Intermittent Power Loss + Flickering Battery Light

[Rev]

'87 2.9 4x4 A4LD

On the last dozen or so starts my truck has been running like crap. Here are a list of symptoms:

Rough/missing idle
Power loss under accelleration
Shaking in 3rd, worse in O/D
Shaking goes away when gas pedal is released
Pedal to the floor at 55mph and tach goes up but no accelleration
Intermittent battery light
10-12mpg

I replaced the entire cooling system (fan clutch, radiator, heater core, thermostat, hoses) and had a complete tune-up (replace plugs, wires, cap, points{?}, timing, etc.) about 2k miles ago. No KOEO or KOER codes. Double checked all electrical/ignition connections.

The battery stays charged and the connections are clean and tight. No smoke out of tailpipe.

I'm about to take it down to a very respectable shop but would prefer to fix myself if I can possibly get some help from the wizards on this board...thanks!

 

[Earl43P]

Have the alternator tested at an AP store (typically free). Clearing up that battery light flashing may cure it all.

 

[IMenriched]

'87 2.9 4x4 A4LD

On the last dozen or so starts my truck has been running like crap. Here are a list of symptoms:

Rough/missing idle
Power loss under accelleration
Shaking in 3rd, worse in O/D
Shaking goes away when gas pedal is released
Pedal to the floor at 55mph and tach goes up but no accelleration
Intermittent battery light
10-12mpg

I replaced the entire cooling system (fan clutch, radiator, heater core, thermostat, hoses) and had a complete tune-up (replace plugs, wires, cap, points{?}, timing, etc.) about 2k miles ago. No KOEO or KOER codes. Double checked all electrical/ignition connections.

The battery stays charged and the connections are clean and tight. No smoke out of tailpipe.

I'm about to take it down to a very respectable shop but would prefer to fix myself if I can possibly get some help from the wizards on this board...thanks!

Agreed get Alternator checked..... maybe that will help the lack of throttle response and high way speed.

double check the fluid level in tranny...also check for vacuum leaks. there maybe something more sinister with the tranny.

 

[Rev]

Thanks for quick reply guys. Parked the Range for the past few weeks while getting my daughters 95 Contour freeway safe again.

Taking the Ranger down to an AP store to have the alternator tested.

BTW no vacuum leaks and tranny fluid level fine.

 

[Wrongway]

Check the battery ground wire that attaches to the engine block. Even if it's tight.. loosen it, then rotate it a few times then tighten it down again.

 

[Rev]

Well...I hopefully found a solution on my own. The previous owner installed a 1987 B2 motor and tranny just before selling. Some of the wiring harnesses weren't running in their factory locations.

Because of the intermittent battery light, intermittent loss of tach gauge and overall rough engine performance, I narrowed it down to either the alternator or the coil. Had the alternator checked and was running fine. However, the belt was a little too loose so I tightened that up.

Just before installing a new coil I triple-checked all the wiring and connections leading to and from the coil. On the last inspection I took closer look at the resistor/capacitor (or whatever that black bubble gum package sized block is) that runs from the coil. It's a green wire and it was resting against the oil dipstick. Right where it connects to the block the casing had worn off and had exposed the wiring underneath. I taped it up, recovered all the wires with new plastic sheathing and zip tied everything away from other parts.

Low and behold, smooth idle, regained acceleration and so far no battery light.

Thanks to all for the help.

 

[Rev]

So the battery light has returned with a vengeance. Did my own test on the alternator and the thing is on the way out.

For a 2.9 there are a TON of replacement alternators available (i.e. 40amp vs 60 amp, internal vs external regulator, etc.).

Recommendations?

 

[IMenriched]

So the battery light has returned with a vengeance. Did my own test on the alternator and the thing is on the way out.

For a 2.9 there are a TON of replacement alternators available (i.e. 40amp vs 60 amp, internal vs external regulator, etc.).

Recommendations?

depends on options you have on your truck ??? power windows & locks, a/c, extra lights... etc.

All that factored in and in general.....get the bigger amps you can....in case you add a couple extra lights it will have enough to keep up with the demand.

