rage2

I was referring to the Lindsey's description of the problem. You should always use inlet temps to determine any enrichment requirements. I've never used a MAF or installed a MAF conversion myself, but I do have friends that have, not on 951's though, and they experience cold start issues.

Is the stock inlet temperature sensor removed/changed in the MAF upgrade? If so, it may be reporting on a different voltage range that might be causing cold start issues. I'm no expert in the area, just trying to throw some ideas around hoping someone would know.

dlr944

WELL I THINK I HAVE AN ANSWER FOR ALL OF YOU USING THE ARC 2 WITH A MAF METER!!! <img src="graemlins/jumper.gif" border="0" alt="[jumper]" />

So here's the deal. Remeber the (grey) wire from the ARC 2 that connects to DME terminal #22 ECU TEMPATURE INPUT (green wire). Well the output (grey) wire from the ARC 2 DOES NOT CHANGE WITH THE TEMPERATURE!!!! This output is a fixed resistance!!! So your car now thinks that it is always warm out!! No wonder I was having problems starting my car in cold weather. The original AFM has a temperature sensor built into it. To compensate for the cold air (more density)you need more fuel. My belief is that without this temp sensor your car can not react or add more fuel to compensate during cold start up (ie enrichment).

To fix this problem I plan to add an input Temperature sensor from Bosch.. If your interested in this solution let me know and I'll update you on my search for an equivalent Temp Senor and if this cures the problem. HOPE THIS HELP OTHERS ON THE LIST
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

Perry 951

I know most hotwire MAFS have 2 wires. One is supposed to be airflow, the other is temp. Now why won't it work? The stock one has a sensor in it, now I wonder how you remove it and make it work on the MAF.... humm......

Let me go get my stock AFM!

BRB!

dlr944

Perry:

The MAF meter that I am using, and I assume your's is similiar if your using the split second equip., has only one output the green wire which goes to the ARC 2. I suppose if we had a two wire MAF we could try this little experiment.

However, I think the next best alternative is to purchase a stand alone temp senor. Lot's of OEMs use this arrangement, MAF and temp sensor (BMW, FORD, etc..) The cost is between $19 and $50 depending on vendor.

If your able to remove your temp senor from the original AFM or able to see a Bosh part number let me know!!!!

BTW: I see your from Cincy... Bearcat Fan??

Perry 951

Yea.. go Cats!

Now.. here is the pic of the green wire, Terminal 22 on the DME.



I looked in the wiring schematics, and this is the Air Temp Input for the DME, not the water as some thought. Now.. since the ARC-2 esentially goes directly into this wire, not a piggyback since the AFM is disconnected. What would happen if the ARC-2 was never hooked to it, and you used the stock temp sender? We will find out when I get mine running.





My Huntley MAF has 2 wires in it. This tells me one must be a temp sensor. So why does it not work as well as stock?



Any ideas? Huntley, SFR, why do the units not have correct fuel enrichment when cold?

rage2

[quote]Originally posted by perry951:
<strong>I know most hotwire MAFS have 2 wires. One is supposed to be airflow, the other is temp. Now why won't it work? The stock one has a sensor in it, now I wonder how you remove it and make it work on the MAF.... humm......

Let me go get my stock AFM!

BRB!</strong><hr></blockquote>

Isn't one wire to provide voltage, and the other wire outputs the voltage drop?

Perry 951

See the 2 wires in the MAF itself?

That is what I am talking about. The one in the front should be air temp, and the rear the airflow.

In the above post, the Grey wire from the ARC-2 attaches to the Air Temp Input of the DME. So why do we have a lack of fuel enrichment? Humm... humm..

Perry 951

Another thing. The DME provides voltage to the stock temp sender via Pin 6 of the DME. If this is disconnected, and it is in our application, the DME is not sending power to the sensor, only recieving an Input from the ARC-2. Therefore, the DME is not seeing a voltage drop since it is not sending any voltage.

So how does it work?

So many questions!

John Anderson

I will gladly take your call, maybe we can sort thisd out over the phone...I don't care if you bought the unit from huntley or sfr...lets get you running and happy :-)

PLease check our website for the new tele number...I'm too lazy tonight to change mu signature.

Take Care!

dlr944

Perry:

Thanks for the pictures! I saw inside the MAF but I not sure about the two wires? How many terminals are in the connector?

As rage2 mentioned there is another wire for power. The split second MAF types have 4 wires:
1. Power Ground
2. Signal Output (to ARC 2)
3. +12 V Input
4. Signal ground.
(according to split second's website)

I don't see any output wire for air temp on your MAF? I see the casting piece you pointed to; I am just not sure there's a wire attached to something in there? It might be there but only the MAF vendor would know.

We lack fuel enrichment becase the ARC 2 inputs a fixed resistance to the ECU. Again this input does not change based on temp - it's designed for the track. If the temp sensor is in your MAF and it produces the same temp. vs resistance (ohms) as the factory sensor then your in luck. However, I am pretty sure it's not there or disconnected, otherwise these kits would plug the MAF temp sensor directly to terminal #22 of the DME and not the ARC 2.

Perhaps you could investigate this further?

Mean while I am going to purchase a seperate temp sensor and drill & tap it into the MAF. After all this is the way Lindsey designed thier MAF.

