Crank and no Start- Puzzled

Bru

Member
Feb 28, 2013
50
29
18
Tampa Bay Area
Here's a photo of the coil pack set up with the white stamped numbers visible. Left to right 1-6-3-4-2-5. The front row in the wire retaining clip is 1-3-4-2 and the back row is 6-5. Each retaining cap has dots to indicate which coil pack it connects to. I've noticed that they come in two colors, either dark gray or black. Those little retaining locks tend to break with age. The 1987 manual shows numbers for the wire routing, but the '91 online manual does not. Here's a photo showing the wire routing as well. The '91 manual has an additional one wire retainer for cylinder 6. I have (3) 1 dot, a 2 dot, and a 3 dot cap, all in black, that I can't use, but would trade them for a dark gray 1 dot cap in good shape.

Coil Pack.JPGSpark Wires.JPG
 

57Bonus

New Member
Dec 14, 2022
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7
3
67
Here's a photo of the coil pack set up with the white stamped numbers visible. Left to right 1-6-3-4-2-5. The front row in the wire retaining clip is 1-3-4-2 and the back row is 6-5. Each retaining cap has dots to indicate which coil pack it connects to. I've noticed that they come in two colors, either dark gray or black. Those little retaining locks tend to break with age. The 1987 manual shows numbers for the wire routing, but the '91 online manual does not. Here's a photo showing the wire routing as well. The '91 manual has an additional one wire retainer for cylinder 6. I have (3) 1 dot, a 2 dot, and a 3 dot cap, all in black, that I can't use, but would trade them for a dark gray 1 dot cap in good shape.
I didn't know there's a plastic retainer just below the coilpacks. My old 87 only had the 3 retainers that are attached to the spark plug valley cover and were in pretty bad shape.
It's most likely my retaining caps were original. They are (faded) black and two or three couldn't stay in place and kept coming slightly loose but didn't seem to affect how the engine ran that I could tell.

7mgte-Coilpacks.jpg
 
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Bru

Member
Feb 28, 2013
50
29
18
Tampa Bay Area
I didn't know there's a plastic retainer just below the coilpacks. My old 87 only had the 3 retainers that are attached to the spark plug valley cover and were in pretty bad shape.
It's most likely my retaining caps were original. They are (faded) black and two or three couldn't stay in place and kept coming slightly loose but didn't seem to affect how the engine ran that I could tell.
There are 2 plastic routing clips that attach to the coil pack itself. There is one in front that you can see in my photo, and there's another underneath that is shown in the manual photo. I guess the whole idea of this routing scheme is to reduce the chance of spark induction in adjacent wires, plus it looks neat.
 
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Ryan_

New Member
May 8, 2013
15
3
3
Earth
reviving this thread as I'm now back to getting this thing going again.

Starts up strong, though I think it may have a vacuum leak as initially it started and idled fine around 1,100 rpm cold, however a minute in it climbed on its own to around 1,500 rpm.

-Now, cold starts and idles around 1,700 rpm.
-When she warms up, it begins to pulse between between 1300-1700 rpm -and sometimes just sit at 1,100 (not idling smooth.)
-Sometimes will die if I give it throttle.
-I had a broken connection for the coolant temp sensor to ecu and hotwired one right up to the ecu plug.
-Also no coolant reading on the gauge, probably another broken connection.

Things I've tried and will try:
-I've checked the TPS is within spec as per the TPMS.
-AFM connections to ECU are good.
-I'll check ISV next weekend.
-I also have a smoke machine / leak detector being delivered before then which I'll use to see if there is still any vacuum leaks.

I've only had this pulsing idle with another supra about 10 years ago, and I remember pulling the EFI fuse and re-installing it and solved the problem. I don't even recall what the issue was.

Also, it might be worth it to note that the battery is not connected to the car -I disconnect the terminals every time I leave cause I don't know when I'll be back and I want to preserve the charge. So nothing is being stored in the ECU.
 

supraguy@aol

Well-Known Member
Dec 30, 2005
4,231
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Atlanta
Hey Ryan- A slightly weird idle is normal if you keep unplugging the battery. The ECU relearns the fuel trims each time you do that, and it takes a few miles of driving to complete. If it won't drop to a normal idle eventually, you may have a sticking IACV. Its very easy to remove and fully disassemble. Mine was slightly rusted and gummed up on the inside. And after cleaning, it really improved my idle.