What exactly does pin 14 do and go?

[David9er]

A few days ago I wired my aftermarket tach to the wire that goes to pin 21 and it is working fine; however, I found that pin 14 had come free from the plastic connector to the ECU so it was most likely not making contact, I tried to tug on the wire so I could shove it back into the connector but the wire came free from a location that I'm unsure of [previos owner had connected wiring by simply twisting wire together and covering with tape with out using a butt connector or soder]. I can't find a solid green wire in the harness and it seems that due to the length of what is left it was spliced into the wire going to pin 19.
My questions are as follows:
1. does it make sense to splice those together?
2. what should be done with wire 14?
3. the car has had cold start and idle issues since I bought it a few weeks back, would this fix any of those issues?

 

[GST with PSI]

1. does it make sense to splice those together?
No, none whatsoever.

2. what should be done with wire 14?
Use this pinout diagram to connect it back to the ECU where it belongs.
1G ECU pinout

3. the car has had cold start and idle issues since I bought it a few weeks back, would this fix any of those issues?
Yes. Although it may not fix your all of your idle issues, your car will never idle correctly unless this is fixed. Pin 14 goes to the idle switch, which is physically located on the back side of the throttle body near the firewall. When the throttle is completely closed, the idle switch is triggered, sending a ground signal to pin 14 on the ECU. When the ECU sees the ground signal, the ECU knows the car is trying to idle (as long as there is no input from the VSS reed switch) and the engine lowers to idle RPM.
In your case, your car never sees a ground signal on pin 14, and therefore will never idle. I'd guess your car is idling high, anywhere between 1000-1500 RPM?
With ECMlink, you can actually simulate the idle switch using the TPS signal. Do you have ECMlink?

Reconnect the circuit properly, and make sure it is functioning by using a DVOM to check for continuity to ground when the idle switch is activated. Use the diagram below to troubleshoot. I've highlighted the circuit of interest in red.

 

[92AWDHX40]

http://www.dsmtuners.com/forums/articles-miscellaneous/217951-how-diagnose-no-start.html

check the cts, that could be a issue for a hard start as well and check engine codes, and read above.

 

[GST with PSI]

Engine codes on a 1G, OBDI = worthless IMO...that is, if you ever even get a error code.

PO said cold start. CTS isn't going to effect cold start. Hot start yes; cold start no. Good link though.

 

[92AWDHX40]

Yes anything to help with a starting issues. Check you mas sensor, check battery voltage while your there.

The idle issue could be a boost leak, or a bad isc, or even a driver on the ecu, I use link to simulate my idle switch.

 

[GST with PSI]

PO, fix pin 14 and then report back with any persisting issues. Don't start trying to fix things that may not even be broken.

 

[David9er]

maybe I should clarify just a tad, the wire is connected to the ECU but the other end of the wire is out in the open about 2" away. I would like to simply run a new wire from where it dead ends now to where it should go.
As for the hard start the colder the car is the harder it is to start, I now its not an electrical issue, I have read it most likely the ECT sensor in the thermostat housing but is there any way to test the sensor I have such as an ohm test and what would the ohm range be.

 

[Phantom DSM]

Engine codes on a 1G, OBDI = worthless IMO...that is, if you ever even get a error code.

PO said cold start. CTS isn't going to effect cold start. Hot start yes; cold start no. Good link though.

Actually the engine coolant temp sensor sends signal to ecu and has been a culprit on cold start. Check if the wires are connected to it, its a 2 wire connector on bottom of thermostat housing.You can test the sensor by checking for resistance with a Dvom at 32 degrees should be about 5.1-6.5 kilo ohms. #5 in the pic

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[boost97gst]

Yea like gstwpsi said, Fix the KNOWN problem first. You dont have a functioning idle switch as far as the ecu can see anyway. Get that taken care of. Very easy on a 1g. Just run a new wire to it and bam. THEN if you have starting issues go through more troubleshooting. The 3rd post of this thread shouldve been you reporting back after you had fixed the idle switch to ecu wire.

