2000 EK1 B20 intermittent non start

[gambate]

i was helping a mate to figure out some electrical problem(s) with his car, we have nfi what the problem is.

history/spec of car:
-b20 was from ek1 with hondata s300
-mate put it in his 2000 ek1 straight swap, engine wiring plug into car wiring no problem car start and run, vtec works, ac works. car running fine for 2~3 weeks.
-also using cai with skunk2 TB with the map sensor hooked up via a vaccum port from manifold.
-CEL will come on upon hitting vtec, indicating temp sensor from SManager, found to have dodgy wiring in the temp sensor / vtec solenoid area. since car was running fine, it was ignored.

-today it refuse to fire up. after a few tries, with key on engine off, the main relay no longer "tick on" to prime fuel pump and "tick off", instead it just buzz like crazy.
-countless on/off key operation later, main relay will sometimes tick on/tick off as it should, engine will fire and run for few seconds before main relay start buzzing and engine will die.

only thing we did so far was swapping main relay with my dc2, my car start and run fine with his main relay, and, the main relay from dc2 buzz like crazy in the ek1.
swapping the relay back, same thing, my car run ok, and the ek1 cause the main relay to buzz.

tomorrow, we will fix the dodgy wiring and see what happens

anything else you guys suggest we should check?

EDIT:
pic of s300
apart from the 10row heatsink, everything else seems to say its legit s300 according to hondata website.

[ECU-MAN]

1. Start by verifying the main PGMFI relay wiring to the ECU and car.


2. can you post a quality photo of the other side of the ECU ?


3. if you have a standard OBDI ECU you can try, the engine should start if you have 240cc injectors.


4. double check your conversion harness for broken wires.


5. does the ECU self test when you switch the ignition to the II position ?. MIL should come on and go out.


6. does the engine light come on and stay on and no click from the Main PGMFI relay.


7. can you read the S300, is the data valid ?


8. pull the S300 out of the ECU and try to start the engine, (expect it to be in limp mode) do you still get the relay buzz ?




Your S300 looks to be genuine

[gambate]

THANK YOU!!! 90 degree japanese bow to ECU-MAN!!
tried took photo of back of ECU, soldering job for S300 is quite bad, found black spot 8.30 o'clock from centre hole, flip to front, viola, burnt transistor...

[ECU-MAN]

From the photos I can say your ECU needs repairs,


Either try that ECU in another car along with the harness and see if the other car's relay buzzes or try another ECU in this car. Even if the ECU wont start the car, it should self test and the relay should click on then off along with the MIL.

[gambate]

what causes the transistor to burnt out? age? short circuit?

[ECU-MAN]

That transistor controls the PSC (purge solenoid control). Looks look it saw 12V,


That should not be the cause of your problems as the ECU can still run with out the PSC. I suspect you ECU has other faults based on the 3rd photo.

[gambate]

yes, the capacitor next to transistor has corrosion on the left leg (not shown in pic)

[ECU-MAN]

If you find out the ECU is the cause of your problems and need it repaired PM me

[gambate]

more corrosion on ICs leg

[ECU-MAN]

This ECU has seen water at some stage. Looks like it can be fixed


What do the ECU connectors look like.

[gambate]

lol, fixed those dodgy wiring and hair blower'ed the ECU, car is running fine now, mate CBF doing more diag

the carpet was soaking wet, must be built up of condensation day after day.

thanks again. save us $$$ to call out an electrician.

[dorikin]

if no visible leak coming from outside, i would check your drain hose from your a/c evaporator is in place

it can leak in that area if you've been running your aircon