justhatched231

I did the following to my 1992 Acura Integra:

Replaced MFR (Main Fuel Relay) with a brand new oem
replaced fuel pump
replaced wiring between pump and MFR

I am getting fuel at the rail, I am getting spark, timing and compression is good but for some reason my injectors aren't spraying and I am not sure if the MFR is working like it should to tell program fuel injection to tell the injectors to spray. I am totally confused. Any help would be great! Please help me !

justhatched231

any ideas?

JdmTypeRdc2

iTrader: (1)

Maybe the ECU or injector clips. Loss of ground/short somewhere along the line maybe?

justhatched231

I am not even sure where to begin or how to test any of the above.

JdmTypeRdc2

iTrader: (1)

check the wires that lead to the injector clips. Make sure these lines are ok and nothing has shorted out.

A good way to check if you are getting current to them is to get a test light and test each individual clip for power. As far as the ECU, it can be sending bad signals to the injectors causing them not to release fuel. Have you tried scanning the ECU?

justhatched231

Its not getting power at the Injector clips. We tested it. How do you scan the ecu?

JdmTypeRdc2

iTrader: (1)

You will need an obd1 scanner. You can purchase one, which i dont really recommend. You can, i believe, rent one at your local auto zone, pep boys etc. Or you can take it to a shop and have someone do a quick scan for you. They should not charge you more than 30 dollars to hook it up and see if it is throwing any codes related to the fuel delivery system

fcm

If you are not getting power at the injector clips/plugs when ign. switch is in run or start then the problem is either the injector relay, [one of the 2 relays in the PGM-FI Main Relay] unlikely as you said you replaced it, but can't hurt to check, or a connection problem between the PGM-FI Main Relay and the injectors, it's a 92 so there is no "Fuel Injector Resistor".

I would start by dropping the PGM-FI Main Relay so you can test the output, there are two (2) yellow/black leads, one is the injector relay output and it should have 12V+ on it as long as the ign. key is in run or start, the other yellow/black is the output from the fuel pump relay, it will have 12V+ on it for a few second after ign. key is turn to run and a constant 12V+ when ign. key is turned to start or engine is running.
If there is power on the injector relays output, unplug the relay and do a continuity check between the output at the PGM-FI Main Relay plug, [yellow/black] and the injector plugs, [yellow/black leads at each injector plug].

While you are at the PGM-FI Main Relay test for power on the yellow/white lead, fuse 38 - 10A [hot at all times] in engine bay fuse box.

You will also have to confirm that there is 12V+ on the two (2) yellow/black leads going to the ECU/ECM, [when ign. switch is in run or start] not sure of pin location but they are the only yellow/black leads going to the ECU/ECM. 94

JdmTypeRdc2

iTrader: (1)

^^^

justhatched231

I checked all of the above and I got power at all. The check engine light is staying on and I pulled the fuel rail and I got fuel and pressure there so I checked to see the injectors are spraying but they aren't seems like they arent getting signal to spray but they are getting power on the one wire.

fcm

Pull the ECU/ECM and test the two (2)yellow/black leads, [they are the only two yellow/black leads going to the ECU/ECM] they must have 12V+ on them when key is in the run or start position, ECU/ECM will not pulse the injectors if these two leads do not have power, the power is supplied by the injector relay, [that is working as you have power at the injectors] but there may be a bad connection someplace. 94

justhatched231

so pull the ecu and test them wires?

justhatched231

I was only getting 6v at the injectors

fcm

The voltage should be 12V+ not 6V, is the cars batt. charged?

Start testing at the PGM-FI Main Relay, drop the relay and test for power on the two (2) yellow/black leads, one is the injector relay output and should be 12V+ when ign. key is in the run or start position, the other one is the fuel pump relays output, it will be 12V+ for about 3sec., [pump priming] when ign. key is in run and 12V+ during crank.

If the above is good, test the two (2) yellow/blacks at the ECU/ECM, both of them should be 12V+ when ign. key is in run and start, it is the injector relay that supplies the 12V+ to the ECU/ECM, [yellow/black leads.

I would also find and test the connections at the injector wire junction connector, the output of the fuel injector relay splits after the relay, one lead goes to the ECU/ECM the other lead goes to the junction connector and is split to the 4 injectors and two leads go to yellow/black at idel air control valve and yellow/black to black at heated oxygen sensor, you should test voltage at the two sensors, if they are also only 6V, [and injector relay output is 12V] then My guess is that the problem is at the junction connector, or someplace in the wiring.

You can also "back feed?" 12V+, using a jumper connected to the batt/ pos.(+), turn ign. on, connect other end of jumper to any of the yellow/black leads at the injectors or at the IACV or the 02 sensor or even at the "output side" of junction connector. 94

trm4life

If the CEL is staying on it's a bad ECU!!