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[quote=”Hinoki” post=159460]When the engine is stone cold, does it run well? This problem ONLY manifests when the engine is warm?
Are there any engine codes at all?
You’ve covered the vacuum leaks.. and while the fuel pressure might be stable, I can’t help but wonder if it might not be that.
If the CPS was out of whack, that’d definitely throw a code. If you don’t have a code, I’d almost say it was a fuelling issue still. But I have trouble with that, because the pressure is solid. Even so, you’re running out of options there. When warmed up and it’s chugging and trying to stall… why not try this? Shut the car off and turn the key to the ‘on’ position several times before trying to start it. if it starts and runs ok for a few seconds, perhaps it’s a fueling issue after all.
-Hinoki[/quote]
Yes it is perfectly fine while cold and there are no codes or pending codes. It starts fine when the engine is cold but when warm it has a hard time starting after stalling. I will do as you suggest when it is warm and see of it gets any better. Thank you for your reply!
I also forgot to mention that the engine misfires when revving down to an idle from a higher rpm.
No check engine lights and no codes.
I thought that exact same thing (Your point number 2) and thought if I kept driving it, it would get better. It didn’t. I also disconnected the battery in an attempt to reset things and it didn’t help. :
By “banging” do you mean “knocking”?? Does it increase in frequency as RPM’s increase? Check the oil level. Many times if the oil is low it can cause the engine to make a knocking noise from lack of lubrication.
There is a vacuum leak somewhere. The air rushing noise is just that, air rushing into the engine from a place where it shouldn’t. The RPM is high because the engine is getting more air than it should (which is equivalent to stepping on the gas).
Check for vacuum leaks. Since you can hear the noise while in the drivers seat, it should be easy to find it with your ears. If it isn’t obvious, use carb cleaner. Eric made a video on how to do this.
[quote=”ToyotaKarl” post=107385]Not so fast about a bad block…
Chrysler 3.5s are known to leak coolant in the valley…. The engine heat hardens and warps the o-ring sealing the heater tube at the front of the engine. Then the coolant then leaks into the engine well underneath the lower intake manifold, filling it up with coolant.
Take a mental copenhagen/smoke break… go out and check the O rings…
-Karl[/quote]
Okay so that o-ring actually has a story behind it.
When I FIRST took off the intake, I had realized that I had accidentally cocked the tube to one side when I was prying the hoses off the heater tube. I removed the tube and found that the oring was damaged. I then went on to the Chrysler site and ordered a new one. (The weird thing is the website only let me go down to 2001, the car is a 2000. Were the motors the same in these two years?)
Anyway I found the o-ring and ordered it, but upon getting it I noticed that the old oring was thicker than the new one. The new one just seemed like a normal o-ring where the old one seemed specialized for this purpose.
I was always concerned about this, and wondered why they would be different. Perhaps I should go to the dealer personally and have them order it? Maybe I should replace the tube entirely? It isn’t in the best shape.
[quote=”ToyotaKarl” post=107385]Not so fast about a bad block…
Chrysler 3.5s are known to leak coolant in the valley…. The engine heat hardens and warps the o-ring sealing the heater tube at the front of the engine. Then the coolant then leaks into the engine well underneath the lower intake manifold, filling it up with coolant.
Take a mental copenhagen/smoke break… go out and check the O rings…
-Karl[/quote]
Okay so that o-ring actually has a story behind it.
When I FIRST took off the intake, I had realized that I had accidentally cocked the tube to one side when I was prying the hoses off the heater tube. I removed the tube and found that the oring was damaged. I then went on to the Chrysler site and ordered a new one. (The weird thing is the website only let me go down to 2001, the car is a 2000. Were the motors the same in these two years?)
Anyway I found the o-ring and ordered it, but upon getting it I noticed that the old oring was thicker than the new one. The new one just seemed like a normal o-ring where the old one seemed specialized for this purpose.
I was always concerned about this, and wondered why they would be different. Perhaps I should go to the dealer personally and have them order it? Maybe I should replace the tube entirely? It isn’t in the best shape.
I found the problem!
Turns out it WAS the EGR pipes that were leaking. Apparently in the process of replacing the heads, the orings that sealed them must have fallen off. I ordered generic ones from pepboys and now my idle is fine! However, they do not seal 100% because they aren’t thick enough. I will need to order the factory replacement ones from Mopar.
Thanks a lot Karl!
Additional Notes:
-The IAT reading and ECT reading were almost identical in the morning.
-The engine has 21 inHg, telling me the intake gaskets are fine.I found the problem!
Turns out it WAS the EGR pipes that were leaking. Apparently in the process of replacing the heads, the orings that sealed them must have fallen off. I ordered generic ones from pepboys and now my idle is fine! However, they do not seal 100% because they aren’t thick enough. I will need to order the factory replacement ones from Mopar.
