LS1 Mustang starts great, no fans or tach
07-14-2007, 12:16 PM
#1
LS1 Mustang almost done! Hey all! I got the old bucket started and it seems to idle fine, and the check engine light isn't on after startup so I think I'm ok there. But my fans aren't coming on, and I'm lost as to what the problem might be. I'm not the most experienced with automotive electrical so any input is appreciated. Here's the dirt:
2002 Trans-Am LS1/T56 w/ matching harness/ecu. Harness and ecu were modified by PCMAmerica to be "stand-alone". I also use the scanmyride.com relay center (minus the AC relay) to control everything. The relay center has two heavy-duty orange leads marked "cooling fan right" and one pink lead marked "cooling fan left" (this lead is split between two of the fan relays. I'm using f-body fans/radiator and simply connected to the factory fan harness as such:
fan 1 - blue wire to #1 orange lead, grey wire to pink lead.
fan 2- white wire to #2 orange lead, black wire to pink lead as well.
They don't kick on when the car heats up, but they did function on a bench test. Obviously I've done something wrong (or the ECU isn't functioning properly, but otherwise everything else works...except the tach, so I doubt it's an ECU issue). Any thoughts?
Now on to the tach. I'm using the lead marked "tach" from my harness (duh!) and hooked it up to my autometer (autogage) tach using the 4 cyl, 2 pulse configuration. It comes on when I turn on the power, but won't read anything. Any ideas? It's a possibility that the tach is old and tired, but it worked before on the last setup.
I can't get any support from scanmyride.com because I think he's out of business, and PCMAmerica hasn't been able to offer much tech support so far either.
2002 Trans-Am LS1/T56 w/ matching harness/ecu. Harness and ecu were modified by PCMAmerica to be "stand-alone". I also use the scanmyride.com relay center (minus the AC relay) to control everything. The relay center has two heavy-duty orange leads marked "cooling fan right" and one pink lead marked "cooling fan left" (this lead is split between two of the fan relays. I'm using f-body fans/radiator and simply connected to the factory fan harness as such:
fan 1 - blue wire to #1 orange lead, grey wire to pink lead.
fan 2- white wire to #2 orange lead, black wire to pink lead as well.
They don't kick on when the car heats up, but they did function on a bench test. Obviously I've done something wrong (or the ECU isn't functioning properly, but otherwise everything else works...except the tach, so I doubt it's an ECU issue). Any thoughts?
Now on to the tach. I'm using the lead marked "tach" from my harness (duh!) and hooked it up to my autometer (autogage) tach using the 4 cyl, 2 pulse configuration. It comes on when I turn on the power, but won't read anything. Any ideas? It's a possibility that the tach is old and tired, but it worked before on the last setup.
I can't get any support from scanmyride.com because I think he's out of business, and PCMAmerica hasn't been able to offer much tech support so far either.
Last edited by Mr. Hyde; 07-16-2007 at 09:27 AM.
07-14-2007, 01:05 PM
#2
Hmm I think the tach might be junk, when I pull out the lightbulb in the face of the tach, it stops working completely. When the bulb is plugged in, it stays dimly lit (with the dash lights OFF) and the tach only responds to me moving the shift-lite RPM selector, but doesn't move with RPM changes.
Oh well any thoughts on the fan situation would be helpful
Oh well any thoughts on the fan situation would be helpful
07-14-2007, 03:44 PM
#4
I found the old wiring diagram from scanmyride.com. It says to put the two orange leads to one fan, and the pink to the other and then ground the remaining lead from the fan. Tried it, doesn't work. What next I wonder? It seems like it should be working. Oh and my car just went into limp mode and the CEL is on...
07-14-2007, 08:53 PM
#5
i dont know what the issue is with the tach but i am having the same issue with a swap i just did for a guy and cant figure out what it is either............ if anyone has any info on this please help... ill try a search i guess.lol....
07-14-2007, 10:55 PM
#6
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Here are a couple of drawings that might help with fan wiring.
http://shbox.com/1/fan_schematic_1995.jpg
http://www.ls2.com/boggs/LS2/engine/coolingwiring.JPG
http://shbox.com/1/fan_schematic_1995.jpg
http://www.ls2.com/boggs/LS2/engine/coolingwiring.JPG
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07-16-2007, 09:41 AM
#8
Ordered the Autometer pro-comp in-dash speedo and tach today, I gotta know how fast I'm going and what RPM I'm spinning to when I'm sitting in rush hour traffic LOL...
Driveshaft will be done this week, so it'll be on the road by the weekend...then I can find out why my CEL is on now!
Driveshaft will be done this week, so it'll be on the road by the weekend...then I can find out why my CEL is on now!
07-16-2007, 05:55 PM
#10
Hi
I got one of the Scanmyride harness setups, too The first thing I did with the fan relay sub-harness was to hook-up a 6v lantern battery along with 2 little lights tha simulate the fans. I found one or two wires wrong when comparing it to the wiring diagram in the GM F-body manual. When corrected, I could get (2) dim bulbs (low speed fan) and (2) bright bulbs on hi fan when controlling the relays. I just used a small piece of sheetmetal for the ground and some alligator clips and wire to make the connections. The bulbs were mounted in little sockets from RadioShack.
Check out anyone's electrical stuff before plugging it in: you'll understand it better for troubleshooting, and find errors before you fry anything.
