Dash Light Lag Accompanied By Exhaust Sputter When Starting LC100 (1 Viewer)

[Les Summer]

I have a problem when starting, and it's not your typical starting problem. I don't even know how you'd categorize it. I have a 2000 LC100 with 270k miles on it. It starts every time, but recently it's begun to do this thing where when I start it there is a delay of the dash warning lights going away (the lights that appear with the key in the on position). The vehicle is still starting, but there is a lag with the dash lights clearing away, and this lag is accompanied by what I can only describe as a sputtering sound of the exhaust before the vehicle starts up, and it happens intermittently.

It'll do this only sometimes, but not always. The problem started after I fueled up at Sam's club a couple of days ago. I noticed a tanker was on site refilling the fuel supply at the same time I was pumping gas, which has caused me suspicion. I've replaced my fuel filter in the last 5k miles, and I have run fuel system cleaner within the last 5k as well. I have a habit of letting my gas guage get down to E from time to time, but have not done this recently.

The vehicle has full power with no hesitation, and runs perfectly smooth, so I don't suspect a fuel pump issue. As a test remedy I've just added some Lucas fuel system cleaner and topped off with high octane fuel, and I plan to just keep running the truck, while keeping an eye on the problem to see if it clears up on its own. I'm thinking I might of got some watery gas, but only time will tell. NO CEL, exhaust noise, or any other issues I can detect.

 

[2001LC]

Where it's certainly possible, you've gotten some bad gas. Typically Sam club & Costco are considered good gas. As they reportedly, spend the money to replace all old metal tanks. So sediment being stirred-up and ground water leakage, is not usually an issue. Most states inspection dep., publicly post the info on fuel station tanks.

Very important with a new purchase, is to baseline. Which includes, a complete tune-up.

 

[Les Summer]

Where it's certainly possible, you've gotten some bad gas. Typically Sam club & Costco are considered good gas. As they reportedly, spend the money to replace all old metal tanks. So sediment being stirred-up and ground water leakage, is not usually an issue. Most states inspection dep., publicly post the info on fuel station tanks.

Very important with a new purchase, is to baseline. Which includes, a complete tune-up.

I agree with you that it's probably a long shot it had anything to do with my issue, but you never know.

 

[Les Summer]

I am beginning to think I have cheap aftermarket CATS on this truck. It sounds like a microwave around 70mph, and always has. The starting lag is always accompanied by a little exhaust rumble, then quiet forever after. I have not yet examined the cats, but I would bet at 270k miles, plus the other evidence of cheap aftermarket parts Ive found on this vehicle, it's the CATS. let me know your thoughts. still not CEL. hmmm...

 

[2001LC]

CATs have nothing to do with rough cold start. CATs need to heat, before being effective. HWY cruising at 55 MPH and up, is where they're efficient. 4,500 RPM, is where seem to hit max temp. If your engine running rich (to much fuel in mixture). You can be dumping fuel in CATs, which can burn them up. If running lean, cylinder head temp goes up, CAT's run hot. You may or may not have aftermarket CATs. Only way to know. Is get under it, with a camera. Post good pictures of CATs end to end including the o2 sensors.

The rough start, with dash lights staying on a bit long. Likely indication, RPM very low on start-up. That it's struggling to keep running. This can be fuel or air starvation, issue with spark.

Inspection and baseline are a must, in any used vehicle. Even at 30K miles on the clock in a 3 yr old. Even a 100 series need's TLC. Buying a 24 year old vehicle, in what I call the rust belt. With 1/4 million miles on the clock. What has been done since buying, other than fuel filter and by whom?

If you've a rust bucket with tons of aftermarket parts. You've likely a ton of work to get done, before you'll have reliable rig. If you've some wrenching skills and ready to get hands dirty and learn. Great, dig in. The forum will be a great resource. If not, find a good mechanic, that specializes in 100 series.

Click on my Master link below. Look at some of me restoration project and work I've done for others. This will at least, help you understand some of what it takes to have a 100 series, that is reliable and safe to drive.