Thanks a lot Karl!
Additional Notes:
-The IAT reading and ECT reading were almost identical in the morning.
-The engine has 21 inHg, telling me the intake gaskets are fine.Yes RPM’s go DOWN.
During the head replacement I had to remove the EGR valve with tubes attached. The tubes went from the valve and plugged into the bottom of the intake where they are fastened by a retaining clip. If I recall, they were sealed with O-rings.
These tubes are actually really close to where I was spraying the TB cleaner. Perhaps I was mistaken in where the source of the vacuum leak was coming from. I will have to double check tomorrow. Man, this list of “things I will do tomorrow” is really growing!
Yes RPM’s go DOWN.
During the head replacement I had to remove the EGR valve with tubes attached. The tubes went from the valve and plugged into the bottom of the intake where they are fastened by a retaining clip. If I recall, they were sealed with O-rings.
These tubes are actually really close to where I was spraying the TB cleaner. Perhaps I was mistaken in where the source of the vacuum leak was coming from. I will have to double check tomorrow. Man, this list of “things I will do tomorrow” is really growing!
[quote=”ToyotaKarl” post=107262]How have you determined you have a vacuum leak between the upper and lower intake mating surfaces?
If so, how big…
Also have you put a Vacuum gauge on the engine? Tested it at Idle, light throttle, medium throttle and WOT?
3k RPM is pretty high to blame a simple vacuum leak IMHO and a vacuum leak should cause positive fuel trim numbers… You are dealing with a rich condition…
Think you may be chasing a “small” red herring right now…
-Karl[/quote]
I noticed that when I spray throttle body cleaner between the upper and lower intakes in a certain spot, the RPM goes down. I can also hear a loud “HISSSSSS” around the same location when the engine is running. A vacuum gauge is a good idea, I will do it tomorrow and post back with the results.
I believe the fuel trims may be caused by a bad IAT sensor. I noticed that when I had my scan tool hooked up, it was saying the intake air temperature was 91 degrees when the outside temp was 74. I checked it again 30 minutes later and it was up to 97. My guess is that the computer thinks the intake air is real hot, so it takes away fuel. This accounts for the negative fuel trim values. (I am assuming that fuel combusts easier when its hot, just like it is hard to combust when its cold outside.) This is just me guessing though.
[quote=”ToyotaKarl” post=107262]How have you determined you have a vacuum leak between the upper and lower intake mating surfaces?
If so, how big…
Also have you put a Vacuum gauge on the engine? Tested it at Idle, light throttle, medium throttle and WOT?
3k RPM is pretty high to blame a simple vacuum leak IMHO and a vacuum leak should cause positive fuel trim numbers… You are dealing with a rich condition…
Think you may be chasing a “small” red herring right now…
-Karl[/quote]
I noticed that when I spray throttle body cleaner between the upper and lower intakes in a certain spot, the RPM goes down. I can also hear a loud “HISSSSSS” around the same location when the engine is running. A vacuum gauge is a good idea, I will do it tomorrow and post back with the results.
I believe the fuel trims may be caused by a bad IAT sensor. I noticed that when I had my scan tool hooked up, it was saying the intake air temperature was 91 degrees when the outside temp was 74. I checked it again 30 minutes later and it was up to 97. My guess is that the computer thinks the intake air is real hot, so it takes away fuel. This accounts for the negative fuel trim values. (I am assuming that fuel combusts easier when its hot, just like it is hard to combust when its cold outside.) This is just me guessing though.
[quote=”ToyotaKarl” post=107255]This is interesting
I have installed the wrong head (I.E. one for a 5SFE on a 3SFE)… They were identical except one thing… An air assist that ran from the throttle body to the head. Engine idled high and had negative fuel trims… took about an hour for me to find the issue.
Also, Coolant can cause issues with O2 sensors… I hate to throw O2 sensors under the bus so quickly but perhaps there may be something there…. If this car had a coolant leak, it could have screwed up the upstream sensor…
What is the position of the throttle plate? (and throttle linkage) If it has it… Perhaps back off the throttle wire adjustment (have seen this give high idle)… perhaps someone adjusted the wire before you had it…
Are the heads the exact proper ones for the job… O2 sensors? Just some things to think about…
All the best
-Karl[/quote]
Thanks for your response ToyotaKarl.
To me, the heads seemed identical. This car has the 3.5L and everything seemed to have a place, didn’t see any connection that wasn’t used on the head. I am not sure this is the issue (thank god!) because upon second guessing myself, I found a vacuum leak between the upper and lower intake mating surfaces. I cannot seem to get it to go away (as mentioned in my previous posts) which is leaving me stumped!
The throttle plate says it is open 10.2% at idle. It has linkage, but even after I REMOVE the cables, the TPS still says 10.2%, meaning adjustment isn’t causing that number, and the engine still does the same thing.