Got a 1990 Honda civic 1.6 DX, That won't start. It cranks, but it won't start up. Everything inside the car works , check engine light comes on. Not getting any spark but have replaced the Distributor, fuel pump, alternator and main relay.
Also replaced the IACU. Thinking it may be a crank shaft sensor but have no clue, any ideas? Don't think it's the igniter because the car does crank. Before it started doing this, it was unable to go over 3RPMS without stalling out and would shut off during idling. Problems after problems have been going on with the car since, we replaced the clutch.

If the Check Engine Light comes on for 2 seconds and then goes out, when the ignition switch is turned to ON (Position II), then focus on the distributor. Replacing the Ignition Control Module (ICM) and coil, located inside the distributor, usually solves the problem. Be sure to apply silicone heat transfer compound to the back of the new ICM. If the problem persists, install the new ICM and coil in a genuine Honda distributor housing--all others are suspect and unreliable, including new aftermarket distributors for Hondas.

Hey there TX,

Sorry it took me so long to get back to you. The engine light stays on, it doesn't go off after 2 seconds, and the distributor is brand new. We did a test on the fuel pump, and it is only getting 6 volts, but that's brand new as well. We are thinking that something is restricting the amount of power that the fuel pump is getting, but aren't sure what. No flashes on the ECU either.

Replace the ECM and the engine should fire right up.

We put the ECM in a 91 CRX... won't start, but it does allow the fuel pump start. In the Civic, it does not allow the ignition or the fuel pump to start. There is no spark. We didn't expect it to start in the 91 CRX, but it does allow the fuel pump to start.

If you install an ECM, with the correct Honda part no. for the 1991 Honda Civic 1.6 DX, I think all of your problems will be solved. It goes without saying that you should check all under dash and under hood fuses with a test light or multimeter. Particularly, check the ACG (ALT) (S) fuse in the under dash fuse box--ensure it's not missing. Similarly, clean the main ECM ground on the thermostat housing. There will be no joy, until the CEL comes on for 2 seconds and then goes out, when the ignition switch is turned to Position II.

Where exacly is the ACG fuse at? It's in a 1990 honda civic 1.5 dx, do you have a picture? Because the panel does not identify an ACG , and the panel numbers only go up to 18.

We also checked all the volts on the under hood fuse box, and it has 12 volts in/ 12 volts out.

The ECM is a pg5 for the honda civic 1.5 DX.

1.6 or 1.5L engine?

I don't have a picture, but they are usually in the top right-hand corner of he under dash fuse box, located near the SRS fuses. You likely don't have SRS fuses since you don't have an airbag.

1.5L engine.

Check fuse no. 12—15 A, ECM, Cruise control unit, Alternator
[This is the crucial ACG (ALT) (S) fuse I frequently refer to, if your Civic does not have the Supplemental Restraint System. If missing, or blown, the CEL will not go out and the car will not start, since it controls power to main relay terminal 5. Terminal 5 controls power to the main relay's first relay, which controls power to the ECM and fuel pump. If terminal 5 doesn't receive power, this relay won't "click," when the ignition switch is turned to ON or Position II.]

Disconnected and cleaned the connector to the housing thermostat and am getting 4.91 ground reading.

OK going to go check the fuses now.

The fuse Alternator Cylinoid use was blown, we replaced that and it started up. Thank you so much we have been working on this car for 3 weeks. :D Thank you profusely.

Very nice job!

Going to take it for a test run around the block and make sure it won't stall out at 3RPMS

Sounds like it was ACG (ALT) (S) fuse. Was it fuse no. 12?

It was fuse no. 14

Does the engine run fine, now?

Yes took it around the block made sure to hit 3RPMS , no stalling.
Idling at 1RPMs
My boyfriend and his dad, says thanks again, and their sorry their dumb lol. You saved us about $250 :D

With everything you have recently done to your Civic, it should be in very good shape. These are great little cars.

Tell them I enjoyed working with them--it's fun to work with motivated people, who take action right away.