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2003 4.3GXi, what is this connector for?

K

kismet

New member
Hi,

So I am completely lost at the moment. I have a 2003 Campion Allante 545i SS with 4.3GXi TBI engine that I recently picked up on trade, 95% finished. I say that, because the previous owner replaced the engine block after it froze + cracked and put it back together to the point that it runs (and well), but hadn't buttoned absolutely everything up.

Now, when I start it, it comes right to life and idles perfectly around 600-700rpm or so. It also revs up as it should in neutral, and I can confirm it will rev over 4000rpm (though I have only shot it up there briefly to see if it was restricted). So in theory it runs as it should. The issue I have, is with the warning chime beeping while it is running. When I put the key in on, it does the double beep and all is well, fires up right to life. Shortly after idling for a few seconds, the warning chime starts. It's goes: "Beep..................Beep Beep...................." and repeats. Though I have looked into it, and I have the Seloc service manual, I can't get a clear view of whether or not the system beeps out trouble codes. And in the even that it does, if that's a 12 it's beeping out, that number isn't in the manual. Now if its 21, that's a TPS issue.

So my questions start:

- Does it beep out the trouble codes once started?
- If so, what code is it referring to?

My first hunch was the sensor that is connected, but hanging freely right infront of the flame arrestor. It comes off of that main harness going over and around the front of the intake manifold and I have absolutely no clue where it goes. By running the part number through google i've discovered it's a common Intake Air Temperature sensor that is connected. ( I say common because it looks as if several manufacturers in automotive use it ) I can't for my life figure out where it screws in. The connector is 2 pin with wire colours Tan/Yellow and Grey/White, and only connects to this sensor and doesn't fit anything else. Perhaps there is a plug in place of where it's supposed to go? But then i've never heard of an IAT that plugs into an intake manifold, they're usually in the intake snorkel/plumbing. But then again I only know of automotive application. The connector is live as it has 5V running to it. Reading my Seloc manual, they make reference in wiring diagrams to the IAT, but they never actually show a location of it, AND I can't match up the wire colours. It's has a threaded brass fitting so it MUST screw into the manifold somewhere, but I can't find anywhere it would go. The pigtail that comes off of it is maybe 5 inches in length.

More questions:

- Is this an IAT sensor? Is this engine known to have an IAT sensor in marine application?
- Is there a trouble code for the IAT? I can't find one if there is.

Lastly, the Temperature gauge doesn't seem to function. I haven't looked too far into it yet, but there's 5V going to the ECT sensor on the thermostat housing (front of the engine), and when I bridge the terminals on the connector it makes no difference on the gauge, it just sits at the bottom of the gauge. Also, when I apply ground to the 5V it also makes no difference on the gauge. When I unplug it, still no difference. When I have the key off, all of the gauges fall including the Temp. When I turn the key into ON or when running, the gauges all shoot up to their resting position, including the Temp.


Does anyone have any ideas for any of these issues? I've attached a picture of my engine sans cover + flame arrestor, so you are able to see what I mean when I talk about that alleged IAT sensor.

Thanks a million in advance. I feel like such an idiot being so confused by what's probably such an simple issue.

CIMG0201.jpg
 
Re: 4.3GXi, what is this connector for?

OK!

So it is definitely an IAT sensor, just not sure if it's necessary for proper operation. Again there is absolutely nowhere to put it.

Second, I looked into the temp gauge issue and it's the sending unit's problem (DUH) not the ECT. I can ground out the sending unit connection and the gauge shoots up.

So all I believe is left, is what's causing the warning chime to go off when running. Does it make a difference that i'm doing all of this running it on the muffs? I haven't had it in the water yet.
 
Re: 4.3GXi, what is this connector for?

Kismet, I have one of those engines and the Volvo shop manuals. I haven't been able to run down to my boat to check but I did review the manuals and found some disparities. First the IAT sensor that you identify is listed in the EFI diagnostic manual with the same color code that you provided - however it states that this sensor is only used in the 7.4 GSI and 8.2 GSI motors both of which are MFI engines. The drawing of the sensor in the manual looks the same as your picture. Second, I want to point out there are two temperature sensors on your motor. One that talks to the computer (2 wire connector Yellow/Blue - Black orange) and one that controls your gauge (single tan wire). The one that talks to the computer is a similar looking to the IAT sensor - and is called an Engine Coolant Temperature Sensor -ECT which has Yellow/blue - Black/orange wires connected to it. I bring this up because the two could be confused and your problem with the temperature gauge.

