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A Few Misc Questions


kxri318

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1986 Ford Ranger 2.9 Auto
I've been having running issues for a while and have some other problems too, maybe they're related in some way.....??

1. I can shift into all gears without the key being in, steering lock works fine when the key isn't in though. The Ranger I got a few parts from at the junkyard wasn't able to shift without the key and I've heard its not normal. Why might my truck be allowing that?

2. My RPM's decrease about 50 RPM when I turn the headlights on, same when my speakers is being used. Headlights don't dim or anything when the sub is on though so it seems like there's enough power from the alternator. I've heard a mixed bag on whether the RPM dropping is normal or not. Some people say it happens, others say it should have something that raises the RPM back up, couldn't find out whether my truck is supposed to raise the RPM when the alternator is being used more. Is it normal?

3. I've got a few vacuum leaks that I'm not sure if they're normal. I did a smoke test and saw smoke come from where the lid of the carbon canister meets the main body of the canister, I saw smoke coming from the breather valve on the driver side valve cover, and I also saw a little smoke coming from the EGR valve. I can't tell if the smoke is coming from the valve itself or where it meets the intake manifold plenum. I'm pretty sure that leak at the EGR valve isn't normal, but I'm wondering if the breather valve or the carbon canister leak is normal. I've heard the canister is supposed to vent, not sure from what part though.
20230924_201838.jpg
 
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rubydist

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1. The safety interlock is disabled or broken, which allows the shifter to be moved without the key on. This is not related to any other issue and as long as you are smart enough to keep it in park when you are not wanting it to move, there is not a problem with this.

2. The added current draw in the alternator causes the engine speed to drop a little. As long as it does not stall from trying to run too slow, its not a real issue.

3. There should not be smoke coming from any of those areas you mentioned. The charcoal canister vents are those egg-looking caps on the top.
 

RonD

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3. When you start the engine cold does it idle higher and run OK, thats Choke Mode?

Computer controls the IAC(idle air control) Valve to set idle
Cold idle is based on coolant temp, the colder the temp the higher the idle
Cold minimum is about 1,000rpm
Idle will slowly drop as coolant/engine warms up
Target warm idle is usually 750rpms for an automatic
When in automatic is in gear idle should bump up to 800rpm, but..............
In 1986 the computer may not have "in gear" software, so it just maintains target RPMs for engine temp, so when put in gear idle drops momentarily then comes back up to Target RPMs using IAC Valve

If power steering or alternator loads down the engine computer should keep RPMs at Target level using the IAC valve

Warmed up engine, idling
Unplug the 2 wire connector on IAC Valve
Idle should drop under 600rpms or engine may even stall, either is GOOD, it means no vacuum leaks
If idle does not drop then computer is not in control of idle RPMs, most likely there is a vacuum leak
OR
If you also do not have higher Cold Idle then IAC Valve is not working at all, needs to be cleaned or replaced
Only use motorcraft or hitachi brand IAC valves
 

rubydist

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RonD, doesn't his 86 still have a carb?
 

RonD

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No, 2.9l's only ever used EFI
2.8l's used carbs
 

kxri318

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3. When you start the engine cold does it idle higher and run OK, thats Choke Mode?

Computer controls the IAC(idle air control) Valve to set idle
Cold idle is based on coolant temp, the colder the temp the higher the idle
Cold minimum is about 1,000rpm
Idle will slowly drop as coolant/engine warms up
Target warm idle is usually 750rpms for an automatic
When in automatic is in gear idle should bump up to 800rpm, but..............
In 1986 the computer may not have "in gear" software, so it just maintains target RPMs for engine temp, so when put in gear idle drops momentarily then comes back up to Target RPMs using IAC Valve

If power steering or alternator loads down the engine computer should keep RPMs at Target level using the IAC valve

Warmed up engine, idling
Unplug the 2 wire connector on IAC Valve
Idle should drop under 600rpms or engine may even stall, either is GOOD, it means no vacuum leaks
If idle does not drop then computer is not in control of idle RPMs, most likely there is a vacuum leak
OR
If you also do not have higher Cold Idle then IAC Valve is not working at all, needs to be cleaned or replaced
Only use motorcraft or hitachi brand IAC valves
1. The safety interlock is disabled or broken, which allows the shifter to be moved without the key on. This is not related to any other issue and as long as you are smart enough to keep it in park when you are not wanting it to move, there is not a problem with this.

2. The added current draw in the alternator causes the engine speed to drop a little. As long as it does not stall from trying to run too slow, its not a real issue.

3. There should not be smoke coming from any of those areas you mentioned. The charcoal canister vents are those egg-looking caps on the top.
I looked a little closer and saw that the smoke is coming from the EGR valve itself and not from where it bolts onto the intake manifold plenum. I found a small spot in the plastic casing of the crankcase breather where it's leaking. I also found out that the carbon canister is fine, it was leaking from the spot its supposed to vent at, it just looked like it was coming from the sides of it.

