Crewton

Hey everyone!
This is my first post for I have just joined yotatech! I recently have bought myself an 86 pickup 2.4 22re. When, I bought this truck, the efi was all working fine, but now I'm having a problem i think with one of the injectors running too rich. #3 is only firing when I accelerate. I know the cold start injectors have problems in these trucks so we unplugged it since its the middle of summer, but it still runs rich. I checked my spark plugs and when I pulled out #3 it was all charred, so I cleaned it, and I swapped it with another from #2 (it was clean and no problems) to rule out the possibility of a bad spark plug, but it did the same thing. I'm wondering if the injector is shot, and it's injecting the wrong amount into the cylinder throughout the rpm range because you can smell the engine running rich. I am having no problems with the other cylinders and they are all running correctly (while vehicle was idling I pulled off and put on spark plug wires one at a time) Could it be the injector? If the computer was shot would it not mess up the other injectors? Any help would be much appreciated! Thanks guys!

Also, is there a way to run a manual diagnostics check instead of using a OBD2 computer? My friend was telling me about a way to do it so if you engine light is on, it will blink a certain number of times according to whatever is wrong with your engine. Thanks again!

bob hennig

a compression test or leak down test will tell you the condition of valves and rings. You never mentioned you changed the plug wire or checked the cap rotor for continuity. Make sure spark is reaching its destination. Also, a can of BG44K is the best injector cleaner I have found and if a pattern issue it will clean up, also the carbon in valves and cylinders. good stuff. Just follow directions. great motor, longevity. Happy motoring!

Crewton

Would it not be kind of pointless to replace the spark plug wires, if sometimes when I start truck it runs fine, but other times its not firing at all or sometimes it fires are certain rpms? For the most part now, it misses as soon as you engage the clutch and the engine has a load on it. I've tried swapping the computer with my friend's to rule that out as well, and still the same thing. I'll try that cleaner you suggested and me and my buddy will do another compression test. It's so odd, before we bought the truck we did a compression test and they all came through around 143-148 which we figured was quite a nice grouping. I've barely had the truck a month when it first started doing this lol.

bob hennig

Thats the time plug wires show a miss, under load, when the voltage spikes are highest. The electricity seeks the closest, best ground which many times is somewhere along a broken down, overheated or cracked cable. Cheap insurance

Crewton

Alright thank you! I will try that tomorrow morning before work and see what I can come up with! I've used injector cleaner before, an additive to my gas when I first bought the truck because I figured it wouldn't hurt. But i'll let you guys know! Thanks for your help so far!

blake.nemitz

my old 22re had a similar problem. it was the injector on #3 and it ended up being in the harness where it splices with number 2. they run in paired pairs 1 and 3 , two and 4. blue wire if i remember correctly about 7 inches into harness from injector

Crewton

K, so I swapped spark plug wires, checked the wires running to my injectors, and soldered them. And still nothing has changed. Me and my friend are going to do a compression test tonight and if its showing low in that cylinder, then I guess I'm tearing into my engine lol. Does anyone know anything about how to do a manual decode for the engine light? if it is possible to do, because the engine light stays on so I'd like to see if that would show me where to check or if it is just like 80% of the engine lights out there that come on all the time.

ChefYota4x4

iTrader: (5)

I believe the 86 diagnostic 'yellow dummy plug' is in the passenger side fenderwall toward the top. there is one right next to it as well. The diagnostic one has two wires and you would check it by looping a wire from one prong to the other...then turn to key to on, DON'T START IT, and see how many times it's blinking. Then, look in any of the manuals(Haynes, Chiltons, etc.) and match the codes your 'flashing' with that in the book.(you might want to clear the codes, first, then run it, then check again for codes....because every time you disconnect something, ...it stores a code...Pull the EFI fuse for 15min. and they'll clear....after all, you don't wanna start replacing things that are only signaling codes because you've disconnected them, right? lol)

The "wires" suggestion is very true, but you've eliminated that, from what I can see. Also, your coil, pick up in the dizzy, secondary and ignitor, from what I know, can also cause problems under load. My rig does the TOTAL opposite...under load, it's GREAT...no pinging, etc.....but at idling, it misses. My Code is O2, and after a few tries with quite a few guru's, we're still having trouble tracking down my miss, etc....

I mention this to encourage you to press on to the next in the P.O.E.(process of elimination)...and, well, to STOP YOU FROM TEARING THE WHOLE THING DOWN, lol....don't do that just yet, ok? These guys are great on here, ...they'll come through, if it's 'net-diagnosable', lol. Your compression is pretty dang good....that's fairly fresh/tight on the compression end.

