Car: 92 Integra
Engine : b16a w/ bolt ons
Tune : Crome for e85 (tuned last summer)

My car has been running extremely rich under VERY light throttle.

So a little more then a week ago I installed a Walbro 255, car had been running fine up until yesterday.
Yesterday I was below e so I drove 10 miles to Valaro where I get my e85 from, car drove fine on the way over there. I then got about 5 gallons and drove another 5 miles to a car meet, car drove fine then as well. It wasn't until a few hours later when I left the meet and drove home that the car started acting up and running super rich.

Here is a video of what my a/f gauge shows

Today, I drove to another meet with it running rich. I reset my ecu at the meet thinking that might fix it, but it didn't. When I left the meet it started running rich every time I barely touched the gas. At idle it started randomly doing it as well. Some times it would stay around 14.7 and other times it would just go all the way to 10 (my gauge only reads to 10). The car bogs down when it's running that rich and at idle the rpms sit super low and it tries to stall so I know my gauge is reading correctly and it's not a false reading.

I don't why it's started doing this, but my thoughts are either I got a really messed up batch of e85, I've got an injector that's sticking, or my tps is off. Any ideas or help would be greatly appreciated. Thanks guys

 

you have an open loop tune don't you?

they are finicky and need to be changed depending on the season as well as any mods

closed loop is MUCH better for part throttle driving

 

Nope it's a closed loop tune. I made sure my tuner did that cause of how much the temps fluctuate here in texas

 

Welp, it's not my tps. It's at 0.510 at idle & 4.60 at wot. I guess that is off by a tenth, but that wouldn't be causing my problem. The voltage went up smooth without and drops or spikes so it's not that. Guess I'm gonna pull my injectors and test those to see if any are stuck

 

Took out the injectors and cleaned them out, didn't hear any of them sticking open or closed. I swapped map sensors and the car still runs richer than what my gauge can register. Doesn't do it constantly though. It's a random occurrence. It'll do it for a couple minutes, then it wont do it for a minute or two, then it starts doing it agian

 

is the o2 working? if the o2 fails you will default to a 10:1 AFR, actually there are a few things that can trip safe mode which is the static 10:1 ratio.

if your fuel trims in closed loop go one way or the other too far this will also set you at 10:1

try pulling the battery for a minute, hook it back up and see if your AFR comes back.

 

you've checked for codes?
so it only does this in around 1 load window? ie, a specific rpm, vehicle speed, and throttle position? or is it doing this at all different windows?

 

Check o2 voltage for normal closed loop activity, which it obviously isn't. I would start with a new or known good o2.
Not to hip on the E85 stuff, but it might be a possibility that o2's life span can be shorter with the use of that fuel. Maybe Racebum can chime in on this???
Also not to sure on the consistency of E85 fuels.

 

i would call www.englishracing.net on the e85 question. myles usually answers the phone and has a massive amount of exp with e85 and hondas/tuning

 

I have not checked the o2, but i'm about to get up under the car and do there once it cools down. I haven't checked for codes, normally my cel would pop on if there were any but I will check in a bit

I doesn't just do it at a specific rpm or speed. It will do it in any gear, any rpm, any speed, any time i'm part throttle.

This is what I did today after taking it to a friends house for advise. I swapped the fpr and it didn't fix the problem, I swapped the iat sensor an it didn't fix the problem either, when I got back from driving around the block after that it started doing it at idle and I was able to get a video of it.

(During this video I did NOT touch the gas or anything else. What you see is what the car is doing all on it's own)
http://www.youtube.com/watch?v=bGkzK...ature=youtu.be

 

Looking at the o2 removed will not reveal any type of failure.
I would just monitor the voltage to see if readings and response are consistent with that of a known good o2.
I would also check voltage to make sure closed to open loop transition is also consistent with that of a known good part

 

Yea the o2 was just covered in black soot, but the wiring was fine. What I did notice was both the pins in the clip on the o2 side and the wiring harness side were really corroded. Two of them looked alright, but the other two were coated in a green build up. Similar to how things look if they've been sitting in the ocean for a long time. I went ahead and cleaned all the pins with some wd-40 and a wire brush. Well while doing that to the clip on the harness side one of the pins that's inside of it fell out... I pushed it back up in there, but 2 or 3 of those pins in there looked like they were moving around or broken from all the corrosion. I went ahead and hooked the o2 back up and didn't get any cel when I started the car. I let it warm up into closed loop and all was good. I drove it down my street, all was good. Turned onto the next street, and then it started running full rich again. It seems to run alright for the first couple minutes as i'm driving. After 5 minutes it just goes rich. I have a feeling that o2 connecter on my harness with the messed up pins is my problem. I think i'm gonna need to hack up the harness put a new connecter on it and buy a new o2 sensor. Any thoughts on that? Thanks

I know that was a lot, hope it wasn't too confusing...

