Thatguy256

Here is what going on, day one I noticed the truck was sputtering 3 cranks later that day and the truck wasn't even able to move but still ran and sputtered. Day 2 went out to truck tested the sensors reset the ECU and now the truck just starts then dies. If I touch the gas the truck will die immediately. Thinking it might be the Throttle position sensor, i put a new one on no change returned the new and put the old one back on. The truck is pulling no diagnostic codes. My gut is thinking it could be the Mass Air flow but with the test being so close to acceptable and no engine code makes me thing the problem might be simple.

I have tested the throttle position sensor, MAF, pulled a plug there is too much fuel, cleaned plugs checked ignition system. All test came out good, MAF tested at 195 ohms which is barely under the 200 to 400 accepted measurements.

Burns85

sounds like the same problem mine is having. im subscribed to see how your problem works out

wickedlowss

My truck was doing the same thing, my o2 sensor was shot. The insides were sticking out out of the holes.

Steve777

Sounds like what I am looking at on my 87 4runner... Be interested to hear when you find out the cause.

rube

sounds like your injectors arent firing and its starting off the cold start injector. theres no way to know if there firing or not unless you have a noid light which i highly suggest you to get because there cheap, available at most part stores and quite handy to have around.

rubes list 'o things to check
-soleniod resister
-coolant temp sensor
-afm
-ignitor
-tps(make sure you adjust it to spec)
- make sure the rubber elbow on the t-body isnt cracked ect and leaking
-check and clean the grounds especially the one that goes to the plenum.

hope this helps get you started!

Burns85

haha, funny thing is I am waiting on a set of headers (with O2 port) to come in. My current setup is O2 sensor welded in (PO was a hack) and the thing is absolute junk so I have a new sensor and then we will see what happens. right now it seems to drown itself in gas

Steve777

Could be wrong, but I doubt the O2 sensor is involved when the engine is first started and cold. It doesn't take part in the regulation until the engine has warmed. [no doubt others will chime in here if I'm wrong].

BTW on my truck, I pulled the O2 sensor out of the manifold and it made no difference (did this to see if maybe the cat was plugged).

Thatguy256

Clogged fuel injectors have crossed my mind along with a possible bad fuel filter. The one thing that makes me thing otherwise is when i do pull a plug there is a nice coating of fuel on them. And given the fact it seems to be happening to on all 4 cylinders makes me think the chances of all 4 fuel injectors going out at the same time unlikely. I got a known good MAF sensor ill put in today and see if it fixes the problem. Iam planning on gettin a fuel pressure tester today and test the pressure as well if the MAF doesn't fix it.

Thatguy256

Having a bad 02 sensor will cause your care to burn rich after it has warmed no big deal except after a long time you can clog your a cat up. In reality the 02 sensor has such a small role to play in the air fuel ratio its trivial. Yes your truck will run better if it replaced not to mention the check engine light will go away, and you will get slightly better gas mileage. Which leads back to what i believe my truck is doing, it is getting a wrong air input and therefore isn't giving the truck enough gas for the amount of air coming in to the point it is dieing meaning a big sensor is out. MAF it gives a pretty decent estimation on the total amount of air entering, TPS fines tunes it a bit more.

Thatguy256

Think i found the problem... Bad fuel pump. Put the new fuel filter on and now she is sputtering which is better than what she was doing before, leading me to think it is a fuel pressure problem. Hope it isn't my pressure regulator so its time for the lesser of 2 evils the fuel pump. Going to get a pressure tester first and verify.

Thatguy256

After replacing the fuel pump, fuel filter and still no running vehicle i did a pressure test all tests good. did a noid test on the fuel injectors all good. Unpluged the cold start injector then started vehicle rougher start but still ran the same as before. Went to starting the vehicle with a spark plug wire pulled one by one. Second and third plug caused a minimal change. Spark is good plugs are good. Pulled the fuel injectors all the injectors screens where clogged expect for one the screen had completely collapsed. Ordering some reconditioned ones today expect to have the truck running again next week. I sure hope so anyway after having a completely rebuilt fuel system.

Thatguy256

Well now i new problem has arrived she starts then dies after 2 secs no matter what i do. I have replaced every part in the fuel system. When you jump the fp and B+ to keep the fuel pump on she will start and run all die... a bit rich and definiatly not a fix. I know the MAF could cause this problem is there any other suggestions as to what can fix this.

sam333

When it dies do you still have spark and fuel?
What were your injector screeens clogged with? Rust? You may still have junk in your tank and its clogged again.

Steve777

Hey 256, if your "start and run all die" was supposed to be "start and run all day" with Fp jumpered, then the fuel system can work, it's just not getting a signal from the AFM.

Could be that the AFM just broke, or the wiring/plug to it, or that you have a loose/open/broken air fitting, so that the AFM door isn't being sucked open when the engine is running (that door being open is what generated the fuel pump signal after you stop cranking).

I'd probably do a recheck of the AFM resistances, especially the fuel pump one. If that is OK, then air leaks or wiring. IIRC jumping Fp is the same as the fuel pump signal from the AFM, if so then the COR relay and rest of the fuel pump wiring are OK, it's just that signal from the AFM.

Then again, if you did not mean to write "all day" then this is just a big nevermind...

sam333

HaHa, I couldnt decifer run all die.

jordang1028

Ever find a solution? I'm having the same problem. Just did full tune up, and fuel filter...still barely runs and dies after 10-15 secs of idling and surging.

Cadin

Post thine remedy, si vous plait! Gracias, Merci, Danke, Xie xie ni, Thank you!

Colombo

I can almost assure you it's the AFM. I resurected a 94 4Runner with a 3.Slow and when I tried firing it up just after putting a remanufactured motor in it, it did exactly the same thing. Start and immediately die.

I can't remember how I figured it out, but I believe I measured the resistance between the contacts with a multi-meter and compared my findings with the FSM. In any case, I got a junk yard AFM and put it on in about 5 minutes, and poof... it ran like a top!

Just fyi, when I was swapping parts from the old motor to the new one, I cleaned up everything real good in the parts washer... yes, INCLUDING THE AIR FLOW METER! Duh! So I'm sure the problem with mine was due to me cleaning it.

Hope this helps! If you need help with how to diagnose it, feel free to send me a message.

Start by downloading a FSM for your specific truck here:
http://www.ncttora.com/fsm/index.html

Then, find the section on diagnosing the various sensors and components. It's pretty straight forward.