Alright I have an annoying problem that I need some outside help with. I bought a 90 CRX with an ls swap. The swap was done like **** so it'll be a trick finding the problem. But, my problem is that when it's cold, the car will not start period. It'll crank and crank and crank and eventually fire and start up, then drops idle and dies again. I've tried replacing map sensor and it did nothing. If I just hold start position and keep cranking it will start up after about 5 seconds, of which most of the time it will hold cold idle at about 1,500 rpm but again if it is super cold it'll just drop idle and die again. Any help is greatly appreciated. Feel free to ask any questions I'll answer them to the best of my ability. Of all things wrong with this car and this is the only one I can't figure out.

thanks guys,
MadScientist

 

Do you have a CEL - if so what are the codes?

Could be a bad/unplugged IACV... try and turn your idle up and see if you can get it to idle that way. Also, check the FITV to be sure it's not screwed in all the way tight. Almost sounds like a massive vacuum leak, not enough or too much fuel... but you haven't posted much to go off of at this point... This is assuming everything else is in working order.

 

I have a CEL, but the harness to jump isn't connected properly so I jump it and nothing happens. The CEL never goes off either. Like I said there are more problems that are underlying but I figured this should be relatively simple ish to figure out. I mean once it starts up it idles fine just as it should, just getting it to that point is what's giving me trouble. It only does it when it's cold. I know for a fact not everything is in perfect working order but I'm trying to widdle down the little problems until I get it all straightened out. That's why I requested that you ask any questions necessary to aid in your response.

 

I was going to go on and on with a lengthy response but then after 5 seconds of searching I found this...

https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/no-start-solid-cel-heres-what-i-did-tons-pics-2458280/

Start from the top and work your way down... I do realize this How-TO is for a '92-00 Honda but many of the steps are the same...

On a side note - you do realize that the codes flash on the ECU themselves correct? You don't need to jumper anything - just pull the carpet up on the passenger side and watch the red LED blink while the key is forward.

 

Since this is an only-super-cold-outside problem, I'd start by checking the main relay for broken solder joints. The board expands and contracts with hot and cold temps causing the base of the joints to crack.

 

I understand the codes flash on an OBD0 ecu if I'm correct? For an OBD1 car you have a two wire harness you can jump prior to starting the car and the CEL will flash the code on the dash. This motor is OBD1 so my assumption is there was an error in the conversion wiring from OBD0 to 1 being that a jumper conversion harness was not used. And CRV the motor turns over without any problems it just won't continue firing under its own power for a certain period of time. And the difficulty of starting completely depends on how cold the car is. Another note to add is that once the car has started up and is running under its own power if I give it any significant throttle input it bogs down then responds and revs up. I'm not sure why this is either.

Thanks for all the input so far guys.

 

are you sure the jumper isnt there?....i couldnt find mine initially its right up against the drivers side shock tower

 

my jumper was in the passenger floor well just in front of the door, 90 crx si

 

Akinas that's where obd1 jumpers are supposed to be located. Again the wiring conversion on this car was more likely done by a nine year old so I'm assuming that's why the jumper doesn't work.

 

You are incorrect... The service connector IS located on the passenger kick panel. The earlier years were on the driver's shock tower under the hood. Since you do have a 1990 model, yours in the cabin.

Ground the pinout going to the ECU. Most people don't take the time to wire in the factory jumper location on a OBD-0 to OBD-1 conversion. The reason being instead of running the wires to the correct pinout they usually have them on the bulkhead connector (if it even has one) so people can run it to a switch or whatever tickles their fancy.

PS - You are absolutely horrible at being descriptive... Every post you make we get another tiny piece of information that is vital to diagnosis. It's hard to know all the details when you hold the key... We are sitting behind a screen over the Internet after all...

 

You're probably right, it is hard to be descriptive for me because I'm on here for thirty seconds at a time. Two jobs will keep a guy busy not to mention two cars. It'd take me an hour to explain all the little details that's why I wanted YOU guys to ask the questions. I'll tell you anything you wanna know about this car, all you have to do is ask.

Now being that I do NOT know everything in the world, do you happen to know which pinout it is on the ECU that I need to ground in order to check my code? If that's what you're saying, I'm exhausted and possibly borderline delirious so I could be misunderstood.

