High idle issue and intermittent shifting cause IAC, TPS?

Tiny
DLVAUGHN1963
  • MEMBER

Here's an interesting design issue. The replacement PVC line is not sufficiently sealed where a secure plug was installed and the hose diameter is different on both sides of the secure plug. The hose has come loose at both sections of the plug. I think the fix for this is either a tubing splice or a single piece hose. It seems the leak is here. When the engine is running, and the hose pieces are held in position the idle returns to normal. So my temp solution is possibly using high temp sealant over the entire hose joint. More to follow.
And the issue of the hissing is when the engine is running and the sound is at or near the evap canister. I've not heard this sound in the four years I've had this car even prior to all this recent engine evap work.

Was this
answer
helpful?
Yes
No
Monday, October 1st, 2012 AT 8:57 PM
Tiny
SATURNTECH9
  • EXPERT
  • 30,706 POSTS

Some hose clamps maybe?

Was this
answer
helpful?
Yes
No
Tuesday, October 2nd, 2012 AT 2:38 AM
Tiny
DLVAUGHN1963
  • MEMBER

I can try some clamps. It seems that whenever I either move the line the idle goes to normal then after a while the engine surges and goes back high. If I'm at a stop and restart the engine the idle is fine. The hose ends where they go into this secure plug t has some sealant that looks to have gone bad so any serious vibration cause it to lose seal. There seems to be no other leaks at the engine and electrically everything else is ok. When the engine transitions from normal to high idle the engine violently shudders as if to shut off.

Was this
answer
helpful?
Yes
No
Tuesday, October 2nd, 2012 AT 2:36 PM
Tiny
GREGHOWARD
  • MEMBER

Gentlemen, thank you for unintentionally saving me some time. My mom has an 01 century as a secondary car. A few months ago I did a full engine rebuild due to some blown gaskets, even polished the heads. It ran like champ and was getting 32mpg highway up until last week. I have the same problems, taking the throttle assembly right now. Hers is throwing a code for the iac but I replaced that when I did the rebuild, with mass airflow sensor and tps. Mileage has been slipping, idle getting rougher, and I too have noticed what sounds like a vacuum leak but, again, I replaced most of the lines. Very frustrating. Keep me posted if you find a solution, I will check back and let you know if I find a fix on this one. Best of luck!

Was this
answer
helpful?
Yes
No
Thursday, October 4th, 2012 AT 2:01 AM
Tiny
SATURNTECH9
  • EXPERT
  • 30,706 POSTS

Use some clamps or get a smaller hose and some lube to get them on.

Was this
answer
helpful?
Yes
No
Thursday, October 4th, 2012 AT 2:46 AM
Tiny
GREGHOWARD
  • MEMBER

I think my problem is the EGR valve, it sounds like that's where the hissing is coming from, and it's the only part in that area that I didn't change during the rebuild. Buying it in the morning, will report back tomorrow

Was this
answer
helpful?
Yes
No
Thursday, October 4th, 2012 AT 6:19 AM
Tiny
SATURNTECH9
  • EXPERT
  • 30,706 POSTS

Isnt your egr valve a linear one meaning its electronic not a diagram type?

Was this
answer
helpful?
Yes
No
Thursday, October 4th, 2012 AT 3:02 PM
Tiny
DLVAUGHN1963
  • MEMBER

Bad hose is my situation and clamps won't work. More to come

Was this
answer
helpful?
Yes
No
Thursday, October 4th, 2012 AT 3:09 PM
Tiny
SATURNTECH9
  • EXPERT
  • 30,706 POSTS

Smaller hoses and lube have you tried that yet?

Was this
answer
helpful?
Yes
No
Thursday, October 4th, 2012 AT 3:54 PM
Tiny
DLVAUGHN1963
  • MEMBER

Because of how the hose is constructed a home made remedy will not work. Where the two lines come together in a "t" it actually vacuums from the valve cover through to the purge solenoid valve, the line is obviously bad. However, this morning I had disconnected the booster vac line and started the engine (of course I forgot I had disconnected it) plugged the pcv hose back into the original purge solenoid valve and the evap line to the lower connector, and plug. With the booster vac line disconnected, it repeated the horrible starting and idle runs I had been experiencing. When I reconnected this line back to the booster, the idle immediately went high and stayed there. When I shut off the engine, restarted it, the idle was slightly higher than normal, but quickly settled down. I let the engine run about 10 min, shifted the transmission in all drive positions, A/C on, and no stumbling, nor hickup or rise in idle. So you wonder what was the fix? Until a new pcv hose arrives, a little dab of superglue on the "t" fitting lines. Once the lines sealed to the fitting, all, for now is well. I have started and run the engine four times, with great success. Will let you know if anything changes.

