I recently bought a 93 delsol. Its has a d16z6 vtec and a 5 speed. The s20 tranny went out recently and the only one i could find was a s40. I installed the new tranny. What i didnt realize was the inside of the starter grounded out. Got everything wired back up and the battery kept sparkin. I kept touching the the battery cable to the batt while i was tracing down the short til i found it. Well the harness got burnt up the first time i hooked it up cause the cable welded its self to the batt lug(thats why i kept touching it afterwards damage was already done). Well i put a new harness it in. Now i keep having a problem that i have to pull the ecu fuse to start the car. Once i start it the first time after i turn it off it has to be pulled and but back in for it to start again. I have replaced the main relay and it still does it. Its not evertime it has to be pulled and reset. Also the solenoid on my IAC valve is humming when the switch is still off. Any one have any idea of what will cause this to happen? The car side of the harness didnt get hurt it was just the motor side. Also i cant tell if the vtec is kickin in since. The new engine side harness wasnt vtec so i ran the 2 wires from the cannon plug to the vtec, and as for the black wire i ran it to ground.

 

15A ECU fuse 31 -- You need to pull this fuse to get the engine to start?

When the engine won't start, does fuse 31 have battery voltage on both test tabs? Does the fuel pump fail to prime and there's no spark at the plugs?

Have you cleaned and tightened the G101 ground on the thermostat housing?

 

I get nothing no injectors, fuel pump, or anything before pullin the fuse. The ecu fuse under the hood. Left rear corner of fuse box by the fire wall. Yes i removed the grounds there and rechecked. Only get volts to one side(which you should thats why the fuse is there for the power to go in one side out the other).

Also if the switch is on when the fuse is pulled and put back in you can hear the fuel pump kick on and the injectors pulse. It acts just like one that the main relay isn't working thats why i thought thats what it was.

 

Actually, all hood fuses should have battery voltage on both test tabs whether or not the key is in ON(II). If only one tab has voltage, then the fuse is faulty.

 

I was talkin with the fuse out. If there is no fuse it will only have it on one side correct?

Oh and when this first started i was blowin ecu fuses like crazy for a few days. it hasnt blown any ecu fuses for a week or so now.

 

Correct. But the best way to check fuses is when they are plugged into the fuse box. Do this test on fuse 31 when the engine won't start. Any time a fuse gets voltage on the hot side tab, the other tab should also be hot. This true for any fuse, including those in the dash fuse box.

 

Thats what i was thinking. Ill check both side tomorrow. Usually you can go all date and not have to reset it like 2 or 3 times. Sometimes you can turn it off and it will start right back up and sometimes not. Some times turn it off and ours later it will start without a reset. never a certain pattern. Some times you have to rest everytime, sometimes dont have to reset all day.


I'm wondering if it could be the ecu short from the short out. I have found one on here with some other stuff im interested in if it is. Bad thing is i dont have a way to check. Dont have a spare ecu or know anyone that has one to try.

 

If the fuse has voltage at both test tabs when the engine won't start, then my guess would be that the ECU was damaged by the voltage surges produced by the bad short. But the wires and hood fuse box must be tested before you jump to this conclusion.

 

I have went through the wires for shorts and melts. ill check the fuse box tomorrow and see whats goin on there. I really couldnt think of anything else. If i dont have power on both sides you thinkin bad connection in the box?

 

Just remember that you must only do tests of the fuses and wires when the engine won't start. Otherwise, you won't learn anything.

 

Yeah i know. Will cause false readings if everything is working right and it starts.

 

Ok i checked this morning. Have power to both sides of the fuse. Once the fuse is pulled and reset then the IAC don't hum anymore. Think its the ECU?

 

It's quite possible.

 

I found one on here im goin to try to order from the guy.

 

Update on this. Changed ecu's, Engine harness, main relay and a few other things still does the same thing. Wired up a push button toggle and a relay to power the ecu. Now I just turn off the switch when I get out and back on when I get back in. Cant find any other probs anywhere so I'm lost at where to go. I did talk to guy at Xenocron. They had one doin the same thing and never figured it out before they got rid of it.