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Did I Kill My Bronco?

4K views 21 replies 10 participants last post by  96EB5.8 
#1 ·
1994 EB
351 EFI
Auto Tranny
3" lift
No mods

It was parked for a few months while gas prices soared. I had a coolant hose leak and had to do an emergency repair roadside just prior to parking it. The system was filled with plain water and of course I completely forgot to add antifreeze prior to letting it sit. I'm in NC so freezing temps are very rare.

Long story short, I took it for a drive after sitting and overheated the engine without noticing until the engine died. I was able to get back home, flush out all the rust, etc. The coolant system is fine but I had a rough idle and it smells like I'm running rich. I automatically assumed blown head gasket or worse.

Checked compression:

1 - 145 (200 on repeat)
2 - 160
3 - 180
4 - 170
5 - 180
6 - 170
7 - 155 (170 on repeat)
8 - 155 (190 on repeat)

Plugs looked normal and all cylinders were getting spark,



so checked fuel:

32 psi when running, 38 psi not running with ign on and 12 psi with vacuum disonnected.

Decided to try a tune up. Plugs, wires, cap, rotor, oil, air filter, fuel filter and some fuel injector cleaner. No difference. Tried an overnight treatment of Sea Foam, no help.

Pulled all codes and nothing for KOEO and KOER except 111. Decided to check vacuum. All lines look fine and was pulling ~ 20 Hg". Since no codes, tried replacing TPS and then the IAC valve. Neither helped.

It runs but I still have the rough idle and rich smell. Is she a goner???
:whiteflag:whiteflag:whiteflag:whiteflag
 
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#2 ·
If theres no sign of water in your oil or oil in your water you should be good on the head gasket. Did you put fresh gas in her? If they sit the gas gets water in it because of all the ethonal they use these days. Also did you reset your computer after replacing the tps and iac? Are you sure you have your tps set properly, theres more to it then just putting the screws back in it and plugging it in. Use the search function to find the tps thread on the proper way to install it.
 
#5 ·
12 PSI fuel pressure whith vacuum off the FPR? isnt it suppose to be like 45 or so? its suppose to be higher than when the vacuum is on. also isnt the fuel pressure suppose to be 35 when everything is normal?
 
#8 ·
Your fuel pressure is highest when there is no vacuum applied to the FPR. The vacuum helps to lower the bypass pressure of the regulator.
 
#10 ·
Most of the time if sensors go bad the ECU will default to values based on a "warm" engine so if anything it would be setting everything leaner.

ECT would throw a code but the Haynes gives you steps to check to see if it's within range.
 
#12 ·
Update:

I'm not one to throw parts at a problem but I'm getting really desperate. The problem still exists and here is everything I've done to date:

Checked compression
Checked spark
Checked fuel pressure
Checked vacuum
Full tune up
Injector cleaner
Sea Foam overnight
Replaced TPS (double checked, installed correctly)
Replaced IAC
Replaced ECT
Replaced injectors ($$$!)

The idle problem still exists and still no KOER or KOEO codes?!?!?

I need some Bronco guru help!
 
#15 ·
Also, I pulled the data after the tune up while idling. Maybe this can help someone help me:

Canst purge ON
ECT (V) 0.6
ECT (F) 192
Engine Speed 724
EVR (%) 0
Fuel PW1 (mS) 3.1
IAC (%) 38
IAT (V) 1.2
IAT (F) 151
Loop status closed
MAP ("Hg) 10.6
O2 Sen1 (V) 0.62
Spark (o) 20
ST FTRM1 (%) 0
Tot (V) 1.4
Tot (F) 138
TP Mode C/T
TPS (V) 1.1
VPWR (V) 14.3
VREF (V) 5.0
VSS (MPH) 0
 
#16 ·
It might be a long shot, but after having my truck in storage, it had similar issues with a rough idle...I found a nest and chewed wires under the air intake (5.8 efi)...after repairing the main harness, it still idled rough but seemed ok at speeds...after troubleshooting like you (parts) it turned out to be another nest in the tailpipe...smelled rich because of the concentrated exhaust...
 
#21 ·
I got busy at work and have not had a chance to work on the issue for a bit but today I replaced the EGR valve, sensor and control solenoid. No improvement on idle.

Checked timing and confirmed 10 BTDC with SPOUT disconnected. With SPOUT connected, runs about 20 BTDC.

Spot checked vacuum and found needle to be steady at all points. Checked vacuum canister and it held vacuum so no leaks there.

I did notice that occasionally I get a puff of white smoke when starting from cold.

Help!
 
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