It's very import a few areas be inspect & corrected:
Brakes- Safety!
Coolant system- Neglect and loose your engine.
Spark plugs- They're walking out-Replace them.
Air filtration & flow-Air filters clogged, seal curled, vacuum leaks, gunky throttle body, MAF senor all need addressing.
Front end-wheel bearing serviced properly, ball joints, TRE, steering rack and power steering reservoir & hoses, stabilizer system. For safe handlining.

 

[Les Summer]

CATs have nothing to do with rough cold start. CATs need to heat, before being effective. HWY cruising at 55 MPH and up, is where they're efficient. 4,500 RPM, is where seem to hit max temp. If your engine running rich (to much fuel in mixture). You can be dumping fuel in CATs, which can burn them up. If running lean, cylinder head temp goes up, CAT's run hot. You may or may not have aftermarket CATs. Only way to know. Is get under it, with a camera. Post good pictures of CATs end to end including the o2 sensors.

The rough start, with dash lights staying on a bit long. Likely indication, RPM very low on start-up. That it's struggling to keep running. This can be fuel or air starvation, issue with spark.

Inspection and baseline are a must, in any used vehicle. Even at 30K miles on the clock in a 3 yr old. Even a 100 series need's TLC. Buying a 24 year old vehicle, in what I call the rust belt. With 1/4 million miles on the clock. What has been done since buying, other than fuel filter and by whom?

If you've a rust bucket with tons of aftermarket parts. You've likely a ton of work to get done, before you'll have reliable rig. If you've some wrenching skills and ready to get hands dirty and learn. Great, dig in. The forum will be a great resource. If not, find a good mechanic, that specializes in 100 series.

Click on my Master link below. Look at some of me restoration project and work I've done for others. This will at least, help you understand some of what it takes to have a 100 series, that is reliable and safe to drive.

It's very import a few areas be inspect & corrected:
Brakes- Safety!
Coolant system- Neglect and loose your engine.
Spark plugs- They're walking out-Replace them.
Air filtration & flow-Air filters clogged, seal curled, vacuum leaks, gunky throttle body, MAF senor all need addressing.
Front end-wheel bearing serviced properly, ball joints, TRE, steering rack and power steering reservoir & hoses, stabilizer system. For safe handlining.

I've done a lot of work to the truck. New coils (Hitachi) and plugs (iridium), always with a torque wrench. Timing belt and water pump, wheel bearings, too much to list. New OEM fuel filter. I've done all the work. Rig has ZERO rust.

Thank you for the complete response. I appreciate you decimating the idea of it being the CATS, kind of puts my mind onto a better course.

The start is peculiar, and it is hard to say what is wrong, because it's hard to describe in words. When I get the faulty start, it is accompanied by an exhaust rumble/noise, which I think is just due to the weakness of the start. Once the vehicle is started, I have ZERO issues. NO idle issues, no stumbling, no problems whatsoever, NO CEL. When I am thinking about it being the fuel pump, the vehicle presents no other symptoms that would lead me to believe it is the fuel pump, yet I feel this is an issue that involves fuel air mix at startup. I'm off the next couple of days, so I'm going to start with checking all my vacuum lines. I'll be sure to get some pictures of the CATS, for good measure, and I'll post them here.

I have been running some cheap fuel system cleaner, and I have a big trip coming up, so we shall see if that is fruitless. I've recently ran Rislone CAT cleaner, about 3k miles ago. If anyone really pushes me to do it, I might try the Rislone again, although I'm more interested in real trouble shooting VS dumping money and guessing.

I'm about to go on an investigation of EFI relay and fuse and see if I can connect any of the symptoms to symptoms related to those items. Hmm.. throttle body was cleaned when I did timing belt, but maybe I can do it better..

 

[2001LC]

I've done a lot of work to the truck. New coils (Hitachi) and plugs (iridium), always with a torque wrench. Timing belt and water pump, wheel bearings, too much to list. New OEM fuel filter. I've done all the work. Rig has ZERO rust.

Thank you for the complete response. I appreciate you decimating the idea of it being the CATS, kind of puts my mind onto a better course.

