97 ram idle issue
#1
07-10-2010, 09:52 PM
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97 ram idle issue
Hey folks,
I did a search and saw some threads about rough idle issues other members were having...and they seem identical to mine.The popular consensus was the upstream o2 as the culprit and a new one was the cure.
my truck is a 97 ram 1500 5.9l....128k
It has new fuel pump/regulator/filter last year and new upstream o2
recently I put in new battery,plugs/cap/rotor/wires,IAC...and the rough idle and stalling in gear persist.
there is no CEL or stored codes.
no vacuum leaks that I could find,pcv is working
10 gallons fresh good gas and a 1/2 bottle STP fuel treatment.
I was told to check the fuel pressure...bought the tester from NAPA...and there's no test port on the fuel rail....anyone know how to check the pressure?
The truck will start...idles very rough around 7-800 rpms...revs freely and will run fine above 2000rpm...but starts to stumble if you let up around 1800rpm down.
doesnt get better when it warms up.
I shut it off and let it set a few minutes...and bunted the key to retsart...it didnt catch on the first try....then cranked and cranked and sputtered as it tried to catch...would only start at WOT,but would stall immediately when you let of the throttle.Rev'd it up a bit...and still will only stall.Let it set over night and it will start and idle rough all over again
My questions are this
1) how do you check fuel pressure on these trucks?
2)if the upstream o2 is only a year old do you suppose it could be faulty already,I've heard some complaints about aftermarket sensors not being up to par?
3)the downstream o2 looks original..do you suppose it could be the culprit even without CEL codes?
4) the converter has a pretty good rattle inside,which I need to attend to,do you suppose its directly related?
I did a search and saw some threads about rough idle issues other members were having...and they seem identical to mine.The popular consensus was the upstream o2 as the culprit and a new one was the cure.
my truck is a 97 ram 1500 5.9l....128k
It has new fuel pump/regulator/filter last year and new upstream o2
recently I put in new battery,plugs/cap/rotor/wires,IAC...and the rough idle and stalling in gear persist.
there is no CEL or stored codes.
no vacuum leaks that I could find,pcv is working
10 gallons fresh good gas and a 1/2 bottle STP fuel treatment.
I was told to check the fuel pressure...bought the tester from NAPA...and there's no test port on the fuel rail....anyone know how to check the pressure?
The truck will start...idles very rough around 7-800 rpms...revs freely and will run fine above 2000rpm...but starts to stumble if you let up around 1800rpm down.
doesnt get better when it warms up.
I shut it off and let it set a few minutes...and bunted the key to retsart...it didnt catch on the first try....then cranked and cranked and sputtered as it tried to catch...would only start at WOT,but would stall immediately when you let of the throttle.Rev'd it up a bit...and still will only stall.Let it set over night and it will start and idle rough all over again
My questions are this
1) how do you check fuel pressure on these trucks?
2)if the upstream o2 is only a year old do you suppose it could be faulty already,I've heard some complaints about aftermarket sensors not being up to par?
3)the downstream o2 looks original..do you suppose it could be the culprit even without CEL codes?
4) the converter has a pretty good rattle inside,which I need to attend to,do you suppose its directly related?
#2
07-10-2010, 09:59 PM
On the newer trucks, you have to get/make an adapter that goes between the incoming fuel line, and the rail connector, that has the right fitting on it.
It is possible that your injectors are leaking down.... hence, only starting at WOT. Need to be able to watch fuel pressure to diagnose, or, pull the fuel rail off the intake, cycle the key a couple times to build pressure, and see what happens. (I really don't suggest this method though, if you do indeed have leaking injectors...... could be FAR to exciting.)
Downstream O2 only monitors the cat, doesn't effect fuel trim.
If your cat is getting plugged up, it might be a contributor, but, it would be more likely to show itself at higher RPMs, than at idle. I don't think that is your problem.
What brand O2 sensor did you get for the upstream one?
Standard question #1: Have you checked your plenum, to see if the gasket is blown?
Done a compression test?
It is possible that your injectors are leaking down.... hence, only starting at WOT. Need to be able to watch fuel pressure to diagnose, or, pull the fuel rail off the intake, cycle the key a couple times to build pressure, and see what happens. (I really don't suggest this method though, if you do indeed have leaking injectors...... could be FAR to exciting.)
Downstream O2 only monitors the cat, doesn't effect fuel trim.
If your cat is getting plugged up, it might be a contributor, but, it would be more likely to show itself at higher RPMs, than at idle. I don't think that is your problem.
What brand O2 sensor did you get for the upstream one?
Standard question #1: Have you checked your plenum, to see if the gasket is blown?
Done a compression test?
#3
07-10-2010, 10:13 PM
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to be clear..the WOT problem was only immediately after I bunted the key to quickly and the truck did not start...then it cranked for several seconds sputtering but not starting,as if it flooded,so I went WOT to get it to start.Which it did,but had to be throttled to keep it running,even after it was ' cleared out' by reving it up a few times and holding it at 3000rpms for a few seconds.If you let completely off it only stalled..and would have to be started again with the same procedure...after 2-3 times it wouldn't start no matter what,wouldn't even sputter.So I left it overnight and the next day it would start as usual,turn the key,start right up,idle rough.
