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Discussion Starter #1
I’m pretty well versed in engine build but this is the first SBF I’ve had with EFI. I’ve learned that asking people who have already done it is worth a lot more than trial and error.

I picked this 89 bronco up pretty cheap and left some room to spend a bit. It’s a 351w /C6 running stock drivetrain. 31 inch tires. The lower end looks good, solid compression, no oil burning even under towing in the mountains. BuT the power is crap. I did a basic tuneup and it didn’t help. Plugs look like it’s running a bit lean, but otherwise no clues. Stock exhaust with no cat and a rather old flow master. Sounds like it’s got a mild exhaust leak but I haven’t gone after it yet. Trying to decide if headers are worth it.
I’m wondering what the “usual suspects” are for this motor. Is it worth upgrading the EFI, or will swapping to a carb be better in the long run? I’m building it as a tow vehicle, not an off road monster, but I’m a hot rodder at heart so it won’t upset me if it sounds a bit grumpy. I’ve got some experience with BBFs and the idea of scrapping it and dropping in a 429 isn’t off the table.

I appreciate thoughts and experiences.
thanks
LC
 

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1996 EB w/5.8 TOO much lift, 44" Mudders & 5:43-5:38's
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I like the idea of something in the 385 engine family, but I'd lean more towards the 460-514 end of the scale.

:p
 

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There's a variety of things that can cause low performance, and these old systems aren't very particular. TPS and oxygen sensor can cause issues without throwing a code. You can bump the timing up a bit to improve the power, just make sure it doesn't ping.
 

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Glad to hear i'm not the only one, i have an 89 with 351w, C6, aftermarket headers with 3 inch cherrybomb exhaust, diff ratios are 3.73 and engine is a rebuilt with approx 60k. It sound good but it's pretty much a gutless wonder, going up hills i just get over with the semi's because it just doesn't have the power.
I have wondered the same over the years and just excepted it's the nature of the beast.

I also talked with a guy that had a F250, 351w and 200k miles saying he pulls a toy hauler up canyons with ease! i cried a little when i got home where no one could see...😂

I did play with advanced timing a bit but i don't have upgraded ignition coil to support it much. Good luck and i hope you can find something i couldn't, following.
 

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Yo Lcmixon,
Welcome!
Here is some info for you; 1989 Ford Brono EVTM, Emissions (yellowish/red book cover) & Pre-Delivery Manuals, Partial via mrnewland1 in Google Drive @
1989 Service manual - Google Drive
Slow scrolling, so download for faster viewing and to see the table of contents, the search feature, etc.

Try a Self Test for Diagnostic Trouble Codes by my pal, BroncoJoe19 @ Code Reader.....
PCM stores the Self-Test program in permanent memory. When activated, Self-Test checks the EEC system by testing memory integrity and processing capability, and verifies that various sensors and actuators are connected and operating properly.

Inspect the air cleaner and inlet ducting to throttle body.
Check all engine vacuum hoses for damage, leaks, cracks, blockage, proper routing, etc. Check EEC system including the wiring harness for proper connections, bent or broken pins, corrosion, loose wires, proper routing, etc.
Check the Powertrain Control Module (PCM), sensors and actuators for physical damage, such as IAC, TPS, ICM, MAP,, etc.

IAC aka IAB in on forward driver side of intake manifold
160388


TPS
160389


Ignition Control Module (ICM)
160390

is mounted on side of distributor

MAP
160391

is mounted of firewall, passenger side


Check the engine coolant for proper level and mixture.
Check the transmission fluid and engine oil level and quality. Make all necessary repairs before continuing with SELF TEST.

The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test. Run it around to heat the engine up and shift thru all gears including Reverse. Make sure A/C is off and transmission is in Park (automatic); or in Neutral for a Manual and; release clutch. Then turn off engine, all accessories/lights (close driver's door) , etc.

Do KOEO test First. Post Code(s) here according to KOEO and KOER.

A helper can assist you by counting the codes. Some use their smart phones to record them.