The start is peculiar, and it is hard to say what is wrong, because it's hard to describe in words. When I get the faulty start, it is accompanied by an exhaust rumble/noise, which I think is just due to the weakness of the start. Once the vehicle is started, I have ZERO issues. NO idle issues, no stumbling, no problems whatsoever, NO CEL. When I am thinking about it being the fuel pump, the vehicle presents no other symptoms that would lead me to believe it is the fuel pump, yet I feel this is an issue that involves fuel air mix at startup. I'm off the next couple of days, so I'm going to start with checking all my vacuum lines. I'll be sure to get some pictures of the CATS, for good measure, and I'll post them here.

I have been running some cheap fuel system cleaner, and I have a big trip coming up, so we shall see if that is fruitless. I've recently ran Rislone CAT cleaner, about 3k miles ago. If anyone really pushes me to do it, I might try the Rislone again, although I'm more interested in real trouble shooting VS dumping money and guessing.

I'm about to go on an investigation of EFI relay and fuse and see if I can connect any of the symptoms to symptoms related to those items. Hmm.. throttle body was cleaned when I did timing belt, but maybe I can do it better..

I get Coils & Spark plugs, form Denso or Toyota Denso. I buy from only Denso distributors or Toyota. There is so much China bootleg junk out there.

Glade to hear zero rust.

Sure wouldn't hurt to do fuel pressure and fuel Injector leak down tests. Typically with excessive leak down. The complaint is long crank to start.

 

[Les Summer]

I get Coils & Spark plugs, form Denso or Toyota Denso. I buy from only Denso distributors or Toyota. There is so much China bootleg junk out there.

Glade to hear zero rust.

Sure wouldn't hurt to do fuel pressure and fuel Injector leak down tests. Typically with excessive leak down. The complaint is long crank to start.

I don't believe it's the Hitachi coils, which I bought from Rock Auto, and trust. it' not a long crank to start. After spending a lot of time with this issue, I can say with near certainty the problem is directly related to how long I let the key in the ON position BEFORE I start the vehicle. So if I just hop in and turn the key from completely being off, and right into starting, it gives me the rumble noise and the start isn't crisp and quick like you have learned to expect.

If I let the key in the on position for a couple of seconds, and then start, I get NO SYMPTOM. I'm beginning to think the "rumble" noise is the starter gear tripping on the fly wheel. so I'm thinking it's either the starter or a problem with fuel delivery at start up. With key in the on position, I'm imagining this is giving the fuel pump time to pump fuel to start the vehicle. The problem is why now all of a sudden do I have to do that to start the truck?

I cannot smell gas under the hood thank goodness. I don't fear fuel leaking from an injector at this time. I wish is it was the starter, then at least I'd know what I must do. I might get a short video clip if you want to hear it. Thanks

UPDATE:
So right after I posted this response I went and got some gas. I just made a 200 mile trip to my moms, so it was fill up time. I finally got a chance to get the engine cover off and have a look. I see no leaks, no smell of gas, but some of the vacuum hose could use replacing. I tried to record, but could not replicate the sound or symptom on startup anymore. I was certain I heard noise from the exhaust, so once again I'm ruling out it being the starter. I don't have a helper, so it's hard for me to start the vehicle and hear where the noise is coming from. I'm leaning back to this perhaps being a fuel issue. To be continued...

 

[2001LC]

If I let the key in the on position for a couple of seconds, and then start, I get NO SYMPTOM. ------

If this consistently repeatable. It may point to electric issue.. Possibly in fuel pump control circuit, throttle body or may be immobilizer.

 

[Les Summer]

If this consistently repeatable. It may point to electric issue.. Possibly in fuel pump control circuit, throttle body or may be immobilizer.

I got home after another 200 miles and shut off the truck. I then tried a normal start, and there was the symptom again. It's something with not enough fuel reaching fast enough, and by the time the fuel catches up to where it needs to be, the vehicle fires up. This explains the lag of the dash lights going off, which I described earlier in this thread. Now as for the grumble that is always accompanied by the laggy start, I believe it's an exhaust noise, or possibly the starter, or a combination of both. Time will tell. I'll eventually figure it out. Evap purge valve?

