Help i am stuck at the track and cant race becuase car only starts some times.


Obd1
S300
Got spark
got fuel

If I reset ecu car will star and stay runingg without cel.
As soon as I shut it off and try to restart... car turns over, cel comes on ans car dies unless I rev it.

I try to pull cel code but doesnt display code.
I resent ecu and car starts without cel. Drives just fine. But I cant keep car running after I restarting it as it just bogs down cel comes on and car dies.



What else should I be checking.

 

Just swapped ecu s300.... same issue.
So we know it's not the ecu....

 

The question is what can cause car to run fine 1 minutes and not be be able to hold idle (& cel stays on) ?

 

try posting this in the engine mgmt forum, you'll prob have better luck over there. especially if you can't pull the code.

 

Sounds like a failing main relay since you already verified the ecu. If your pump still runs, the coil inside that give the injectors +12v could be failing. In some cases the key's start position will prime the pump, but the run position will not power the main relay's pump coil so you lose pressure and the engine dies. You could also have a loose wire in the ecu harness, specifically one of the wires leading to the main relay for one of the two coils inside.

You could try a temp jumper wire to basically hardwire the injectors or pump for +12v power.

 

Are you using the same S300?

You also never said what kind of car this is in or any other things about your setup... namely what chassis it is. If it is an 88-91 Civic they are notorious of Main Relays going bad.

 

Yes, 88-91 civic, coverted to obd1 & running s300, walbro 400, fic 1050cc


I did test 2 other main relays too.
The results where the same.
The reason why I was doubtful it was main relay is that main relay will thow solid CEL or any blinking CEL code. Also the car starts each time (after I reset on/off battery switch for about 10sec) & runs normally.

The problem is that after I shut off car & try to restart it (doesn't matter if it's secs, mins, or hours after shut-off) the car crank, starts up with CEL & will not hold idel unless I give it throttle. NOTE: when it's running in this mode there is NO green light on S300... as if it's running on some limp mode or safe mode.

My only solution at this point (car does pass tech) is to turn kill switch OFF wait 10sec to turn it ON in order to have car start normally.



*** this issue did not happen last race event when I did the battery relocate/kill switch.
*** The only electical change I did was wire in manuel fan switch with relay (not spliced into any part of engine harness).

 

S300 v1 by chance? Those are notorious for failing. Specific details help here...

Is the kill switch interrupting the negative or positive side of the battery? A user here had similar problems and fried his S300 v1 upon bumping the kill switch. Given, there are way too many variables, but given no light on S300 I would contact Hondata for a RMA number. It most likely is the Hondata unit itself since you tried a good socketed ECU. The key being it flooding the car when the CEL is on and no codes being able to be read in SManager.

 

P28 S300 v2
bought new from authorized hondata dealer last fall.
6 race events & about maybe 1,000 miles of use thus far.

it interups power to fuse box & to alt.




What do you mean "it flooded the car when CEL is on" ?

 

You said before you had to keep the throttle open otherwise it would stall when the CEL was on / intermittent. This tells me you are running on ECU limp mode and injector size isn't being compensated for.

I had a friend that wanted to install some ID1000s. I socketed his ECU and installed his S300 for him as well as loaded the basemap. I gave him all the parts for the install - ID1000's, adapters, S300 ECU, etc... He calls me later and says he got the injectors installed and it runs like **** and won't stay running unless he holds open the throttle. He moved it back and forth a little in the garage trying to "clear it's throat". I tell him the basemap should work, but maybe I screwed it up so I sent him another one. He proceeds to ask me if he has to have the S300 ECU in the car to load the basemap. I told him it would be a PITA to have to remove it if you couldn't have it in the car and to just leave it in there. He replies that he never put it in to begin with...

Long story short it ran with the large injectors with the throttle open. Sorry for that long BS but some how you are losing the S300 connection to ECU. No green light on the S300 is not a good sign it means it isn't powered.

I personally would contact Hondata directly. They usually reply back very quickly.

 

no, thank you for that example as it helps illustrate what your saying.

I'll send hondata an email tomorrow.
My next event is on 20th. hopefully i get it sorted out by then.

 

oh one more thing.

I did test all the ecu harness which would feed power to ecu
http://www.ff-squad.com/technet/wiring.obd1.htm
A25 & D1
both showed 12v.

 

This is the direction I'd go in. Good luck.

 

That was my solution a few years back.