91 LX 1.9L failed emissions

[fordescort1991davl]

My 91 escort LX 1.9L failed emissions for NOX the standard is 2.50 and it came up 2.59. Probably an EGR system problem, but I was told by emissions that it was running hot. The radiator and fan assembly were replaced 2 months ago. Any suggestions on a quick fix just to get it thru Emissions.

[FordMan59]

Originally Posted by fordescort1991davl

My 91 escort LX 1.9L failed emissions for NOX the standard is 2.50 and it came up 2.59. Probably an EGR system problem, but I was told by emissions that it was running hot. The radiator and fan assembly were replaced 2 months ago. Any suggestions on a quick fix just to get it thru Emissions.

If you think it's the EGR system, I'd suggest taking the EGR valve off cleaning it, checking the EGR tube for restrictions and last and most importantly run something into the intake at the EGR port like a screwdriver or stiff piece of wire . I've had to remove the EGR valve from a few Escorts to clean the gunk from the intake port. The overheating problem might be a bad temperature sensor or cooling fan relay. Are you loosing any coolant? If so you may have a blown head gasket.

[mightymoose_22]

You may be in need of a new catalytic converter... it could be plugged.

[denisond3]

I would agree about cleaning the parts of the EGR system.
I wonder how the tech figured it was running hot? Its normal for the fan to come on when the car has been idling of course, and the gauges in these cars can read way too high if the engine is running and there is a bad ground connection at the weird little connector at the negative terminal of the battery.
I have an infrared thermometer that you point at things to find out the temperture. You can get them as low as $30- $40 from places that sell Chinese tools or from ebay. Mine shows me 190f-205f at the upper radiator hose - about the time the fan come on its low speed.
And if yours has the EGR tube running down behind the motor and plugging into the exhaust (instead of around to the side and connecting into the exhaust manifold like the later 2nd gen Escorts had), see if there is a rubber tube going from the middle part of the larger EGR steel tube, and back to an 'egr pressure sensor' mounted on the firewall. That tube may have gotten fried and broken open. Its a special rubber, but as no parts place knew what I was talking about, I replaced it with ordinary fuel line hose.

[RahX]

NOx is created by high combustion temperatures. Run some GOOD combustion chamber cleaner through the engine to clean out any excess carbon that may be in there. Excessive carbon buildup in the cylinder can raise the compression ratio which raises NOx emissions. A catalytic converter is designed to handle HC and CO normally. There are types that handle NOx but they're not usually found on all cars. Not sure if yours has one or not. Being that it has an EGR I would lean towards no. And definitely check out the EGR system like the other guys said, that could be another cause.

[zzyzzx2]

How many miles are on this car?
How many miles on the O2 sensor?
When was the last time the MAF, throttle body, or IAC were cleaned?
How many miles on the spark plugs?
Have you checked for vacuum leaks?