Was this
answer
helpful?
Yes
No
Thursday, October 4th, 2012 AT 4:28 PM
Tiny
SATURNTECH9
  • EXPERT
  • 30,706 POSTS

Sounds good keep us posted.

Was this
answer
helpful?
Yes
No
Thursday, October 4th, 2012 AT 5:20 PM
Tiny
GREGHOWARD
  • MEMBER

Where is purge solenoid located? I'm doing the EGR valve now (it started raining, took a break). Last night while looking at it seemed to be the source of the "whooshing" sound. It's about the only old part left.

Was this
answer
helpful?
Yes
No
Thursday, October 4th, 2012 AT 6:15 PM
Tiny
DLVAUGHN1963
  • MEMBER

The canister evap purge solenoid is just behind the egr valve. Follow the pcv hose behind and under the ignition coils(if u have the 3.1 eng). There are two vac lines one from the pcv the other goes to the evap canister.

Was this
answer
helpful?
Yes
No
Thursday, October 4th, 2012 AT 9:16 PM
Tiny
GREGHOWARD
  • MEMBER

Thanks

Was this
answer
helpful?
Yes
No
Thursday, October 4th, 2012 AT 10:36 PM
Tiny
DLVAUGHN1963
  • MEMBER

At a loss. Now what is happening is the engine performance is really bad. When starting, the engine runs extremely rough to the point of stalling. When the engine is shut off and restarted repeately, the problem does not go away. Although when letting the car sit idle for about 5 minutes the idle is then fine. Do you remember telling me something about the coolant temp sensor? Would this be my culprit?

Was this
answer
helpful?
Yes
No
Thursday, October 11th, 2012 AT 12:03 PM
Tiny
SATURNTECH9
  • EXPERT
  • 30,706 POSTS

Are all the hoses fixed?Do you have any coded in the computer?

Was this
answer
helpful?
Yes
No
Thursday, October 11th, 2012 AT 4:34 PM
Tiny
DLVAUGHN1963
  • MEMBER

You will enjoy this.
I"m not sure what fixed the idle issue but, it is gone. Possibly combination of repairs
1. PCV
2. PCV vent tube
3. Evap canister vent solenoid
4. IAC valve
5. Cleaned EGR Valve.

Now I have no codes except for a random engine misfire. My goal at this point is to replace all the wires. The coils all have good fire and I'm not sure what plugs/wires age are at this point. So I will go there. I pray the injectors are good, but that is another issue.
I did have my codes checked at autozone and a P0300 and P0404 hence why I cleaned out the EGR Valve and replaced the seal/gasket. As of Now, I have NO codes. Repeat NO codes from the engine. Even the cylinder misfire code 0300 has not resurfaced. More to come.

Was this
answer
helpful?
Yes
No
Friday, October 12th, 2012 AT 4:33 PM
Tiny
SATURNTECH9
  • EXPERT
  • 30,706 POSTS

Wow you went all out on that engine lol keep me posted.

Was this
answer
helpful?
Yes
No
Please consider a donation if we helped you
Friday, October 12th, 2012 AT 9:16 PM
Tiny
GREGHOWARD
  • MEMBER

I replaced the EGR valve and the Buick ran perfect. The rough idle and poor gas mileage went away; it ran like a dream all week. Today my mom called and told me that the rough idle has returned. Why on earth would it run great for a week and then go right back to having this problem! As I said before I had rebuilt the engine from the heads up a few months ago, the EGR valve was the only part I had not replaced. It was running better than new up until a few weeks ago, now, like you, I'm stuck with this mysterious problem. It runs fine, plenty of power and smooth, but it's idling rough and losing gas mileage. This is getting frustrating!

Was this
answer
helpful?
Yes
No
Saturday, October 13th, 2012 AT 5:20 AM
Tiny
DLVAUGHN1963
  • MEMBER

Here's the situation at this point
I have replaced all 6 plugs
four broke at the ceramics, two had worn tips but suspect bad gap and just old plugs. They had Autolite 606 plugs.
Got the new plugs in, starts and idles fine, BUT, still have surging and misfiring. When the car is running and I'm driving for about 1/4 mile it runs horribly, but after that, the car settles and runs fine. This happens anytime the car is shut down and restarted. Any other suggestions? I have checked the coils, but they seem to be producing good spark. I will take the coil wire caps off and look at the spark in order and see if they seem to be weak at the cap. Then possibly look into either coil, or bad ICM.

Was this
answer
helpful?
Yes
No
Saturday, October 13th, 2012 AT 2:13 PM

Please login or register to post a reply.

Related Engine Idle High Questions

Recommended articles