1986 Ford Ranger vehicle looses power on hills

Tiny
DANCASSIDY
  • MEMBER
  • 1986 FORD RANGER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 140,000 MILES
My ranger looses power on hills suddenly and then runs normally for while at at which point it loose power again. This continues off and on. Changed the fuel filters (2).
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Saturday, November 15th, 2008 AT 11:10 AM

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Tiny
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I would suspect low fuel pressure (weak pump?) Or weak ignition system.

Start by doing a fuel pressure test. I think with engine running you should get around 35-45 psi.
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Saturday, November 15th, 2008 AT 7:30 PM
Tiny
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Thanks will do precisely that. I checked the spark and the color is blue. Several other things:

1. The engine coolant continually needs replenishing. There are not any leaks that I can find. Not water in oil or auto trans. No white smoke coming from exhaust except when cold. How would I detect such a leak? Could it be a fine slow leak through the block into the exhaust. If so, would a block sealer work. What would you recommend.

2 I get a code 84 and 33 after having replaced the egr vent solenoid. The egr sensor was replaced too and no code coming up for that. I have voltage at both wires at the solenoid and the vacumn hoses are ok as is the egr valve. Any ideas. Got codes 21 and 24 too.
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Saturday, November 15th, 2008 AT 8:40 PM
Tiny
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1. Pressure test your cooling system as well as the radiator cap. When you do so check your oil level: if it's higher you probably have a leaky intake manifold gasket.
If you're loosing a lot of pressure in a short period of time and are unable to find any external leak, you can suspect a leaky head gasket, or cracked cylinder head.
I assume you check all the 'usual' areas for external leaks already (water pump, hoses, radiator, etc). Have you checked your engine drain plugs? You should have two of them (one on each side of the engine).
About the block sealer now. Some people say it's okay, some say it's not. In some cases it may work if the leak is very small, but if too big it won't work at all. It's not a permanent fix anyway.

2.
For your EGR problem do the following:
Apply 5-10 in hg to the egr vacuum nipple with a vacuum hand pump. If.
-engine doesn't stall or run roughly
-idle speed does not drop by more than 100 rpm
-idle speed doesn't return to normal after vacuum is removed
. Replace the egr valve.

21: engine coolant temperature (ECT) out of self-test range
24: air charge temperature (ACT) sensor out of self-test range
Check these sensors and replace if necessary.
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Saturday, November 15th, 2008 AT 11:20 PM
Tiny
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Funny thing is that using the hayes manual procedure, the codes won't clear for some reason. Am using a non digital voltage meter. I wanted to clear and recheck. What do you think I can do now?

I understand that the ford cologne v -6 is famous for that. I am thinking of by passing the heater and installing alum seal and running for several hours. Understand if it is a small leak that it might work. What do you think?
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Sunday, November 16th, 2008 AT 12:40 PM
Tiny
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You sound pretty much sold on the idea of using some sealer.
If you're lucky it fixes the leak. Momentarily at least.
However, it probably won't help if you're dealing with a blown head gasket, or something major like that.
It could also do more bad than good by plugging areas that don't need to be plugged.
I know you would like a definite answer about this, but the truth is it's impossible to say if a sealer will fix your problem or not, or if it will make it worse. Some people have had good results, but other called the sealer company to express their disatisfaction (to put it nicely).
What I'm saying is do some research about these products before you make a decision.
By the way, have you done a pressure test on the cooling system? It may help finding the leak.
You could also check for exhaust gases in the coolant with a tester.
You should also check the compression in each cylinder.

Clearing codes now.I'm not sure what haynes recommends; have you tried to disconnect the battery? It will delete all the data and your car may drive a little different for a while, but once the ecm relearns everything you should be fine. Unless you haven't fixed the problems and the codes come back.
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Monday, November 17th, 2008 AT 11:46 AM
Tiny
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Checked the fuel pressure and regulator and they are fine. 37 psi. I found the radiator cap was holding only 7psi. It should be 13. Replaced it. Checked the new one too. I understand the coolant can boil if the pressure is not maintained. Maybe that is what was happening. Will find out in any case. The coolant pressure test held on the radiator and engine ok. Crossing my fingers.

So. Cleared the codes and the 84 and 33 come up as the y have in the past. There is 12 volts to the at the solenoid vent valve-both the red and yellow wires. There is a vacuum signal to the vent valve and barely a signal at the egr. So maybe there is not enough vacuum to open it. The vacuum lines seem fine. I tested both for leaks. I had replaced that vacuum solenoid with a ford part last november when the 84 code first came up. What can I do now? By the way the egr valve tests fine. Thanks for working with me on this. Dan
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Monday, November 17th, 2008 AT 9:45 PM
Tiny
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Good job on the radiator cap! 7 psi was definitely too low. If your system holds the pressure, you shouldn't have any leak, so no need for that sealer ;)
One problem out of the way!

