1999 Civic Ex auto.
Another Crank but No start.
Got the car with it halfway tore apart. I think the previous owner went to r&r the D16y8 and found out he was in over his head. Complete nightmare. At first I wasn't getting power through main relay for anything. No clicky. Now only one side is getting power after fixing a broken wire at the ecu ground junction connector behind the intake mani. So fuel pump primes when ignition is on and runs on start. Cel stays on for a few seconds with key on and then goes away, along with srs light. Now I'm not getting spark or injector pulse. Fuses all test good and grounds are in place including the one on tstat housing. A speed sensor on the trans is disconnected/harness connector ripped apart and knock sensor is broke as well. I'm just wondering if these two can cause a no start and if I'm missing something along the lines. It has a new import direct main relay in it as well. If someone could point me in the direction of some decent wiring diagrams that would be terrific.

thanks for the help.

 

Update:
12v power is at all injectors and coil checks good, power through it. I have no tach movement when cranking. I'm assuming ecu isn't grounding. Anyone have a link to ECU grounding tests. It's a p2e ecu.

 

Another update:
Injectors are pulsing, no power to crankshaft position sensor when key is on. No CEL either. The two other pins are directly to ground. Where does the CPS get power from?

 

Sounds like the crank signal is missing. Check the CKS. Diagrams coming.
OK go to fundamentalbaptistministries dot com /honda/
Your diagrams are 4 and 5

 

Should it only have 5v on it? Regardless, no power out of pcm on c22 when key on or when cranking. What supplies power to this through the pcm?

 

C31 is the supply. The shielded wire is C22 and it's the signal wire. It's will produce a square wave if the supply is good. Check the C31 for voltage. Key on.

 

No voltage on C31 at ecu with key on. It's also a P2P ecu. I apologize for my mixup.

 

If the pin tension of the connector is good the PCM is bad. It would be nice to see what a scan tool shows for the other sensors with key on. I think there are others that will be without power. You have narrowed down the problem.

 

Well the CEL comes on for two seconds as the fuel pump primes and then goes away. I've opened the ecu and it appeared good inside. No burnt caps or tracks. I guess I'll try to track down a new pcm. Having no Knock Sensor connected nor a transmission sensor would cause this?

 

The PCM will supply power regardless of other sensors or modules being out of the system. If the power and ground are good to the PCM it should be providing power to the CKS with the key on. You have found your problem.

 

Alright. Well I ordered another ecm off of ebay for 42 bucks. should be here by next monday. I wonder what caused it. I know there were sensors depinned from someone trying to rip the connectors apart. Mainly just the front o2 and a couple on the transmission. Would a short be the culprit? On a separate circuit? I feel like a fuse should have blown in that case.

 

The power supplies the PCM produces are not prone to failure but they do go bad. GM has some early models that are real bad. Honda are better but not exempt from failure. As for a short causing the failure I doubt it. They have protection circuits built in to keep that from happening. That don't mean they always work.
Good luck.

 

Thanks for the help man. It's been a disaster with this thing. I had the engine back out because the previous owner had done some questionable stuff. Crank to flexplate bolts were barely tight as well.
I was always use to seeing ecus go in dsm's. They were visible when you popped it apart. I can't see anything wrong on the inside of this one.

 

You will not always see the problem by looking at the circuit board. We rebuilt many different modules and many will not LOOK bad. What usually is bad that you cannot see is a transistor or chip. They will blow and you cannot tell by observation. it requires specialized test equipment. I'm pretty confident you have found your problem. I say....pretty confident because I've been fooled before.

 

I mean there are literally no other tests to do. None of the other connections in the diagnostic block could effect just this power, correct? One black wire was broke so I just ran it back to another black wire since the plug just connects all of them I thought that would be good enough. Doing that got the main relay working.

 

Replacing the ecm did not fix the issue.

 

That sucks. Are the power and grounds to the ECM good? Load test the circuits.

 

 

I figured it out. Turned out it was the coil. I had power through and ohmed it out, but never actually checked to see if the icm was triggering it. Not too upset I bought an ecm because it was dirt cheap off Ebay. The new coil from a local parts store was twice as much as the used ecm. The so called good junkyard engine has a pretty wild knock and I've got am intense idle surge from about 1.5k to 3k rpm. Its probably a mixture of base ig timing being off and a shot iacv. I'll have to get a scan tool or jump the diag plug, but for now it runs.

I had decided the main relay was fine after finding I had power and pulse on injectors and power through the dizzy.

 

Ohm testing a coil is notorious for false negatives (test says the part is good though it is actually bad). The coil is prone to burn out from firing into an open circuit. Never run or even crank the engine with a spark wire disconnected unless you have also cut power to the coil by disconnecting the harness wires going to the distributor.

 

especially when doing a compression test, remove power to the distributor.