Car: Lexus GS300 1995 1st gen. Automatic transmission. 250k miles.
Problem: First thing - I disconnected the negative battery terminal. I cleaned the Volume Air Flow Meter with an electronics cleaner and cleaned the throttle body with a throttle body cleaner. I disassembled the plastic air intake in order to get to the throttle body. I did not remove the throttle body. I sprayed the throttle body cleaner towards the throttle valve. I pulled the accelerator/throttle cable in order to open the throttle valve. I also sprayed the cleaner into the opening. Now the car has long cranking and the engine (if cranked) immediately dies (as if it cannot breath?). I tried starting the engine several times throughout a day: one time the engine sputtered and died within 0.5-1 second; the other time the engine died immediately. I cranked for 5 ticks/clicks of the starter.
Suspects:
1) Broken calibration of the throttle position sensor. People usually say that one person should turn ignition key into ON position and press the accelerator pedal to open the throttle valve, so that the other person cleans it. I was alone and the system seems mechanically simple so I pulled the accelerator/throttle cable lever (see the image). Several times, I accidentally opened the valve by pushing it with a toothbrush instead of pulling the throttle lever.
2) Volume air flow meter (I guess it's like a MAF in newer vehicles): I did not see any sensing elements such as wires or resistors (see the image). I firmly attached the connector to the air flow meter.
3) There was a small crack on the PCV (positive crankcase ventilation) hose. It got bigger when I remove the hose. I used some duct tape for now.
Extra:
I have a high confidence that I assembled everything back correctly. There is no leaks in the air intake. I attached all connectors and hoses as they were before. The air filter looks all right.
OBD1 codes:
No new codes. There have been the following codes for years:
21 - Main oxygen sensor fault (left bank [radiator side] oxygen sensor)
27 - Sub-oxygen sensor circuit fault
28 - Main oxygen sensor fault (right bank [firewall side] oxygen sensor [ 02 sensor ])
Also, after driving 200 miles in a day and idling in the traffic jam for 20 minutes, I got a code 71:
71 - EGR system malfunction.
I drove the car twice after the 71 code and the engine worked good as always (no shakes, no stalling).
This code disappeared after I disconnected the battery.
Thoughts:
How can I single out the throttle body vs the MAF? I was thinking to crank the car while pressing the accelerator pedal. It is OK if transmission is in Park?
Images:
Throttle-body-with-2-valves: the first sub-throttle valve is normally fully open; the second valve is normally fully closed.
Volume-Air-Flow-Meter
Maybe you got some crud into your idle air control valve, you might want to try cleaning it. Also, replace that cracked PCV hose. FWIW, I seriously doubt you hurt anything by opening the throttle plate the way that you did.
Can an engine not start at all if there is a leak in the PCV hose? I ordered a new one.
Also, I floored the accelerator cable and tried cranking to no avail. I guess that means that the idle air control valve is not a culprit. Thanks.
The pcv hose being cracked would cause a vacuum leak but not a no start condition. I think your problem is related to a lot of cleaner and carbon entering the manifold and causing a no ignition situation, which would result in an accumulation of fuel. Try keeping the throttle plate open for a few hours. Pull the plugs, or at least a couple of them and see if they are dry and clean. Good luck.
I was thinking to crank the car while pressing the accelerator pedal. It is OK if transmission is in Park?
Yes, it is completely fine.
How can I single out the throttle body vs the MAF?
If you have a scan tool , check the MAF sensor readings while the engine is running. It should be linear with the rpm. You can also remove the MAF sensor (or disconnect the connection), if the engine runs fine then, the MAF sensor is culprit.
I'll try disconnecting the MAF sensor and cranking the engine. Also, I think I sprayed some cleaner beyond the second throttle valve. Some cleaner fluid and paper towel specks could go into the engine. Can they cause serious issues?
Cleaner fluids evaporate fast and if they got into the engine, they burn and it is unlikely that they cause long term issues.
Yes. Try pressing the pedal to the floor.
Try starter fluid. See if you can run the car with it.
I tried both disconnecting the air flow sensor and pressing the accelerator pedal to the floor. The issue persists.
Could you look at the 1-minute video? I tried cranking 3 times: the last time I pressed the accelerator pedal. At the end of the video, you can see some fuel fumes coming out of the PCV hose. The duct tape did not really help. I am ordering a new hose from lexuspartsnow, but the waiting is long.
The engine has never had any starting problems. The fuel talk is half full (or half empty 😏). Now I am without a car this awesome Summer.
Any suggestions? Appreciate.
I am going to:
- check the spark plugs (as @oldandy recommends)
- check that spark occurs in every cylinder
- try starter fluid (as @ recommends) (although I smell a lot of gas coming from the engine compartment when cranking).
I have a few questions:
1. Do I have to disable the fuel delivery system in order to check that spark occurs?
2. Can I remove the fuse EFI - 20 (see the image below) to disable the fuel and test the sparks?
3. Can I remove the fuse IG2 - 30 (see the image below) to disable the ignition and test the fuel?
Fuses descriptions:
EFI - 20 - Electronically controlled automatic transmission system, multiport fuel injection system/sequential multiport fuel injection system
IG2 - 30 - Electronic ignition system/distributor ignition system
4. My distributor's cover has some sludge. It is normal? Lexus 1995 GS300; automatic; 250k miles.
5. In order to get access to all spark plugs, I have to remove the throttle body first. Am I supposed to reattach everything back for each cylinder test (spark/compression)?
6. I assume that, when I sprayed the throttle body cleaner beyond the throttle valve, some cleaner droplets got into the intake manifold or even into cylinders - and the cleaner vapor dissolved the oil on the cylinder surfaces, thus lowering compression. I am thinking of adding a few droplets of engine oil into each cylinder to raise their compression (make them wet). Is it a good idea?