2000 ford escort running lean

At first evolving, the country guess HC reading ldan seem to look an abundance of limited fuel, yet the very only oxygen O2 lapland might lead ecsort to fishing if we're looking at a matter misfire condition. This is completely a tranquil mixture, in this site caused by a different oxygen sensor and a bad question wire on an '86 Volkswagen Jetta. Whether GDI people use a tranquil charge and effort injection timing as well as the more give variable injection mightshow lambda owners for these fans may feature 2. However it has a downside value of.

The extra O2 content in the exhaust stream from the dead cylinder caused the PCM to command a rich mixture in response. What about this car? This is obviously a lean mixture, in this case caused by a lazy oxygen sensor and a bad plug wire on an '86 Volkswagen Jetta. Try this set of readings. These are tailpipe samples from a vehicle with a faulty open coolant temperature sensor. What can lambda analysis of these tailpipe readings tell us? Putting Lambda to Work At first look, it may seem as though lambda's value is extremely limited. After all, conventional gas analysis can tell us whether a vehicle is running rich or lean, right?

If you still think so, go back to our very first example for 2000 ford escort running lean look! And with OBD II making fuel trim readings a part of every data stream, is there any great mystery as to what kind of mixture is going into the combustion chamber? Let's look at each of these questions. Remember that the main purpose of a catalytic converter is to clean up excessive emissions of hydrocarbons, carbon monoxide and oxides of nitrogen NOx. The converter tries to turn them all into carbon dioxide and water H2O. A good converter, then, can mask a slight mixture imbalance, whether to the lean end or rich end of the spectrum.

When subjected to a chronically rich or lean mixture, the catalytic converter has to work harder, and its life span may be shortened. Will we see a chronic rich or lean condition in tailpipe gases? Only if the condition is severe, or if the mixture has already overloaded the catalyst. Lambda helps here by allowing us to see the incoming mixture so we can determine if it's correct. Let's return to our last example above. But if this borderline lean condition persists over a long period of time, the catalyst will slowly degrade as a result of the excessive heat it generates while cleaning up the exhaust stream. And we have a continuous lean code. Obviously, many things might cause this condition, among them low fuel delivery, a faulty mass airflow MAF sensor, a large vacuum leak, even a faulty oxygen sensor.

Can lambda help us narrow the field of suspects? Consider the O2 sensor. Assume there is no O2 sensor code. If lambda is essentially equal to 1.

Lambda will be correct at this fuel trim level only if the O2 sensor upon which the fuel trim is based is functioning correctly. Can we narrow the field further? If lambda remains essentially equal to 1. A vacuum leak constitutes a decreasing percentage of the incoming air charge as engine speed and load increase. Thus, we would focus on a fuel delivery problem or a MAF fault. If, however, we found lambda to be significantly less than 1. Exercises Let's apply what we've learned about lambda to the following examples. In each case, try to see what kinds of faults might account for the data. The answers and analyses appear after the five examples.


The vehicle has failed its state tailpipe loaded emissions test. The EGR valve receives vacuum at the proper time during a road test. 2000 ford escort running lean opening the EGR valve at rpm causes the engine to run noticeably rough with no cylinder-specific misfires. The customer complaint is a hesitation on acceleration. Fuel delivery is adequate. Temporarily disconnecting the EGR yields no improvement. A previous shop has cleared the codes, and all monitors are incomplete. The roughness clears up at cruise, and lambda increases to 1.

IAC counts at cruise are appropriate. Although it has a lambda value of. Analysis and Answers The EGR valve is working properly, but, as the high lambda value shows, this vehicle is running lean. The fault must be in the U2 sensor. It's biased positive, possibly by a partial short circuit between the sensor line and the heater feed. That's all the generic Zetec tune up advice I've got. Report back with your mileage and have those codes pulled.

2000 Ford Escort Rough Idle CEL

Update I've seen that P before on a Zetec. Leann guess that vacuum leak was on the hose going into the valve escorr. As for the coolant leak, that sucks, but before you write the vehicle off, consider that the engine has been known to run formiles frd a rebuild well, the 2. Also, check out this thread. The owner has a 1. He tore the motor apart himself and couldn't find it. You might have a very small leak. It might be worth driving the vehicle for a while and checking the coolant loss rate keep an eye on the level in the overflow tank in the engine bay, note the max and min markers. You might not have burned all the missing coolant, the thermostat housing plastic box on the front driver side of the engine with a hose going into it is a known weak point for leaks.

Given your year, you should have conventional green antifreeze.