I have a B16a swap in my 90 crx dx and it runs great when its cold, however once it gets warmed up it begins to run like crap. It boggs down when I hit the gas, and it blows out black smoke from the exhause and theres a coating of unburned fuel on the back of my car. The warmer the car gets the worse it gets. It doesnt overheat or anything it just runs real bad. I am throwing a code for knock sensor and I have checked it a few times and there seems to be nothing wrong with it... plus it wouldnt make my car run this bad. Once the car is warmed up and I stop driving, or shut the car off... then go to hit the gas or start the car it gets really bad. I can push the gas all the way to the floor and all it does is rev at a constant speed for a little while and then all of a sudden like something starts to work it revs right up. But once it goes back down in rpms the car is really hard to get the rpms back up. I was getting 6mpg then for a while I started to get like 12-15 and now I think its back down to 6mpg. I have started to put lucas injector cleaner in, because I have heard that, that is a good product. I felt a difference the first time I put it in, but the second time it started to act bad again. I have 2 ecus and they both do the same thing everything is hooked up properly so I dont know what the problem could be. Does anybody have an idea?

 

have you made sure your Vac Lines are on where they should be?

o2 sensors good?

 

I have brought it to different shops and they have changed to O2 sensors and checked the vacuum lines so they are all good.

 

Do a Compression Check, or a leak down check

 

I did a compression check and its like 210 across how can I do a leakdown check? I know this a dumb question, but is it something I can just do or do I have to bring it somewhere?

 

good chance its your coolant temp sensor...This adds more fuel when the car is cold to compensate for the denser cold air, and when the coolant warms up, this tells your ecu to cut back on the fuel...So if these go bad, you'll run rich as donald trump, which it sounds like ure doin

 

Wouldnt it be throwing a code for that though, the only code I'm throwin is for my knock sensor

 

why dont you fix the code for knock sensor ? why do people insist on driving the car with while the ecu is throwing codes?

 

I have tried to fix it, but everybody says that the knock sensor is a plug with only one wire... mine has 2 and I'm positive that its the knock sensor, because all of the pics of them on the internet show where it is, and the plug I have there has 2 wires out of it, I have been trying to fix that for about 6 months now and am still dumbfounded

 

how have you tried to fix it? replacing it? rewire? checking at the ecu clips? reset the ecu?

 

all of the above except replace, do you know how much they cost?

 

well if you get it from honda im sure it will be alot....but check ebay sometimes they have them..

 

i think the ecu refuses to do vtec w/ the knock code. so that might have something to do with it.

also, are u using 91oct?

 

no I'm using 89 and I'm hitting vtec

 

it wont necissarily throw a code for the coolant temp sensor, because it may already be running in limp mode cuz of the knock sensor code, so a combination of the coolant temp sensor and the limp mode, that could be your promblem, just a thought

 

so how could I tell if the coolant temp sensor is no good?

 

I have the same motor and yr car but mine is an si im throwing the knock sensor code and its doing the same thing but I have yet to find a knock sensor to replace it with exept at honda they are asking $180 and any shop ive went to is dumfounded also. get back at me if you find a fix

 

i dunno if there is a specific resistance between the two terminals a certain temps, im sure there is but i dont know em off the top of my head, or you could just replace it anyways, there like 18 bucks or sumthin
I guess you could pull it out, check the resistance, then get some hot water, put it in the hot water for a min. pull it out and check it, see if the resistance changed, that would be the ghetto way, haha

 

Well I just bought a new vtec subharness to try to fix the problem possibly. I'll let you know how it goes.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nappyroots827 &raquo;</TD></TR><TR><TD CLASS="quote">i dunno if there is a specific resistance between the two terminals a certain temps, im sure there is but i dont know em off the top of my head, or you could just replace it anyways, there like 18 bucks or sumthin
I guess you could pull it out, check the resistance, then get some hot water, put it in the hot water for a min. pull it out and check it, see if the resistance changed, that would be the ghetto way, haha</TD></TR></TABLE>

you have to check the resistance at certain temps. so u cannot pull it out to test. get a manual all the specs are in there. a 88-91 EF manual will work cuz the sensors are the same electrically.

 

http://www.rockauto.com/catalo...,2483
http://search.ebay.com/honda-k...srtZd

 

 

Just wanna say I'd be shocked if its the knock sensor, when i got my car it had no O2s, IAT, IAC, or Knock sensor and it ran "fine" hit vtec and everything. I've since rid myself of all the CELs and the only thing that made a noticable difference was the IAT. Would i reccomend you get a knock sensor? Yes. Do I think that will help you? Unless it has something to do with the fact that I was running 93 and you're running 87 no.

It sounds more like the coolant sensor also its rare that a coolant sensor trips a CEL due to the fact that there is no out of range for the sensor... if its cold its one way if its hot its the other if it breaks it just thinks its whatever temp its at all the time, the ECU dosen't have any information to believe otherwise.