Help needed

noz-e8tr · 11-30-2018, 08:34 PM

Hey guys. I fear I did something dumb and need help sorting it out. When I did my freeze plugs on the drivers side I unplugged all sensors and moved the harness out of the way. I normally label or take pictures so I can get everything back right. But I didn’t do it this time for some reason. I’ll blame it on old age. Anyway, I have several connections that use the same connector. I was hoping they would just kind of “fall” into place, but I still have like 3 identical connectors that “could” go to any of the 3 sensors. Basically I’m looking at the knock sensors, the cold start injector and one other that hooks to a connector mounted on a thin metal tab What I really need is picture/video showing the sensors connection and where that connection goes to meet the wiring harnesses. Start with the knock sensors. Where does it connect to the harnes? A few pictures would probably help me figure it out. Video would be stellar.

Btw. 1990 740 Turbo. Help a dumb bro out.

Text pictures or video if possible to 361-815-5826. Or pm me. What ever works for you.

bobxyz · 11-30-2018, 09:43 PM

There are some nice new harnesses, along with labelled pictures, available on Dave Barton's site -- 240turbo.com

iLoveBeingTeaBagged · 11-30-2018, 10:33 PM

If it’s anything like a 240, I may have some advice. Also, could peel back the rubber boot and check wire colors, then compare them with a wiring diagram.

On a 240, the knock sensor and temp sending plug come from the same loom. Only those 2 connections. Since they are different, it will be obvious that the one that isn’t the temp sensor, is the knock sensor. Then, on the other loom, I think it’s the IAC, TPS, and maybe a red wire for the starter? Anyway, based off the pics I took during my engine swap, one of the wires for the TPS is white/blue. So that one connects to TPS, and other would default to IAC. Also in my experience, cold start injector connector is always blue. Again, this is all from looking at and working on a 240 recently..

Let me check my 1990 744 NA.

Edit: my apologies. It’s a bit different from the 240 loom (duh). However, I can tell you that my CSI connector is blue, knock sensor connector is black, IAC connector is white/gray, and TPS connector is black.

noz-e8tr · 11-30-2018, 10:55 PM

This may help a lot. I’ll look closed at colors tomorrow.

Quote:

Originally Posted by PromiseRing

Let me check my 1990 744 NA.

Edit: my apologies. It’s a bit different from the 240 loom (duh). However, I can tell you that my CSI connector is blue, knock sensor connector is black, IAC connector is white/gray, and TPS connector is black.

noz-e8tr · 11-30-2018, 11:07 PM

Ok just went out in the rain and took a quick look. If the connector colors above are accurate on a 1990 turbo, I have the CSI and Knock sensors backwards. This is what I really needed to know.

iLoveBeingTeaBagged · 12-01-2018, 12:11 AM

Quote:

Originally Posted by noz-e8tr

Ok just went out in the rain and took a quick look. If the connector colors above are accurate on a 1990 turbo, I have the CSI and Knock sensors backwards. This is what I really needed to know.

Every CSI connector on a b230 lh2.4 I’ve ever seen is blue. So if that’s your only concern, I’d swap them around. I would assume that the blue connector gets 12v on cold start cranking/idle. The knock sensor should not (assumed).

noz-e8tr · 12-01-2018, 10:31 AM

That’s what is was. Root cause of my car running crappy was my stupidity. CSI and knock sensors connection was switched.

dl242gt · 12-01-2018, 11:56 AM

Good find. Without the knock sensor detected the timing was always pulled making it run crappy.

noz-e8tr · 12-01-2018, 12:49 PM

Crappy does not even begin to describe how bad it ran. Guess that knock sensor is kind of important. Lol

Quote:

Originally Posted by dl242gt

Good find. Without the knock sensor detected the timing was always pulled making it run crappy.

iLoveBeingTeaBagged · 12-01-2018, 01:34 PM

Quote:

Originally Posted by noz-e8tr

Root cause of my car running crappy was my stupidity.

I think that’s the case with every car on this forum.

11-30-2018, 10:33 PM	#3
iLoveBeingTeaBagged Board Member Join Date: Feb 2014 Location: Midwest	If it’s anything like a 240, I may have some advice. Also, could peel back the rubber boot and check wire colors, then compare them with a wiring diagram. On a 240, the knock sensor and temp sending plug come from the same loom. Only those 2 connections. Since they are different, it will be obvious that the one that isn’t the temp sensor, is the knock sensor. Then, on the other loom, I think it’s the IAC, TPS, and maybe a red wire for the starter? Anyway, based off the pics I took during my engine swap, one of the wires for the TPS is white/blue. So that one connects to TPS, and other would default to IAC. Also in my experience, cold start injector connector is always blue. Again, this is all from looking at and working on a 240 recently.. Let me check my 1990 744 NA. Edit: my apologies. It’s a bit different from the 240 loom (duh). However, I can tell you that my CSI connector is blue, knock sensor connector is black, IAC connector is white/gray, and TPS connector is black. __________________ Feedback Thread Current: 93' 244T m47 93' 245 m47 90' 744 AW70 94' M-Edition Miata, 93k 95' Camry auto, 246k 93' Camry auto, 278k Past: 80' 242gt m46 88' 245T m47 92' 940 turbo AW71 94' 945T AW71(L?) Last edited by iLoveBeingTeaBagged; 11-30-2018 at 10:46 PM..

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11-30-2018, 09:43 PM	#2
bobxyz Board Member Join Date: Aug 2014 Location: Boulder, Colorado	There are some nice new harnesses, along with labelled pictures, available on Dave Barton's site -- 240turbo.com

11-30-2018, 11:07 PM	#5
noz-e8tr Board Member Join Date: Aug 2003 Location: Ocean Springs, MS	Ok just went out in the rain and took a quick look. If the connector colors above are accurate on a 1990 turbo, I have the CSI and Knock sensors backwards. This is what I really needed to know.

12-01-2018, 10:31 AM	#7
noz-e8tr Board Member Join Date: Aug 2003 Location: Ocean Springs, MS	That’s what is was. Root cause of my car running crappy was my stupidity. CSI and knock sensors connection was switched.

12-01-2018, 11:56 AM	#8
dl242gt Can play the blues Join Date: Jun 2002 Location: S NJ, a suburb of Phila.	Good find. Without the knock sensor detected the timing was always pulled making it run crappy.