High idle after warm up.

[birddog321]

I finaly got my 2.8 running again, but after taking her for some test donuts I noticed that the idle is a little eratic, almost dieing at times. I njoticed that there was a vac hose disconnected from under the air cleaner going to a sensor of some type. I believe that it is a sensor to monitor fresh air/exhaust mixture. One of the connectors was broken, so i used the broken piece to bypass the sensor. This made the idle smooth out a little but now the idle is very high.
Is this a carb issue or do I have a vac leak or could this sensor be the cause of my rough idle problem?

 

[dangerranger83]

Once min warms up mine has a high idle but I just tap the gas real fast to rev it up quickly and it gos back to 800rpm. Im running the Duraspark set-up on mine.

 

[birddog321]

Mine is bone stock but the quick gas thing didn't work.

 

[dangerranger83]

Well maybe adjusting the TPS may help you out. It also has a throttle actuator that sets the idle for you. Both could just need adjusting. The TPS is the thing that is hooked to the butterfly shaft on the passenger side of the carb. It basiclly tells th computer what it needs to do.

One thing that my dad and I did on his old 84 that he had running the setup was just unplug the throttle actuator and then adjusted it until the idle was set to where we wanted and just left it unplugged. Do I recommend this, Im not sure but it solved our problem.

In the end the Duraspark setup was/is the way to go.

 

[birddog321]

Where is the TPS located? Maybe I can look at it when I get home

 

[enginepaul]

TPS is on the throttle shaft, passenger side. BUT I think a vac leak is most likely.
I'm not familiar with pre-85 Rangers, but the only thing newer ('85) 2,8's have connected are 1) the breather cap 2) the air temperature sensor - electric - and 3) a vac operated cold air flapper type 'valve' on the intake spout that is supposed to bring in air from just above the exhaust manifold.
As many will say - if you can DuraSpark it - do it. Otherwise you will have to get everything working properly for the best results and that's expensive and time-consuming.
Anyway - I'd start looking for a vacuum leak as the first step.

 

[dangerranger83]

My problem was when I had a vaccum leak on mine it wanted to die. But since you have the computer setup still, whats its trying to do is the opposite and that is trying to kep it running though whem my dads 84 had the factory stuff on it, it still wanted to die. But nothing says that his was working correctly either.

 

[birddog321]

Does the Water Temp have anything to do w/the choke. I wasthinking that it could be in a sate of "Warming Up" even though it already has. I ask because the wire going to the Temp sensor broke at the connector before the coil went out. I installed an after market temp sensor so I could get better feedback than what my stock guages were giving me

 

[birddog321]

TPS is on the throttle shaft, passenger side. BUT I think a vac leak is most likely.
I'm not familiar with pre-85 Rangers, but the only thing newer ('85) 2,8's have connected are 1) the breather cap 2) the air temperature sensor - electric - and 3) a vac operated cold air flapper type 'valve' on the intake spout that is supposed to bring in air from just above the exhaust manifold.
As many will say - if you can DuraSpark it - do it. Otherwise you will have to get everything working properly for the best results and that's expensive and time-consuming.
Anyway - I'd start looking for a vacuum leak as the first step.

Thanks, I am going to work on it this weekend.The info on this site is insane

 

[birddog321]

The radiator and thermostat were both bad. After replacing these the idle is a little better. Still have to check for Vac leaks.

 

[kimcrwbr1]

I finaly got my 2.8 running again, but after taking her for some test donuts I noticed that the idle is a little eratic, almost dieing at times. I njoticed that there was a vac hose disconnected from under the air cleaner going to a sensor of some type. I believe that it is a sensor to monitor fresh air/exhaust mixture. One of the connectors was broken, so i used the broken piece to bypass the sensor. This made the idle smooth out a little but now the idle is very high.
Is this a carb issue or do I have a vac leak or could this sensor be the cause of my rough idle problem?

It sounds like that vacuum line goes to the EGR purge solenoid the closest solenoid to the firewall. I needs to be plugged into the large vacuum fitting goind up into the air cleaner. It allows air into the egr valve to close it and it pulls filtered air inside the air cleaner. To test your egr you can connect it to manifold vacuum while the engine is idleing the engine should stall. As far as your high idle is your choke plate all the way open when the engine is up to temp. There is a choke relay next to the start solenoid and make sure your getting power to it and the choke thermostat. When it is cold push the pedal down once and see if the choke snaps all the way shut. Start it the pull off should open it about 3/16 of an inch let it run a couple of minutes and then adjust the high idle speed it is the screw below the choke pointing back at the firewall then let it warm up for about ten minutes the choke plate should be fully open and when you tap the throttle it should idle normally. Just make sure the intake air temp sensor is plugged in on the air filter and all other sensors are plugged in before you start or run it. You may need to reset the computer by disconnecting the battery for 30 minutes any time you change/clean a sensor or run it with one unplugged. Check your timing is good before adjusting the carb and the idle is controlled by the computer at around 700 rpm the idle screw by the throttle cable should not be touching the throttle lever so back out on it until you get the carb adjusted then you turn it down to where it almost touches the throttle lever at an idle it is called the ainti diesel screw and just keeps the throttle plate from closing all the way when you let off the gas until the idle motor takes back over.

 

[birddog321]

Thanks, I will give it a shot tomorrow after work if I get a chance. I worked on it all day today. Replaced the Radiator w/one from an Exploder from the JY. I do know that the Choke opens all the way and one of the connections for the sensor in the Air Cleaner broke last week. Before it broke, if I disconnected the line going to the sensor the Idle would speed up and ran a little better. After it broke I bypassed it and left it that way. But I will try the high Idle in the Morning before I go to work