 

[GST with PSI]

Yes, OP, connect a new wire where the old one ends, and reconnect it to the idle switch pin in the rear of the throttle body

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Actually the engine coolant temp sensor sends signal to ecu and has been a culprit on cold start. Check if the wires are connected to it, its a 2 wire connector on bottom of thermostat housing.You can test the sensor by checking for resistance with a Dvom at 32 degrees should be about 5.1-6.5 kilo ohms. #5 in the pic

Could you explain how? When the engine is cold, what signal is the ECU getting that it cares about in open loop? We are talking about a COLD start here. The coolant temp sensor has high resistance at low temperature, and lower resistance at high temperature. For those of you running ECMlink, go unplug your coolant temp sensor and observe what the ECU sees? It will be a ridiculously low (cold) reading. Your car doesn't care if it is -74 or 74 degrees. As long as the 1G ECU sees less than 190 degrees (among other factors as well), the car will stay in open loop, and dump a shit ton of fuel in an attempt to get a cold engine to start based on the open loop lookup table.

When your car is cold, go completely unplug your coolant temp sensor and try and start it. I guarantee you, if the only issue is the unplugged temp sensor, it will start just fine.

My point is, I've never know a bad coolant temp sensor to keep a cold car from starting. A hot start however, is an entirely different story, and would definitely be effected by a bad CTS.

 

[David9er]

Thanks a bunch GST with PSI, that was an awesome pic, hard to miss that one. I'll get a new overlay run this afternoon at work.

So if you Don't think it's the ECT sensor what should I check?

 

[92AWDHX40]

I never had a problem with a cold or hot start, how long does it take to start? The cts is a fairly cheap part to replace from anywhere, if in doubt you could replace it.

 

[GST with PSI]

Thanks a bunch GST with PSI, that was an awesome pic, hard to miss that one. I'll get a new overlay run this afternoon at work.

So if you Don't think it's the ECT sensor what should I check?

Fix your idle switch, and see how the car runs. If it runs great, then STOP reading this. If not, then go completely unplug the coolant temp sensor and try and start the car. Does it start? Plug it back in and start it again. Is there any change?

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If you suspect your CTS is bad, you can remove it from the water neck and test it as outlined below. Although, I personally don't think this is your issue, it isn't out of the realm of possibility I suppose.

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If it still runs like crap, I would start by doing a BLT. Make sure there are no leaks anywhere in the system.

Next, check to see if you have a block off plate installed in the FIAV. You should be able to clearly see something sandwitched between the upper and lower throttle body halves.

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If you can't see a plate sandwiched between the upper and lower TB halves, the PO still may have blocked the FIAV with JB weld or something, and you would need to disassemble the TB to check.

You can also take a look at this link. It's not directly addressing cold starting, but the information still applies:http://www.dsm.org/how-tos/tttt/tttt3.html

Engine Internals:
272 cams? forged internals?

Lastly, why the hell are half of the mods in your profile ending with a question mark? Does that mean you don't have any idea if you have forged internals or not? Update your profile with a clear and concise mod list. It will really help others help you. With the mods listed, you can't be running a stock ECU alone? Do you have a datalogger or ECMlink on the car?

 

[David9er]

Again thanks for all the help, I rewired PIN 14 to the TB switch and the idle is down to about 850rpm, so after a BISS adjustment that should be fixed.

As for the cts I unplugged it and the car ran noticeably worse, in fact I think it had a random miss, it absolutely ran much worse without it so I'll inspect the TB tomorrow and report back.

The Items in my profile that have question marks are items that the previous owner claimed it had but I have yet to confirm [he claimed a lot of things to "sell" me the car that I have found to be untrue]

 

[Phantom DSM]

Yes, OP, connect a new wire where the old one ends, and reconnect it to the idle switch pin in the rear of the throttle body

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Could you explain how? When the engine is cold, what signal is the ECU getting that it cares about in open loop? We are talking about a COLD start here. The coolant temp sensor has high resistance at low temperature, and lower resistance at high temperature. For those of you running ECMlink, go unplug your coolant temp sensor and observe what the ECU sees? It will be a ridiculously low (cold) reading. Your car doesn't care if it is -74 or 74 degrees. As long as the 1G ECU sees less than 190 degrees (among other factors as well), the car will stay in open loop, and dump a shit ton of fuel in an attempt to get a cold engine to start based on the open loop lookup table.

When your car is cold, go completely unplug your coolant temp sensor and try and start it. I guarantee you, if the only issue is the unplugged temp sensor, it will start just fine.