How did you get the factory temp sensor out??

GO CATS!!!

Perry 951

John -

Thanks for stepping up and answering the questions. I would rather discuss this on the forum so everyone can get the answers, and more importantly, the fix for it.

No matter where we got the units from, almost all the manufacturers are using the same thing. So how does the DME know air temps with the MAF? There is an input, but either the software in the MAF does not provide enough cold enrichment, or the DME does not know what the signal is from the MAF.

Since the power output to the sensor is disconnected, the DME is sending 0 volts to the sensor, or more correctly, amps since there is no draw. Then it sees whatever voltage is from the MAF temp sensor. I don't see how it can calculate the voltage return without knowing how much is sent. It is just seeing random voltage.

So what is the deal?

Perry 951

To get the sensor out, remove the cover. It is glued on quite well, so hopefully you did not want to use your AFM again. There are 3 screws on the resistor board that are held in with Locktite. I had to drill mine. Once you get the board out, grind off the 2 nipples that hold the sensor in. Open the barn door and push the sensor out the top.

If we cannot get the MAF to work right, I will intall the stock one into the MAF, hook it back up to stock wiring, and not hook up the ARC-2 wire to Pin 22. Question is will the ARC-2 work fine without it?

Also, there are 2 resistor coils in the MAF itself. They are the hot wires. You can see it in the pic if you look close. This means there are 2 sensors. There are only 4 wires that lead from the sensor, if one is a temp sensor, there should be 6 wires total that need to be hooked up. You would add Temp SGO and Temp PWR I would think. I have not found out what pin 6 is on the DME, but that is what goes to the stock temp sensor.. and 22 is the return signal.

rage2

Interesting Quotes...

[quote]Originally posted by TurboTim:
<strong>Our mass-flow set-up uses the existing airflow meter temp wire to allow the new mass-air sensor temp reading to be interpreted by the ARC2 and then the DME.A seperate temp sender justs adds clutter under the hood and isnt neccessary.</strong><hr></blockquote>

and

[quote]Originally posted by dlr944:
<strong>I don't see any output wire for air temp on your MAF? I see the casting piece you pointed to; I am just not sure there's a wire attached to something in there? It might be there but only the MAF vendor would know.

We lack fuel enrichment becase the ARC 2 inputs a fixed resistance to the ECU. Again this input does not change based on temp - it's designed for the track. If the temp sensor is in your MAF and it produces the same temp. vs resistance (ohms) as the factory sensor then your in luck. However, I am pretty sure it's not there or disconnected, otherwise these kits would plug the MAF temp sensor directly to terminal #22 of the DME and not the ARC 2.</strong><hr></blockquote>

and...

[quote]Originally posted by perry951:
<strong>To get the sensor out, remove the cover. It is glued on quite well, so hopefully you did not want to use your AFM again. There are 3 screws on the resistor board that are held in with Locktite. I had to drill mine. Once you get the board out, grind off the 2 nipples that hold the sensor in. Open the barn door and push the sensor out the top.</strong><hr></blockquote>

So, TurboTim (SFR) says their kit uses airflow meter temp sensor, but doesn't the MAF kit completely remove/replace the stock barn door airflow meter?

If that's the case, the MAF kits don't look like they have temperature outputs going to the ARC2, but the ARC2 has a temperature output going back to the #22 DME harness (green wire). Where's the ARC2 getting the signal from? Is it possible that the MAF sensor actually measures the air mass (amount of oxygen) therefore already "temperature compensated", and the ARC2 merely interpreting the numbers and giving a simulated temperature reading?

Inquiring minds want to know... =)

tecart

here is the problem as i see it, there are 3 wires to hook up with the #2 loom in the arc2 install pages: one is violet-ecu signal input that hooks into greenw red stripe on dme terminal#7, one is grey-ecu temperature input that hooks into solid green wire on dme terminal#22, one is yellow-throttle position switch that hooks into white with black wire on dme terminal #2, NOW we all know that terminal#2 wire goes to the throttle position switch, no problems here, but terminal #22 and #7 are supposed to go to the stock airflow meter but that has been disconnected as we are now using a maf kit. so if these 2 wires are not sending a signal to our new maf kit then maybe this is the big problem, why even tap into #22 or #7, wouldnt the car run the same if i took these 2 wire taps off of #22 and #7? Can huntley or sfr please help me make some sense of this, is this a cause of my leanness at idle?

dlr944

I don't seem to be getting my point across. The grey wire from the ARC 2 is a fixed resistance between 1.5k to 2k ohms. Therefore, the DME thinks that the temperature is roughly 72F. (You can figure out this by looking at the resistance vs temp. of the AFM in the 944 Manual).

Using the grey wire from the ARC 2 is fine if you live in a mild part of the country or use your car for the track. For track cars this is probably the perfered method because you now have one less sensor which could fail.

If you want temperature control, then you need to figure out a way to tap into the MAF assuming it has a temp sensor that's compatible with the DME or add independent temp sensor that connects to the DME. In either of these cases you just remove the grey wire (it's just there to send a fixed resistance to the DME) and connect the new temp senor to DME input. This is of course is my belief.

DLR944