nashulee

Howdy,
I have a 89 4runner with an 22re that has about 7k miles on it. It develops a miss under when under any sort of throttle after it has run for about 40 minutes. The truck is not over heating, the temps have been verified by the temp gun on the head when it is run this long and I am getting pretty consistent temps at around 195 to 200 degrees.

It seems to run pretty darn good until about the 45 min part. This is my first Yota, so I don't have anything to compare to. When Cold and first half hour of running, it feel strong at first take off, seems to let off a little around 2300rpm then picks back up at around 3100RPM. It runs smooth as a baby butt down the highway almost all the way to work for me, then at almost the same point it starts to hesitate and when if I throttle down it bogs coughs and spits.

I have had the truck for about two weeks. It has been doing this all along. Last week the miss under heavy throttle turned into not running at all even when cold and after some investigation, I found that the rear injector wire clip was broken and the rear injector was not working. I am ordering some new injector clips and pig tails as soon as I can find them. For now, that rear injector clip is zip tied on.

I am getting a code pop up as as I start to drive, but when the code pops up the truck runs great. It is not until I have driven for a while that it starts acting up.

Any help or direction I can get from yall would be great,

Thanks

Rerunn

Hm a miss under load could be spark related. At 7k is it a rebuilt motor?

bbrideau

sounds like a wiring fault in dizzy, my truck used to have intermittent issues and i would get an engine code i think it was 12 or 22, no rpm signal something. have you tried to pull the code? it could be something non related to your problem but it might also help, vague as the obd 1 codes are they can sometimes help to isolate issues

bruno4turbo

check that you have NKG plugs, if you have any other brand they aren't OEM and they can cause problems.

if its a fresh rebuild, like 7k usually means, if you have NKG and they aren't fowled (look horrible) then it can be your CPS (crank position sensor), or TPS (throttle position sensor) they don't cause a miss, but on my dad's truck (ford), and sisters car (nissan) they would "stumble" under hard acceleration until we changed those.

theres many things that cause an engine to miss, or stumble. since its a time sensitive thing i don't think its a vacuum or mechanically related since it would be apparent more often than just after 30-40 min.

don't just start throwing parts at it hoping one will fix the problem. look around for any loose components, a loose ground wire, bad/dirty electrical connections, if any of your plug wires are loose, or rubbing up against anything (exhaust manifold loves to eat wires... had that problem)

may be a vacuum line not routed right, when i did the rebuild on my 22re I had to guess the vac lines, and it would get a stumble every now and again, until i got all new lines and figured out how to rout them right.

pix or your engine would be helpful, sorry if it seems I'm throwing things at you, just trying to cover the bases. good luck!

snobdds

If this only happens when it goes into closed loop (or when the engine is warm), then it is some sort of sensor problem. Start by checking the coolant temp sensor that goes to the ECU, not the dash.

The sensor may be cycling between telling the computer the truck is hot and cold. When the truck is warm, it runs in closed loop and all the sensor dictate the fuel, air etc. When in the truck is cold, it runs in open loop and runs off pre-set fuel, air settings. When the sensor fails, this cycling makes the engine miss when going from one setting to another.

Always start with the temp sensor if only a miss when the engine is warm...

nashulee

Man, Thank you both. That is great info and I will head that way. It is the sort of direction I was looking for. I will post some pics this afternoon or tonight!

nashulee

By the way, I did pull codes, and it is giving me a 51 and 52

The thing is , it throws the code as soon as I start to drive. But it is not running bad when it throws the code initially. So here is my plan tonight.I would like to reset the computer, clear of of codes. Then drive it and when the light first comes on im going to check the code right then. I am very curios as to weather or not it is throwing both codes at that time. I don't think it is because it still runs good, it does not run like its in safe mode. But then later on after I drive I while, I think something else is tossing code and thats when it goes into safe mode. I thinks that's why I am getting the miss because if I understand right, in safe mode it retards the timing 5 degrees and I think the way the timing is set on this motor. its too much.

bbrideau

52 is knock sensor, once that comes on it retards timing and makes you run pig rich. 9 times out of 10 its not the knock sensor that is faulty its the wire that goes to it that goes brittle. I think it actually retards it 15 degrees, i could be wrong on that one but i know its a major lack of power when it does it, pull the cables off your battery and wait a few minutes before putting them back together and take it around the block a few times see if the codes come back

nashulee

Well, I found that the knock sensor is broke in half. It looks good, but when I touched it, the wire just pulled out of the sensor along with part of the sensor itself. Hmmm, is that baaaad???? I am looking for another knock sensor now.

bbrideau

I actually have another knock sensor in my garage if u end up not finding one, i suggest getting one from a wrecker if u try to buy one at a parts store your looking at about 300 dollars, i lucked out and paid 10 dollars for one at pick n pull for my truck and got a freebie from another wrecker.

nashulee

Well, I replaced the knock sensor and it is running 1000 times better. However, it still develops the miss after about a half hour of driving. More ghost chasing