I am getting ready to buy a hatch thats has a b18c1 swap, the only thing that I am worried about is that he says that everytime that he hits VTEC the check engine light comes on; he said when he shuts off the car it goes away. Why would this happen? Should I stay away from this car?

 

check the connection between the ecu and vtec solenoid, mine didn't have a good connection so vtec would kick in, but once it did the cel came on, but when the car was shut off, it reset

 

does it go off when it drops out of vtec?

 

did he hook the CEL light to the vtec signal wire? some people do that, so they know when they are in VTEC, pretty gay though because you'll never know when you actually have a CEL code.

 

TekSI, that sounds like the problem but Im not sure if it is or not, do you know of any other problems that can cause this?

93ejay1, I'm not sure if it goes off or not when he goes out of VTEC, what would that mean either way?

Pioneer162, I don't think he hooked it up that way b/c he told me he has no clue why this happens.


Thanks for the quick response guys. I forgot to add he is running a Mugen chipped P28 ecu.

Do you guys think I should stay away from this car or do you think its a minor problem that can easily be fixed?

 

minor problem. so vtec does work, but you get a cel? check all wiring (3 wires), check the screen in the pressure switch, check voltage from sensors. with a p28, the pressure switch ground can be grounded to the head, or run to an ecu ground, with the p72 it runs to the ecu. I would crossreference the p72 to p28 pinouts to make sure that's not the problem. any vetc cel will go away when you restart the car.

 

if it goes away when u drop out of vtec then it could be he hooked up an egagement light and theres no big deal.

before u buy it have him check to see what code its throwing. i wouldnt stay away becauses its most likely a minor problem, it could even be thw wiring

 

Yes vtec does work, there is no change in the cars performance when the cel comes on.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 05r1 &raquo;</TD></TR><TR><TD CLASS="quote">Yes vtec does work, there is no change in the cars performance when the cel comes on.</TD></TR></TABLE>

IMO, check the pressure switch ground. I've had plenty of probs with vtec in the past, and that's the only prob i've experienced that had a cel without affecting performance. If it helps, solenoid is A4 pinout, pressure switch is D6, and pressure switch ground is A26 (P72 only). If the ground is to A26 on a P28 ecu, and the reading is over 1v, it will throw a cel.

 

does he have a knock sensor hooked up?

 

IHateJDM: is the pressure switch ground a big deal? And where can I find it? Is it replaceable or do I switch wires or something?

Sorry if I sound dumb but this is my first honda, and I dont want to make a mistake.

I'm not sure if he has the knock sensor hooked up, but I can ask in like an hour.

Thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fasthatchb18c1 &raquo;</TD></TR><TR><TD CLASS="quote">does he have a knock sensor hooked up?</TD></TR></TABLE>

p28 doesn't look for knock, only p72. the ground is just the black wire coming from the plug on the pressure switch. i can just be grounded to a bolt on the head for a p28. the stock p72 looks for it at a26. I say this is the most likely, because it's really the only difference in wiring between the 2 ecu's.

 

yeah I didnt read the whole post

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fasthatchb18c1 &raquo;</TD></TR><TR><TD CLASS="quote">yeah I didnt read the whole post
</TD></TR></TABLE>

your post did make me realize that we don't have the cel code though, so it really does help. 05r1, you need to pull the code to make sure we are diagnosing the correct sensor. Also, does he have a vtec light, switch, or a vafc installed?

 

IHateJDM I will try to get that info asap.

One more thing he had a 50 shot of nitrous "ZEX" on this motor for awile. Do you think there is any concern with that?


What if he didnt retarded his timing and he let his motor lean out. Do you think there could be damage internally?

 

nitrous wouldn't affect vtec. as long as he retarded his timing and didn't let his motor lean out, a 50 shot wont hurt a gsr.

 

How's the oil level, you wouldn't believe how many times I see this in a day. Just a suggestion, good luck.