Check the electrical connector at the solenoid; is it loose, rusty, high resistance? Also check your ground connection.
Also, back in 1986 Ford started introducing the PFE sensor. Is that the sensor you replaced?
If not I would check it out, and maybe replace it.
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Tuesday, November 18th, 2008 AT 11:30 AM
Tiny
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Last November a code was set for both and I replaced both. I am getting a vacuum signal at the egr when engine is warmed up and in drive. But it is weak as compared the the signal entering the solenoid. I wonder if I have an internal leak in the valve. It is a ford part.

Certainly will recheck the connection. Should I hear an audible click when the solenoid is on. Noticed that there is voltage to both terminals on the solenoid even in park-12volts. Is that normal? Thanks
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Wednesday, November 19th, 2008 AT 9:47 AM
Tiny
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If you have vacuum at the solenoid but very little vacuum at the egr valve when the solenoid is powered on, the problem would lay either in the solenoid itself, or the wiring, or possibly the computer control.
Also, have you made sure that the vent port on the solenoid is not plugged?
You may have a piece of filter foam in there; unless you replaced it recently, I would go ahead and replace it; it may be the source of all your egr problem.
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Wednesday, November 19th, 2008 AT 1:26 PM
Tiny
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You mean the gray cap on top of the solenoid. Will check it. I just replaced the solenoid with a new one last Nov as I might have told you. How would I check the computer control issue? As mentioned there is power 2 both wires at the solenoid when the key is turned on. I would think the computer would engage the solenoid when the vehicle is in driver or motion and it is warm. Otherwise the egr is not engaged until warm right?
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Wednesday, November 19th, 2008 AT 10:12 PM
Tiny
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Your EGR valve is not " engaged' until the engine is warm and under load, you are correct; however, you may still have a little bit of vacuum that passes the solenoid (eventhough it is not powered on) and gets to the valve, which from what you previously said is what you're experiencing.
What I'm thinking is that your solenoid is not working right; since you replaced it, the problem probably lies either in the wiring between the solenoid and the ecm, or a connector, or in the ecm itself (the solenoid is grounded inside the PCM through a Quad driver).
Basically your EVP voltage doesn't change like expected when the solenoid is supposedly powered on (hence code 33); it is probably the result of the solenoid not cycling as expected (hence code 84).
The 12v supply you get at one terminal is normal, however I don't think you would have voltage at the other terminal with key on, engine off.
Check the connector and wiring to the ECM and replace if necessary. If the wiring and connector are good, the problem may be in the pin at the PCM (#33 I believe) or the driver in the computer itself. Since you already tried to replace a bunch of stuff, I would try to replace the wiring/harness between the solenoid and the ecm; if it fails to fix the problem, your ecm (quad relay) would likely be defective, assuming all the tests and repairs mentioned in all the previous posts were done right. If you get to this point, I'd suggest you take your truck to a Ford technician for an accurate diagnostic, before replacing the ecm.

Hope this help.
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Thursday, November 20th, 2008 AT 4:18 PM
Tiny
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R: I finally got the truck out for a long drive yesterday. And the vehicle still just looses power suddenly for a bit-kinda like an injector suddenly stopped working and a bit later it suddenly runs great again before repeating the episode an so on. The code I got was 25. So don't know where the knock sensor is on the vehicle or how to test it.

I had replaced the fuel filters a couple of thousand miles back. What do you think? Should I put some injector cleaner in the tank as a first step? Then what? I checked the spark and it seems ok. The coil checks out ok too. New cap and rotor and new wiires several thousand miles back also. How can I check these injectors. What do you think about this.

Regarding the egr issue; where is the best place to get the ford wiring diagram without spending a fortune for the egr system? Thanks. Dan
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Wednesday, December 3rd, 2008 AT 10:28 PM
Tiny
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Hi there,

- Do you still have the egr codes? A problem with a knock sensor can be related to a defective egr system
Also, we talked a good bit about the egr because of the codes you were getting, but have you ever checked your timing and compression?

- You can start with a good injectors cleaner; it may help. Make sure you fill your tank with good quality gas from a reputable company: cheap gas contains less additives which can quickly result in your injection system getting clogged-up (You ve seen the Shell commercial haven t you?). Moreover, cheap gas may not have the proper octane level which can result in your engine detonating.

