Ive been running around with blown 1st and 2nd o2 sensors blown (I ran a cherry bomb in place of my cat.) And now the truck has problomes starting . On cold starts with is fine. But on starting after driving for a bit, it doesnt want to start. It turns over, but if I dont press the gas the runner wont turn over. So I replaced the starter with a Bosch starter , you figure problome solved, right? But no its more of the same. I went and threw it on the computer diagonitics and it reads that eveything is fine, except for the o2 sensors . They read 1st and 2nd "no closed loop." Could the o2 be the cause of my problomes??? or is it somthing else? I checked all my grounds and connections. So I think I have done every thing, so you guys got any ideas? But if it is the o2 I gotta contact Gadget and buy the o2 simulator and some o2 sensors.

The truck is a '97 4runner 2wd 3.4L v6 auto. Thanks for the help guys

 

...Or put the cat(s) back on and call it legal.......

 

cats already back on the truck, that was dealt with long ago. I just got figure out why it wont start when the motor is warm

 

When cranking, do you have the check engine light on?

When cranking, do you hear the fuel pump running? You may need to have someone else crank it for you while you listen.

Gadget

 

the check engine light is on already from the blown o2 sensors. I gotta go listen for the fuel pump thing. Hopefully I dont gotta replace the fuel pump. What should I be listening for with the fuel pump. Thanks Gadget I was waiting for you to chime in on the topic.

 

The reason I asked if the check engine light is on when cranking the engine is that indicates that the ECU is powered up during the starting process. If it is not on when cranking and it will not start is shows that the ECU does not have power.

Gadget

 

It goes on as well as all my other lights in th gauge cluster. I just went anh listend for the fuel pump, but did not hear anything unusal. What should I be looking or listening for Gadget? My problomes only occur when the engine is warm and at no other time. Kinda fishy huh? I cant figure why it would only happen on a warm engine. Got any ideas what it could be Gadget? Thanks and mahalo

 

You need to find out if the fuel pump is coming online when the engine is cranking. On the 3.4, there is no prime cycle like on other vehicles, it will only start the pump when there is an RPM signal reaching the ECU.

You can tap the fuel pump wire under the rear seat and see if it gets 12 volts during cranking. If not, then you have trace back from there. There is a circuit opening relay in the dash that turns the pump on, but its main voltage supply comes from the same power junction that powers the ECU. The ECU should trip the circuit opening relay on an RPM signal.

Anyway that is were I would start and then trace back. If it is getting voltage during cranking you can open the cap and listen while someone cranks the engine. You should be able to hear it run. If you still can not figure it out, take the line off of the rear of the filter and aim it in to a bucket and see if fuel comes out on cranking. A quick on crank off should answer that. If it is working then a ton of fuel will be coming out so be careful.

Now if you had the old MAXX fuel kit I would suspect a leaky fuel injector on shut down. If when it finally fires up you get a lot of black smoke, then that is the likely the problem.

Gadget

 

it has nothing to do with the injectors I hope. I have run seafoam through them before. I gotta check out the fuel pump wire. Which ones are they? Its fishy to me to say its gotta be the pump setup other wise I think I would get more eratic idel at the starts. No matter is the engine is warm or not. But I'll try and test the pump lines and wires tommrow. Thanks for the info gadget.

BTW Gadget I was wondering about the o2 simulator. I need 2 new sensors. I buy a new front sensor do I need to buy a new rear one, or will the simulaator take care of the rear o2?
thanks and mahalo

 

When you ran the scanner, what codes came up (the number). If it just says no closed loop, there are more things than the oxy sensor that can cause that. How many miles on it? Does it have a working 195 deg thermostat?

 

Our rear O2 sensor design is unique and will only work with a properly functioning rear O2 sensor. This is so it will always pass emmissions.

You need a shop manual. Look up the diagnostic by symptom section and look up hard starting and follow the diagnostic proceedure listed to get you to the true problem as fast and cheaply as possible.

Gadget

 

thanks guys, I gotta check that out. I gotta go back to my mechanic to track down the exact code number of thats wrong. Thanks gadget I'll be contacting you soon for the o2s and the similator. Hey Yoda what other things came up in your experenises when it reads "no closed loop"