My point is, I've never know a bad coolant temp sensor to keep a cold car from starting. A hot start however, is an entirely different story, and would definitely be effected by a bad CTS.

You are correct. I did not word it properly. I posted for OP to check for the 5.1-6.5 kohms at 32 degrees to make sure the sensor is working. I assumed his wiring was ok. I wanted to make sure it is giving the correct signal to the ecu for the cold start fuel enrichment to occur, otherwise it would give the ecu the wrong signal and it wont dump the proper fuel on cold start.
I could not post the pic you did from the manul, thanks
Looks like the idle switch helped a lot.
Im not sure if OP has tested his sensor yet ? Has the cold start issue went away or was it warm when you disconnected cts and car ran worse?

 

[19Eclipse90]

Fix your idle switch, and see how the car runs. If it runs great, then STOP reading this. If not, then go completely unplug the coolant temp sensor and try and start the car. Does it start? Plug it back in and start it again. Is there any change?

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That is the switch for the A/C system. You're looking for the switch with the two prongs in the shape of an L -- No. 5 in the pic Phantom DSM posted -- which is located lower on the thermostat housing.

 

[GST with PSI]

^Right. I should have pointed that out, I just couldn't find a better picture of the sensor. It is actually the sensor almost directly below the plug pictured.

 

[David9er]

That is the switch for the A/C system. You're looking for the switch with the two prongs in the shape of an L -- No. 5 in the pic Phantom DSM posted -- which is located lower on the thermostat housing.

I know that is the A/C switch. I unplugged #5 with the two prongs that look like a "T", and like I said the car started the same but ran like complete shit, there isn't a FIAV blocking plate and the FIAV works normally.

What should I check next?

 

[GST with PSI]

Can you describe what it is doing now that the idle switch is fixed? Is it idle surging at all?

 

[David9er]

It's a little odd, I haven't noticed a surge but at a stop light sometimes it will idle normally and sometimes it will idle at like 1000-1500 but if I slip the clutch just a tad with it in gear then let it go it will normalize.

As for the cold start I'm at a complete loss, under 50* it takes about 5 mins worth of cranking for it to stat and 10 mins if its under 30*, over 50 or if the car is already warm it take about 2-3 cranks

 

[92AWDHX40]

Post a picture of your plug

 

[David9er]

Which Plug?

 

[GST with PSI]

It's a little odd, I haven't noticed a surge but at a stop light sometimes it will idle normally and sometimes it will idle at like 1000-1500 but if I slip the clutch just a tad with it in gear then let it go it will normalize.

I'd bet your idle switch needs to be adjusted properly. Sometimes, if it is just out of adjustment, the throttle will trigger it, sometimes it won't. When you are at a light and the car is idling high, try to quickly snap the throttle, immediately letting off the pedal after the snap. If the idle drops right afterward, the switch needs an adjustment. Loosen the one bolt holding the switch, and adjust it so that the throttle triggers it properly. You should be able to kinda hear or feel it click when it is activated.

As for the cold start I'm at a complete loss, under 50* it takes about 5 mins worth of cranking for it to stat and 10 mins if its under 30*, over 50 or if the car is already warm it take about 2-3 cranks

10 minutes of cranking in stupid long. Doesn't your battery go dead before the car starts?

 

[92AWDHX40]

Could be a bad ecu check that out.

 

[David9er]

I'd bet your idle switch needs to be adjusted properly. Sometimes, if it is just out of adjustment, the throttle will trigger it, sometimes it won't. When you are at a light and the car is idling high, try to quickly snap the throttle, immediately letting off the pedal after the snap. If the idle drops right afterward, the switch needs an adjustment. Loosen the one bolt holding the switch, and adjust it so that the throttle triggers it properly. You should be able to kinda hear or feel it click when it is activated.

Are you talking about the BISS adjustment mentioned here:VFAQ BISS adjustment?

10 minutes of cranking in stupid long. Doesn't your battery go dead before the car starts?

I don't crank it continuously, about 10 secs on, 20 off. And yes in that weather the starter does start to slow down so it will kill this battery sooner than later if it keeps up. I wonder if it may have a poor tune on it, the car has an alternate start switch that is wired in parallel with the key so either one will engage the starter and start the car so lone as the key is in the on position I believe this was done to reduce stress on the actual key which has a slight twist to it.