Garret & Steve in process of building E30-LS1 (1986 BMW 325 with '99 Camaro motor & T56) -- all done except for exhaust system
I got one of the Scanmyride harness setups, too The first thing I did with the fan relay sub-harness was to hook-up a 6v lantern battery along with 2 little lights tha simulate the fans. I found one or two wires wrong when comparing it to the wiring diagram in the GM F-body manual. When corrected, I could get (2) dim bulbs (low speed fan) and (2) bright bulbs on hi fan when controlling the relays. I just used a small piece of sheetmetal for the ground and some alligator clips and wire to make the connections. The bulbs were mounted in little sockets from RadioShack.
Check out anyone's electrical stuff before plugging it in: you'll understand it better for troubleshooting, and find errors before you fry anything.
Garret & Steve in process of building E30-LS1 (1986 BMW 325 with '99 Camaro motor & T56) -- all done except for exhaust system
07-25-2007, 11:32 AM
#13
Sure! I used the t-bird turbocoupe pedals, and mounted a wilwood univeral master cylinder (forgot what PN, but it's the same internal dimensions as the factory f-body piece) with a fabbed steel bracket that bolts to the brake and gas pedal mounting bolts; it positions the master directly between the brake and gas pedal arms on the firewall (where the steering column exits the passenger compartment). Macleod suppled the -4 AN line w/ quick disconnect. So far it seems to work great except that the clutch is slipping badly. It's a SPEC setup with unknown mileage, so I'm going to swap in the LS7 setup. Everywhere I've looked it seems that slippage isn't typically a symptom of improper bleeding, as I've bled the thing until I'm positive no air is coming out. It goes into gear effortlessly and shifts smooth, just slips when you get on it. I posted in the manual transmission forum and the only reply I got was to swap in a new one...I'm open to any suggestions for troubleshooting but I think it's just wasted.
07-25-2007, 04:20 PM
#14
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Originally Posted by Mr. Hyde
Sure! I used the t-bird turbocoupe pedals, and mounted a wilwood univeral master cylinder (forgot what PN, but it's the same internal dimensions as the factory f-body piece) with a fabbed steel bracket that bolts to the brake and gas pedal mounting bolts; it positions the master directly between the brake and gas pedal arms on the firewall (where the steering column exits the passenger compartment). Macleod suppled the -4 AN line w/ quick disconnect. So far it seems to work great except that the clutch is slipping badly. It's a SPEC setup with unknown mileage, so I'm going to swap in the LS7 setup. Everywhere I've looked it seems that slippage isn't typically a symptom of improper bleeding, as I've bled the thing until I'm positive no air is coming out. It goes into gear effortlessly and shifts smooth, just slips when you get on it. I posted in the manual transmission forum and the only reply I got was to swap in a new one...I'm open to any suggestions for troubleshooting but I think it's just wasted.
Is it hard (difficult to get at) to bleed the lines or refill the fluid? I don't guess you have any pictures of it all to share do you?...
07-25-2007, 04:53 PM
#15
I might be able to get some pics this evening, depends on what time they unlock my shackles here at work...
I mounted a remote reservoir in the engine bay so it's easy to fill, and bleeding is just like an f-body, only a little easier to get to I'd say...just reach up the side of the tranny from underneath. As far as the master goes, I bench-bled it before bolting it in. I'd say it's sort of a PITA to get to, but not impossible.
I mounted a remote reservoir in the engine bay so it's easy to fill, and bleeding is just like an f-body, only a little easier to get to I'd say...just reach up the side of the tranny from underneath. As far as the master goes, I bench-bled it before bolting it in. I'd say it's sort of a PITA to get to, but not impossible.
07-26-2007, 06:55 PM
#16
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Originally Posted by Mr. Hyde
I might be able to get some pics this evening, depends on what time they unlock my shackles here at work...
I mounted a remote reservoir in the engine bay so it's easy to fill, and bleeding is just like an f-body, only a little easier to get to I'd say...just reach up the side of the tranny from underneath. As far as the master goes, I bench-bled it before bolting it in. I'd say it's sort of a PITA to get to, but not impossible.
I mounted a remote reservoir in the engine bay so it's easy to fill, and bleeding is just like an f-body, only a little easier to get to I'd say...just reach up the side of the tranny from underneath. As far as the master goes, I bench-bled it before bolting it in. I'd say it's sort of a PITA to get to, but not impossible.
Yeah pictures would be great. I'm sold on the ls2/t56 swap for my car, but I'm just gathering info about the clutch linkage. From what I can tell now alot of F-body guys complain about the hyd. setup, but I think most of their problems are from using stock GM master & slave cylinders. They all seem to think it would be better to have a cable setup and they fail to realize how stiff that will be with a heavy duty clutch. Right now my SPEC stage IV will give you a workout around town. If I can get a T56 and use the right parts with the T-bird pedals I think it would work great as long as it fits alright. Do you have any clearance issues with the driver side header and the master cylinder?
07-26-2007, 08:26 PM
#17
what we need is the old gm style hyd. clutch. everthing was out of the oven ... I mean bellhousing.
there are some threads on here where you need to use a 10k ohm resistor between the tach wire and a 12v in run power wire to get many of the tachs to work. now I have no idea if that will help your tach problem but it might
there are some threads on here where you need to use a 10k ohm resistor between the tach wire and a 12v in run power wire to get many of the tachs to work. now I have no idea if that will help your tach problem but it might
07-27-2007, 12:11 PM
#18
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On the fans... if you're using the PCM to turn them on, know that it doesn't command them on until after 220*. I had the same "problem" when I first fired my car. It just wasn't getting hot enough to kick them on. If your wiring is ok, that may be your issue. The fan turn-on temp can be changed with a handheld tuner, HPTuners, or EFILive.