Fortunately I have a few minutes so I will try and explain as much as possible:
The wiring conversion this guy did for the ecu was horrid, it's a scramble of stray wires and electrical tape. Hell the engine sits in the bay an inch crooked for some odd reason. The car used to be a boosted drag race car. It has a welded differential in the B16 trans that's under it. All he did prior to selling the car was swap the block and axles and put some junk *** parts back in it to make it street legal. Your service jumper appears to have been under the passenger corner the whole time so yes you are correct in it's location. I first thought it was put there with the obd conversion but just never hooked up because of laziness, but who knows, it doesn't work that's all I know. The engine harness is a wreck, it's missing the entire o2 sensor harness, I don't know where the hell it is or where it even comes from to wire in a new one. It's had the fuel purge tank removed, the map sensor is laying in a pile of tucked wires tied to the throttle body by a two foot piece of vacuum line. I've replaced spark plugs and wires and that map sensor and the alternator and the battery and done random little wiring repairs which has helped in its starting only slightly. Again the CEL stays on from the moment it receives power. I haven't had time or money to replace the fuel pump just yet although that is on the list, it does seem to work fine. It primes fine even when the car doesn't start. I can hear it working all the time, never had any problems in that are. Now I wondered about a large vacuum leak but I was understood if there was a vacuum leak then the car would idle high once it was running under its own power. Again once it gets up and runs by itself it's as it it never had a problem. It idles as the ECU tells it to and is completely normal. For example in the summer, if the car sat for two days and I got in it and started it it would damn near start right up, although again I would have to wait for it to warm up a little bit before I could drive it for reason of like I said earlier it wouldn't respond well to throttle input, it would bog down as if the damn thing was carbureted. Now if it's cold, like right now, I'll have to hold it in start position and crank it solid for about 5 seconds, the car will start up and idle in between 1500 and 2000rpm as normal, then it's as if it loses everything and within about two to five seconds it loses rpm and will die down and shut off. In which case when I turn it to start position again it'll turn over and after one or two rotations you can hear it fire like once then it'll just crank and crank and crank for five seconds and then do the idle thing again. But I usually stop starting it once it fires to avoid burning my starter. Occasionally it will try and try to hold idle but drop to all of 100 rpm and shake the car as if it were running on two cylinders, then either shut off because it can't hold it or finally rev back up to normal idle, then most likely die again. Again once it holds idle if I mash the gas to the floor it just bogs way down then sputters up the revs till I let it off again.

I don't think there's anything else I'm missing for goodness sake but I could be wrong and probably am. So if this tickles your fancy for a description then have at the responses and questions, I'll check anything I can.

 

Pin "D4" is the one you are looking for to ground out... I have supplied a picture that lists all the pinouts for your future reference...



Thank you for the information... a story does help but important vehicle details is what is needed the most (like how you left out it was an OBD-0 to OBD-1 swap for instance). These small details completely change the troubleshooting guidelines/locations.

It somewhat sounds like the FITV (Fast Idle Thermal Valve) -and not to be confused with the IACV (Idle Air Control Valve)- is turned all the way in and may be stuck. Check your codes first and look at the FITV. There is no other "obvious" part that would cause your described symptom.

 

o/p can we get some picture to see what you're working with, that'd help so much

 

Let's see if I'm correct, FITV is on the bottom of the TB? I know the IACV is on the back side of the intake mani. I am planning to make these checks early next week once I can get the car in the garage so I'm trying to gather as many tests as I can before I get started.

I will also put pictures up of everything I can to help.

I apologize for not mentioning the obd conversion. Thought I did. Oh well. Now is there any easy way to check the FITV without taking off the manifold? And just for curiosity how would the FITV being stuck all the way in prevent it from starting like that? I just figured it would cause the car to simply idle high for no reason, same in relation with a bad IACV. Please correct me if I'm wrong.

How do you post pictures anyway? Do you absolutely have to have a URL or is there a way to just add one from a file saved on my computer?

Also, would you happen to know how I could wire in an o2 sensor? I'm sure that will probably help the car run better at least. I have the sensor and connectors I just need a place to start and wire it all in.

 

Here is more detail on how to clean it and such... it is possible to leave it connected and just take off the rear cover plate and adjust it from there...

https://honda-tech.com/forums/acura-integra-6/%2A%2A%2A-how-%2A%2A%2A-clean-your-fitv-aka-fast-idle-thermo-valve-1564019/

Some engines rely on them to compensate for colder weather start up. The IACV can't supplement enough air on its own and uses the mechanical "sensor" to help out. Once the engine warms up (which it senses because it has coolant running through it) it closes that vacuum source and the IACV takes over complete idle operation.

For pictures - you can click on "Go Advanced" (right to the right of "Post Quick Reply") and it will allow you to upload pictures from your PC.

Wiring an O2 is completely easy... I would pull your ECU cover to see if it is chipped first. If it is they may have your O2 disabled and could cause some of your running issues.


The factory wiring is as follows:

White = O2 Signal (D14)
Green/White = O2 Ground (D22 or similar logic ground)
Orange/Black = O2 Heater (A6)
Yellow/Black = O2 Power (A25 or switched +12v source)


Aftermarket wiring is as follows:

White = O2 Signal (D14)
Green = O2 Ground (D22 or similar logic ground)
Black = O2 Heater (A6)
Black = O2 Power (A25 or switched +12v source)

Obviously it matters - if you get an O2 heater code switch the two black wires around - simple as that.

 

That writeup is great, I'll definitely try that too. Ill be able to pull the FITV assembly off most likely so I'll try that, if not I'll just pull the cover off and unscrew the valve. Now would that cause the car to not respond well to throttle input? Like what I described earlier?

Like I said first I thought there was a vacuum leak somewhere mainly because I smelled fuel when the car finally got started. Also swore I heard a leak so yea. But a vacuum leak would cause it to idle high constantly and it doesn't so that eliminates that problem. The FITV sounds like it could be the problem. Like I said either tomorrow or Thursday I'm going to pull all this apart and have a go at it. Speaking of which what would you like me to upload pictures of? I'll upload them as soon as you tell me what ya want.

