2.5L ('98-'01) Need help diagnosing surging/rough idle issue.

[saminator0107]

Hello! I am new to this forum. I have recently purchased a 1999 ranger 2.5L Manual 5 speed 4x2. When i purchased it it had a code for large evap leak and high idle. It would idle high and surge real bad. When i push in the clutch to switch gears it holds the current rpms and does not drop down. (unintentional rev matching ) I replaced the Idle air control valve, the EGR vacuum solenoid, and the EGR canistor purge valve. I cleared the codes and took it on a ~10 min test drive and let it sit in the driveway running for about 10 mins as well. While the codes have not returned, it still surges and idles rough. I cannot seem to figure it out. I have checked for vacuum leaks by spraying around some brake kleen around the engine bay, and did not hear a jump in idle.


Any help is much appreciated.

 

[Brain75]

probably have a vac leak still - brake cleaner only works so much... have to buy/rent/build your own smoke machine most likely....

 

[saminator0107]

Okay. Ill try checking for vac leaks again. Do you know of any common spots for a vac leak? Or is it just anywhere? The old owner replaced the PCV valve and i looked at it and it seems new.

 

[Brain75]

I would kinda gloss over any place in the middle of a run and double check each end of every vac line - seems all the issues are ends (as far as "ends" I am including the splice and one way valve).

 

[scotts90ranger]

Curious how many miles are on it, there seems to be a repeating issue of these engines getting recessed valves at around the 250k range that makes for some similar situations, my 2.3L is doing similar...

 

[saminator0107]

Curious how many miles are on it, there seems to be a repeating issue of these engines getting recessed valves at around the 250k range that makes for some similar situations, my 2.3L is doing similar...

Its got 235k on the clock. And i sure do hope
it isnt..... that would really suck. Maybe if i can get this thing running right ill go give it some seafoam and an Italian tune up, haha.

 

[saminator0107]

I would kinda gloss over any place in the middle of a run and double check each end of every vac line - seems all the issues are ends (as far as "ends" I am including the splice and one way valve).

Yeah i looked it all over. I didnt see anything that jumped out at me. Then again, it is dark outside. I may try to check again tommrow. I did however back out the idle screw for the throttle body, which seemed to help with it idling high. It does still idle weird, sometimes its at about 900 RPMS and then sometimes it wants to idle around 1100. The holding RPMS is still an issue though. I do feel like it MAY be a vac leak, but to me if its large enough to cause it to hold rpms like that it would have to be a somewhat large leak. Im curious if it may be the EGR valve. But then again, i feel like a failing EGR valve would throw a CEL, but who knows.

 

[Brain75]

might do a compression and leakdown - that would rule out valve recess.... valves recessed to the point of not sealing oddly will pass compression but not a leakdown test.

 

[saminator0107]

might do a compression and leakdown - that would rule out valve recess.... valves recessed to the point of not sealing oddly will pass compression but not a leakdown test.

Yeah. My buddy has a fancy snap on scanner that can read live data and has a scope on it. Im headed to his place friday and he said we can take a look at the ranger while im there. Im hoping the live data will give us some more info. My cheapo scanner cant do all that unfortunately, lol. Having a second pair of eyes look over the truck might also help as well. Maybe he will see something i didnt.

 

[saminator0107]

might do a compression and leakdown - that would rule out valve recess.... valves recessed to the point of not sealing oddly will pass compression but not a leakdown test.

Also, forgot to mention. When the engine first starts it revs up to about 2.5k rpm then settles. Not sure if this is normal for these trucks to rev that high on startup.

 

[Brain75]

nope, they run autonomously until they get to operating temp at a higher idle then once up to temp all the emission wizardy starts in and takes control. I think mine is pretty close to normal stock and it is like 900-1100 rpm cold, 650-700 rpm warm (@idle)

 

[saminator0107]

nope, they run autonomously until they get to operating temp at a higher idle then once up to temp all the emission wizardy starts in and takes control. I think mine is pretty close to normal stock and it is like 900-1100 rpm cold, 650-700 rpm warm (@idle)

Alright. I took a youtube video so yall can see how it sounds in idle. It sounds okay to me, but i have no idea what its supposed to sound like. I tried to back off the idle screw to about 900 rpm when the truck was warm but it started to stumble pretty bad. Lowest i could get it was about 1000 rpm.

This is the link:

- YouTube

Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube.

youtube.com

 

[Brain75]

is this a cold idle or did you get it up to temp before recording?

 

[Brain75]

and I'll also throw out that the tach could be off - you could have a tach reading 200 rpm high and your 900 is actually 700 so trying to get it down to 650 is impossible... Ford wasn't terribly precise with the tach (on my 2nd gen it is adjustable very easily... dunno about 4th gen).

 

[saminator0107]

is this a cold idle or did you get it up to temp before recording?

This was a warm-ish idle. It idled for maybe a minute before the video. And yeah. The previous owner said he replaced the cluster from an explorer (i think explorer? i could be remembering wrong) because the original cluster didnt have a tachometer. Said he kept the same mileage. I checked carfax and the mileage seems to be accurate. Also he sais the battery light has stayed on since he replaced the cluster. Got the charging system load tested and everything checked out okay. So, not sure why its on but thats not really my main concern at the moment.