Crewton

So we cant find that diagnostics plug, the manual is confusing about the explanation of where this plug is, because it leads us to 3 or 4 other plugs. We also did a compression test and it came up as this

1. 135
2. 140
3. 115
4. 135

The #3 cylinder is the one that is only firing sometimes, and the compression is kind of low, but it should not be low enough to not fire. I'm thinking about doing a swap out with a completely different efi wire harness, and see if the problems is somewhere else in the wires. (looks like the previous owners did a lot of homemade wiring) I am sure I could find a new harness for not too expensive either around town or on the internet.

ChefYota4x4

iTrader: (5)

Not TERRIBLE, but that's actually quite a swing. If you have time, I guess it can't hurt to verify your harness, etc....just BE DANG SURE you don't forget to mark EVERYTHING, lol. But first, I think there are other things I would be checking. I'm going to find the thread asap and post the permalink for you, here, so you can figure that out, first.

One thing codes wont tell you is WHY you have such a gap in compression on #3. 20-25 pounds, Crewton? Could very well be the valves for that cylinder are way out of wack. It could also be a bad ring, but first, you'll need to do a wet test to see if that cylinder comes up a chunk when adding oil to it. All plugs in but that one, and a few squirts of oil in there, ...then crank it over 5-7 times. If it comes up to 130-135, ....that's definitely a sign of either rings or valves, ok? It's not a matter of 'not enough compression to fire', ...rather, it could be too much oil leaking past the rings or bad valve alignment, where they're not opening at the right time, or not enough.

Also, "not firing".....are you verifying this by the #3 Pipe of exhaust not getting as hot as the rest, .....or what???

In regards to the wire/plug for the diagnostic port. Look on the fender wall, above the steering pump....you should have 2 plugs next to each other. I believe one should have 3 wires going into it and the other should have 2. The one with 2 is THE DIAGNOSTIC PLUG. it doesn't plug into another connector, ....it plugs into the fenderwell, on the driver side, next to another yellow plug that also plugs into that fenderwell, ...ok?

I"ll try to find the pics, but I'm very tired after a 16 hour day and need to rest. I WILL find it though, just hold up on tearing apart the harness, etc., lol.

ChefYota4x4

iTrader: (5)

https://www.yotatech.com/forums/f116...l#post51484730

Read though this link/post and the few after it, ok? ^^^ is the name of the thread, before the 214936. You should be able to go through the thread from that permalink, but if not, just search in 'new posts' for those words.

Best wishes, ...hope you're able to figure out the codes

Crewton

Thank you very much for the help! I've verified that this cylinder is not firing by hearing it missing. Power loss, and a kind of chugging sound. When we undo the #3 spark plug wire, the engine does not bog down, or change while it is idling. I'll check out that post and go from there. I'd like to check valves, that was actually one of our next steps in me and my buddy's process of elimination. Also, a new wiring harness goes for around $200>.< not going for that much money yet lol. I'd rather try to find a parts truck, or get it off another efi truck. Thanks again!

ChefYota4x4

iTrader: (5)

Do this, Crewton, ok? ......Have someone start the motor, while you keep your hand on the #3 Pipe. Start tapping your finger on it after a few seconds as I'm not trying to get your burnt, lol. Also tap the others, next to it, and be sure that it's 'COLDER' than the rest as it's initially warming up. I had spark at my #2, but NO FUEL, ....and so after discovering it wasn't heating up, I had to first check for spark, ...then moved on to fuel, where I discovered, FINALLY, that I had power to the #2 injector(using a noid light kit borrowed from kragen-o'reily's), .....thus, I had to tear down the intake again to get that injector out, where I discovered by walking into RC injectors, "We pumped it and after 3 seconds and a gentle rap on the bench a bunch of brown goo broke free...it's fine now". And it's been fine ever since. Something in my fuel line beyond the filter, or from the damper, broke free, finally, and clogging my #2 injector on THE FIRST FIRING AFTER A FRESH BUILD! GRRRR, lol.

I mention this because MULTIPLE things can go wrong that are FREE to verify, eliminate or confirm as 'bad'....and some are FAR less labor intensive than others. Your compression level on that #3 doesn't eliminate other issues like spark, fuel, etc.....but IT DOES, more than likely, point toward one of two things, ....Rings or Valves being off(or damaged).

Check the codes, FIRST, but don't be surprised if there either aren't any.....or rather/also, if there are, ....if they really have nothing much to do with the #3 being low.

How are you verifying, Crewton, that #3 is misfiring? ....By guessing, due to low compression? I only ask, because later model toys are the only ones equipped with more advanced diagnostics, some of which even can tell the owner, "Misfire in #4", etc., ya know? Pulling the wire to #3, I'm guessing, is how you're narrowing it down, right? So now, take that #3 wire and lay it somewhere away from sensitive sensors, etc., and place a screwdriver with a rubber handle up to the connector in the wire(not touching) and see if it arcs. Just don't hold the wire, hahaha. It helps if it's dark. I have a wire tester, which actually lights up a bulb while attached to the wire, when the wire is good. I think it was 8$ on sale at Kragen, lol.