So putting this altogether, if your color code is correct on the IAT sensor, your motor does not require it. I can't explain why it is there, perhaps the original assembler purchased the sensor in order to connect it to the connector then couldn't find a place to install the sensor. Second, if you have a temperature sensor problem with your gauge it is the sensor with the single tan wire attached to it that you should replace. Lastly, the audible beep that you hear on start up is linked to two switches, the oil pressure warning switch and engine temperature warning switch. It should beep at start up and will quit beeping once the oil pressure exceeds 4psi plus or minus 2. It will beep if you lose oil pressure or begin to overheat. Because it keeps on beeping I would suspect it is not wired correctly to one or both of these switches, the horn is defective or you don't have any oil pressure or its overheating! Easy to check the oil pressure and overheat. To test the switches you need to take the wire off the switch and momentarily ground it. It should beep when grounded. If it keeps on beeping even after you remove the sensor wire, the wire is in contact with a ground and you will have to isolate it. Let us know how it goes and good luck.

russb
 
Re: 4.3GXi, what is this connector for?

Russ, thank you!!

I'm ecstatic that I can finally cap off that connector and tie it to the harness. Thanks for clarifying for me. You're also bang on about the temperature gauge. I totally knew that there was an ECT and a sender too, not sure where my mind was when I wrote this up. But yes, I did check the sender and it's indeed bit the dust.

I definitely have adequate oil pressure, as it registers on the gauge normally and quickly as started. I'm definitely not overheating either, because it starts the beeping right as the engine starts from cold. So it must be a wiring or switch issue as you say. I'm going to assume the situation is the same for the oil pressure and engine temp switches, that they are mounted in addition to the oil pressure and temperature senders?

If i'm understanding you correctly:
- it beeps when there is inadequate oil pressure. If they control the ground circuit, a lack of oil pressure grounds the oil pressure switch making it a normally closed switch; so it beeps until proper oil pressure is sensed, at which point the switch opens and the ground is broken, thus cutting out the beeping.

- it beeps when the engine temperature is too high. That means when started from cold the switch has to be normally open; so when the temperature reaches a certain point the switch closes and the circuit is grounded, turning on the warning beep.

Does all of that then mean, that if I remove the wire from temperature switch it shouldn't be able to signal the warning beep as it won't be able to close the switch and complete the ground circuit? And if I ground the temperature switch it should beep. Does the same go for the oil pressure switch? If I disconnect it, it will no longer have a complete ground circuit so it should not beep. And if I ground it, it should beep as the circuit is completed? That sounds correct to me.

Thanks for your help Russ, very much appreciated. I will locate the sensors and try it all out tomorrow and let you know what I find.
 
Re: 4.3GXi, what is this connector for?

One last thing, is the engine temperature warning given through the ECT sensor? Or does it have it's own switch like the oil pressure switch?

EDIT:

Ok so I read up in the manual a bit more and here's what they're saying.

-Low oil pressure - Steady beep + engine protection mode
-High exhaust riser temp - Steady beep + engine protection mode
-High ECT - Steady beep + engine protection mode

-Active DTC - Intermittent beep, normal running mode unless code demands otherwise

The beep I have is definitely intermittent. It goes: "beep..................beep beep....................". Therefore if what they claim is true, I must have an active DTC that is not oil pressure, exhaust riser temp or engine coolant temp related as they would give a steady beep. The only trouble is, I don't have a marine scan tool. Is there any other way to figure out the trouble codes?
 
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Re: 4.3GXi, what is this connector for?

Kismet, as I understand it there should be an initial set of beeps when you first turn the key. This to test the beeper circuit and warn anyone who might be at the engine that it is about to start. After it starts and the oil pressure goes above 4 psi the beeping should stop, exactly as you described. If the engine is now running without beeping and a short while later it begins to beep (a secondary set of beeps) I think its trying to tell you something. Your description of how the oil/temp switches work is correct.

