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Surges at idle and does not rev.


Alaska Diesel

Well-Known Member
Joined
Sep 22, 2019
Messages
52
City
Palmer Ak
Vehicle Year
1986, 1987
Engine
2.9 V6
Transmission
Manual
I have a 1986 Ranger, I got it a couple of years ago and have put the following parts on it. Injectors, spark plugs, calipers, bearings, clutch, and rotors. I started to drive it and noticed that when I would put the throttle peddle down to the floor it would not rev up but die down. I drove it 25 miles before one of the intank fuel pumps went out. I switched tanks and got another 25 miles before the other fuel pump went out. Trailered it home and changed the fuel pumps. Also changed the high pressure pump. Ever since then though it has not run well. When first starting the idle jumps all around. And to keep it from dying I have to put the throttle on a little bit then let it off very quickly. After a bit and the engine has warmed up some I can rev it up by pumping the peddle. But if I just put the peddle most of the way to the floor it will die.
I've noticed that there is a lot of moisture in the exhaust.
Things I've checked so far are these: good consistent spark to each spark plug, fuel pressure regulator is working correctly, map sensor. I found the egr wasn't working so replaced that and it still runs just has bad.
If I rev the engine up and then let the clutch out with the rpms high it will move forward. But if I let the clutch out even slipping it with the rpms down a little above a high idle it will instantly die.
I've tested the fuel pressure and it was good.
Any ideas? I'm so stomped over this one.
 
Have you checked for trouble codes? What about the fuel filter in the fuel reservoir (before the high pressure pump) and after the high pressure pump? Fuel pressure may still be good, but flow low due to clogged filters. Not sure what would cause the pumps to burn out at nearly the same time, but I would check the filters and perhaps voltage at the pumps.

You mentioned moisture in the exhaust. Is the coolant level going down? If not, it's probably just condensation. Are your fuel tanks in good shape (no water/contamination)?
 
I checked for trouble codes via the test light method. These are what I got.
I also changed both filters before the high pressure pump. On mine there is not a filter after the high pressure pump.
Both pumps went out from the rubber rotting. The truck had sat for a good many years.
 
33 - egr did not open or respond; (I got a good working egr and put int)
13 - idle too high, screw adjusted in; (it won't stay running with the idle down where it's supposed to be)
77 - system did not receive a goose test;
25 - knock sensor not tested, ignore if not pinging; (not pinging
 
Giving it a blip with the throttle to keep it running seems too me its running rich.

The TPS shouldn't be adjusted for idle. There is a procedure for adjusting it, maybe in the tech section.

The IAC controls idle. Perhaps the IAC is stuck. Take it off and apart and clean it.

Fuel injector stuck open? The test procedure is to hold the throttle down to the floor and see if it wants to start. This is the clear flooded engine procedure and the injector won't be activated. If it tries to start that means leaking injectors.
 
The internal passage between the EGR valve and the intake gets clogged up after a while. That, or the EGR position sensor (EVP), or the EGR solenoid will give you a code 33.
 
First off, dont screw with that screw. Put it back how it was. @adsm08 knows the proper procedure for it.

To me it sounds like you have compounded issues. First off the idle is almost guranteed to be a IAC bad.

When my ranger pulled a code 33 (EGR flow insufficent) i found my EGR passage so blocked up that i had to hammer a briggs head bolt thru the mound of carbon. I alao replaced the EGR flow sensor (little black box by throttle cable), but im not sure if i had to or not.

As far as the bogging....how much steam/moisture is coming from the exhaust? Are you losing coolant? A massively cracked head could cause that as coolant doesnt ignite like gasoline.

The only other thing that could possibly cause both the issues your having is a TPS, I didnt seee that mentioned.
 
I figured it out. So the 33 code was because my egr was clogged up. That is why I replaced it. That made absolutely no difference though. I went to check the ECT and since I ran out of time I just put the sensor back in the hole barely to keep the coolant from bursting out and left it unplugged. Now it runs like it should. Your right I shouldn't have to mess with that screw. And now that it's not trying to choke the beast to death that screw can go back.
 

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