 

absolutely could be causing your problem. the o2 signal is highly sensitive, reading mV. if you've got corroded pins the voltage could be read as lower, the ecm will see that as lean.

try running with it disconnected. see if the bogging and low idle subside

 

Ok so I unplugged the o2 and as soon as I fired it up it threw a cel. I let it warm up, it went into closed loop and the afr bounced around from the mid 11's to near 13. The idle was also erratic and bogged down and up. I guess the pins in that o2 connecter are alright since it wasn't throwing a code before. They're clean now, but the problem is still there.

I took the pcv valve out and cleaned it, put it back in and there wasn't a difference with that either. I guess my next step now is to get a new o2 sensor. I can't think of anything else it would be

 

Ok so doing some research apparently a bad ect (engine coolant temp sensor) can cause problems like this without ever throwing a cel. In my head I can see this causing my problem. If the ect acts up and tells the computer the engine is cold of course the ecu is gonna dump more fuel in. I looked up the part numbers and it appears both my b16 and my b18 in my other car have to same ect sensor, so I'm gonna swap the known good one into this car tomorrow and see what happens

 

how can the ecm be going into closed loop with the o2 disconnected?
how are you figuring that because the o2 disconnected causes a code and having it connected doesn't, actually qualifies the o2 signal? it doesn't. you're not understanding what the code setting criteria is for a primary o2 code to be thrown.
i'll explain a few important points to you here;
first. no MIL does not mean no code. did you check for codes BEFORE you went ahead and disconnected the o2 sensor? that would have been key, since now you'll obviously have an o2 code and won't know if it was from before or after you'd disconnected it.
second. on a scale of 1 to 10, 1 being the car driving perfectly normal and 10 barely running, a persons complaint will be at about a 3-4. a code being stored, active or pending, will be at about a 5. an MIL will be at about a 7.

anytime you have a code you must first understand the criteria for which it is set before you can begin to diagnose it. and that criteria does not change. ever.

but anyways, back to the topic. so you're saying that with the o2 disconnected, it still ran like crap?
yes, a bad ect can cause an excessively rich mixture. but so can A LOT of other things.
but rather than just replace it and see if it works, why not test it? matter of fact, you could have quickly tested all the parts that you hung on this problem with a simple multimeter.
an ect will read high resistance cold and low resistance hot. just like an iat and just like most other temperature sensors. this is what's known as an NTC sensor. negative temperature coefficient. the exact resistance value is not all that important. just that when cold, it will read high. probably around 10Kohms. when hot, it will drop waaaay down. probably around 20ohms. so test resistance first cold, then hot. see what you get. if you get a high resistance value when hot, you know it's bad

 

Ok that's a lot of info for me to take in.

Let me start off with the closed loop thing.
I believe my car is going into closed loop with and without the o2 connected because of the rpm drop my car does when it goes into closed loop. It's sudden, abrupt,and I can see and hear it. It's been like that ever since I got it tuned...idk why it just does that. It's a very clear thing that I can easily get on video if you'd like to see what I'm talking about. I don't think it's a normal thing, but I've never had an issues with it being like that.

The cel code thing.
I don't know what "MIL" stands for, but I did check for codes yesterday (Sunday) and the only code I had was #20 for the eld. Which I've always had cause my car doesn't have an eld. My tuner turned that off in the tune so the cel wouldn't come up unless I checked for it. I should of mentioned that I had already checked for codes, that was my fault for not doing so.

The o2 being disconnected.
I unplugged the o2, started the car, it threw a cel as soon as it fired up. I let it idle for however long it was until it came up to operating temp and I heard it do it's thing I mentioned earlier which I believe is it going into closed loop. At that time the rpms began to bounce up and down along with the afr (rpm 300-800. afr - 12.2 13.0). I figured then that clearly the o2 being unplugged wasn't helping, so I shut the car off. I NEVER drove the car with the o2 unplugged. If I should of...oops, again my fault for not doing so.

The testing that I did on the other stuff.
I did use a multimeter to test my tps. The reason I didn't use it on the map, and iat sensor was because to me it was just easier to pull the known good ones off my other car. Same thing with the fpr, I just swapped it with the one on my other car. None of that helped so I put everything back. (other car is a 91 db1)


I will test the ect tomorrow with the multimeter like you said. If I need to drive around with the o2 unplugged I will do that also (I left it unplugged for the time being). I'm trying to make this as least confusing as possible, but I know that's not always doable, so I appreciate you working with me here. I'll keep you and anyone else looking at this posted as I continue to work through this.

 

MIL= malfunction/money indicator light

you can not go into closed loop with the o2 disconnected. the o2 provides feedback to the ecm in order to make fuel trim adjustments. this is closed loop. i'm not sure what you're experiencing, but it isn't closed loop.

if the problem was still occurring with the o2 disconnected, and you know it was, then driving it while disconnected isn't necessary. it's not the problem. unless the wires are shorting.

i guess you can't datalog with this setup, huh?
i wonder if the tuning is an issue. although, i can't really see this just happening out of the blue if it were.
water build up is a concern with e85 and ethanol. how much fuel is in there now? have you tried filling up the tank since?