 

[2001LC]

"when I start it there is a delay of the dash warning lights going away. The vehicle is still starting, but there is a lag with the dash lights clearing away" "and this lag is accompanied by what I can only describe as a sputtering sound of the exhaust before the vehicle starts up, and it happens intermittently."
"If I let the key in the on position for a couple of seconds, and then start, I get NO SYMPTOM"

BTW: Make sure your HVAC system is off (not on Auto, fan off).

You symptom: Lag in dash lights: Suggest Low RPM at start up.
IG ON and wait: Suggest electrical circuit issue.
Engine cold or hot, rough start. Fuel starvation or combustion.

Water in gas, I'd 98% rule-out. Since you've filled up again, form different source.

It's been suggested. The fuel pump gets, ~3 seconds of power when IG key turned on. To pressurize the fuel rail for faster start. Although I've never confirmed this.

But, what is for sure: Fuel pump is not powered/running continuously while IG key just turned to ON (engine off). Not until engine crankshaft is turning during engine turning over (cranking) to start or engine running, does fuel pump run!

By turning IG on and waiting, then all good. This may indicate electrical issue. In that the ECU is getting or processing info to slowly. The EUC is getting signals from a number of places. This includes; Crank sensor, MAF meter (sensor), alternator, relays, etc.

I'd first look under hood. Starting with battery and it's cables, grounds and wires of crank & MAF sensors.
I'd look at air filter and inside air box for air flow issues.
I'd also be looking at coolant level. For signs, engine has been running hot or overheating.
I'd be looking over engine: at vacuum lines, wires, coils (are they Denso) and such. I understand you feel confided with coil choice, but it's a rabbit hole we go down.
I'd be hooked to tech stream, scanning for DTC confirmed or pending.
I'd watch crank speed/RPM through tech stream.
I'd listen on cold start for exhaust tick. If heard, see if remains or goes away once op-temp reached.
I'd look for cylinder misfires.
I'd take test drive while monitoring: data, of which include Fuel trims & Engine Coolant Temp.
I'd then move on to fuel pressure test, fuel pump control circuit testing and starter signal testing in that order.
Worth mention is some of the 2000 had throttle body issues.

Here's PROBLEM SYMPTOMS TABLE, from diagnostic section FSM:
Cold engine (Difficult to start)
1. Starter signal circuit
2. Fuel pump control circuit DI−137DI−119

Hot engine (Difficult to start)
1. Starter signal circuit
2. Fuel pump control circuit DI−137DI−119

Low engine idle speed (Poor idling)
1. A/C signal circuit (Compressor circuit)
2. Fuel pump control circuit DI−771DI−119

Rough idling (Poor idling)
1. Compression
2. Fuel pump control circuit EM−3DI−119

 

[2001LC]

It's Rabbit hole! You've done to much to "list". But did list one part, coils, which is not OE or OEM. Any time parts not OEM from Toyota or at least OE Denso direct from Denso distributor. I've concerns. As I've correct many issues, replacing non OEM or bootleg parts.

"IG ON and wait:" Because of that statement from you. I do not think below your issue. But still worth consideration, is bad fuel. Fuel from old metal storage tanks, can be nasty.

This came for 06LZ 250K miles. Started okay. But Long Term Fuel Trim (LTFT), hung around 7% , which is not great. Issue was not fuel pressure, but fuel flow restriction.
After vacuuming fuel tank, R&R fuel pump and filter. LTFT a respectful ~3% now.

 

[Les Summer]

"when I start it there is a delay of the dash warning lights going away. The vehicle is still starting, but there is a lag with the dash lights clearing away" "and this lag is accompanied by what I can only describe as a sputtering sound of the exhaust before the vehicle starts up, and it happens intermittently."
"If I let the key in the on position for a couple of seconds, and then start, I get NO SYMPTOM"

BTW: Make sure your HVAC system is off (not on Auto, fan off).

You symptom: Lag in dash lights: Suggest Low RPM at start up.
IG ON and wait: Suggest electrical circuit issue.
Engine cold or hot, rough start. Fuel starvation or combustion.

