Extremely Frustrating Fuel Pump Wont "energize"

[MySi93]

Greetings,
I have a 1993 Civic Si Hatchback, this is a second owner car. I have had it for sixteen years. It has 357,000 miles (stop)
I have been building cars for over fifty years. I am sixty eight and i love this amazing car. I have been restoring classic cars for over
fifty years also. I guess my point is I have been working on cars a long, long time. I keep this car because mechanically it is very near being!
restored; You name it, the car runs amazing, has all kinds of power, can hardly hear it idle. (did full valve job, new timing belt, water pump, and
much more recently. I could list all the major and minor repairs, but I will stick with this issue. It has driven me nuts. I will try very hard to
describe what is going on. And let me thank in advance you all for your help!

We all know when you turn you on the ignition switch you will hear the fuel pump start, energize, prime, whatever you want to call it?
The fuel pump has to come on and run to pressurize the fuel inj. rails. Once pressurized it will shut off, fire car and it will start. The PMFGI
relay will run the fuel pump, etc.

This issue is totally intermittent, only outside temperature and moisture seem somewhat consistent but not totally.
Yesterday after being in a storage unit for 4 days in fairy cool climate, fuel pump came on, car started fine, drove it home, ran perfect.
This AM, it had rained last night, it got somewhat cold, and the fuel pump will not come on, it is still moist outside, and damp ish.
I am in Boise, winter is not here it is about fifty four, cloudy.
Some times when it won't start, actually many times I could gently jiggle wires at PMG, to fuse box, in general, in can be insane.
It wont come on, I reach towards fuse panel, I don't even touch anything and it comes on. I know this all sounds either typical or
and easy fix, or insane, take your pick. I am a good mechanic. Here's more background:
NEW:
PGMFI (2)
Fuel pump (X2)
Complete ignition (not just the lock) had to pull the column (this was what the Honda dealership diagnosed) They were wrong!
All wiring and harness from top hat of fuel pump to front wiring.
Checked all fuses
ECM re-built by reputable company who tested it and returned it as "good"

This car is in highly excellent shape, I have done huge amounts of work to keep it running so amazing.
The car never ever shuts down once it starts, will run forever, and usually once car is driven some it wont do it
but that isn't always true. Again so intermittent, no rhyme or reason, just what I have talked about so far here.
I tried a few hours ago, no start, I will go out and try right now, just for kicks? Nope nothing.
Honda, best mechanic in town? Every time I take/tow it to a shop, it always starts for them and of course they can't fix whats
not broke (whatever) I apologize for my ranting. I am better then this I have owned over 80 classic cars, I love this car.

Please help!













ig

 

[nd4sped]

Im assuming you mean the fuel system relay when you refer to "PFMFI". Which is located just under the left side of the dash on the drivers side. If not, here is a diagram. Sounds like you have done more than a good job on diagnosing and working this issue. Last comment jives 100% with what I was assuming while reading your post.



This very much sounds like an electrical contact issue. As the temperature drops the contacts are contracting and quick possibly loosing contact during cold conditions. Additionally, when it rains this creates high humidity and at a molecular level all metal gets water droplets on them. These collect and eventually create condensation that eventually the eye can see.
However on small electrical components and contacts, we don't see it so we don't assume it. I would begin with cleaning all the electrical contacts, primarily starting with the "jiggle this part to start".

If breaking down junction boxes does not sound like fun, you can always order new ones online. Sometimes Honda still has them as many of the plugs are still used in other applications. OR OR OR, like, me, go junk yard diving for new connectors.

Hope this helps and nice EGg. Seeing an EG that is unmolested now is really hard to come by. Keep it another 10 years then sell at premium for your Golden Years

 

[MySi93]

Hey everybody, my thread about my civic fuel pump issue. After a year, even after a company checked and tested the ECM. Had numerous shops give wrong diagnosis. I tool the ECM out again. Took the covers off. Every thing looked fine. However the ECM has a memory side a power side. On the power side is an IC. IC 17 on board. This component was/is defective. I have ordered the cheap part foe $10 on ebay. Because of all the crazy temperature and moisture issues it would energize the fuel pump. Through experimenting, I have the ECM on floorboard, I heat up the ic with a blow dryer, and the fuel pump comes on and car starts and runs great. A whole year of trying to fix this. It is starting and running fine. If you read my very long post, you might understand how happy I am to get my hatch back.
Thanks ya all.

 

[nd4sped]

Glad to hear it. The Honda ECU's are know for the capacitors going bad. This is a very typical issue. You can find all the parts you need for ECU repair on https://www.hamotorsports.com/