90 Bronco 351 hot start problem
#1
90 Bronco 351 hot start problem
When it's up to opperating temperature, if I park my 90 Bronco for like say 10-15 minutes and restart it, it chugs, misses, surges and just is plain snotty. After a minute or two it cleans out and runs fine. If I let the truck cool off completely it starts fine and if it's just a couple minutes it's fine.
It's an EFI 351 with 160k on the clock. It probably could use plugs and wires but I think the problem is fuel related. My thoughts are that injectors are leaking down into the engine. A couple minutes and there's not enough time to cause a problem. An hour or two and the fuel has evaporated. But 15 minutes is enough to leak down and have the fuel just sitting there. So when I start it it's pig rich...
Any ideas?
It's an EFI 351 with 160k on the clock. It probably could use plugs and wires but I think the problem is fuel related. My thoughts are that injectors are leaking down into the engine. A couple minutes and there's not enough time to cause a problem. An hour or two and the fuel has evaporated. But 15 minutes is enough to leak down and have the fuel just sitting there. So when I start it it's pig rich...
Any ideas?
#4
When was the last time you checked your plugs? Have you pulled the dizzy cap and cleaned the rotor and contacts really well? I had a post below concerning the TFI, but after reading your post again, I suggest checking the obvious first. Concerning the TFI, if you stil experience problems, you may wanna check it. I also had a fuel pump related failure that had the obvious signs of not wanting to start after sitting for a short length of time.
Does this Bronco have the TFI module located on the dizzy itself or is the remote-mounted TFI module?
This could also be your Hot-start problem. The TFI dizzy mounted systems had failures due to overheating. This was overcome with the remote-mounted type on the driver side fender well near the cab.
If you think this could be TFI related, you could remove the TFI and clean it really well and if you have some dielectric grease, put it on the back of the module and the plate where it bolts up. Ensure that the area is clean of any debris and grease. If you have access to some thermal compound, you can use a product known as Artic Silver instead of dielectric grease.
The TFI may or may not be your problem, but if it's aged, cruddy, has stress cracks, chances are it could be ready to go out. There are tests for the TFI. If you decide to replace it, be sure to buy Motorcraft and get the same color as the OEM one.
Does this Bronco have the TFI module located on the dizzy itself or is the remote-mounted TFI module?
This could also be your Hot-start problem. The TFI dizzy mounted systems had failures due to overheating. This was overcome with the remote-mounted type on the driver side fender well near the cab.
If you think this could be TFI related, you could remove the TFI and clean it really well and if you have some dielectric grease, put it on the back of the module and the plate where it bolts up. Ensure that the area is clean of any debris and grease. If you have access to some thermal compound, you can use a product known as Artic Silver instead of dielectric grease.
The TFI may or may not be your problem, but if it's aged, cruddy, has stress cracks, chances are it could be ready to go out. There are tests for the TFI. If you decide to replace it, be sure to buy Motorcraft and get the same color as the OEM one.
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BlueOvalRage
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