Unless you are going to get crazy and add 20 extra lights, winch, massive stereo...hairdryer, microwave satilite TV...etc. then just 1 alternator won't cut it, dual alternator set up or portable generator in the back is needed.

http://www.therangerstation.com/tech_library/alternator.htm

http://www.therangerstation.com/tech_library/DualBatteries.html

 

[RustedRanger]

My alternator was overchargeing and fried the battery,I found that out by checking it with a voltmeter while running. Thankfully I did check it cause it was charging 17 volts and would have killed the new battery. I just changed the regulator.

 

[Rev]

Took the alternator out and had it bench tested...3X...works fine. Symptoms are worse than ever. I'm thinking I might have a short or loose ground somewhere. I spent 2 hours cleaning and reattaching grounds and tracing wires...everything seems to be OK.

Starts fine, idles at 1700-1800rpm until warm, drops down to 950rpm. Once at normal operating temp it starts to miss and pour black smoke.

Update 9:25pm PST 11/13 - Took it out for a drive to my parents...about 15 miles on city streets and county roads. Under acceleration the truck runs fine. Once I let off the gas or keep the peddle at cruising speed the engine misfires and it pours black smoke.

HELP!

 

[creepinjeepster]

Someone else had posted about a possible bad ground. Said he checked his wires and they were good. Ended up replacing both the grounds (battery to block and block to frame) upon replacement, noticed they were worse off than he originally noticed. You may still have a ground problem.....

 

[holyford86]

sounds like you are having an o2 sensor problem, look for an orange ground wire going to the back of the passenger side head, make sure it's alright, check your o2 sensor for proper operation as well.

 

[tommy182018]

it sounds to my like the o2 sensor aswell it dont take reading from it untell it is worm so that would explain why it only does it when it is worm i had the same problem check the orange wire from the 02 senser and maybe take it and ground it else were that is what i had to do i just ran it right to the battery for test perpases and it fixed it the i just had to find a new place closer to ground it i grounded mine right to the frame next to the sensor neaver had a problem again tell the sensor went out from age replaced it and done 3 years no problem ..... let us no what happens

 

[Rev]

sounds like you are having an o2 sensor problem, look for an orange ground wire going to the back of the passenger side head, make sure it's alright, check your o2 sensor for proper operation as well.

Hmmm...no orange wire from the HEGO (Heated Gas Oxygen Sensor)/02 sensor. According to the wiring diagram for an '86 2.9:
Black (Terminates at #49 on the Electronic Control Assembly)
Black/Light Green (Appears to be Ground)
Gray/Yellow (From ignition switch to inline fuse link "X" which is dark blue)

Hopefully on the right track...pulled codes and now get a "HEGO sensor out of range/lean condition" error.

UPDATE 11/14

Went to the local Pick & Pull and traced down the above wires in a wiring harness inside a junked B2. The Black wire ran uninterrupted through the main wiring harness that terminates somewhere in the passenger firewall. The Black/Light Green wire joined other ground wires near the Y in the main wiring harness underneath the air intake manifold on the passenger side. The Gray/Yellow wire ran to the drivers side near the coil where there were two inline capacitors or fuseable links and then the wire changed to dark Dark Blue and terminated in a gray 8-pin connector on the drivers side wheel well. I cut the length of Gray/Yellow wire with the two capacitors or fuseable links left intact.

Got home and cut out the old Gray/Yellow wire then soldered and taped the connections. While pulling out the old wire, I noticed at least 2 broken connections where the wire turns Dark Blue. I also found the Orange ground wire coming from the wiring harness near the distributor. It was "grounded" along with the main firewall ground (flat woven line on the firewall on the drivers side) to the aluminum intake manifold on the drivers side. I grounded them to the steel exhaust manifold near the back of the motor.

FYI - According to the wiring schematic the Orange wire is the main ground from #49 of the Electronic Control Assembly (where is this located?)

I then examined and re-taped the HEGO/O2 sensor wires that go down to the sensor itself, which I also replaced for good measure.

Took it for a short drive and so far all is good! No engine miss or smoke!!

Tomorrow or Monday I'm going to test for codes and then clean the plugs as I'm sure they're fouled from the lean condition.

Thanks everyone for the help!

I also replaced the