Frazzleddad

Stock 1998 Civic CX Hatch with D16Y7 5speed

Pulled my son's car into garage a week ago (he's away at school with my car while I was to repair his) to change oil and replace gas tank (leaking at the seam). Finished both tasks and the following resulted. Been trying all week by searching Honda forums and trial and error but still have no answer.
My replacement parts were taken from known running vehicles. I am the manager of a salvage yard so the expense of throwing replacement parts at the problem has been none. End results are the same with all used parts switched out and retried multiple times.

Car would not restart (turns over but will not fire)
That was strange so I tried scan tool ( same one used numerous times on his car) but it would no communicate with ECU and I noticed the main relay was not clicking nor the pump priming.
With key on (II) no priming and CEL remained on instead turning off.
I have confirmed with multimeter: All fuses in car are good and I'm getting power to main relay (tried 3 to be sure)
Visually confirmed to be getting spark to be sure that was not an issue....(installed new distributor about 8 weeks ago)
Have tried 3 ECU's ( original and 2 replacements ) and today I was about to test the connectors for the ECU with multimeter (I had key in on position) and as I plugged connector A in, the relay clicked and pump primed. With connector C plugged in I will get the same result but when connector D is plugged in...it's back to square one.
One good thing(maybe?) without D plugged in the CEL will come on, blink once, and then remain on. Figured good time to try scan tool and retrieved codes P0118 (coolant temp sensor) P0113 (intake air sensor) and P1298 (ELD). Found the Honda service bulletin concerning the wiring below intake near oil filter and hoped that the was the answer thinking when I had changed the oil filter and bumped the harness. Inspection of wires showed the frayed wire had been previously re-taped so I removed it and applied a fresh coat of tape to the frayed(not broken) wire but it did not solve anything. I am assuming the 3 codes are a result of connector D not being plugged into ECU.

Where I stand now :
Connectors A and C plugged in will allow scanner to communicate,CEL will flash once and then remain on, pump will prime and engine will almost fire,it tries to catch (without D connected there is no TPS,MAP, and various other sensors not hooked up so that is not a surprise that engine will not run)
With A -C - D all plugged into ECU the CEL never flashes-it just comes on and stays on, pump does not prime, scanner cannot communicate, and car turns over but of course without fuel (and who knows what else is being denied) there is no near fire.

Ready to so any help for a guy who's been around and working on cars (this is my first time for Honda) for nearly 40 years will be greatly appreciated
Edit: Forgot to mention I checked the 3 grounds I could see (Neg term to body,block to body,ground on thermostat housing). Is there any I may have overlooked? I'm aware of proper grounds being essential.

Frazzleddad

As a seller of used parts I understand that electronic components will fail without rhyme or reason but also experience puts a strong leaning to cause and effect theories, hence the hope that changing the oil filter disturbed the harness below intake manifold producing the P1298 ELD code. In no way can I profess to have much knowledge of the Honda PGM-FI system but from what I've learned, can it be possible that a short in one of the sensors associated with connector D can produce a shutdown of the ECU if that sensor is actively wired into the system?
After work today my next effort was to be: one by one unplugging each associated sensor (probably starting the the fuel tank pressure sensor) because I did install a new tank and transferred over the original pump and sending units. After removing each component from the system, I plan to reinsert connector D back into ECU to see if it will power up and start the main relay/fuel pump prime procedure. Below is the wiring template I am working off of. If anyone has any other ideas or direction to head, I'm all ears.

sdaidoji

iTrader: (1)

oh, darn...

if our resident pro member ezone have not said anything, I bet you have a pretty difficult issue...

electrical is not my thing, so good luck...

ezone

Sorry I'm late man, I work for a living, plus I'm all doped up on cold meds. Not feeling at the top of my game right now.

What's attached to the D connector on the ECM......?

MAP,
knock,
ELD,
FTP,
TPS,
IAT,
ECT,
O2#1,
O2#2,
sensor grounds,
G101 ground,

So it stands to reason any of these would set codes while the connector is unplugged....

Logically, retrace steps here:
You say you had the gas tank out--- now everything went haywire....
ECM-D connector has some effect on the symptoms.......
FTP is fuel tank pressure sensor, could it be shorted (5v sensor line) causing the ECM to shut down?
Pinched harness?

Unplug it and recheck,
maybe lower the tank straps by several turns and recheck?
(might need to disconnect the battery to reset the ECM after each attempt)

After post #2, did you gain any improvements?

Frazzleddad

@ sdaidoji
Thanks for your concern but I have solved the issue. It was in fact the Fuel Tank Pressure Sensor, not just a faulty one but I am guessing it was actually shorted (no doubt by myself somehow during the fuel tank replacement). Upon taking it down from the left top side of the tank seam I disconnected it, plugged in the D connector to the ECU, turned the key to on (II), and heard the sweet sound of the fuel pump prime. Other posts I have read detail dealing with a faulty FTPS but the car is still in running condition. Apparently, a shorted or fried one will not allow the ECU to function. Car is running fine and CEL is off but of course throwing a P0450 code. Once it is run a bit I'm sure the CEL will appear but hopefully by then I will have it swapped out with a good one.
I could say that the 18-20 hours spent tracking this gremlin down was a total waste of time but I prefer to think of it as time well spent learning about a fuel/ignition system of which I knew nothing.
Although no one popped in with any advice in the single day my OP was up I wish to thank the moderators and all contributing members of this forum. Their experience and sharing of it helped guide my thought processes and did help eliminate the most common and probable causes of the non-start that I was up against.

One last thing: As a mid fifties guy who has never posted to one of these forums I would not how to go about it, but I was hoping that it was possible for a moderator to change the name of the thread to something like : Shorted(Fried) Fuel Tank Pressure Sensor : or something along those lines. That may help someone in the future with similar symptoms find the thread and hopefully avoid the headache that I experienced. Thank you.

................... lol

Frazzleddad

@ ezone

You must have been posting as I was typing (lol..very slow hunt and peck).
Your logic is sound and I thank you for the time and effort.

Frazzleddad

BTW, I meant to mention that to confirm a fried FTPS would shut down the ECU, after car was up and running I plugged the sensor back in and it killed the engine immediately. No harm done to the ECU. I guess it was designed to do that.

ezone

I see your fix is pretty close to what I was thinking it would be. Glad to see you got it figured out.

When posting on a forum (depending on how busy the forum is) you might want to give it a day or two for the regular and active members to have a chance to read at our leisure and reply. I know that doesn't help when you need answers in a hurry, but sometimes that's the best we can do.


EDIT: I believe YOU CAN go back and edit the title of the thread

sdaidoji

iTrader: (1)

Frazzledad,

glad you found the problem, and happy to hear your kind words and willingness to be of help to the community.

sorry for not being really of help...

never mind how ezone expresses himself, that's how he rolls, as his avatar says

but he is our beloved "if he does not know how to solve it, he will find a solution"

ezone

Did I say something wrong? (sure wouldn't be the first time)

Thanks. I try sometimes.

sdaidoji

iTrader: (1)

Nah, the first sentence is mellow, the second is instructive, and the third is also instructive, but a snowflake could get hurt (which is not the case here, but since frazzleddad have been so nice, I mentioned it

But had to mention you are our beloved

ezone

Now that the title was edited I can see what time the first post went up... I must have been too loopy to even think about it yesterday. Been fighting this cold since about friday. Wasted the decent weather we had saturday trying to sleep half the day.

sdaidoji

iTrader: (1)

Hope you get better soon