I have this 4Runners that I can get it to run very good even on snap throttle while is on open loop, As soon as it warms up it just dies.

If I could keep it running while is hot without going on closed loop I could try to read the ECU parameters and find out which one/s are causing the problem.

I would suspect that temperature sensors (AFM or Coolant sensors) but then it dies I can measure as quick as I can and do seem to be doing the job calling for closed loop.
I do not have access to OBD-1 Scanner.

Any ideas?
Thanks

 

Ideas? yes. provide enough information so that we can help you. i don't know what you drive. put that information in your post, or better yet, put it in your signature so we KNOW what year and engine you are asking about.

the 1st gen 4runner doesn't use obd-1. just a paperclip.

 

1995 4Runner A/T 2X 3VZ-E Quit 5 months ago on the road on a traffic light. Had engine light with codes 12 14 and others that cannot remember
Replaced:
New Distributor. plugs, HV wires, igniter, coil, Knock Sensor (now mounted on engine lifting ear-passenger side), starter motor, 2 used ECMs; new TPS,
Managed to run with a weird engine speed jumping back and forth from about 1700 to 2100 rpms
Checked fuel and all pump with banjo for a month and pressure 39 PSI always with regulator, about 45 without vacuum to regulator.
Found some air intake leaks by plugging every pipe connected to intake manifold I could find. (metal plugs to EGR) and took every VSV valve of the electrical connectors and vacuum lines. All plugged well.
Checked 5 Volts ref voltages and return signal to computer from TPS and Air Flow meter when cold and looked reasonable
Took plugs out and lots of rich burning, cleaned them and back
Primary volts at coil scoped and seems reasonable, HV ignition cope had show not very even firing voltages before cleaning plugs. Did not check now.
Starts cold idling well throttle very responsive, as soon it warms up runs like crap for a few seconds and quits. My assumption is tat goes into closed loop and sees something horrible.
No difference with paper clip ON or OFF on main data connector
No engine lights now.

Thanks for any help, otherwise car going to the junk. I am lost !!!

 

might be worth checking the brake booster vacuum line for leaks as a less obvious source of unmetered air.

 

Thanks wallytoo, I have done it and reconnected because it was not a source of leaks
Thank you

 

hopefully someone with a bit more familiarity with the 3.0 (3vz-e) will chime in. i guessing the issue can be solved with the proper troubleshooting/testing.

wally

 

You should stick with a single thread until your issue is fully resolved, you have several that are asking specific questions but all related to the original issue. This makes it clearer exactly what you are dealing with, and it's a good read also.

You could force open loop by putting a fixed resistor in the engine coolant temperature senders place.

You could force limp mode, or at least fixed valve VTA, by unplugging the throttle sensor.

There are also TE1 and TE2 which are used in some of the drive mode tests. Without digging through the FSM and TCCS hand book I don't recall which is for what tests off hand.

What ever happened with your ox sensor tests? Is it possible these plugs/signals got reversed such that your pre-cat sensor is sending to post catalytic? This will make the ECU max out its adjustment for fuel and not store a code because the engine stops abruptly I think.

 

Not a lot of details, maybe it's helpful.

 

Superb, I could not find that on my Service Manual.
I screen copy and will do right now, was ready to give up.
Thanks a lot.
Sorry about my bad decision to post each problem on a separate post, I thought if i did that i would be hijacking the original post. That I have been told on other Forums.

 

Thanks CO_94_PU; I tried one trip with that yesterday and but the time I quit did not get any MIL light. SO I figure it may take at least two trip for it to show up.
Early this morning i m taking advantage that it runs well while cold and take across the street to his owner. There I will run a couple more trips but it will be on his driveway and if no results i am giving up.
I am giving up. but here goes a not with thanks to all those members that provide assistance.

I really agree and feel that maybe more than one of the items mentioned on this forum are the cause of my nightmare.
And I thank you from the bottom of my heart for all the time and good advice you are providing.
But, and here is the but: I need to recognize that more than six month working on the car of my neighbor not only for free but buying myself some of the parts I replaced because I know his financial situation; is more than I can handle.
I have been checking voltages and resistances until the cows come home as some one said, and part of the problem not attributed to the car is that I am closing into the 82's. Never been a car mechanic but I have always fixed/maintained my cars since my first car.That is all my experience level
It has become every day more difficult to focus, to remember what values I read 15 seconds ago or what the heck was that I was doing.
I think it is time for me to admit defeat as much as I hate it, even ashamed that I have a BS in Mechanical Engineering I always felt it was nothing that I could not do, if others can do it, I could do it too if I was given enough time. Proved wrong here and now.

Today, a sad day, the car is going across the street and he will try to sale it on Craigslist. On more test I will do is the "Test Mode" as suggested by someone yesterday I cannot remember where. Using T2 and E1 jumped for enhanced diagnostics. I did one run yesterday and as always the engine run well, no misses, no lights. But It may take more than one "Trip" to pop up the light.
I have to admit defeat, and just give my elder neighbor his car back.
Sometimes I have thought of buying the car from him until I can fix it, many priorities with the family have been pushed to a second level just to work on this car almost like a blind person without a stick and limping.
I need to sincerely thank all the people that have taken the time, to help me even that most of the time they have seen that I was almost like a lost case.
I never posted anything because it would only be armchair thinking and would run other people on the incorrect path.
But I appreciate those on those on this and other forums trying to understand what I meant, and make sense of sometimes meaningless question. Got also good chuckles and learning many times reading the bottom quotes of seasoned people not only in life but also on the profession.
Thanks to you all , tat have done a wonderful job at opening some path for soles that kind of on the clouds.
I am posting a curiosity, a pic of my first car in Montevideo-Uruguay. Ford Model T 1925 that I bought when I was 18 from a chicken coup and myself re-bored the block to fit scrapyard Ford Model A 1931 using eccentric bushings at the piston main pin to accommodate longer old "T" connecting rods.Not related but probable a chuckle to some.

Thanks to all,
Wilson (Fermin is the distressed owner)