1.8 Questions for the masses Options

[rick 918-S]

I was helping my old high school pal attempt to get a 1.8 running. The car is his daughters. She really wants to take it on her drivers test. May be even this week. We had some strange stuff occur.

The car was purchased at Auction. It had an engine fire due to a cracked clamp on the cold start valve. The fire consumed the center of the engine harness. Through the generosity of Betty and Clay they received a parts box at no charge. Thank you again you two!

I came into the picture when they had everything installed and we attempting to get it running.

Turned out they accidentally broke the inlet on the cold start. So I was lucky enough to source one from Jim Hoiland. Thank you Jim!

So with this install it would crank and barely run. Fuel pressure was at 40ish PSI. My friend Lowell smoke tested the intake system. All was tight.

Once we had it firing barely.. Lowell pulled the plug on the AFM and the car raced to life. Weird I know.

Pulled the plugs and notice #3-#4 were wet with Gas. #2 was dry like it never got fuel and #1 looked normal.

Lowell ordered a set of Injectors. We believe due to the process of elimination two of the injector were stuck open and one was stuck closed. Noid lighted all injectors that they are getting signal.

Any thoughts on the reason the car kept running with the AFM unplugged? Lowell thought possibly the injector that were stuck one were being siphoned allowing the engine to keep running.

[timothy_nd28]

The airflow meter keeps the fuel pump running after the key is released from the start position. Inside the airflow meter is a set of contacts that electrically closes when the flap is deflected, which turns on part of the dual relay, which in turn, supplies power to the fuel pump.
Unplugging the connector to the airflow meter would keep part of the dual relay from turning on, thus no fuel pump action. I can see the engine running with the connector off, but only for a short time as the fuel pressure would quickly decrease. There is momentary power from the ignition switch start position going to the fuel pump, but is lost when the key returns to its run position.

So, why is the engine running with the air flow meter unplugged? Was the fuel pump wired to bypass the dual relay? It would be interesting to see a fuel pressure gauge connected to monitor the pressures while starting the car, and seeing what the pressure does as the key is released to the run position as the engine runs and the AFM connector off.

If I was working on the car, I would check the integrity of each fuel injector circuit. Start with removing the + wire on the ignition coil (this keeps you from burning up the points in the distributor while performing this following test).

Remove the ECU connector, and with the key to the run position, check for voltage on pins 14,15,32,33 (ECU connector) to battery ground. You should be seeing 12 volts. If you do, that proves that the ignition key is turning on the dual relay, the dual relay is passing voltage to the resistor pack and that fuel injector coil has continuity.