If fuel pump came on when MFR jumper was installed, but hesitates when MFR is controlling, a faulty MFR is indicated, despite MFR being replaced.

When I was having fuel pump problems I rigged one old MFR w/ internal jumper (under the plastic shell) and installed this MFR. Car cranked and ran fine.

Only issue w/ running a modified MFR is the fuel pump would possibly continue to run in a severe front end accident (likely purpose of MFR) which stops engine. If a fuel leak exists then fire hazard would be increased. You should not permanently run this modified MFR if you try this.

regards

 

OK, I know it seems like the MFR but I'm more sure now that it's not.

I tried to crank it today, fuel pump would not come on after more than a minute with key at start position. I took key out, left doors open, aired it out, and blew computer area out with a fan for a while just to see if it's a humidity thing. After 30 minutes or so of this I put key back in, & turned to start. In about ten seconds the fuel pump came on. I cranked it and ran 5 minutes or so. The I tried taking the key out and putting it in a few times. Each time the time for the fuel pump to come on would be less and less, like something was warming up and working better. Maybe the MFR. So I took out the key, replaced the MFR with the old one I replaced originally, ( kept it in the trunk just in case it wasn't the problem), and when I put the key and turned to start the fuel pump came on in just a few seconds. So something seems to be either warming up or drying out or both and making it work better, but I don't think it's the MFR.
I'm wondering shouldn't the pressure stay built up enough to crank it without the pump coming on anyway? Especially if I just took the key out and put it back in?

 

Seems to be a humidity related problem but I suppose it could be temperature, it rained all week and the few times I put the key in and turned to start the pump never came on.
Suppose to be sunny this afternoon I think I'll try drying out the MFR side of the dash first , maybe with a hair dryer. If that doesn't work I'll do the same to the computer side.

 

OK, the Hair Dryer experiment worked.
I tried just opening doors on a hot day, and airing it out, fuel pump wouldn't turn on. Tried blowing with leaf blower, still nothing (very humid out). Tried switching Main fuel relays , nothing.

Got hair dryer and placed it near the bottom of the cover of the computer, near the circle in the picture

http://postimg.org/image/41hyr105r/

I let it run 30 minutes or so on WARM, not hot, turned key over and it cranked immediately, just like it should. Drove it a while, and turned it off, and as it sat and cooled down the delay would gradually get longer and longer, until after a couple hours the fuel pump would not come on, even after minutes of waiting.
Anything under that cover besides the computer that could cause this problem?
I'm thinking of installing a hair dryer if I can find one that plugs in the cigarette lighter, but that might be a drain on the battery. Also I guess I would start by removing the bolt circled and the ones like it to get the cover plate off?

 

just to be sure I repeated this and it worked again, is one of the bolts sticking out the back of the cover a ground? I'd like to loosen and tighten it if so.

 

I think the grounds go through the wiring.

It sounds more like an ECU or possibly a TCU problem to me.

You can also try shaking that wiring harness in the picture then check if the engine starts. You may want to unbolt that cover, remove the electrical connectors and check for loose pins on the ECU and TCU.

 

I tried pressing on the wires, and jiggling a little, no luck with that.
I'll try taking it apart next, soon.

 

I tried pulling the codes one more time, since I have reset the computer and drove it 30 minutes or more since the last time. (disconnected battery cables and touched them together for a minute to reset)

This time I got transmission (D4) codes 13,14 & 18, nothing from check engine light.

 

13 and 14 point towards a bad ECU. I have no code 18 listed, so that would mean a bad TCU or you counted the flashes wrong. I would stop by a u-pull-it junkyard to find an ECU from a 94/95 accord, automatic transmission, that is an EX. ECUs from manual transmissions, and LX/DX will not work properly.

There is a ground on the driver's side of the upper intake manifold that you should unbolt, clean bolt and eyelet with a wire brush or sandpaper, then reattach. See G101 in the pic:

 

I'm pretty sure it was 18, I did think it was weird that it wasn't in order.
From what I remember it started with one long, then 8 short, then went one long and 3 short, then one long and 4 short.

I would expect it to go in order but I'm not basing that on anything, just makes common sense it would