ok i recently had a mini mi swap (d8/y8). everything went great except when i drove it around with the new ECU (p08) the car had some problems. as soon as it cranked over the car would die, unless i gave it a little gas. and i would have to give continuoes gas until the car headed and it was fine after it was warm (idling problem.) at first i thought it was because i hadnt had the vtec hooked up yet. then i thought it was the o2 sensor since i was still using one wire sensor. so this weekend i hooked up the vtec (hopefully i did it right) and started the car and drove around for a little bit. i dunno if it was my imagination but i can feel the vtec kick in even though its sohc. but the problem was still there. so i changed the o2 sensor (again, hopefully i did it right) and still nothing changed. the car still has problem idling and it dies unless i feed some gas for few minutes. and the whole time im using my p08 there is a CEL. and the thing that pisses me off is that i was trying to check the code of the CEL by jumpering those two wires but the freaking CEL ONLY comes on when the engine is running. i turned the key into on position and the CEL goes away and comes back when i crank the engine. i tried to kill the car by taking the clutch out when its in 1st gear. and that made it so that the CEL stayed on while the key was in ON position and then tried to jumper the wires but nothing! the stupid CEL does not blink and its pissing the hell out of me. im gonna take to a honda dealer this friday but until then any ideas on wtf is causing this stupid CEL!? thanks

 

Burn that FUC*KER!!!

and then take it to the dealer, be like "i dont know what happened "

 

that wasnt much of a response

 

bump, god i thought this was good enough tittle to attract alot of people. i guess not. but in all seriousness please help and give some useful information.

 

Are you jumping it right? Did you try with the key in both the on position and with the engine cranked?

Ive never heard of a fuel injected car dieing like that. My carb. crx dies like hell on a cold start. It requires tons of gas to get warmed up. But its different for you because when you push the gas youre accually giving it air. Sounds like some kind of sensor in your new head is wigging out.

Maybe if you got the ecu chipped for your new motor setup it might clean that **** up. Since youre new setup will require new timing/fuel maps to run like a champ.

I hope i helped a little, just wait for someone who knows for sure what it is. So many guys on here, one of them has to know what your problem is. :s

 

If your CEL is coming on, then a code will be stored. I don't think you're retrieving the codes properly. Jump the 2 pin connector with the ignition off. Then turn the key to the on position, and the CEL should blink out your code. It will not work if you try to jump the connector while the ignition is on, it must be off first. Once you have some codes, then it should be easier to figure out your problem.

 

my bad man, i was just being stupid

Double check the wires for reading the ecu codes. If your sure its correct, plug in another ecu and read out the codes again. Possibly the self diagnostic portion of the ecu is bad.(anythings possible right?)

The ecu has its own "idle map" for when the car is cold so i dont believe the o2 sensor or vtec function could be causing the idle problem.

Does your car have the little idle thermo valve under the throttle body? Might want to look into that. It uses coolant and a little thermostat to raise the idle when its cold...

 

thanks for the infos. ill recheck everything tripple times and try to check the CEL and if all else fails and ill take it to honda.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by project_delta &raquo;</TD></TR><TR><TD CLASS="quote">If your CEL is coming on, then a code will be stored. I don't think you're retrieving the codes properly. Jump the 2 pin connector with the ignition off. Then turn the key to the on position, and the CEL should blink out your code. It will not work if you try to jump the connector while the ignition is on, it must be off first. Once you have some codes, then it should be easier to figure out your problem.</TD></TR></TABLE><TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Wickedsol94 &raquo;</TD></TR><TR><TD CLASS="quote">Are you jumping it right? Did you try with the key in both the on position and with the engine cranked?

Ive never heard of a fuel injected car dieing like that. My carb. crx dies like hell on a cold start. It requires tons of gas to get warmed up. But its different for you because when you push the gas youre accually giving it air. Sounds like some kind of sensor in your new head is wigging out.

Maybe if you got the ecu chipped for your new motor setup it might clean that **** up. Since youre new setup will require new timing/fuel maps to run like a champ.

I hope i helped a little, just wait for someone who knows for sure what it is. So many guys on here, one of them has to know what your problem is. :s</TD></TR></TABLE>

im doing exactly what ur guys are telling me and i dont think that im doing it wrong. i took it to honda today and they asked for 100$ just to read the code on the CEL, so i said F that! so i tried checkers, autozone, advacned auto and none of them could do a diagnostics test on a OBD1 car. i dunno what else to do.

