??? (choking out or stalling)
03-23-20, 12:50 PM
#1
Driver School Candidate
Thread Starter
??? (choking out or stalling)
I have a 98 LS 400. I can be driving fine, and then all of a sudden it will start choking out or stalling then die. Then after an hour or two, and sometimes the next day it will start fine and run fine for a ways. Then, it'll do it again and will not start. I've changed the fuel filter and ran Seafoam through the system. It throws no codes. I don't think it's an ECU problem. Y'all reckon it's a fuel pump? I just hate to change that and it may be something more simple and cheap.
03-23-20, 01:39 PM
#2
How many miles are on the car?
Do you let the car warm up before you head down the road or is it still cold when you take off? If it's cold when you take off, does this problem typically happen when the car reaches normal temp? Any odd smells from the exhaust?
I've seen this issue with catalytic converters, fuel pumps, crank sensors, wiring problems, battery connections, etc. This might be a tough one to diagnose online.
Do you let the car warm up before you head down the road or is it still cold when you take off? If it's cold when you take off, does this problem typically happen when the car reaches normal temp? Any odd smells from the exhaust?
I've seen this issue with catalytic converters, fuel pumps, crank sensors, wiring problems, battery connections, etc. This might be a tough one to diagnose online.
03-23-20, 01:59 PM
#3
how long ago since the fuel filter change?
that job will inevitably introduce air into the fuel system causing issues you are experiencing; albeit temporarily.
priming the fuel system a few times (toggle the key between "ACC" and "ON" but do not engage the starter) may get rid of the air.
where did you use the seamfoam? through the intake? in the tank? i hope it did not ruin the fuel pump which could only be a coincidence and not the cause.
high miles can lead to fuel pump failure.
that job will inevitably introduce air into the fuel system causing issues you are experiencing; albeit temporarily.
priming the fuel system a few times (toggle the key between "ACC" and "ON" but do not engage the starter) may get rid of the air.
where did you use the seamfoam? through the intake? in the tank? i hope it did not ruin the fuel pump which could only be a coincidence and not the cause.
high miles can lead to fuel pump failure.
03-23-20, 02:30 PM
#4
Driver School Candidate
Thread Starter
How many miles are on the car?
Do you let the car warm up before you head down the road or is it still cold when you take off? If it's cold when you take off, does this problem typically happen when the car reaches normal temp? Any odd smells from the exhaust?
I've seen this issue with catalytic converters, fuel pumps, crank sensors, wiring problems, battery connections, etc. This might be a tough one to diagnose online.
Do you let the car warm up before you head down the road or is it still cold when you take off? If it's cold when you take off, does this problem typically happen when the car reaches normal temp? Any odd smells from the exhaust?
I've seen this issue with catalytic converters, fuel pumps, crank sensors, wiring problems, battery connections, etc. This might be a tough one to diagnose online.
I've taught her to never start and tak off, rather wait till it idles down before taking off. So, there's that...it doesn't get too cold here in South Texas. It mostly happens when warm... But, last week (to answer the other reply) when I changed the filter, I started the car and just let it idles while I was cleaning up... Within, about 15 minutes, probably less, it died and I could smell fuel. So, I didn't think it would be the fuel pump. Normally, i've been driving and smell nothing.
Also, from time to time, I get the low catalyst bank 1 code.
03-23-20, 02:33 PM
#5
Driver School Candidate
Thread Starter
how long ago since the fuel filter change?
that job will inevitably introduce air into the fuel system causing issues you are experiencing; albeit temporarily.
priming the fuel system a few times (toggle the key between "ACC" and "ON" but do not engage the starter) may get rid of the air.
where did you use the seamfoam? through the intake? in the tank? i hope it did not ruin the fuel pump which could only be a coincidence and not the cause.
high miles can lead to fuel pump failure.
that job will inevitably introduce air into the fuel system causing issues you are experiencing; albeit temporarily.
priming the fuel system a few times (toggle the key between "ACC" and "ON" but do not engage the starter) may get rid of the air.
where did you use the seamfoam? through the intake? in the tank? i hope it did not ruin the fuel pump which could only be a coincidence and not the cause.
high miles can lead to fuel pump failure.
But, the problem was pre-existing the filter change.
03-23-20, 03:03 PM
#6
It's entirely plausible that the fuel pump is overheating or not working correctly. When the car shuts off, can you turn it to accessory and hear the pump whining? I'm assuming it doesn't make a difference whether you have a full tank or not?
When you get it home, can you pull a spark plug and see if it's covered in fuel? Fuel pressure regulator could be failing, injector o-rings could be gone.
When you get it home, can you pull a spark plug and see if it's covered in fuel? Fuel pressure regulator could be failing, injector o-rings could be gone.
Last edited by WhiteUCF; 03-23-20 at 03:06 PM.
03-23-20, 03:26 PM
#7
Lexus Champion
The will start, hard start, won't start scenario you describe is indicative of fuel pump failure.
Even if another contributing factor, your original fuel pump is on borrowed time.
Use OEM fuel pump, fuel regulator, o-ring, hose, hose clamps and fuel tank sock/filter.
Consider replacing both fuel dampers and related crush washers as part of fuel system tune-up.
