Hey all,

Glad to have found an active Ranger forum, I only hope y'all can help me get mine running. Got a couple issues:

First off, it was super low on power from idle, and really seemed to miss at idle. Drivable, never stalled or anything, and would maintain highway speeds. I'm not sure what happened, but it felt like it progressively got worse. It was throwing codes for EGR not opening and bad TPS, so I replaced the TPS and the EGR diverter valve thingy. No real change- it still seems real iffy and now has a tendancy to die at idle, while driving. This is brand new.

I cannot get the TPS to hit 1v- when off the throttle, it shows .7v. When installed, I can't get much below 1.2v. Any ideas?

The EGR I tested and it seems to be OK. Holds vacuum, pops closed quickly.

Plugs/wires should be good, the TPS is new BWD, and the EGR diverter valve thing is also new Duralast. I have no idea what more I need to do to get this baby going.

 

Welcome to the forum

Ranger I assume
Year?
Engine?
Manual/automatic?
2WD or 4x4?

Anywhere from .69 to .99v is what TPS should show when throttle plate is closed
Above 4.5v when throttle plate is wide open, so 4.5 to 5.0v

There is a screw on the throttle linkage on most years, "looks" like an Idle Screw, it isn't, it is an anti-diesel screw, but can also be used to set TPS low voltage, .69-.99

Also post the actual code numbers, they often don't mean what you think they do.
i.e. "TPS out of range" could be failing IAT or ECT sensor

 

My bad...1986 Ranger 2x4 2.9l automatic.

The throttle shows 1.2v when closed and I am unable to adjust it low enough. Even with that anti-diesel screw not touching the stop, it's still right at 1.2v. The TPS hits .7 when I remove it from the throttle, so I think it's good, but since I have to tension it a bit to install, that seems to mess it up.

I have a sneaking suspicion that the EGR thing might actually be because it's staying open all the time (it always thinks the throttle is slightly open), who knows.

 

See if you can elongate the mounting holes a bit more or drill them out to larger size, so TPS can be turned a bit more.
Newer style may not be right for the '86 2.9l

EGR is not used when engine is cold or anytime when under about 1,500rpm, it should only open when engine is under a load, i.e. accelerating or climbing a hill
Exhaust gases Cool down cylinders, they slow the burning.
NOx, a poisonous gas, spikes high when cylinder temps get too hot, like when accelerating or climbing a hill
The EGR system adds exhaust to intake air to slow this heating up.
As a added benefit is also helps prevent pinging/knocking under load, which is caused by hot cylinders pre-igniting Regular(87 octane) gasoline.

You can unplug the vacuum hose on the EGR valve(plug the hose with a screw or bolt) put another hose on it and then start the engine
Suck on the hose, engine should start to stumble as exhaust gases go into the intake.
Stop sucking and idle should return to normal
EGR valve is OK

EGR valve can get carbon build up inside so can't close all the way, causing rough stumbling idle, but they can be cleaned

 

I cleaned the EGR, it does not pass air through unless the valve is opened. I'll try this tonight.

So, it didn't die or stall out until it got warm, that's why I was thinking the TPS/EGR were having issues.

Is there any chance I can temporarily disable the EGR or block that off without affecting running too much? Only for 20-30 miles to test it out- I have no intention of keeping the emissions messed up

Thanks for all the help.

 

Just unhook the Vacuum hose on EGR, plug the hose and drive.

Won't hurt anything

TPS is a "learned" sensor, computer expects under 1 volt, and will usually set a code if it doesn't get it, but shouldn't cause engine issues unless something else is wrong with TPS or its wires

 

Alright, check this out...

Replaced the TPS with one that has the proper voltage, shows .99 and smoothly glides through 4.7ish at WOT.

The EVR was displaying zero continuity/infinite resistance, the new one seems fine. 45 Ohms

Replaced map with new BWD unit also

At this point, I had no codes showing on the KOEO or continuous tests. Same drivability issues.

Ran KOER. I messed up on the TPS test, as you can tell. Didn't know it required that, whoops.

12 (IAC issue? The IAC was just cleaned and it will shut off if i unplug it)
21 (ect?)
22 (map sensor?)
16(unsure)
13(unsure)
77(my fault, TPS issue)
25 (knock not sensed?)
74(something about brakes, not sure what to do)

At this point, I went ahead and replaced the ECT and air charge temp sensor. ​​​​​Still no real change in drivability. I also am unsure of how to fix the idle issue

Any thoughts?

 

Stop replacing sensors :)

They rarely fail, and it is very confusing for the computer.
MAP sensor is THE main sensor for air/fuel mix ratios, it can fail but usually issue is its vacuum hose to intake, cracked or split, or electrical connector is corroded/loose.

Reset computer, unhook battery for 5 minutes, or unhook both battery cables and touch them together to drain capacitors in the computer(clears it memory) then reconnect cables.
You have to do this any time you change something on the engine
So computer can Relearn sensor ranges

Drive truck until fully warmed up, see if CEL(check engine light) comes back on.
Whether it does or not check for codes

2 digit Ranger codes here: OBD-I Diagnostic Trouble Code (DTC) Applications - 2-Digit Ford Codes

Yes 25, 74 and 75 can be ignored

The other codes and the driveability issues are looking more like a computer fault than engine fault.
12, 13, 21 and 22 at the same time point to that
16 points to TFI ignition


You may need to pull out the computer and open it up to look at the circuit board inside, see if there has been some damage from leaking capacitors or ??

What it should look like here: Ford EEC-IV

Leaking caps here: '90 Bronco EEC Interior Photo by dolittleproject | Photobucket

And here: http://www.f150forum.com/attachments...set-eec-2-.jpg


The TFI ignition/spark system was a common problem as it got older, usual symptom was slow or no start after engine was warmed up.
TFI module on the side of the distributor becomes heat sensitive so engine runs fine until module warms up, then............problems
This didn't set codes

You can test TFI systems and check the old wiring carefully: http://www.therangerstation.com/tech...agnostic.shtml

 

There is no CEL on the truck, as far as I can tell. I have unhooked the battery and done all that. Really doesn't seem like it warming up affects anything.

I guess I can pull the computer, but is there anything easier I can check?

 

I added to post

Some years didn't have a CEL on the dash, or do you mean there is a CEL but it is not working?

"So, it didn't die or stall out until it got warm......."?

 

I don't mind replacing sensors, unless it's hurting something- they're pretty cheap and I'd like the thing to be drivable and fairly reliable soon.


I do not think my truck even has a CEL.

About how it stalled when it was warm...I'm not sure. It did stall out, but started back up instantly, and kinda felt like a low idle issue. Drove it yesterday and it didn't do that.

I'll check the TFI stuff tonight. I guess I was trying to say that drivability wasn't affected by the engine warming up, it runs the same cold or hot from what I can tell.

 

Then I would hook up a vacuum gauge to the engine

Read here on the tests to do: Technical Articles: Engine testing with a Vacuum Gauge - at Greg's Engine & Machine

No matter how many sensors or add-ons they put on an engine it is still just a self power air pump so vacuum gauge can tell you alot.

Test for clogged exhaust

Also pull a couple of spark plugs, the tips can tell you if engine is running too rich