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New to the forum, sorry if I make a mistake on this thread. I have a 2000 LS400 and I have been having a stalling issue for quite a couple weeks now. Haven't been able to drive the car up the road it seems. It only happens when it is somewhat warmed up. It stalls at every stop sign or stop light. Has also done it whilst turning slowly and on idle.
Have found similar threads but none of them seem to have the exact issue I am having
Have replaced the following:
Transmission
Fuel Pump
Fuel Pump Relay
Fuel Filter
Entire TB Assembly
Idle Up Valve on Power Steering
Accessory Belt
Belt Tensioner
Not sure what else to do as I have spent more than $4000 on this one issue. PLEASE HELP!
Last edited by LS400Brae; 07-02-23 at 05:11 PM.
Reason: Needed to add something
I have no ideas of how to help other than the following moonshot:
Since there is no port dedicated to idle, idle control is performed only with the throttle valve. This area around this valve and the air assist system become contaminated with carbon in as little as 20,000 miles.
I'd simply try to add a jumper wire between FP and +B (left edge) to bypass the fuel pump resistor. This resistor is short-circuited by the ECU and the fuel pump relay for a while when the engine is starting and some more after that. When this resistor is open, the fuel supply is completely stopped and the engine halts. To use a jumper wire is a quick and easy way to conform the engine halt problem which occurs after the engine is started.
I'd simply try to add a jumper wire between FP and +B (left edge) to bypass the fuel pump resistor. This resistor is short-circuited by the ECU and the fuel pump relay for a while when the engine is starting and some more after that. When this resistor is open, the fuel supply is completely stopped and the engine halts. To use a jumper wire is a quick and easy way to conform the engine halt problem which occurs after the engine is started.
Yamae, is there any danger of leaving the jumper wire in place and test driving the car for an extended period of time to see if the engine stalling stops occurring?
Is the solution replacing the Fuel Pump Resistor or is the repair more complicated?
I'm not having this problem - my question is more for knowledge sake.
A good question. The biggest problem is the heat. There goes peaking more than DC 10A current because the fuel pump motor consumes that much of energy. The accumulated heat melts the plastic housing if the jumper wire is used for long time. You can try to add a jumper wire just for the confirmation but an extended period is not safe.
The jumper wire itself should be also OK to handle more than 10A of DC current of course if used for long time. You can use a paper clip temporarily but it's only for up to a few to several minutes. I recommend to use a AWG20 wire or thicker to use as a jumper wire.
It is not difficult to replace the Fuel Pump Resistor which is located near the battery. All you need is to disconnect the connector and unbolt the resistor block then install a new.
A good question. The biggest problem is the heat. There goes peaking more than DC 10A current because the fuel pump motor consumes that much of energy. The accumulated heat melts the plastic housing if the jumper wire is used for long time. You can try to add a jumper wire just for the confirmation but an extended period is not safe.
The jumper wire itself should be also OK to handle more than 10A of DC current of course if used for long time. You can use a paper clip temporarily but it's only for up to a few to several minutes. I recommend to use a AWG20 wire or thicker to use as a jumper wire.
It is not difficult to replace the Fuel Pump Resistor which is located near the battery. All you need is to disconnect the connector and unbolt the resistor block then install a new.
Does the resistors plug come out with ease? Looks to me like you have to go into the fender well to disconnect the plug from the frame?
If you're just going to throw parts at it, the Fuel Pump Resistor, P/N 2308050030 (23080-50030) is no longer available new.
However, before going through the trouble of locating a replacement (ebay), unplug and remove the resistor and test it with an ohm meter. The resistance specification is valid only ~20C/68F.
More has been uncovered, been doing some thinking and this happened after I did my Belt tensioner. We had to remove something power steering related for clearance issues. Maybe something on the pump? Also Car no longer throws codes and yet still stalls. New Fuel Pump Resistor reads the exact same as the old one from the car originally. Thought another thing it could be related to was something do to with the brake booster since it seems to happen once the brake pedal is pressed and whilst coming to a stop. Anymore thoughts?
07-02-23, 05:09 PM
2000 LS400 Abrupt stalling after warming up...