You will need to remove lower and upper back seat cushions to access fuel pump.
Mind the rear (color coordinated) seat belt guides... They are brittle and will break if not careful. Carefully unscrew them from the seat backs. They will break should you attempt to unlatch them.
Be sure to acquire back seat lower cushion plastic "sockets". (pink and yellow) that the lower seat hooks into.
They are fragile plastic and break easily.
Careful.when extracting these from chassis, as the sheet metal chassis slots they plug into will bend if you are not careful.
If you let someone else perform replacement, be sure they understand this, and inspect their interior work before leaving shop.
P.S. Forget about teaching girlfriends anything
Last edited by YODAONE; 03-23-20 at 03:37 PM.
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03-23-20, 04:28 PM
#8
Driver School Candidate
Thread Starter
On 1999 LS400 had to replace original fiel pump at ~175,000 miles.
The will start, hard start, won't start scenario you describe is indicative of fuel pump failure.
Even if another contributing factor, your original fuel pump is on borrowed time.
Use OEM fuel pump, fuel regulator, o-ring, hose, hose clamps and fuel tank sock/filter.
Consider replacing both fuel dampers and related crush washers as part of fuel system tune-up.
You will need to remove lower and upper back seat cushions to access fuel pump.
Mind the rear (color coordinated) seat belt guides... They are brittle and will break if not careful. Carefully unscrew them from the seat backs. They will break should you attempt to unlatch them.
Be sure to acquire back seat lower cushion plastic "sockets". (pink and yellow) that the lower seat hooks into.
They are fragile plastic and break easily.
Careful.when extracting these from chassis, as the sheet metal chassis slots they plug into will bend if you are not careful.
If you let someone else perform replacement, be sure they understand this, and inspect their interior work before leaving shop.
P.S. Forget about teaching girlfriends anything
The will start, hard start, won't start scenario you describe is indicative of fuel pump failure.
Even if another contributing factor, your original fuel pump is on borrowed time.
Use OEM fuel pump, fuel regulator, o-ring, hose, hose clamps and fuel tank sock/filter.
Consider replacing both fuel dampers and related crush washers as part of fuel system tune-up.
You will need to remove lower and upper back seat cushions to access fuel pump.
Mind the rear (color coordinated) seat belt guides... They are brittle and will break if not careful. Carefully unscrew them from the seat backs. They will break should you attempt to unlatch them.
Be sure to acquire back seat lower cushion plastic "sockets". (pink and yellow) that the lower seat hooks into.
They are fragile plastic and break easily.
Careful.when extracting these from chassis, as the sheet metal chassis slots they plug into will bend if you are not careful.
If you let someone else perform replacement, be sure they understand this, and inspect their interior work before leaving shop.
P.S. Forget about teaching girlfriends anything
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WhiteUCF (03-23-20)
03-23-20, 04:33 PM
#9
Driver School Candidate
Thread Starter
It's entirely plausible that the fuel pump is overheating or not working correctly. When the car shuts off, can you turn it to accessory and hear the pump whining? I'm assuming it doesn't make a difference whether you have a full tank or not?
When you get it home, can you pull a spark plug and see if it's covered in fuel? Fuel pressure regulator could be failing, injector o-rings could be gone.
When you get it home, can you pull a spark plug and see if it's covered in fuel? Fuel pressure regulator could be failing, injector o-rings could be gone.
The following users liked this post:
WhiteUCF (03-23-20)
03-23-20, 04:35 PM
#10
It's not a bad job at all. This is for a ucf10 but it's quite similar in procedure.
https://www.lextreme.com/lexus-ls400...ade-1990-1994/
https://www.lextreme.com/lexus-ls400...ade-1990-1994/
03-23-20, 04:37 PM
#11
Driver School Candidate
Thread Starter
It's entirely plausible that the fuel pump is overheating or not working correctly. When the car shuts off, can you turn it to accessory and hear the pump whining? I'm assuming it doesn't make a difference whether you have a full tank or not?
When you get it home, can you pull a spark plug and see if it's covered in fuel? Fuel pressure regulator could be failing, injector o-rings could be gone.
When you get it home, can you pull a spark plug and see if it's covered in fuel? Fuel pressure regulator could be failing, injector o-rings could be gone.
03-23-20, 04:40 PM
#12
Driver School Candidate
Thread Starter
It's not a bad job at all. This is for a ucf10 but it's quite similar in procedure.
https://www.lextreme.com/lexus-ls400...ade-1990-1994/
https://www.lextreme.com/lexus-ls400...ade-1990-1994/
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WhiteUCF (03-23-20)
03-23-20, 05:04 PM
#14
Driver School Candidate
Thread Starter
None the less, I appreciate it. Also, pretty sure it's gonna be the pump. Back at the car now, and can't hear it. Of course there's quiet a bit of traffic. I even crawled under it... Sort of. My big head and bigger belly stopped me from getting under it further.
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WhiteUCF (03-23-20)
03-24-20, 03:47 AM
#15
Driver School Candidate
Thread Starter
Ok, went to car this morning and it started up without a hitch.. got it out of that parking lot to the truck stop parking lot, as I have to go haul something... My girl followed me and said it was throwing out a strong fuel smell. Is this indictive of anything?