1994 Mercury Topaz Code 186 Miss

MERCURY TOPAZ
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SCARFACE
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  • 1 POST
I have a 1994 Mercury Topaz with 92,000 on it. I have a code that keeps popping on the check engine light the code is 186 it says something about injector pulse width timing. It also states something about BARO sensor problem. The ccar misses and stutters a bit on take off and has BAD gas milage too. I have given it a complete tune up and everything on the exhaust system is new. Can you tell me what triggers this code and how to remedy the missing problem? Thanks for any help that you can give me.
Jul 16, 2006 at 10:13 AM
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MIKEYBDMAN
  • ✓Experienced Mechanic
  • 623 POSTS
Inspect the air cleaner and air inlet ducting.
Check for unmetered air between Mass Air Flow (MAF) sensor and Idle Air Control (IAC) solenoid.
Check all engine vacuum hoses for damage, leaks, cracks, blockage, proper routing, etc.
Are all the above vacuum checks OK?
If so, try this:
Key "OFF".
Install fuel pressure gauge.
Verify manifold vacuum is connected to the fuel pressure regulator if applicable.
Start and run engine at idle.
Is fuel pressure between 35-45 psi? If yes, check for bad injectors. If no, check for proper fuel pump operation.
Jul 16, 2006 at 10:25 AM

Suggested Repair

Inspect the air cleaner, inlet ducting, and vacuum hoses for leaks or unmetered air between the MAF sensor and IAC solenoid. If those checks pass, verify idle fuel pressure is 35-45 psi with manifold vacuum connected to the regulator; then check the injectors if pressure is good, or the fuel pump if it is not.

Conversation Summary

A 1994 Mercury Topaz with 92,000 miles repeatedly sets code 186, described as related to injector pulse-width timing and a BARO sensor problem. It misses and stutters on takeoff and has poor fuel mileage despite a complete tune-up and a new exhaust system. The expert recommends checking the air cleaner, inlet ducting, unmetered air between the MAF and IAC, and all vacuum hoses, then testing idle fuel pressure at 35-45 psi and following up with the injectors or fuel pump as indicated.

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