 

Lol @ the money light. The closed loop thing makes sense, idk what my car is doing then. I'll get it on video just for the hell of it.

When the o2 was unplugged and the car was idling, it didn't do what it did in the video I posted before (full rich @ 10.0), it bounced around in the 12's. I think in order for me to see if it still runs rich with it unplugged I need to drive it. I'll get a video of that as well.

I could datalog...if I had the datalogger. My ecu is set up for it and I think i'm going to invest in one now.

Every other part of the tune seems alright like the wot, start up trim, all of that so I don't think the tune would just drop or mess up one part of itself. Idk for sure on that though.

I've never heard of water pooling with e85, but I know people have gotten bad batchs before. That was one of my first thoughts cause this started happening after I got that half tank of gas last Thursday, but I let that run down below E and got fresh gas from another station on Sunday morning and the problem is still here. Don't think it's that. I did clean the tank out a few weeks ago when I put that Walbro in so I know the tank is clean.

So tomorrow aka today now it's 2am i'm going to
-check the resistance on the ect when cold
-check it again when it's hot
-get video of it right when it does that idle drop thing which I thought was closed loop (o2 plugged & unplugged just cause the afr acts different)
-drive the car with o2 unplugged and see if it still goes to full rich (afr 10.0, that's as far as my gauge reads which is why I call it full rich)

I think that covers what I need to do next...

 

hmm. yea if you cleaned the tank out recently, water wouldn't have accumulated that fast. if you're already set up for datalogging, you should definitely take advantage of it, whether it helps in this case or not. that o2 connector being corroded is highly suspicious. especially since you said when you disconnected and reconnected, it ran good for a short period. take it for a drive disconnected and see what it does

 

Ok so far today this is what I have done.

Unplugged the ect sensor and tested the ohms when the coolant was cold (sitting over night), I got a reading of 2.5 kohms. I'm guessing the coolant temp was around 60-70 degrees based on the temp in my garage. So according to my acura shop manual that's what it should be around.

I then let the engine fully warm up, checked the resistant again, and got a reading of 360 ohms. The acura shop manual says it should be between 200-400 ohms, so again I'm guessing that is correct.

I then went ahead and started the car with the o2 still unplugged and got a video of it as it warmed up to that temp where my rpms drop and do that thing that I thought was it going into closed loop.

I then shut it off, plugged the o2 back in, reset the ecu, and started the car. I got another video of it warming up to that same spot, but this time it slowly went richer and richer up to 10.0. I'm actually surprised it did this at idle right off the bat, because normally it doesn't so this at idle. Normally it only does this when i'm driving. I'd say 95% of the time while driving, 15% of the time at idle so i'm glad I was able to get this on video.

When the car is acting normal, it warms up to that certain temp, the rpms drop down, and my afr is steady around 14.7 along with a steady idle of around 800. I'm not saying this rpm drop thing that I thought was closed loop is a bad thing or a problem. I just wanted to show you what it does, and how it acts different with and without the o2 plugged in.

Anyway here is the video of that

I just drove around (while waiting for ^that video to upload) with the o2 unplugged. I stayed at a very light throttle most of the time since that's where the problem is. The car still ran rich, but it did much better. It didn't just go to 10.0 and stay there. It moved around in the 12's most of the time. I saw a few mid 11's and some 13's, but it never pegged full rich.
Here is that video. Hopefully you can see what the afr says, I shouldn't of used my wide angle lens (mute it...it's nothing but wind noise)

Ok just drove around with the o2 plugged back in and ecu reset while ^that one was loading. As soon as I started driving it just went richer and richer until it hit 10. I didn't even make it to the end of my street before it did it lol. I'm gonna say it's my o2 sensor...and or that clip on the harness side needs to be replaced.
Here is that video (switched lenses so the gauge would be closer to the camera, but forgot to change the settings so it's a bit bright and hard to see...oops)

What are your thoughts on all of that?

 

i'm confident that you got it, bud. replace the sensor and pigtail. update with the results, if you could please

 

Sweet =] I'll get those later this week and I'll keep you posted. Thanks again man I really appreciate it. Hopefully this will solve the problem so I can make it out to cars & coffee this sunday

 

well, if it works, you can thank beecee18. since he got you sniffing the o2 trail. and if it doesn't, blame him! haha. jk.

 

Thank you beecee18 & el crapitan!!! I got it fixed =]

I put a new pigtail on the harness side and put a new o2 sensor and it's back to running how it should. I'm not sure if it was the harness connector or the o2 that was at fault, but they're both new now so I shouldn't have this problem again anytime soon. Thanks for all the help guys