90 accord with engine swap??? no start

I don't have experience with Honda's. I am looking at a 90 Accord that wont start after a thermostat swap. Checked for loose wires or dirty connections in the vicinity of the thermostat, nothing. While looking thru the pathetic Haynes manual, I did notice that the distributor shown in the book for this car did not match what was actually on the car. The distributor on the car has some type of hall effect sensor resembling a cam position sensor. I talked to the owner and I was told that they don't think this is the original engine because it has markings from a local scrap yard. Now I need to find out what motor it has in order to correctly diagnose the problem. About the problem, it doesn't get fuel. The pump won't come on. Apparently, the fuel pump is not getting a signal from the "main relay" under the driver side dash. The relay was replaced by the owner using one from the scrap yard, still the pump did not come on. I used a power probe, test light, and a jumper to wire the relay. The terminal that feeds the ignition came on and the one for the pump remained powerless. I think it's the relay. Owner took the car to a local shop nearby where they hooked it up to an analyzer and came up with the conclusion that the distributor is bad, hmmmm... Does the dist. turn the pump on in some way, directly or indirectly?? Any experienced replies would be greatly appreciated. Thanks in advance.

Is the car a manual or automatic transmisson? Is there 12 volts on the blk/yel going into the main relay? What about voltage on the grn/blk wires going to the ECU (there should be none, it is the ground source for the coil that turns the fuel pump on). Power to the fuel pump coil comes in on the yel/blu through a 10A fuse from the 80 Amp fuse off the battery. If voltages going into the main relay is Ok, the only thing that could keep the fuel pump relay from closing is a ground to the coil which comes from the ECU. I don't think the distributor comes into play until the starter is activated. The fuel pump will come on momentarily as soon as the key is turned on if voltages and grounds are good.

Or it could be a bad main relay. The main relay is not complicated and can be disassembled, examined for cold solder joints and resoldered. It consists of 2 relays and two diodes and a resistor. The resistor and diodes are in the fuel pump coil circuit. With it disassembled you can apply voltage to the coils and see if the relay closes. Then at the diodes on one side of the relay and ground to the other side. The relays should click.

Is the car a manual or automatic transmisson? Is there 12 volts on the blk/yel going into the main relay? What about voltage on the grn/blk wires going to the ECU (there should be none, it is the ground source for the coil that turns the fuel pump on). Power to the fuel pump coil comes in on the yel/blu through a 10A fuse from the 80 Amp fuse off the battery. If voltages going into the main relay is Ok, the only thing that could keep the fuel pump relay from closing is a ground to the coil which comes from the ECU. I don't think the distributor comes into play until the starter is activated. The fuel pump will come on momentarily as soon as the key is turned on if voltages and grounds are good.

It's an automatic. Since all the fuses are good and we seem to be getting spark, I assumed the power was getting to the main relay. I will check the blk/yel wire for voltage. On a side note, when the car wouldn't start I checked for spark by removing the plug wire and placing it so it would arc to ground, I didn't get anything out of it. The owner did, however, sprayed starting fluid in the intake tube and cranked it, it started, well tried pathetically anyway, ran for about 3 seconds flat. I assume that means it's getting spark, probably a weak one though.

Power to the fuel pump coil?? Do you mean power to the "main relay"? Is the coil inside this relay? With the relay connected, I did verify power with a test light coming out of the terminal leading to the front (engine bay??). According to the book, the 12v constant was good, the ground was good (verified with a power probe). When the ignition was turned on, the "remote" came on and sent power out of only one terminal, not two like I think should happen, once again, according to the schematic in the "book". And it does "click", but still no power to the pump.

The main relay has two sources of power going to it. One is straight through power for the fuel pump and the other is for the ECU and also powers the coils for the relays. The coil for the fuel relay is inside the main relay box. You heard clicking but there are two relays, so which one was clicking? or were both?

The main relay has two sources of power going to it. One is straight through power for the fuel pump and the other is for the ECU and also powers the coils for the relays. The coil for the fuel relay is inside the main relay box. You heard clicking but there are two relays, so which one was clicking? or were both?


By straight thru, do you mean constant regardless of ignition status? That would make that one straight to battery, yes? (besides obvious fuses and such). And the other for the ECU and coils in the relay, that is ignition activated, right? As far as the clicking goes, it sounded like one. It didn't sound any different from any other relay on other cars like for the horn, lights, power windows and such. I'll check it again, maybe I can open it up and see if both coils are being activated when power is sent to the relay.

Straight through means that this power, which comes through the ignition switch and a 15 Amp fuse, goes through dry contacts on the fuel pump relay and then to the pump. In addition, this power activates the main relay coil/contacts that applies power to the ECU and the coil that activates the fuel pump relay. So ,when the ignition switch is turned on, the main relay is activated which then activates the fuel pump relay.