1999 5.7 Gsi engine alarm question

[monkfe]

I had purchased my 1999 Parker with a 5.7 gsi (throttle body fuel injected) about four years ago. It didn't come with an engine alarm installed, so I located an aftermarket one and after dealing with some instrument issues (checking the resistance of the sending wires etc) I happened to have the wiring harness open and so I cut the Tan/blue wire and connected it to the alarm with the positive side attached to the purple ignition wire (off the alternator) and zip tied it to the engine. when the key is put to the "on" position the alarm goes off (as expected), but when the engine starts, it continues to sound?. So I spoke with a friend who worked on these engines in the past and he confirmed that should be the correct wire which a wiring schematic seems to confirm. So what would be causing this alarm to continue to sound. He suggested if the oil switch was bad it may cause it to continue to sound, but I removed the wire with no change?. Thanks in advance.

 

[mklearl]

Bad oil pressure switch or bad temp sensor switch. I believe you have 2 of each. One sensor for the gauges and one for the alarms.

 

[monkfe]

Yes that is what my mechanic friend though as well... he said to disconnect them one at a time to see which one shut the alarm off, neither one worked. I replaced the oil pressure switch a couple years ago, but the temp sensor is original. This is the two pin temp sensor on the thermostat housing and the single spade oil switch next to the oil filter were talking about here....

 

[alldodge]

Oil pressure switch and water temp switch have two terminals each. The single terminal senders are for the oil pressure gauge and water temp gauge.

The outdrive lube bottle is another one which can cause the alarm.

I cut the Tan/blue wire and connected it to the alarm with the positive side attached to the purple ignition wire

Where did you cut the tan/blue wire?

 

[monkfe]

The wire was cut about 1.5 ft from the round engine connector, enough to bring it onto the top of the engine. I'm pretty sure the oil pressure switch has only one terminal. I'll try and attach a pic of it. The gauge sender has a much larger diameter (uses a ring terminal)and sits at the back of the intake manifold near the distributor. I recall that the engines in marine use are usually at least 10yrs behind whats in vehicle production.

 

[alldodge]

The normal placement of the alarm is under the helm. You cut the wire on the motor side and mounted it on the motor, is this correct?

 

[monkfe]

yes that's correct...there was no alarm connected under the helm, I don't even see the wire in the harness at the helm. There is a rear helm, so maybe at one time it was connected there...

 

[alldodge]

If you disconnect all the sensors and the alarm still sounds, then there is another ground somewhere. It could be where the rear helm is, don't know but if there is a horn there it may be shorted out

 

[monkfe]

Hmmm...with the wire disconnected (cut) , anything at either helm should be irrelevant I can check the resistance on the wire running to each of the sensors and see if there is any ground connection tomorrow...

 

[alldodge]

Guess it depends on which end of the wire you used.

 

[monkfe]

Ok, I've figured it out... the tan/blue wire was actually the out drive sending wire( I realized it when I followed it back to the second station where the harness opened up. The correct wire was the brown/blue stripe wire, which isn't even on the wiring diagram. I confirmed it by checking the continuity back to the pin on the ecu. reattached the original wire back to where it was, put the key to start and got two beeps. Nice when you figure this stuff out...