I read a little about the plenum,but am not clear as to what to check or what the symptoms are?
as to the compression test,I have not.
the plugs were a few months old,I pulled all and they looked fine,it doesnt blow any smoke,but I could try that....how many pounds shouild I be looking for...in the 120 range(guessing)?
I read a little about the plenum,but am not clear as to what to check or what the symptoms are?
as to the compression test,I have not.
the plugs were a few months old,I pulled all and they looked fine,it doesnt blow any smoke,but I could try that....how many pounds shouild I be looking for...in the 120 range(guessing)?
#4
07-10-2010, 10:59 PM
For compression, Dodge says anything over 100 is 'acceptable'......
For the plenum, take off your air box, crack the throttles wide open (engine NOT running), and peak down there. See any oil? If you do, time to yank the intake. Many many many threads on this.
It sounds like it is flooding out, or leaning out...... plenum would have to be REALLY bad to cause it to lean out, and you would see evidence of burning oil on the plugs, would not necessarily see any smoke.....
Have you replaced the IAC motor? (Idle air control motor, screws into the back of the throttle body) That might be a piece to look at as well. Oooops. scratch that... I see you did. What brand is THAT feller?
For the plenum, take off your air box, crack the throttles wide open (engine NOT running), and peak down there. See any oil? If you do, time to yank the intake. Many many many threads on this.
It sounds like it is flooding out, or leaning out...... plenum would have to be REALLY bad to cause it to lean out, and you would see evidence of burning oil on the plugs, would not necessarily see any smoke.....
Have you replaced the IAC motor? (Idle air control motor, screws into the back of the throttle body) That might be a piece to look at as well. Oooops. scratch that... I see you did. What brand is THAT feller?
#5
07-10-2010, 11:25 PM
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just ordered the hughes plenum kit and gasket set...in talking with my brother-in-law(previous owner) he said last year to get it inspected he had multiple cylinder misfire code...he put in new plugs and the upstream o2 so it would pass...he then took it off the road a few weeks later because it snapped a tie rod(fell out in the driveway)...it then sat all winter and he sold it to me for cheap because he didnt want to work on it anymore.....he knows only to put gas in and change the oil..not mechanically inclined at all.
so in reading the other threads...and the misfires from leaking plenums and soaked plugs and trashed o2's....it got me thinking that...the truck has maybe only a few miles since the inspection repairs...and I know he didnt do the plenum repair...and it looks as though its never been apart...so I say try...it cant hurt.
the IAC is advance auto part...bosch?? not sure.
I put that in yesterday...cleaned the throttle body with some starting fluid...and shot some down the butterflys while it was running....slightly improved the idle...but its still pretty rough.
I'll run a compression test tommorrow if I can...and log the results...maybe get to yanking the intake if I'm feeling ambitious.....gotta pull the distributor anyhow...one of the cap screws snapped off...might as well fix it while I'm in there
so in reading the other threads...and the misfires from leaking plenums and soaked plugs and trashed o2's....it got me thinking that...the truck has maybe only a few miles since the inspection repairs...and I know he didnt do the plenum repair...and it looks as though its never been apart...so I say try...it cant hurt.
the IAC is advance auto part...bosch?? not sure.
I put that in yesterday...cleaned the throttle body with some starting fluid...and shot some down the butterflys while it was running....slightly improved the idle...but its still pretty rough.
I'll run a compression test tommorrow if I can...and log the results...maybe get to yanking the intake if I'm feeling ambitious.....gotta pull the distributor anyhow...one of the cap screws snapped off...might as well fix it while I'm in there
#6
07-10-2010, 11:30 PM
#7
07-10-2010, 11:46 PM
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no... the truck is at my moms house...been doing the repairs there...will take a peek tommorrow...I remember seeing a good deal of black build up around throttle blades,thus the reason I shot some cleaner thru there.
my list of repairs so far
new:
battery
fuel pump/regulator/filter
coil
serp. belt
cap/rotor/wires
IAC
muffler
tires-hankook dynapros
rotors/pads/calipers
shoes/wheel cylinders/rear brake lines
front fenders
patch club cab corner...cut out rust weld in new metal..do the necessary body work, chip gaurd the lower section of the truck.Repaint the lower 2/3s of the truck silver.
I've got about $2500 cash tied up in parts alone...who knows how much time??!!??
Thought I would buy it and fix it up,as its a pretty solid truck,and then see if I could resell it and make a few bucks....but at this rate I'll do well to break even.
my list of repairs so far
new:
battery
fuel pump/regulator/filter
coil
serp. belt
cap/rotor/wires
IAC
muffler
tires-hankook dynapros
rotors/pads/calipers
shoes/wheel cylinders/rear brake lines
front fenders
patch club cab corner...cut out rust weld in new metal..do the necessary body work, chip gaurd the lower section of the truck.Repaint the lower 2/3s of the truck silver.
I've got about $2500 cash tied up in parts alone...who knows how much time??!!??
Thought I would buy it and fix it up,as its a pretty solid truck,and then see if I could resell it and make a few bucks....but at this rate I'll do well to break even.
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