At cold start it kind of does what it wants. Sometimes it starts at about 1700ish rpm then falls down to idle slowly, sometimes it starts at 1700ish RPM then immediately drops to about 900 RPM and surges up and down until it smooths out (Smooth as in it doesn't surge hard, the idle still sways a bit and runs real rough but is much more steady). The idle walks at all times regardless of cold or warm. It misfires a LOT at idle. Seems to clear up when driving 1900+ RPM , not sure if the higher rpm is just masking it though. It might be misfiring when coasting/going slow at around 1200rpm, I can't tell if I'm hearing misfiring or not because I struggle to hear my exhaust over the road noise at a low RPM.

The truck idles at 850-900 rpm in park and 650-700 in drive. The idle is all over the place, it wanders as it pleases.
I unplugged the IAC while it was idling and it had no effect at all. It used to change when I unplugged it, but doesn't change anymore. When I took it to an electrical shop to have it looked over, the guy replaced 3 connectors that had broken clips including the IAC valve connector. He seemed to do a good job so I don't think it's the connector, but I figured I'd mention it.

Also, I tried to measure manifold vacuum and my gauge immediately maxed out at -20 in Hg so it may be right at -20 or could be stronger. That was at idle.
 

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Does the emergency brake work? Long as that engages you should be ok, long as it gets fully locked in
 

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There is no connection from the key switch to the transmission from 83 to 89. With no key automatic shifter is fully functional. Junkyard truck was broke or a column shift.
 

kxri318

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Does the emergency brake work? Long as that engages you should be ok, long as it gets fully locked in
There is no connection from the key switch to the transmission from 83 to 89. With no key automatic shifter is fully functional. Junkyard truck was broke or a column shift.
Parking brake works fine. Good to know that being able to shift while the key isn't in is normal though. The truck at the junkyard was basically the exact same truck as mine but just extended cab. 1986 2.9 with the A4LD.
 

kxri318

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Do you guys think the EGR might be leaking because its stuck open cause of gunk or do you guys think it's a different reason? The truck did have an issue at one point where the coolant temp sensor connector was messed up and not making contact, so it ran so rich it turned spark plugs black while idling for 10 minutes. The EGR valve is about 3k miles and 2 years old so it hasn't seen much use, but I haven't looked inside of it ever to see how gunked up it's gotten.
 

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I can't answer that KX but surely someone will eventually
 

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Get a length of vacuum hose that will fit on the EGR valves port
Put it on the EGR valve
Start engine
Feel the EGRs unplugged vacuum hose, it should have NO VACUUM, EGR is not used cold at all and only used warm when at higher RPM, never at idle
If there is vacuum on that hose the EGR modulator/vacuum valve is bad, leaking

Now suck on the hose you added, that will open the EGR valve, engine should start to stumble as exhaust gas comes in at idle
Stop sucking and idle should go back to normal
If that happens then EGR valve is not leaking

If you suck in exhaust gas EGR valve is bad, lol
 
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@kxri318 ,
If you are willing to put in the time, while it will never be a stump puller your little 2.9l can sing the sweet, delightful song of performance; it should have a solid idle once up to normal engine temp and should not misfire with a properly timed good tune up.
 

kxri318

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Get a length of vacuum hose that will fit on the EGR valves port
Put it on the EGR valve
Start engine
Feel the EGRs unplugged vacuum hose, it should have NO VACUUM, EGR is not used cold at all and only used warm when at higher RPM, never at idle
If there is vacuum on that hose the EGR modulator/vacuum valve is bad, leaking

Now suck on the hose you added, that will open the EGR valve, engine should start to stumble as exhaust gas comes in at idle
Stop sucking and idle should go back to normal
If that happens then EGR valve is not leaking

If you suck in exhaust gas EGR valve is bad, lol
No vacuum at the EGR at cold start. When I sucked on the hose it ran a little worse. Took a few times of trying that to see if it was actually getting worse or if it was just running that bad normally. I noticed though that the engine shook a bit more when doing that. Didn't seem like I was breathing in exhaust either lol.

I cleaned out the EGR valve a bit while I was in there and took it for a test drive right after. I got down the road then the truck cut out and I smelled burning. Found out the ECU relay cap fell off and it grounded straight to the body and now the truck just cranks so I had to push it home. There's burn marks on the relay so I've gotta go find another relay and hope I didn't fry the ECU. The ECU relay part number is RY-111, right?

Just tested power at the relay connector and got 11.55v at pin 2, while measuring the battery directly gives me 12.2v, about 150-200 mV up to 0.4v at pin 4 (was kinda all over the place), and only a few mV at pins 3 and 1.

I did try unplugging the IAC while it was cold to see if that affected it then and when I unplugged it, the idle dropped a bit. Wonder why its not doing anything when warm though.
 
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kxri318

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@kxri318 ,
If you are willing to put in the time, while it will never be a stump puller your little 2.9l can sing the sweet, delightful song of performance; it should have a solid idle once up to normal engine temp and should not misfire with a properly timed good tune up.
I've been fighting this thing for two years to get it to run right and even took it to a guy at a shop who worked on the trucks when they were new and and he gave up. I got the truck timed right at 11 degrees BTDC and the timing was confirmed by the shop, near all sensors were replaced/checked, new spark plugs, plug wires, distributor cap, rotor, rebuilt injectors, different ecu, different TFI module, EGR valve, EGR solenoid, ect. I've probably spent more time working on the truck than driving it
 

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