More Escort Issues

[Wicked_Sludge]

a while back i had a post going regarding my '89 escorts widely inconsistent fuel mileage. one tank i would get 34+ (reaching as high as 39 a few times) MPG, then the next i would only get 25...with no major changes in driving style (i run a vacuum gauge on this car). i eventually came to realize that part of the problem was that i was running my battery low with a power inverter and the load the alternator placed on the motor was appearantly enough to cause a noticeable drop in economy. after i stopped using the inverter, my mileage stabilized somewhat, with my lowest being near 30.

fast forward to present day. my mileage has dipped to the mid 20's a few times since then...so the power inverter theory may have just been coincidence. until recently, i had nowhere to start on this problem because everything on the car seems to be in good working order. then last week, i started getting check engine lights, coming on for anywhere from 5 to 30 seconds, then going back out. i pulled the codes and got 41, 42, and 85...all O2 sensor related. since mileage and maintainence records are unknown, i just replaced the sensor. now a few days later, ive been getting the same codes: 41 - no HEGO switching detected, system lean. 42 - no HEGO switching detected, system rich. and 85 - adaptive lean limit reached.

i did some searching on yahoo and came up with THIS POST regarding code 85. i will look at that tomorrow (DVOM is at work)..but until then, does anyone have any ideas why this car appears to be bouncing back and forth from rich to lean? there are no appearent vacuum leaks, the wiring to the O2 seems to be solid and the connector is corrosion free.

 

[almostclueless]

Grounding issues? intermittent electrical issues can be the worst to deal with.

 

[Ozwynn]

just take it out behind the barn and shoot it.

 

[Wicked_Sludge]

Grounding issues? intermittent electrical issues can be the worst to deal with.

i can only hope not, but its possible...if not probable. after all, this car is old enough to vote diagnosing electrical problems is not my strong suite.

i put 12v to the purge solenoid and it opens and closes normally. will test the connector for 12v tomorrow after work.

 

[almostclueless]

Heck, with a computer controlled vehicle that old, I'd probably carefully label then disconnect, test, clean, and reinstall the entire wiring harness and ground points myself.....using factory wiring diagrams. I'd also probably replace all relays for the heck of it.

 

[envious8420]

sounds like the fuel pressure reg is taking a dump.

 

[Butch2112]

Hummm electrical problems gasoline issues sounds like a hazard to me is it insured?

 

[Natedog]

I thought this was the 'other' kind of escorts...lol! But seriously, I second this opinion:

sounds like the fuel pressure reg is taking a dump.

 

[Ozwynn]

Wicked, is that car worth fixing, like you said it is old enough to vote. How much could you sell it for and what would it cost to replace it ......... around here that is a $200 car and can be replace as such .......... thats why I like saturns because they don't have any rust. compast cars are a dime a dozen. drive that 1 till it quits running, strip it, send the rest to the scrapper and replace the car with another recycled beer can (or milk jug in the case of a saturn)

 

[Wicked_Sludge]

id rather not go through the hassle of messing with all the connections if there is nothing wrong with them (and thats the case primarily). a "if it aint broke dont fix it" kind of thing.

i just went and pulled the vacuum line off the FPR and it is dry. Ill try to get a pressure gauge on it tomorrow during lunch. I would love for it to be as simple as a bad FPR.

EDIT for BDAB:
I see what your saying BDAB. This car is a beater. I bought it solely for commuting to work and for getting good mileage and im not going to dump tons of cash into fixing it. I would, however, like to at least pinpoint what the problem is so I can make an educated decision on wether or not its cost effective to fix the problem. Other then the economy issues, the car runs good, has a good body (this year escort does NOT rust), and is (dare i say) sporty and fun to drive. I’d hate to unload it because of this problem and risk ending up with another beater that has worse issues.

 

[Bill]

A power inverter isn't going to affect your fuel economy much, if at all. The only thing a power inverter will do is increase the load the alternator has to keep up with. Air conditioning will affect fuel economy more than the alternator.

If your fuel pressure regulator was that hosed you would have noticed driveability problems a long time ago. How is the driveability? Any hesitation or bogging?

Have you done any basic tune-up? Spark plugs, air filter, etc?

Have you considered the possibility that the gas pump is shutting off a gallon or two short of filling the tank, and pump on the next fill is filling the gas tank to capacity? This will throw your calculation way off. Instead of comparing the fuel economy tank to tank, try calculating your fuel economy over four or five fills (total mileage over four or five fills, divided by total gallons used).

 

[Wicked_Sludge]

driveability is good. the engine is a little "rough" below about 2200 RPM at cruise...but nothing approaching hesitation, sputtering or bogging. full throttle acceleration is smooth and powerful, and cruise above 2200RPM is smooth.

All tune up items have been checked. New fuel and air filters and EGR valve. Spark plugs, wires, rotor, cap, PCV valve have all been checked/cleaned accordingly.

The fuel pump theory is one that was brought up in my last post. I shot compressed air through the tank fill vent thinking maybe it was plugged, causing the fuel to back-up and shut the pump off early. I always use the same gas station for fueling, the same station I use for both my other (and identical) ‘89 escort and my truck...both of which get steady mileage (34 in the case of the other ‘scort). As far as calculating mileage on a multi-tank basis, I’ve started a log for just this purpose. Unfortunately I only have one tank through it so far. I don’t think its going to reveal anything other then overall low economy however, as I’ve had far more 25-26MPG tanks then I have had 39MPG tanks (the average of 25 and 39 is 32, which is still a little low IMO)

 

[baddis]

have you checked for a vaccume leak? iirc i had one in an 89 and had issues and found it on accident

 

[Wicked_Sludge]

no appearant vacuum leaks

 

[baddis]

well it was an idea