1994 Toyota Trecel lopes at Idle

Tiny
THEWHIP
  • MEMBER
  • 1994 TOYOTA TERCEL
  • 4 CYL
  • MANUAL
  • 202,000 MILES
Wouldn't pass smopg test high nox high HC. Engine light indicates code 71 EGR so I took off EGR and there seemed to be no vacume. I reved up engine and started to feel more air from chamber but then it started loping. Replaced EGR valve and it started working when throttel up but still lopes. Seems like vacume leak. Lopes the same as not having PVC hooked up. Pulloed off hose from PVC and put finger over hole and it stops loping. Replace PVC but5 still lopes. No loose vac hoses that I can see.
Wednesday, March 2nd, 2011 AT 6:04 PM

7 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
When was the last tune-up?

Test the EGR valve transducer and the control solenoid-make sure it getting vacuum

Inspect/Test EGR Vacuum Modulator
Disconnect the vacuum hoses from ports P. 0 and R from the EGR vacuum modulator.
Block ports P and R with your finger.
Blow air into port 0. Check that the air passes through to the air filter freely.

Start the engine and maintain speed at 2,500 rpm.
Repeat the above test. Check that there is a strong resistance to air flow.
If a problem is found, replace the EGR vacuum modulator.
Reconnect the vacuum hoses to the proper locations
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Wednesday, March 2nd, 2011 AT 6:17 PM
Tiny
THEWHIP
  • MEMBER
  • 4 POSTS
Tune up was over a year ago but car is not driven that much their was no timing problem when I tried to have it smog tested. I will conduct these suggested tests.
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Wednesday, March 2nd, 2011 AT 6:31 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Keep me posted
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Wednesday, March 2nd, 2011 AT 6:33 PM
Tiny
THEWHIP
  • MEMBER
  • 4 POSTS
EGR vacuum modulator seems to be ok. I don't know what the EGR valve transducer is or the control solenoid? But there is no change in idle when I push up on the diafram yet the diafram seems to go up when I raise idle. Idle raises and lowers consistantly.
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Wednesday, March 2nd, 2011 AT 7:41 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Clean out the EGR valve port thoroughly could be clogged-up between the intake and exhaust port
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Wednesday, March 2nd, 2011 AT 7:45 PM
Tiny
THEWHIP
  • MEMBER
  • 4 POSTS
Ok
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Wednesday, March 2nd, 2011 AT 7:47 PM
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Seems to me you got it going-So what was the fix for the high Nox DTC 71-
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Monday, March 28th, 2011 AT 8:18 AM

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