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engine harness questions

Garageman00

Garageman00

New member
Joined
Feb 20, 2013
Location
Visalia, Ca
so i have a 1990 240 engine harness. it plugs into my 1991 volvo 740 turbo lh 2.4 ecu and ezk but it seems to be missing the 2 prong connector that goes into the head... and another one that goes into the block. probably more. anyway im a little confused as to why it doesnt match the 1991 harness as far as the engine is concerned. i was told this is the harness i needed but it doesnt match.... i have both the ENTIRE harness out of the 740 and this other one i need to make it work somehow can i get any help? im feeling kinda lost on this right now...

thats my build thread if it helps.
http://forums.turbobricks.com/showthread.php?t=293046

IMAG0301_zpsdwbimetb.jpg
 
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The 240 and 740/940 harness are basically completely different but I am assuming you know that.

The 240 harness is the one you want to be using.

Can you be more specific as to the "two prong connector that goes into the head" Are you referring to the coolant temp sensor that goes to the coolant gauge (sensor in the front of the head) or the one to the rear which goes to the ECU?

Volvo changed coolant gauge sensors over the years from a one-wire to a two wire... is that what you're referring to?

I don't know any wires that go into the block... unless you're referring to the crank sensor in the back of the block.

A little more specifics might be helpful.
 
im assuming one is a coolant temp sensor and the other is an oil pressure maybe warning light thing? im not really sure... but yea i will give you anything you need to know to help...
 
Garageman00 said:
im assuming one is a coolant temp sensor and the other is an oil pressure maybe warning light thing? im not really sure... but yea i will give you anything you need to know to help...
Click to expand...

IIRC, they are both for the gauges and may not be directly incorporated into the harness.

The lower pic (round plug) is for the oil pressure light and the upper D plug *I think* is for the temp gauge on the dash. I don't believe that the ECU gets engine temp from that one.

The oil pressure just grounds out when the oil pressure is too low. Or you can remove that and install a VDO sender for a gauge or gauge/light combo.
 
That would make sense. I wonder where the coolant sensor is then... Maybe on the old radiator. Luckily I kept that I will have to check.
 
Volvo made single wire temp sensors... did you check for a lone single wire?
 
The black one with two round nipples is for 7/900 temp gauge. 200 temp gauge sensor is with one pole (flat) connctor.

1800 got Smiths "gauges*", dont know is there direct sensor replacement.

*or mechanical random variable generator

Edit: coolant gauge temp sensor from B20E (at rear in cylinder head) should fit.
 
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If your using the stock 1800E temp gauge just put your old sender from the B20 in place of the D shaped 2 pin sender. The 240 harness will have a yellow wire that connects to it.

The other sender is for the oil pressure light. Look for the wires that go to the alternator. There should be a black wire in that harness that goes to the oil pressure sender.
 
I was getting all different gauges. But for right now I just need the engine to run. I'm mainly worried about how to hook up the relays and fuses if those 2 are just for gauges.
 
i read the green book and im guessing the answer to what all these do is in there i will find the specific page... but im assuming they are for the fusebox and relays and ignition and stuff which is what im trying to figure out now. im wondering if i have to trace all the wires back or if it just lists it easily or something... well i will give it another look. but thanks for your help.

oh and i dont have any new gauges yet for this, or a fusebox (other than the old huge 740 one) so all that im just going to try to make it up somehow so any suggestions on a good way?

IMAG0307_zpsa5kpxzxf.jpg
 
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