Water in gas, I'd 98% rule-out. Since you've filled up again, form different source.

It's been suggested. The fuel pump gets, ~3 seconds of power when IG key turned on. To pressurize the fuel rail for faster start. Although I've never confirmed this.

But, what is for sure: Fuel pump is not powered/running continuously while IG key just turned to ON (engine off). Not until engine crankshaft is turning during engine turning over (cranking) to start or engine running, does fuel pump run!

By turning IG on and waiting, then all good. This may indicate electrical issue. In that the ECU is getting or processing info to slowly. The EUC is getting signals from a number of places. This includes; Crank sensor, MAF meter (sensor), alternator, relays, etc.

I'd first look under hood. Starting with battery and it's cables, grounds and wires of crank & MAF sensors.
I'd look at air filter and inside air box for air flow issues.
I'd also be looking at coolant level. For signs, engine has been running hot or overheating.
I'd be looking over engine: at vacuum lines, wires, coils (are they Denso) and such. I understand you feel confided with coil choice, but it's a rabbit hole we go down.
I'd be hooked to tech stream, scanning for DTC confirmed or pending.
I'd watch crank speed/RPM through tech stream.
I'd listen on cold start for exhaust tick. If heard, see if remains or goes away once op-temp reached.
I'd look for cylinder misfires.
I'd take test drive while monitoring: data, of which include Fuel trims & Engine Coolant Temp.
I'd then move on to fuel pressure test, fuel pump control circuit testing and starter signal testing in that order.
Worth mention is some of the 2000 had throttle body issues.

Here's PROBLEM SYMPTOMS TABLE, from diagnostic section FSM:
Cold engine (Difficult to start)
1. Starter signal circuit
2. Fuel pump control circuit DI−137DI−119

Hot engine (Difficult to start)
1. Starter signal circuit
2. Fuel pump control circuit DI−137DI−119

Low engine idle speed (Poor idling)
1. A/C signal circuit (Compressor circuit)
2. Fuel pump control circuit DI−771DI−119

Rough idling (Poor idling)
1. Compression
2. Fuel pump control circuit EM−3DI−119

Thank you , I will use as a guide. I am going to replace a few hard vacuum lines this pay, even though they are likely not the culprit. The fuel tank mess you pictured is interesting...
My coolant stays full, thank goodness. I check it weekly. I've a new OEM Radiator and thermostat in there too. I will run the OBD today and let you know my findings.

 

[Les Summer]

It's Rabbit hole! You've done to much to "list". But did list one part, coils, which is not OE or OEM. Any time parts not OEM from Toyota or at least OE Denso direct from Denso distributor. I've concerns. As I've correct many issues, replacing non OEM or bootleg parts.

"IG ON and wait:" Because of that statement from you. I do not think below your issue. But still worth consideration, is bad fuel. Fuel from old metal storage tanks, can be nasty.

This came for 06LZ 250K miles. Started okay. But Long Term Fuel Trim (LTFT), hung around 7% , which is not great. Issue was not fuel pressure, but fuel flow restriction.
After vacuuming fuel tank, R&R fuel pump and filter. LTFT a respectful ~3% now.

View attachment 3471108
View attachment 3471109
View attachment 3471110
View attachment 3471111

You sound like someone who will appreciate it, so here are the things I've done in the last 10k miles:

New air filter
oil changes and OEM filter every 3k miles
Iridium plugs and Hitachi coils from Rock Auto
Aisin timing belt and water pump kit from Rock Auto (I didn't want to bother with going further and doing crank seals, and I have no leaks I can see)
All the little elbow hoses running down the front face of the engine were replaced while I was doing the timing belt
Koyo bearings and races, purchased from cruiser teq I believe, and with Timken grease
Front and rear brake pads aftermarket Bosch (give it a try)
PCV valve and hoses, OEM
OEM radiator and thermostat, plus OEM red coolant
OEM fuel filter
Serpentine belt
New fog bulbs, high end Sylvania Halogens
Steering wheel re-wrap, for fun
Every fluid front to back was totally replaced; transmission fluid (Toyota OEM), front and rear differential + transfer case (liquimoly), and P/S fluid (OEM)
Fuel cap OEM Toyota from dealer. Got burned on a knock off "OEM" from eBay first though
Throttle body cleaned during timing belt change

The previous owner did a lot of work to the truck too. They already had new ball joints and heater T's from what I could see. I have not even fully inspected to see all what was done, but a lot of it I see was not on the CarFax record. I think the timing belt was done more recent than I thought too, but I'd of done that anyway unless I'd of known it was done at Toyota recently, which I did not.

