PLZ Help 92 LS400 Won't Start

[92grayls400]

Hi Everyone I'm new to Lextreme. Can someone please help me figure this out? My car will turn over but will not catch. When I try to crank it, it will turn like it wants to catch but then dies after about 4 or 5 tries.

 

[Lextreme II]

what do you mean then dies after about 4 or 5 tries? Do you noticed its harder to start in the morning? Double check your fuel pressure regular. Test the PR is its loosing fuel pressure.

 

[92grayls400]

OK I'm sorry I wasn't clear before. It does not catch at all. It tries but never catches. I noticed the plug that plugs into the MAF/AFM is real loose. I tried pushing it and holding it in place while my wife tries to crank the car, it made the starter turn faster but it still didn't catch. Could this be the problem?

Let me give you a little history. I just bought the car from one of my employees Grandmother for $200. She kept the maintenance up and regular. She just had a tune up done on the car. She says it was driving fine and about 2 weeks ago it would not start. So I really don't know for sure what it was doing before that.

I hope this helps a little more than my first post.

 

[stevechumo]

Does it crank hard at all? Plug the MAF sensor to its original place. Install a new high cold cranking amp battery that exceeds factory specs. Check all spark plugs, wires, rotor caps, and coils. Check the fuel pressure regulator. There're more to check, but do it one step at a time.

 

[92grayls400]

Ok, Here is where I am now. I took the MAF/AFM off and sprayed starting fluid into the throttle body and the car cranks and runs as long as I spray the starting fluid. Does that mean it's a fuel related problem?

How do I check the Fuel Pressure Regulator? Where is the fuel pressure regulator?

 

[92grayls400]

I guess the feul pump wasn't getting any power. I pulled the cover off the fuel pump and this is what I seen. Any help would be appreciated.

 

[92grayls400]

After trying all morning I was finally able to pull trouble codes. The only one I get is #24. IAT Sensor signal.

Can anyone tell me where it's located?

 

[Lextreme II]

You need to check fuel pressure. Is either fuel pump or FPR is loosing pressure. The FPR is located in your left hand side when you are looking at the engine. Something like this will work. Mityvac Pump When you pressurized the fuel system to about 38-42 psi, the pressure should stay at for a while. If it deosn't stay, the either your fuel pump or FPR and sometimes both diagrams are bad.

IAT is Intake Air Temperature Sensor and its most likely is not the problem.

 

[stevechumo]

The wires leading to the fuel pump seem to look loose. Make sure they're all connected and insulated right. If they're loose, the fuel pump won't work. After checking the FPR, disconnect all spark plugs, turn the ignition to ignition II but don't start the car for 10 seconds, turn off and try again. You'll hear the fuel pump working "Eeh..eeh...eeh" to build up the pressure.

 

[92grayls400]

Ok I will try that. I got off work too late today. Tomorrow will be an early day. I hope that works.

 

[92grayls400]

Okay the fuel pressure regulator is fine. The fuel pump isn't getting any power. Someone had straight wired the sending unit (that green wire from the sending unit to the radio in the above pictures). Where do I go from here? What will cause the fuel pump to not get any power?

 

[stevechumo]

Okay the fuel pressure regulator is fine. The fuel pump isn't getting any power. Someone had straight wired the sending unit (that green wire from the sending unit to the radio in the above pictures). Where do I go from here? What will cause the fuel pump to not get any power?

I don't have time to take out the carpet covering the fuel tank & pump to show you, so sorry. However, you may trace all the wires up and see if all the wires are matched. Get a 12V tester and test all the wires. That's how I'd play lottery with an educated guess and never won though. Just kidding.

 

[92grayls400]

I tested the wires. The ones going to the fuel pump isn't getting any power. What could cause this?

 

[stevechumo]

I tested the wires. The ones going to the fuel pump isn't getting any power. What could cause this?

Check the fuse.

 

[92grayls400]

Ok I can anyone tell me where the fuel pump ecu is located on a 92 lexus ls?

 

[stevechumo]

Ok I can anyone tell me where the fuel pump ecu is located on a 92 lexus ls?

The ECU in the SC is located in the front passenger side, right in front of the leg space, either under the carpet or inside those black plastic panels. I don't remember exactly. Perhaps the LS ECU is located at the same place as the SC. There're 2 ECUs. The big one is the main one that controls the engine, fuel...etc. The smaller one is only for the hydraulic fan.

 

[Zuffen]

The fuel pump ECU in the SC is right behind the drivers left shouder.

 

[92grayls400]

I would like to thank everyone for helping me. I finally have it fixed, it was the fuel pump. Replaced it and the sending unit and it runs fine. I really appreciate the help.

 

[stevechumo]

The fuel pump ECU in the SC is right behind the drivers left shouder.

This surprised me. I never thought the fuel pump ECU of the SC is there. I opened the whole interior panels to install the stereo system but I don't recall there's any ECU there. But well, I always know that I don't know everything.

Congratulation on your fixed problem. Let's boost it.