1991 Bronco
5.0 (recently installed rebuilt junkyard engine)

I have finally got the truck running right - no crazy high idle (TPS) no voltage problems (VR) but I still have a couple bugs I'm trying to work through.

First - I get a check engine light while driving.
I pulled the codes & get a 111

is there another way to check the codes?

Second - 4th gear (overdrive) has a vibration - it almost feels like a wheel goes out of balance & the truck bounces or thumps. Only get it in 4th gear when going slow (45mph) if I get up to higher speeds 60 or so - the vibration goes away. No idea what this could be.

 

Double check vacuum lines EVERYWHERE paying particular attention to the area of the EGR, Diverter valve, TAB and TAD solenoids. Any loose lines in this area can cause erratic performance. In fact a loose vacuum connection at the EGR triggers the CEL almost immediately with the engine at op. temp. Did you run BOTH tests? (KOEO and KOER)? The KOER test is the dynamic test that will pinpoint issues that don't get recorded into the KOEO test results and won't show up anywhere but during the KOER.

Just a couple of questions about problem one (1). Can you identify any particular conditions that might cause the CEL to come on? For example, "always happens going up hill" or "happens only after the engine is fully warmed up". If not, does the CEL coming on change anything in the performance? Does it come on and stay on or is it intermittent? If there are no vacuum issues and you have no fault codes being generated, you could be chasing an electrical short.

As to the second issue, check the double-cardan u-joint at the front end of the rear drive-shaft. Being a double-cardon setup means it has a centering ball and socket assembly that can dry out or wear down that causes mis-alignment when the shaft is under little to no load (cruising) or negative load (deceleration).

 

Are you sure you don't have an engine misfire?
I've had plenty of customers come in complaining that their vehicle shakes or bucks at lower speeds while in high gear and most of the time I find out it's misfiring. Even a slight misfire can cause a noticeable thump while in 4th and at low speed because the engine has such a load on it that it just transmits through the drivetrain.

 

the 91 would have 2 digit codes not 3.

what year is the junkyard motor?

 

I have a 1990 with the 5.0L engine. I've had all kinds of problems with it, from the ignition actuator breaking to the cooling system being clogged up with stop leak.

It's running pretty good now after working on it for two years, part time I mean.

The Ford Service Manual indicates that before diagnosing the transmission issues all the engine issues should be fixed first. I was trying to determine a slip came from while in overdrive gear. So I had to work thru all the engine first.

As far as the overdrive goes, I only use the overdrive when I'm at cruising speed. It slips otherwise. So for ordinary around town or out on the trail it's in D without the white circle. When I get up to 55 on the freeway that's when I shift into Overdrive. Then I can crank it up to about 70.

 

Vacuum leak - yes

Misfire - possible - but since I did the tune up I thought I had that beat.

Since the engine was replaced - there is 1 vacuum line that I can't find where it plugs into.

I'll post pictures here in a little bit.

#8 cyl had a black plug when I replaced them - I put in all new wires, plugs, cap & rotor & after replacing the TPS sensor I thought I had the misfire beat.


I do not know how to perform the KOER test. So the "11" code I get is KOEO.

big help guys - Let me fiddle around a little bit & I'll post more info.

 

I plugged the 2 vacuum leaks I had - 1 was near the EGR valve - I had forgot to plug in the line on the throttle body when I replaced the TPS.

The second I mentioned before - I found it was on top of the plenum.

So I took it out for a run - the check engine light comes on once the engine gets up to temp & stays on constant -

I might still have a misfire - though I have no idea what could be causing that now- maybe an injector - this was a junk yard engine after all.

How do I check the codes with the engine running? I took it to the local parts store & they couldn't read anything with their computer.

 

Hopefully this will help:
Fuel Injection Technical Library » KOER Test

 

Thank you!

I ran the test - I plan to re-run it as well. I got this string of numbers - not sure if I caught them all correctly

after the 4 flashes & the tap on the gas I saw this.

11
73
32
22
55
36

or maybe it was

117
332
225
536

in any case - it was a string of 1171332225536

I think that means the EGR valve is not working but not sure. Not that I care if the EGR valve works.

 

According to Kemical^^^ the 91 uses 2 digit codes.

 

2nd test.

The codes seemed to run in 3 digits with a space or pause in between

172
221
225
526

I did notice the dip stick tube has become disconnected & I was getting significant vapor blowing out.

 

I found the 172 is the O2 sensor
225 is a knock sensor

what is a 221?
what is a 526?

 

Blow by aint good

Might want to do a compression test and cylinder leak down test. Or just drive it til she blows

 

I think I just need to reattach the dip stick tube.
I found a 221 is a spark timing is off.

 

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