 

[Les Summer]

BTW: Make sure your HVAC system is off (not on Auto, fan off).

It is always off.

 

[Les Summer]

I noticed while I was in there today, I'm going to have to replace the injector seals. The ones I can see from looking down, that seat in the block, look like they are dust.
The pictures of my scanner were taken right after a cold start. About a 40 degree day. Also, the symptom disappeared on me again.

 

[Les Summer]

UPDATE:
Checked battery and alternator. Battery is good testing with multimeter with vehicle off, and with the vehicle turned on the battery is charging, so alternator looking good.

The symptom of the aforementioned noise described when I do a "fast start" is absolutely NON EXISTENT if I simply let the key in the on position for about 3 seconds before I start the vehicle.

My next move is to replace fuel injector O rings. They are overdue anyway. I will reassess symptoms after doing that job.

 

[Les Summer]

I'd first look under hood. Starting with battery and it's cables, grounds and wires of crank & MAF sensors.
I'd look at air filter and inside air box for air flow issues.
I'd also be looking at coolant level. For signs, engine has been running hot or overheating.
I'd be looking over engine: at vacuum lines, wires, coils (are they Denso) and such. I understand you feel confided with coil choice, but it's a rabbit hole we go down.
I'd be hooked to tech stream, scanning for DTC confirmed or pending.
I'd watch crank speed/RPM through tech stream.
I'd listen on cold start for exhaust tick. If heard, see if remains or goes away once op-temp reached.
I'd look for cylinder misfires.
I'd take test drive while monitoring: data, of which include Fuel trims & Engine Coolant Temp.
I'd then move on to fuel pressure test, fuel pump control circuit testing and starter signal testing in that order.
Worth mention is some of the 2000 had throttle body issues.

Wires look good and battery tested good. Alternator also tested good.
Air filter is new.
Coolant level has not dropped at all, even after recent round trip of 300 miles.
Vacuum lines, some are on order for replacing. Nothing cracked or broken. Hitachi coils are brand new and better than the Denso, SAY WHAT!
I posted my scan results from my OBD scanner, and all looks clear.
RPM crank speed using tech stream? not sure what tech stream is..
No ticks, just a little rumble when I "Fast Start". If turn the key to on position for a few seconds, then crank, I get no symptoms and the truck starts fine.
Test drive while monitoring fuel trims and coolant temp is a GREAT IDEA. I will probably do this soon.
I don't know how to do a fuel pressure test, but only because I've never done one. Fuel pump circuit testing and starter signal testing I've never done either, but I can learn anything.
Throttle body issues I doubt. I read about that though. Vehicles accelerating on their own, that sounds scary, but no, mine does not do that ever.

 

[medtro]

My next move is to replace fuel injector O rings. They are overdue anyway. I will reassess symptoms after doing that job.

I would do a before and after fuel pressure tests for scientific reason.

 

[Les Summer]

For anyone who has a scan tool, and does not know anything about what to determine from its values, this is an excellent video. You can get an idea of what values to look for when OBD scanning your LX470. The vehicle Scotty uses in his video is a 1998 Lexus LX470 with over 310k miles. Scotty goes over the different fuel trim values, MAF, etc. It's a great cheat sheet.

I'd first look under hood. Starting with battery and it's cables, grounds and wires of crank & MAF sensors.

I notice the recent MAF (g/s) reading I took is 11.12, which is HIGH compared to the reading in Scotty's video, and one of the first suggestions of things for me to check by member @2001LC