BEWARE OF FAN, BELTS, PULLEYS, HOT HOSES, IGNITION HIGH TENSION WIRES, AND ENGINE COMPONENTS⚠

Or ask local mom and dad parts stores if they will test it for you.
Or purchase a coder reader such as Equus 3145 Innova OBD I Code Reader for Ford EEC IV Engines at Walmart & most parts stores

Diagnostic Routines Symptom Flow Charts — Chart 13

Symptom​
OASIS Number​
➡ Lack/Loss of Power
614000​
—Acceleration​
614500​
—Cruise​
614600​
Note: Verify symptom is reported under normal driving conditions without engine/vehicle excessive load conditions.
160383


160384


160385


See my Vacuum leak test in post #11 incl some jowens126 HVAC Control Panel pics/info @ Help with dtc codes and idle

1989 Ford Bronco Dealer Brochure

1989 Bronco Lubricant Specifications by Ford via Gary

Register with VIN to see most Ford dealer maintenance/repairs done @ any dealership nation-wide @ Welcome to Ford Owner | Official Ford Owner Site


For any Bronco questions, it's better to post each seperately in Noobie Bronco Tech Questions. Flame free zone. This will get more attention and you can build up your post count to get into other sections such as Bronco and Ford Parts/Accessories (75 posts required to participate due to scammers who preyed on our members).

To save you time and for better responses, please fill out your Bronco info with location, year, engine size, transmission type, transfer case type (manual or electric shift), locking hub type (automatic or manual) info & major mods such as a Lift, etc. .
Bronco info is now able to be put under your user name.
Click your profile button in the top right and go to account settings.


On that first page, named Account Details, scroll down to "Vehicle Info" and type in up to 100 characters.

Now you can simply enter your information in the text editor and click save.

Forum FAQs includes for example, How to Use Search. See more tips!

Baba Looey's Favorite FSB Links (lots and lots of tech links)

See and Vote in our Full-Size of the Quarter & Full-Size of the Year Contests @ Voting
You will get ideas by those competing.
Also see the prizes! They are freaking awesome!

Al
 

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Discussion Starter #6 (Edited)
so the saga continues. I tried testing with a jumper and couldn’t get anything. So I picked up an OBD1 scan tool.

I am getting a code 67 and 96. I can’t get past it to run the KOER. I noticed that there was nothing plugged into the fuel pump plug behind the air cleaner. (See attached picture)

thanks
 

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Discussion Starter #7
Update. I’ve run diagnostic tests for the fuel pump relay. Everything checks out with the exception of the dark green/yellow wire. The guide I was following says to remove the relay, and probe test the DKG/YEL wire for voltage while cranking. There is no voltage. Did I read it wrong and I’m supposed to be checking for ground? Still getting a code 96 when I scanned
 

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95 Bronco, 351W, E4OD, 4.56 gears, 35x12.50x15 Patagonia MTs.
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Why are you testing the fuel pump relay if the truck runs?
 

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Ok, i'm starting to remember some of the same shit from my Bronc and that specific code way back...things to try if you haven't already:
Fuel pressure at the rails and the pressure regulator, if this goes bad which mine has twice already, the (front) high pressure pump works harder to keep the psi up and could be flailing. (I also replaced this).
Rear low pressure pump is also an issue with these old boys and mine was shutting off from overheating and throwing errors like yours as well, I replaced this as well and no more problems but not exactly sure which one was throwing the code.
Maybe your not getting the fuel it wants due to poor pump performance?.....my two cents.
 

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Discussion Starter #11
Ok, i'm starting to remember some of the same shit from my Bronc and that specific code way back...things to try if you haven't already:
Fuel pressure at the rails and the pressure regulator, if this goes bad which mine has twice already, the (front) high pressure pump works harder to keep the psi up and could be flailing. (I also replaced this).
Rear low pressure pump is also an issue with these old boys and mine was shutting off from overheating and throwing errors like yours as well, I replaced this as well and no more problems but not exactly sure which one was throwing the code.
Maybe your not getting the fuel it wants due to poor pump performance?.....my two cents.
That would make sense. Looking at what’s been touched and what hasn’t, it looks like the tank pump has been changed, but the front pump looks original and the bolts in the skid plate over it haven’t been off in ages. Thanks for the idea, I’ll take any wisdom I can get over trial and error.
 
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