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Toyota Service
Toyota Service, Toyota Expert
Category: Toyota
Satisfied Customers: 4605
Experience:  30+ Yrs of auto experience, Award Winning Svc. Manager; Just Answer Customer's Choice Award Winner
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Toyota: Got a 91 4Runner, V6 that was running a bit weak when

Customer Question

Got a 91 4Runner, V6 that was running a bit weak when pushed, but ran fine when not pushed. It recently sputtered and died going up a hill and it won't run now. I've replaced the fuel pump and filter with no result. If it sits for a while, it will kick over roughly for about 5-10 seconds, then die and not refire. Plugs, wires, distributor replaced recently. Fuel pressure regulator replaced a couple of years ago, but it was Beck-Arnley, not Toyota.
Any ideas?
Submitted: 1 year ago.
Category: Toyota
Expert:  Toyota Service replied 1 year ago.
Hello. Welcome to Just Answer. Please allow me to assist you. Is the truck available for a quick test?
Customer: replied 1 year ago.
Not right now, I'll be able to test tomorrow. What should I test?
Expert:  Toyota Service replied 1 year ago.
Please open the hood and locate the small rectangular diagnostic connector. Open it and look under the lid. Under the lid there should be a plastic label identyfing. the various terminals. Locate the followinfg terminals:FPB+ Take a paperclip and jam each end securely into FP and B+ Then try to start the engine. Advise if it starts
Customer: replied 1 year ago.
Ok. I also did the diagnostic jumper, got a trouble code of 21, which I believe is O2 sensor. I recently replaced that as we, code may have been left over from that. Could defective O2 sensor cause engine fail?
Customer: replied 1 year ago.
It'll probably be tomorrow, late evening obligation tonight.
Expert:  Toyota Service replied 1 year ago.
The O2 sensor would not cause the engine to not start. The oxygen sensor input is actually not used until the sensor gets up to an internal temperature of 650 degrees. ON startup, the air temperature, air volume and coolant temperature are the main inputs to control the fuel injection
Customer: replied 1 year ago.
That's what I thought, thanks.
Expert:  Toyota Service replied 1 year ago.
You are very welcome.
Customer: replied 1 year ago.
Did the jumper test. Did not start. Kicked over briefly (maybe a couple of seconds), then died like before.
Customer: replied 1 year ago.
BTW I have a multi meter, so I can check voltage, continuity, etc
Expert:  Toyota Service replied 1 year ago.
Place the jumper between B+ and Fp. Place the DVOM red lead to the jumper and the black lead to the battery negative terminal. Advise if you have the same reading as if you would get placing the DVOM probes across the battery posts.
Customer: replied 1 year ago.
Voltage across battery terms = 12
Voltage jumper to battery neg = 0
Expert:  Toyota Service replied 1 year ago.
Please recheck jumper volts with key on.
Customer: replied 1 year ago.
That was both key off and on. Also checked to ensure jumper was fully inserted. On way to work, will you be available on weekend? I can also insert probe in each receptacle.
Expert:  Toyota Service replied 1 year ago.
Run a wire from the battery positive terminal straight to Fp and try to start. I'll be available this weekend.
Customer: replied 1 year ago.
Mr. Jumper! I haven't used one of those since my power plant startup days! Everything is digital now... :-(
Expert:  Toyota Service replied 1 year ago.
Let me know if spoon feeding power to Fp causes the engine to start.
Customer: replied 1 year ago.
Ok, I properly installed the paper clip (it wasn't contacting the B+ term) and got juice to Fp, but no start.
Expert:  Toyota Service replied 1 year ago.
Let's remove a wire connector from a fuel injector; any one will do. See if you have power going to it with the key on. One of the two wires should have power.
Customer: replied 1 year ago.
Aren't the injectors under the intake plenum?
Customer: replied 1 year ago.
After it has sat for a bit (overnight so far), it will kick over for a second before dying.
Customer: replied 1 year ago.
Maybe the cold start injector? That's accessible.
Expert:  Toyota Service replied 1 year ago.
No. What I think you have going on here is the engine is starting on the cols start injector, the regular injectors are not energizing to let the gas into the intake. See if it starts with starting fluid or spraying gas into the intake tube. If it starts up and runs as long as you manually add fuel, it is a pretty safe bet that the sensor that tells the system when to apply a ground to the other (non-powered) wire is not happening. This signal comers form the distributor. The next step is to see if it starts via starting fluid or gasoline manually added. If it starts and runs as long as you give it gas (manually), we either have a bad distributor, a bad computer or no power to the injectors. Let's try to start it on starting fluid or gasoline sprayed into the intake.
Customer: replied 1 year ago.
There was no power to the cold start injector, can't access the other 6 without removing the intake plenum. Not s job I want to tackle today.I'm on California, we don't have starting fluid here. ;-)
Expert:  Toyota Service replied 1 year ago.
There is only power to the cold start injector whilst cranking the engine. Perhaps some regular gasoline from a lawn mower can. Pull off the air tube from the throttle body. Add an ounce of wet gasoline and clamp the air tube back on; then try to start.
Customer: replied 1 year ago.
I'm going to pick up some starter fluid, but not sure I'll get there today.
Expert:  Toyota Service replied 1 year ago.
ok
Customer: replied 1 year ago.
Sprayed starter fluid into the air intake immediately downstream of air filter element (lifted lid and sprayed in). Tried twice, no start, didn't even fire. There is a hose from the left valve cover to the air intake hose that feeds the plenum, should I try there too?
Expert:  Toyota Service replied 1 year ago.
Pull a spark plug ans hold it close to a metal part on the engine with insulate pliers. About 3/8" away from the metal. Use insulated pliers. Have someone crank the engine. See if you have spark.
Customer: replied 1 year ago.
Got spark. Also pulled that recirc hose from the left valve cover and shot starter fluid into intake hose just upstream of throttle, no fire.
Expert:  Toyota Service replied 1 year ago.
Looks like we need to check the timing marks. The timing belt may be off. Place the crank pulley at the Zero line. Remove the distributor cap and note exactly where the distributor rotor is. the end of the rotors should be directly under where the spark form the rotor transfers to the number one cylinder portion of the distributor cap. If the rotors is a bit before or a bit after the center of the number one position of the cap, we need to replace the timing belt.

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