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1988 Ford Bronco 351w, c6, auto locking hubs, manual transfer case, 3inch lift, 33s
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10 Posts
Discussion Starter · #1 ·
I started a thread a while back regarding some injectors I bought, and trying to increase my mpg. Just as an update, I did go with the stock injector size, I installed those along with a new TPS sensor, MAP sensor, IAC valve, a new 02 sensor, replaced the FPR, and Motorad Fail-Safe (192-195 deg) thermostat. I just did the IAC valve because It would start up and run great, then I'd drive into town, about 25 30 minutes, and kill it, come back to the truck, it would not idle right, a little tougher to start, then if I stopped it again to get gas or something, it would be even harder to start idling much worse and feels like its missing. Having just done the IAC I'm not 100 percent sure it fixed my problem. But coming back from the gas station I got a solid 4mpg,(before I did the iac) and I at least used to get 7. I can smell fuel. I know something is wrong, it just seems to be above my understanding. I can smell fuel out the pipe, and when I get on the gas in the cab, i just replaced the injectors, and they are sealed up good, so they shouldn't be leaking. And having not driven it with the new IAC I dont know what the mpg is, but I could still smell fuel when I was letting it idle after the installation. Any ideas what It could be????
All is appreciated!
 

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Registered
1988 Ford Bronco 351w, c6, auto locking hubs, manual transfer case, 3inch lift, 33s
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10 Posts
Discussion Starter · #2 ·
Update; After driving with the iac valve, the mpg is still awful.
 

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1991 351w/E4OD/3" lift/4.56/33" tires/LSD FR+RR
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497 Posts
Perhaps faulty ECT sensor (Engine Coolant Temperature). At cold startup your computer sends more fuel in the mix (rich mixture). As the engine warms up the ECT senses engine temperature rising and will tell the computer to lean out the mix (sending less fuel). If the ECT is faulty it will continue to tell the computer to keep the air/fuel mix rich (adding a constant high amount of fuel to the mix creating bad gas mileage) even though the engine is warm. In other words the computer is always thinking the engine is warm, and never leaning out the fuel/air mix. ECT sensor is something you may want to test before replacing... there are plenty of to-do articles. Easy and cheap to replace though.
 

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Registered
1988 Ford Bronco 351w, c6, auto locking hubs, manual transfer case, 3inch lift, 33s
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10 Posts
Discussion Starter · #4 ·
Thanks! I'll get right on testing the ECT
 

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Registered
1988 Ford Bronco 351w, c6, auto locking hubs, manual transfer case, 3inch lift, 33s
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10 Posts
Discussion Starter · #5 ·
I replaced the ect and it helped the idle, but it's still running way rich, the exhaust is now getting dark, and the smell of fuel is very strong
 

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82 XLT Lariat 351w, Edelbrock 1406 4bbl ,C6 auto, auto locking hubs ,33x10.5x15
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4,254 Posts
Have u checked fuel pressure?
 

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1990 EB, 5.0
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436 Posts
I'd check the fuel pressure at the rail as suggested above. Could be you need to replace the Fuel Pressure regulator. But the Ignition Control Module (ICM) and the Engine Control Module (ECM) could also be suspects. Hard to tell from the info provided.
 

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Charlie don't surf..
'92 Ford Bronco XLT
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16,139 Posts
Stop throwing parts at it..have you checked for codes yet? If not that's a good place to start..pull your plugs, do you have fuel on them? If so those new injectors might very well be leaking.
 

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Registered
1988 Ford Bronco 351w, c6, auto locking hubs, manual transfer case, 3inch lift, 33s
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10 Posts
Discussion Starter · #9 ·
I have checked for codes, got nothing. But I'll be checking the fuel pressure soon! Thanks all for the advice
 
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