The beeper does not beep out trouble codes. There are two ways to read the DTC's, the expensive way with an electronic marine scan tool and the inexpensive way with flashing light code tool (volvo marine version is 10 pin - automotive version is 12 pin). I use the code tool, about $28, Volvo part number 3851088. I recommend you buy one, you will need it to read trouble codes and you need it to time or check the timing of the engine and to clear trouble codes. It is a small plastic rectangle that plugs into a plug on the engine. It is the marine version of the old automotive short out two pins and watch the light flash stuff.

Regarding the source of the temperature data to the beeper, this originates from the ECT sensor - the other temp sensor is wired directly to the dash gauge and doesn't connect to the ECM/beeper. I have never looked for a switch associated with the ECT sensor but there is one involved. If you remove the wire from this switch and ground it, it should sound the beeper. Similarly if you take the wire off your oil pressure switch and ground it it should cause a beep. These test indicate that the beeper and its associated wiring works.

If you are convinced you have good oil pressure and it is not overheating I would suspect the beeper wiring (intermittent ground) or the oil pressure switch or the water temperature switch. Reading from my manual there are two tests for these switches you will need an ohm meter.

Oil Pressure Switch, replace if it fails either of these tests;

1. with engine off and switch wire disconnected there should be full continuity (zero) reading between the switch terminal and the engine block.

2. with engine running and switch wire disconnected, there should be no continuity (infinity) reading between the switch terminal and engine block.

Water Temperature Switch is calibrated to make or break contact at 200 degrees plus or minus 5 degrees. Attach ohmmeter to the switch and make the following test. Replace switch if it fails test.

1. Immerse switch in a container of oil, heat oil over flameless source and check temperature with cooking thermometer.

2. Below the make/break temperature, the ohmmeter should show a no continuity (infinity) reading. Above the make/break temperature, the ohmmeter should show full continuity (zero) reading.

Happy cooking and let us know how it goes.

russb
 
Sorry about not replying right away. Weather has sucked.

I ran it up and noticed that it does stumble under full throttle when blipped to wide open in neutral. If I do this several times in a row it'll beep consistently with no pauses, which is a hard warning I believe? So there has to be more of an issue. Disconnected the ECT made no difference. Also I ran it for about 30 minutes to see if the temperature would actually register on the gauge and it does; takes a while to get a bit warm though. Also, once it warmed up the idle became low and rough, and wanted to die out. Definitely more of an issue at hand. I should also state that the oil pressure on the dash mounted gauge is where it should be when running. Where can I get my hands on one of those code readers for as cheap as you say? I can only find it for $100+.

To add to the injury, I think I may be getting water in the oil. Unless it's condensation buildup from running it and not letting it warm up a million times, or water somehow draining through the throttle body or elsewhere in the engine bay, the oil level seems high. When I pull the dipstick, one side of it looks milky and the otherside the oil is clean. I'll probably drain and fill the oil a few times with some cheap stuff soon and monitor the level after running it.

Last issue; I noticed that once the engine was warm and I had the water running and attached to it, it had a lot of trouble cranking the engine at speed. The starter would turn a bit and then almost stop, then turn a bit and almost stop.. not enough to make it want to start. I can compare that to the first start of the day that goes like this: Attach ears, turn on water, crank engine - starter spins engine to life within a second. What happens when it's warm: Engine was just running, turned off engine, ears are attached with the water running still, crank engine - starter labours as I described previously and will not turn fast enough to start the engine, remove ears and water drains out, reattach ears with water running and crank engine - starts right up. Is the water pressure labouring the starter? Is that even possible? My first guess was that the cylinders are filling with water when I have the water running and the engine off while the system is still pressurized. I can't confirm that because I haven't pulled a plug to take a peak after. But then if I removed the ears and the water drains out, it starts fine again after. What the hell?

Talk about issues. I'm considering waiting this season out and buying a remanufactured long block for it along with all new sensors next year. Are there any ways to identify where water may be leaking into the oil? I know a compression test would reveal if it's a head gasket, but that's probably the least likely of the issues. Remember the block and risers were replaced along with all gaskets; everything else (heads included) was reused (except for all bearings and such). The fact that it runs like ****e at idle once warm makes me want to think it's an intake manifold crack that's leaking the water.
 
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