Best wishes on the valve adjustment, READ IT CAREFULLY to avoid doing it improperly.

PS> I mean NO OFFENSE if you know much of this already....how would I know either way, right? lol. Trust me, I'm just learning over the last few months, ...so I'm just mentioning things you can check/test that cost ya nothing, in case you didn't know.

PSS> I remember you saying you pulled #3 plug and it was charred, right? That is very telling, and you can find all kinds of info and even pic's in the manual that will tell you what to look for when you find plugs like "this, or that", etc.

Crewton

Another thing you can do to test the spark in the plug is just taking the wires off all spark plugs and taking out a spark plug, connecting it to the wire and while having someone ground it out holding it with insulated pliers turn the engine over. We did that and it was sparking. Now the spark was orange, and according to spark plug spark guide:

Red is dead
Blue will do
White is right

Orange probably is not the best colour. So it might even be that. But what does not make sense, is the fact that sometimes it fires and runs smooth, but other times it does not. Sometimes when it has a load on it, it fires and sometimes it does not. Sometimes when its idling it fires, and sometimes it does not. You can really tell by how choppy the engine is, it noticeably changes when it does and does not fire.

Crewton

So after a lot more trial and error (even checking to make sure the o2 sensor was grounding properly), I think I've come up with the solution. The engine is loping under acceleration and when idling the rpm changes slightly back and forth (about 200 rpm difference). So I think this is pointing toward a TPS. Hopefully I've finally found the problem anyway

mheinle

I am curious if the TPS did turn out to be the problem here. I have a 99 4Runner that is loping at acceleration only at slower speeds. I have changed Plugs, Wires, Cleaned MAS with no luck. I really noticed the problem after replacing the rear CAT and forward O2 sensor. So far it is still acting up when accelerating.

myyota

The TPS won`t keep the injectors from firing, like chefyota said, you could have a bad injector, but that`s just a guess.

mheinle

Thanks for the reply...Good to know it is not the TPS I don't want to waste time on dead ends. I am going to try throwing some seafoam at it since that appears to work for others. I will also try cleaning the throttle body out to see if it does anything for it. I peeked in there today and it has a decent coat of crud but nothing to impressive.

Crewton

Yeah, well I figured I would try it. Rule out absolutely everything right? Otherwise you might miss something silly haha.
Basically now, as far as I know I've ruled out everything except the timing chain skipping a tooth, or a valve or an injector. I don't think it could be an injector now. I went down to a local injector and turbo charger specialist shop and talked to the guy there and trouble shooting with his he says it does not sound like an injector, that it sounds more like valves not opening properly.
When I let off the accelerator you can hear a rattling sound, like a constant "ssszzzz" but as soon as you accelerate it goes away. My friend says it sounds like it could be the timing chain so when he comes back from holidays were going to check that out and if that is not it, sounds like were going to pull the head off and get the valves reseated and checked, make sure they are in proper working order and are not broken and sealing properly. While that is all apart I'm going to check the injector as well just to rule that out too Thanks for your feedback guys its been helpful to have some more troubleshooting input! Good luck on your never ending problem with your yota too Chef!! Yeah, well I figured I would try it. Rule out absolutely everything right? Otherwise you might miss something silly haha.
Basically now, as far as I know I've ruled out everything except the timing chain skipping a tooth, or a valve or an injector. I don't think it could be an injector now. I went down to a local injector and turbo charger specialist shop and talked to the guy there and trouble shooting with his he says it does not sound like an injector, that it sounds more like valves not opening properly.
When I let off the accelerator you can hear a rattling sound, like a constant "ssszzzz" but as soon as you accelerate it goes away. My friend says it sounds like it could be the timing chain so when he comes back from holidays were going to check that out and if that is not it, sounds like were going to pull the head off and get the valves reseated and checked, make sure they are in proper working order and are not broken and sealing properly. While that is all apart I'm going to check the injector as well just to rule that out too Thanks for your feedback guys its been helpful to have some more troubleshooting input! Good luck on your never ending problem with your yota too Chef!!

mheinle

So I went ahead and cleaned my throttle body with no change. I really did not notice this until after the the fron O2 sensor was changed. Could this cause the issue? I am no expert on this by any mean but if the O2 sensor monitors the fuel/air mixture and can tell the injectors to put more fuel in if nessesary is it possible it sends a lean signal the injectors compensate causing the O2 to see a rich mixture and then tell the injectors to lean out? This process just going back and forth during the acceleration. Maybe a stretch I don't know.