

I've got 270k on the dash, and I've no idea if they are original injectors. I plan to rebuild them, but replacement sounds like it may be a wise option too.

 

[Les Summer]

MAN! I got the rail off and inspected the injectors... Each and every injector on that side needs new o-rings and seals. Ordered kits for each (driver's side) and not touching the others (passenger side) until they start leaking or having issues. Definitely not an easy job. Lots of brackets and such in the way. Not terrible, but not easy either.

How many miles on yours? Sorry if you already answered that on here. I have 270k miles on my LC100, and I'm pretty sure I'm running original injectors. I plan on replacing seals soon, they are about dust, but is replacement of all the injectors a better option?

 

[Eyedaho]

How many miles on yours? Sorry if you already answered that on here. I have 270k miles on my LC100, and I'm pretty sure I'm running original injectors. I plan on replacing seals soon, they are about dust, but is replacement of all the injectors a better option?

OEM injectors are pretty expensive, but that depends on your budget of course.

 

[fooldall1]

How many miles on yours? Sorry if you already answered that on here. I have 270k miles on my LC100, and I'm pretty sure I'm running original injectors. I plan on replacing seals soon, they are about dust, but is replacement of all the injectors a better option?

I have 289k on mine.. Yeah, I wouldn't really worry about NEW injectors - The Denso's are pretty solid. Just buy the o-ring kit (and buy a few spare) and/or pick up ONE rebuilt injector (like I did from Amazon- Denso) in case one is cracked. That is what happened to me- one of the injectors was actually cracked. This weekend, I will also have to do the other side because I just KNOW that those o-rings are toast on that other side, too. I can't let it go like that.

 

[fooldall1]

OEM injectors are pretty expensive, but that depends on your budget of course.

I got the seal kit(s), and one Denso-Rebuilt Injector from Amazon.. Liked them so much bought one more spare and more seal kits and doing the other side this weekend.

 

[2001LC]

Word of caution when replacing injectors, without removing intake manifold. Clean area really well first. You do not want dust/sand dropping in.

 

[Les Summer]

Word of caution when replacing injectors, without removing intake manifold. Clean area really well first. You do not want dust/sand dropping in.

Just bought a Milwaukee battery vacuum from Home Depot for a 100 bucks today, just for this occasion.