Hi, guys I've been on here before looking for information about a problem I've been having to no avail. Maybe someone can help me out. Sorry if this post is in the wrong place.

I have a 1992 Acura Integra LS with a B16A2 engine and a YS1 trans.
The problem Im having is that the fuel pump is not getting power. I have replaced the Main Fuel relay with a new one, check and replaced fuses, triple checked all wiring including wiring at the ignition switch. Cranks but no start, has great spark and nothing wrong with timing. I can get the car running when I energize the pump directly to the battery though. I am at a complete loss. The car doesn't have a fuel shut off switch however I don't know if there is something else that acts as a shut off?? please help.

 

Help please

 

See the top portion of this page, especially "How does it work?". This explains the relationship between the ECU and the PGM-FI Main Relay.
http://www.tegger.com/hondafaq/start...html#mainrelay

 

I will take a look, thanks for tip

 

Have you made sure the PGM-FI Main Relay as all three(3) powers?

12V+ constant , [hot at all times].
12V+ switched, [hot in run and start].
12V+ switched, [hot in start only].

Also make sure IGP1 and IGP2 at ECU/ECM both have power when ign. is in the run and start positions, they are the only two(2) yellow/black leads going to the ECU/ECM and both must have power for fuel p[ump to work. 94

 

I have checked for the 12v+ constant that is good. I just now finished tracing and testing all wires for shorts or grounding out. I also retested my main relay which is also good. I'll check the 12v switched and ecu wires for power in a few minutes. Its just weird When I test for power everything is fine but still wont run with out a direct hookup to the battery.
You don't suppose the crank sensor is cutting off power do you?

 

Ok, please clarify that Im testing the correct wire for switched power (when the key turns) The thick yellow/black wire with red dashes/ terminal/pin 7 ?? On first key position I get a negative reading of about .2 when key turned to start position I get a negative reading of .5
Testing on dc setting.
btw battery is a little low on volts 11.98

 

2 wires coming out of the ecu yellow/black are coming up negative reading .02v

 

Yes, the first switched power is a black/yellow, pin 5 from fuse 24-15A. [under dash fuse box], it turns on the fuel injector relay and is the fuel pump power, once it goes through the fuel pump relay.

Yellow/white is the 12V+ constant, pin 8 from fuse 38 -10A. [engine bay fuse box] it is input to the fuel injector relay.

The output from the fuel injector relay is yellow/black, [there are two(2) yellow/blacks. the other is the fuel pump power lead from the fuel pump relay].

The yellow/black from the fuel injector relay is what powers the fuel injectors, [also yellow/black leads and IGP1 and IGP2 at ECU/ECM.

Check for power at the fuel injectors.

If you do not have 12V+, [or whatever your batt. voltage is] at IGP! and IGP2 the ECU/ECM will not "turn on" so it will not supply the ground the fuel pump relay needs, green/black, pin 1.

Try this, turn ign. on and use a jumper to supply a ground, [from black ground lead, pin 4] to the green/black, if pump turns on, the problem is no ground from ECU/ECM because IGP1 and IGP2 do not have power.

If you have power at the fuel injectors and not IGP1&2, you have a connection problem between the PGM-FI Main Relay and the ECU/ECM. 94

 

hmm, I will try that in the morning. Thank you alot for trying to help me. Moving in a week and cars gotta go too ya know.

 

I have no ground from ecu, what does this mean?

 

The ECU has TWO grounds: One is permanently "on" and the ECU just monitors it. The other is turned off by the ECU when it wants to turn off the fuel pump.

If you had studied the diagrams on my page (referenced above) you would have seen that.

 

That even has me confused, did you mean the PGM-FI Main Relay has two grounds, one constant and the other one controlled by the ECU/ECM???

To OP, if the PGM-FI Main Relay is not getting a ground from the ECU/ECM, [green/black] you need to check and make sure IGP1 and IGP2 both have power, [12V+] when ign. is in both the run and start positions. 94

 

That's correct.

Study the diagrams here:
http://www.tegger.com/hondafaq/mainr...ion/index.html

 

then what do you mean by, "One is permanently "on" and the ECU just monitors it"??? 94

 

I do not know exactly why the ECU has that permanent ground, but that is how Honda does it.

If I had access to the ECU schematics and knew the exact function of each chip, I could probably figure out why it is done that way. Or you could, because something like that seems to be more up your alley than mine.