For example, here is a picture of the ECU wiring.

 

Alright, so far I took apart the FITV, gave it a super good cleaning, put it all back together. Now a side note is that it's about seventy out right now. I tried to start it and it did the same thing. It cranked for about five seconds started revved to about 1800 rpm, then dropped and died again. When I reinstalled the FITV I turned the plastic screw in about a full turn, and it didn't seem to affect it whatsoever. I'll try and pull the back cap off being that it's in a convenient location and try pulling the screw out some more, being that maybe it was too far in causing the idle to be too low. I will post after I try that. Also, I noticed that the FITV has two coolant lines running to it, one of which is bending at a ninety degree angle about an inch after leaving the FITV. It appears to be kinking slightly, but not a full on kink. I don't know for sure if this is a problem but I felt that I should mention it.

 

Ok so I turned the screw out a full turn and a half and it idled higher, (go figure). Now again being that it is not cold outside I can't accurately measure whether this is going to help the starting problem or not. Now my analysis tells me that I would want to turn it out to increase the idle to help it start more easily? If I'm wrong tell me. I thought about 1800rpm was normal for a car's cold idle. When it heats up it drops right down to about 1000 +/-. This warm idle was before I cleaned the FITV. I haven't had a chance to let it warm up to see where it idles yet, but from my understanding it is under control of the IACV once it gets up to temperature. The FITV is primarily used to control cold weather idle.

 

Ok update again:

I pulled out the ECU and gave it a go over for the most part. I'm still diagnosing more problems from the childish wiring conversion. I'll upload pictures as soon as it lets me. For some reason it'll only let me upload certain pictures I take. Now, just as suspected, pin D4 (Service Check Signal) goes to nothing. Also the ECU is NOT chipped, and there are wires ****ing everywhere that either come from somewhere and go nowhere or come out of the ECU and go nowhere. For some reason the VTEC solenoid wire (Pin A4) splices to a green wire then goes off somewhere, not sure yet where. I'm not sure why it's hooked up but whatever. Also pin D14 which is the primary heated O2 signal wire goes to nothing, so I am going to wire in an oxygen sensor once I go over what wires to run and where. There are what seems like conversion connectors taped in there somewhere, I'm assuming OBD0 ECU's use two main harnesses instead of three for OBD1. Again pictures will be up soon.

 

This is what I have to work with as of the moment.


This is the supposed conversion thing the guy wired in.

 

I described the functions of both the FITV and IACV, albeit not in depth. You are correct in your assumptions but your wording is off. When you screw it all the way in you restrict vacuum - out you supply more vacuum. The FITV isn't necessarily strictly for cold weather (I have a bad habit for not explaining all the details) but also for when the engine is cold. Since the IACV has cold coolant in it and can't full compensate the idle (also the O2 being a 1-wire has something to do with it as well) so a mechanical device was introduced.

 

OBD-0 has 3 connections to the ECU just like OBD-1 does and so on...

 

This is the wire coming out of D4 for the Service Check signal. I grounded it out to the post that the ECU mounts to, only ground I could find at the time, and I got three codes. Being that I read the flashes right Lol being that a short flash is a 1 and long flash is a 10


First code was Code 6 - Which is the Engine Coolant Temperature Sensor. This makes sense because the coolant fan will not turn on under the control of this, I had to wire up a switch to turn it on when needed. Moving on.

Second code was Code 10 - Which is the Intake Air Temperature Sensor. To be honest I didn't have a clue this car even had one. So that was is a mystery to me. Any assistance in that one would be appreciated. I'll probably have to chase wires from the ECU pinout to see if it's connected to anything. And if not I'll probably have to wire something up. Or whatever works. Again I didn't even know that OBD1 ECU's had an IAT.

Final code was Code 20 - Which is the Electrical Load Detector. I remember from the diagram seeing a pinout for it I believe, so I'll chase down wires to figure that one out. And again any assistance in that is appreciated. I'm not sure what exactly the ELD does or where it is.

 

I'm not the best at details either, when I said cold start or cold idle that's what I meant, not necessarily referring to cold weather but referring to the fact that the engine is cold. I'm going to try and upload some more pictures so you can see what I'm working with.

This picture shows the white wire coming from D14, the primary O2 sensor wire. The odd thing about it is that the ECU is not throwing a CEL code for O2 primary or secondary. So Idk what's up with all that.

 

If I'm not mistaken I believe the IAT sensor is a two wire sensor located on the Intake Manifold runner. I can't get it off at the moment, the two philips head screws in it are struck so the PB blaster is working as we speak. Maybe it'll come out Idk. If that is what I think it is, I'll probably have to replace it being that it's one of the reasons the CEL is on.

Update: I researched a little and it is exactly that, the IAT. Now will any OBD1 IAT fit and work properly? I found a few on eBay for like 13$ one is from an OBD1 H22 and another which reads nearly the exact same part numbers and even is identical in the picture as mine, is from a Honda CBR 600. I know that's a motorcycle but if my assumptions are correct it will function the exact same and still work. Corrections?