1990 4.9 run ability issue
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4wd Low
Joined: Dec 2021
Posts: 14
Likes: 0
Hi, I finally made it to the shop. Update on van. I pulled the ECU and found 2 leaky capacitors. I replaced the ECU and van runs 90 percent better. I'm still trying to figure out why I get a misfire under a load like getting on the freeway. Doesn't happen all the time but when it does its noticeable. Couple things I'm trying to figure out. I found a green ground wire that's bolted to the left motor mount by the coil. The other end of the wire is not attached to anything however the bare wire looks clean and cannot locate where its attached to.
Also there is a sensor/sending unit that sits between the coil and the distributor. Can anyone tell me what that is?
Thanks in advance
Also there is a sensor/sending unit that sits between the coil and the distributor. Can anyone tell me what that is?
Thanks in advance
Hotshot
Joined: Jul 2020
Posts: 10,401
Likes: 2,607
From: Near Salt Lake City
Don't worry much about the green wire bolted to a motor mount
Most likely just a ground a previous owner installed
Interrogate the plug wires for your miss under load
Post a picture of that wire
1990 4.9 I know of nothing that should be between your e core coil and the distributor but a coil wire
There is the oil pressure sending unit on the block you may be looking at
Post a pic of that too
Most likely just a ground a previous owner installed
Interrogate the plug wires for your miss under load
Post a picture of that wire
1990 4.9 I know of nothing that should be between your e core coil and the distributor but a coil wire
There is the oil pressure sending unit on the block you may be looking at
Post a pic of that too
Thread Starter
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4wd Low
Joined: Dec 2021
Posts: 14
Likes: 0
Hi, Thanks for reply. Plugs wires are all new. also new distributor and coil. I did replace plugs back in Nov 2021. Only has less than 8k on them. They were all carbon up as truck was running rich. I did clean them up and reinstalled. Runs good with no load but sputters/misses underload. If I gradually accelerate. it doesn't sputter as much.
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