Hello forums, I just recently re-built my 1997 Honda Prelude Type SH with various mods, cams, sleeves, pistons, etc. Anyways I had modified my engine to the point where my stock ECU just wasn't going to cut it, so I got a Hondata S300 and jumper harness for my OBDIIa car. Anyways I've installed and loaded a tune from someone that says they had the same cams as I do (BC Stage 2 Hi-Boost) and adjusted it for my newer injectors and some other slight things but nothing regarding fuel trims or ignition timings or anything, I've also installed a wideband and two analog gauges since. When I tried to start the car however it seems as if for some reason I am not getting any spark whatsoever, I quadruple checked the timing and am confident it can't be that, nor on the distributor side either. I have power going all the way to my coil and my coil wire doesn't have any excessive resistance, I got a new distributor cap and rotor and the spark plugs have maybe 100 miles on them so I doubt it's anything to do there. I'm not the best when it comes to electrical diagnosis but from what I could see I found no physical issues preventing my car from firing so I am just coming here to see if there are any settings I could've accidentally messed with or some other issues to look for that someone can help me out with.
Also I did manage to load the fault codes on my laptop and found Codes 6 and 20 for the ECT and ELD, I know the ECT is from the analog gauge I installed which had me disconnect the oem ECT from the head and the ELD could be from the fact that I'm using it for my wideband(?) I'm not too sure how that could affect it or cause my engine to not start, some insight would really be appreciated.
S300 Installed Now Won't Start
Re: S300 Installed Now Won't Start
You should try the ECU on a known working vehicle to see if it will run there. This will rule out a problem with the ECU or vehicle.
You need to have the ECT wired to the OEM sensor so that the ECU reads it correctly.
You need to have the ECT wired to the OEM sensor so that the ECU reads it correctly.
Re: S300 Installed Now Won't Start
I was wondering if it could be anything I unknowingly did that could prevent the hondata from sending an ignition signal to my spark plugs so the engine can turn over properly. I know I used the A10 ELD pin for my wideband and now I have an error code for it however I don't really understand what that means or if that error would cause my engine to not start.
Re: S300 Installed Now Won't Start
ELD will have nothing to do with getting spark.
Re: S300 Installed Now Won't Start
what about the CKP? I read that it was a common issue with my car when swapping to Hondata ECUs as the CKP is on my oil pump housing instead of in the distributor itself such as the OBD1 distributors, would I have to install a jumper harness like I've seen others do? I narrowed my no spark issues to either my distributor itself or my ICM which could not be firing due to the CKP not being read properly due to the Hondata being a different kind of ecu compared to my stock Prelude's ecu
Re: S300 Installed Now Won't Start
The adapter harness you use should allow for that. But if the signal is not getting to the ECU then it could cause an issue.
Re: S300 Installed Now Won't Start
The harness I used was only for the obd1 hondata to my obd2a wiring. I do know there are jumper harnesses for the ckp sensor to an obd1 distributor I could buy but I'm not sure how to check if I actually NEED that. How would I go about checking if the ecu is getting the signal from the ckp for it to send to the icm?
Re: S300 Installed Now Won't Start
What distributor are you using?
Re: S300 Installed Now Won't Start
The stock OBDII distributor with an MSD Cap and Rotor (part no. 89293) with the internal coil removed as I have an aftermarket external coil as well (MSD Blaster SS part no. 8207)
Re: S300 Installed Now Won't Start
And does this run on the stock ECU?
Re: S300 Installed Now Won't Start
Yes it ran perfectly fine for about 2 years of us owning the car with the stock ecu. I never touched anything with the ignition system when doing any work on my car besides replacing the cap and rotor a couple times.
Re: S300 Installed Now Won't Start
Will it run NOW on the stock ECU?
Re: S300 Installed Now Won't Start
Let me try and reconnect the stock ecu and see if it works really quick, standby
Re: S300 Installed Now Won't Start
Upon swapping back to the stock ecu it seems that I must have a bad base tune or something loaded as the stock ecu got the spark plugs to fire and the car would've start if I didn't kill the battery lol. Got a buddy in the next town that could make a base tune for me though as the ones in the hondata vault aren't good enough it seems
Re: S300 Installed Now Won't Start
The other possibility is that your OBD1 ECU is bad and will have to be replaced and you will need to get the s300 installed into the replacement ECU.