You could also have your injectors cleaned at a shop either by running some cleaner at the fuel rail while the engine is running, or by removing the injectors altogether.
The " off-car cleaning option would give the best result and your injectors could be flow tested; but it is more expensive.
To know for sure if you have dirty injectors, you can perform a fuel pressure drop test:
Here is the procedure you can find online:
This test measures the drop in static system fuel pressure when each injector is energized. The amount of pressure drop for each injector is then compared to see if the injectors are dirty and need to be cleaned or replaced. This test requires an "injector pulser" ($90 on Amazon) tool to energize the injectors.
To perform this test, turn the key on or energize the fuel pump for a few seconds to build up static pressure in the fuel system. Then turn the key off, pulse one injector for the specified time and note the pressure drop for that injector. Turn the key back on to rebuild static pressure and repeat the test for each of the remaining injectors.
An injector that is pulsed 100 times for five milliseconds should produce a minimum pressure drop of about 1 to 3 psi, and no more than 5 to 7 psi, depending on the application.
The difference in pressure drop between all the injectors should be 2 psi or less. If you see more than 3 psi difference between the highest and lowest readings, the injectors are dirty and need to be cleaned or replaced.
If you see no pressure drop when an injector is energized, the injector is clogged or defective and needs to be replaced. If the pressure gauge needle bounces, the injector is sticking."

- As far as the wiring diagrams you could check " alldatadiy or " . They both offer factory wiring diagram as well as just about any info you need to fix your car.
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Thursday, December 4th, 2008 AT 6:53 PM
Tiny
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R: Thanks for that detail. Today I used some Lucas fuel injector cleaner and drove for 15 minutes as well as an octane booster. With any luck this will help.

HEY but I think since the temp gauge reads a bit low, this vehicle has 144 k miles on it, and I think the heater is not kicking butt that I will change the thermostat as it is cheap. I am thinking that maybe this surge is from the fact that the vehicle is going in and out of closed loop causing this sudden loss of power and then suddenly runs good again and repeats. I will let you know if one or both of these results in any improvement. I like the autozone web site with their online basic manuals. Checking there I found out that this vehicle apparently has no knock sensor so I guess the code 25 isn't anything to worry about. Othewise will have to go deeper. Stay tunes. Dan
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Thursday, December 4th, 2008 AT 10:48 PM
Tiny
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I forgot to comment on your discussion of the of the egr system. I don't believe the egr has anything to do with the drivability issue as is is not opening at all and not stuck open. I am looking to get a original ford manual. I just missed one on ebay last eve.
I wished I had not relied on the diagnosis of a mechanic shop specializing in fords. I guess the say the codes and told me to replace the solenoid and egr sensor without going deeper, though they made several other good calls in all honesty. Happens all time. So unprofessional to spend $$ on unneeded parts isn't it. I always find out that with stuff like this it usually myself that has to in the end figure it out. I bet many other have found out the same. Dan
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Thursday, December 4th, 2008 AT 11:02 PM
Tiny
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I understand; it's hard to find a really good mechanic who actually does real troubleshooting instead of guessing and 'shotgunning' parts at the car.

I think I'm with you; I'm starting to wonder if you really have an egr problem. That's why I mentioned timing and compression.

After I posted my response last night I did more research myself about the knock sensor (I don't know the location of all the knock sensors for all the models and brands), and I could not find anything about it for a 1986 Ranger. So I went to my garage looking for my Haynes manual buried underneath a pile of books/tools/cra@#. After a couple of minutes of digging, I finally found it and looked what Haynes had to say about this sensor. Well. Nothing I guess because I didn't find anything about it. It didn't even show code 25.

Hopefully, cleaning your injectors will help; it can't hurt anyway.

Let me know if replacing the thermostat helps.
If replacing the thermostat doesn't fix your low heat problem, check your heater core as it could be getting clogged.

As far as your low reading on the temp gauge, you may also want to check your fan clutch: it may be defective resulting in overcooling.
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Friday, December 5th, 2008 AT 8:44 AM
Tiny
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I will check that fan clutch. I will disconnect and plug the egr vacuum hose to see if somehow if it is not opening and closing; can't hurt. Dan
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Friday, December 5th, 2008 AT 11:21 AM
Tiny
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R: I forgot to mention that according to autozone there is no knock sensor on the vehicle. The code 25 says "no knock detected when the engine is goosed" or something like that
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Friday, December 5th, 2008 AT 11:25 AM
Tiny
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Let me know how it goes; I'm curious to hear if your problem was related to a closed loop open loop condition.
Also maybe your termperature switch/coolant sensor is getting bad.
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Friday, December 5th, 2008 AT 6:22 PM
Tiny
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You know r: I replaced the thermostat and checked the cts sensor. They are both ok. The fan clutch is ok as well I think that open closed loop thing I was thinking about is not the problem.

I did run a fuel pump test while back and the ranger had 37 psi running and when I gunned the engine the pressure went up 5 psi or so. I disconnected the vacuum hose to the pressure reg and the pressure went up as it is supposed to. This vehicle has two pumps. Wondering if one or the other is intermittently not working right. Would you suggest a scheme to recheck every thing related to the fuel pumps. I had changed the filters less than 2k miles ago. Compression ok and it starts well by the way. Dan
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Friday, December 12th, 2008 AT 11:32 AM

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