 

https://honda-tech.com/zerothread/1171263

just to make sure ur doing it rite

on my car i couldnt check the cel unless i jumped it wiht the car running
i don thtink its a good idea
but i was all out of good ideas at that point so i used my bad one
i dont realli advise it, but if you realli are stuck then maybe
my car runs fine now, no elecrical problems becuase of the jumping while running

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by egcivic &raquo;</TD></TR><TR><TD CLASS="quote">https://honda-tech.com/zerothread/1171263

just to make sure ur doing it rite

on my car i couldnt check the cel unless i jumped it wiht the car running
i don thtink its a good idea
but i was all out of good ideas at that point so i used my bad one
i dont realli advise it, but if you realli are stuck then maybe
my car runs fine now, no elecrical problems becuase of the jumping while running</TD></TR></TABLE>

lol the other day i left the jumper wire in there and forgot about and left it inthere while i was driving around (and the CEL didnt blink), so i dont it will do anything bad. plus its a honda so im sure it will be fine.

 

Yes you can jump the connector while it's running. i do it all the time.
Be sure your IAC valve is plugged in to the right connector. That was my mistake when i did my swap.

 

yup mine too, i think the iacv, intake temp sensor, and hmm one other one i forget is all the same connector

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MooGoCow3 &raquo;</TD></TR><TR><TD CLASS="quote">Yes you can jump the connector while it's running. i do it all the time.
Be sure your IAC valve is plugged in to the right connector. That was my mistake when i did my swap.</TD></TR></TABLE>
yeah i had it wrong the first time and the car died after running for few seconds so i switched them and it was fine after that. but do u guys think that the timing has something to do with it since im using a JDM ECU p08 not a p28?

 

i would suggest just going over the basics, check your cam timing, ignition timing, and if you can rent a fuel pressure gauge and a compression tester, do those as well.. when you do a mini me swap im pretty sure the cam timing has to be off by a certain amount of degrees, not to stock settings..

 

I wonder if that JDM ecu even has on board diagnostics? I think the OBD stuff is just for the US market, but im not 100%.
Try the USDM p28 and see what happens...Maybe youll at least be able to get some fault codes out of it.

 

yeah thats a good idea, unless some one in the Denver area wants to let me borrow their ECU for like 2min. im not gonna buy one.

 

Disconnect your ecu (or you can pull your ecu fuse or d/c the battery) to reset it, then fire it back up. When/if it throws the cel, jump that connector. If the cel wasn't there immediately, then it should show one. Sometimes a bad ecu will just show a constant cel. A bad chip burn (or no chip) will usually show a constant cel if things are that bad. Also, if there is no cel and you jump the service connector, it will just show a solid cel (and in my experience, the SRS light too).

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by _RedRiceR_ &raquo;</TD></TR><TR><TD CLASS="quote">

im doing exactly what ur guys are telling me and i dont think that im doing it wrong. i took it to honda today and they asked for 100$ just to read the code on the CEL, so i said F that! so i tried checkers, autozone, advacned auto and none of them could do a diagnostics test on a OBD1 car. i dunno what else to do. </TD></TR></TABLE>

Wow that's some weird ****...all the autozones by me will test ODB1 or 2 for free...but with the situation you're in right now u should spend $100 for it to throw all the codes out that it can, write 'em down, fix 'em yourself...man sometimes you g2 bite the bullet and from what it sounds like from ur original post you're gonna have to bite the bullet...

 

Update:
can a bad gasket cause the starting up problem? cuz i used the same throttle gasket from the mini-me swap. and i tightened the throtle bolts some more and that somewhat fixed the starting up problem, no longer do i have to give it some gas. but it still idles funny.
i also heard that a bad sensor will cause some problems. like the one thats in the back of the intake manifold, i had to jumper the wires cuz the old harness wouldnt reach there. anyway the idling problem isnt bothering too much. the stupid ECU is. still have no progress on fixing that problem. also, more problem appeared when i drove it around. when im flooring it or pressing it down almost all the way, i can hear really fast clipping noise come fromt he engine bay area. my friend said it maybe the rocker arms thats causing that noise. any thoughts on that?

 

why dont you just use the right ecu.

you cant fix a broken car when your already using the wrong parts.

 

If you have another ecu laying around try it

 

i used my old ECU today, from the cx, and there was no CEL so i couldnt check the code on it. and i drove it around it was noticeably slower. i will a just the timing this weekend and see if that works out.