crs.wdp
New Member
- Joined
- May 6, 2020
- Messages
- 9
- Reaction score
- 1
- Points
- 3
- Location
- New Jersey
- Vehicle Year
- 1991
- Make / Model
- Ranger
- Transmission
- Automatic
First time posting here but I've been reading all the posts on here as well as other sites trying to solve my high idle. I'm running out of posts to read so I figured I'd try posting it and see if anyone has any more tips.
It idles at 1200/1300 rpm. Its a 1991 Ranger 4.0 OHV Auto 4x4 STX reg cab 6ft bed.
This is where I'm at:
-I swapped the IAC with a made in USA Hitachi, as per one of the threads I read which mentioned only Motorcraft and Hitachi worked well on the rangers. It didn't seem to affect anything.
-If I unplug the IAC it drops to 1000.
-I did a smoke test with a cigar but couldn't find anything before I felt like I was gonna pass out, ha. All vacuum lines are in good shape. In addition to the smoke test I checked with starter fluid and propane. I've unhooked and plugged the vacuum tree and no change. I individually checked all vacuum lines with a vacuum pump and they all hold vacuum. I'm pulling 18 inches of vacuum at idle.
-New PCV and has tight seal.
-New air cleaner
-I've checked the voltage of the MAF, ICS, BMAP (Hz) and the IAC, all of which seem to be in line with specs found on the interwebs.
-The MAF sensor wires were cleaned and that certainly helped with the performance of the engine but not much of a difference in the idle.
-TB was cleaned and doesn't seem to have much gap around the buttlerfly.
-I don't see an EGR valve or a DPFE sensor. Not sure where the DPFE is if I have one.
-The A/C coolant lines are disconnected and the electrical wires don't have any voltage but I do get a light on the control switches in the cab if I press in for A/C. I can apply voltage to the compressor and see the clutch engage so I know it's current state is disengaged. Could it be possible the ECM is bumping the idle thinking that the A/C compressor is continuously engaged?
-The vacuum line that runs from just in front of the TB to the evap canisters has a solenoid. I can apply voltage and get it to funtion but does not have a perfect seal, not sure if it needs a 100% seal. Also, the connection is not complete (no voltage) see attached photos. Anyone know where / what this plug above the driver side valve cover plugs into?
-Is it possible the coil pack or another part of the ignition system is faulty and causing a high idle?
-The engine runs pretty smooth. At idle and when stopped at a light in gear it rumbles / shakes just a bit, but doesn't seem to misfire. Acceleration seems ok and there is no knocking or pinging.
Thanks is advance for help / advise.
It idles at 1200/1300 rpm. Its a 1991 Ranger 4.0 OHV Auto 4x4 STX reg cab 6ft bed.
This is where I'm at:
-I swapped the IAC with a made in USA Hitachi, as per one of the threads I read which mentioned only Motorcraft and Hitachi worked well on the rangers. It didn't seem to affect anything.
-If I unplug the IAC it drops to 1000.
-I did a smoke test with a cigar but couldn't find anything before I felt like I was gonna pass out, ha. All vacuum lines are in good shape. In addition to the smoke test I checked with starter fluid and propane. I've unhooked and plugged the vacuum tree and no change. I individually checked all vacuum lines with a vacuum pump and they all hold vacuum. I'm pulling 18 inches of vacuum at idle.
-New PCV and has tight seal.
-New air cleaner
-I've checked the voltage of the MAF, ICS, BMAP (Hz) and the IAC, all of which seem to be in line with specs found on the interwebs.
-The MAF sensor wires were cleaned and that certainly helped with the performance of the engine but not much of a difference in the idle.
-TB was cleaned and doesn't seem to have much gap around the buttlerfly.
-I don't see an EGR valve or a DPFE sensor. Not sure where the DPFE is if I have one.
-The A/C coolant lines are disconnected and the electrical wires don't have any voltage but I do get a light on the control switches in the cab if I press in for A/C. I can apply voltage to the compressor and see the clutch engage so I know it's current state is disengaged. Could it be possible the ECM is bumping the idle thinking that the A/C compressor is continuously engaged?
-The vacuum line that runs from just in front of the TB to the evap canisters has a solenoid. I can apply voltage and get it to funtion but does not have a perfect seal, not sure if it needs a 100% seal. Also, the connection is not complete (no voltage) see attached photos. Anyone know where / what this plug above the driver side valve cover plugs into?
-Is it possible the coil pack or another part of the ignition system is faulty and causing a high idle?
-The engine runs pretty smooth. At idle and when stopped at a light in gear it rumbles / shakes just a bit, but doesn't seem to misfire. Acceleration seems ok and there is no knocking or pinging.
Thanks is advance for help / advise.
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