Hi,

I have 95 Escort with the 1.9 engine and auto transmission. Recently the engine started cutting out for a fraction of a second, usually multiple times per episode. Most of the time it runs fine. There is no rhyme or reason to it. It may do it while idling, though not usually. It may do it under load or almost no load, though so far never when letting it ride on compression. It may do it as I pull out of a parking space or away from a light with the throttle barely cracked. In that case, it usually stalls and has to be restarted. It can do it while under way, in which case the TCM interprets the problem as a need to downshift one gear and does so for the duration of the cutout. It can do it in Drive or Park. It usually does it when warmed up but can do it cold. After an episode in which it cuts out several times in quick succession there can be a weird sulfurous smell in the car. (Maybe it's possessed?) If a cutout is long enough, the Check Engine light flashes but then goes out again as soon as the engine goes back to running.

I replaced the fuel filter and it went away but not for more than a couple of days. Also tried a new fuel pump but no change.

Today I hooked up a code reader. No codes on the engine off test. On the engine running test, it showed code of 538, which apparently means the RPM did not increase sufficiently when I momentarily put the throttle to the floor. It showed a 536, which is braking on/off circuit not activated during test. Then it showed a 20, which is something about a cylinder not putting out like the other ones and requires further testing. The 536 and 538 codes are generated during the test, so I'm not sure what codes the Check Engine light is setting, if any. I have to scare up a timing light to do the rest of the tests with the code reader.

So, any thoughts? Thanks.

 

It would seem there is a short period of excess fuel. Why , not sure. The odor could be from a too rich condition as would be the flashing check engine light.
Now all we have to do is find out what is going on.

As you have determined the 536 and 538 are operator error codes during the test.
The 20 is an invalid code because , first it is not authentic and also either the system will provide 3 digit codes or 2 digit codes but not both.
I kinda remember working on these older systems and you had to check each individual component because the system did not always provide direction.as an OBD II system does.
I do recall where there were a lot of problems with the original ignition coils shorting out internally.If this were what is happening , it might explain why no or weak spark is being delivered to a cyl causing incomplete combustion and hence a lot of unburned fuel. Just a theory and the older systems were a challenge to diagnose.

 

Thanks; that's all helpful. We'll slap a spare coil in and see what happens, since that's the easiest place to start. Would a too-rich condition cause a little black smoke? Or does the excess fuel all burn up in the cat? Will that damage the cat?

If the fuel pressure regulator was allowing too much pressure, could that cause the problem?

 

Yes, a too rich condition can cause some black smoke..

Fuel pressure regulators can cause black smoke if the diaphram inside is ruptured. Because it is connected to a source of manifold vacuum to control the pressure, if the diaphram is ruptured it will allow fuel to be drawn from the fuel system into the intake manifold providing a rich condition.. Many times you can remove the vacuum line from the pressure regulator and if you see gasoline come out , you have your answer. Problems from fuel pressure regulators don't come and go as appears to be happening here.

In answer to your concern about excess fuel damaging the catalytic converter, yes, it can because the converter will try to cleanup the excess hydrocarbons (fuel) and overheat. When that happens the substrate in the converter can melt and clog the substrate. That is why an excess fuel condition can get expensive and it is not just using more fuel , but destroying the converter and they can be expensive to replace.

 

When I pulled the vacuum hose off the regulator no gas ran out, but I could smell it.

 

If the regulator is still original, I would consider replacing it.

 

Thanks for the help. We replaced the regulator and the problem appears to be solved. But that's tentative, because after we replaced the fuel filter the problem went away also but then came back big time. The friend who did the work also found that the EGR line had worked loose and retightened it.