Frustrated - need help!

[colovette]

1996 Exploder - engine runs VERY rough, won't idle for long, can't drive.

This is my daughter's truck and she broke down at school. I had the truck towed home and found the fuel pump was bad. I changed the pump and checked the error codes. The only code was low coolant temp, so I didn't do anything else. She drove the truck for several days with no issues. Last week she broke down on the way to school. I met her and moved the truck to a safe spot then checked the codes. The codes posted were the O2 sensor on Bank 2 and the low coolant code. I got the truck home and replaced the O2 sensor and cleared the codes. The truck still won't run for more than 20 seconds before dying. So far no error codes are displayed.

Any ideas?!?!?!

Thanks!

 

[yavapaires]

Why have you not fixed the low coolant temp problem? That could have an effect on the O2 sensor.

 

[MNgopher]

Fix the issue causing the low coolant temp code - likely a bad thermostat. You likely killed the Oxygen sensor by not fixing it the first time. Long term running rich due to a bad thermostat can kill those sensors and after that take out the catalytic convertor(s).

As far as whether that will solve the stalling issue, I'd guess not.

 

[colintrax]

One, calling it an exploder won't make me wanna help you.
Second, why have you not fixed the low coolant? Do you not realize that an engine runs best at x temp.

 

[steadyhand]

The others are correct in that you should have fixed the coolant issue right away. Some don't realize how much the ECM depends on information being fed back to it about the engine temp. If the ECT is bad the ECM will not know how much fuel/spark to give the engine.

If the issue is not the ECT but rather a thermostat being bad the ECM will be getting a reading it knows is not normal. The ECM will continue to give x amount of fuel/spark based on the temp. If the computer thinks the engine is cold it will keep giving it more fuel.

Also, contrary to what some believe it isn't a good idea to reset codes until AFTER you have fixed all issues you believe to be causing the codes.

Each time you reset codes, you delete the tables in the ECM so now it must relearn its fuel ratios and what not after several miles of driving.

It has been experience that if you have fixed the problem there is no need to clear codes. The CEL will just go off because the ECM no longer sees the problem when it compares current info being received to it's current data logs.

 

[drbenz]

The others are correct in that you should have fixed the coolant issue right away. Some don't realize how much the ECM depends on information being fed back to it about the engine temp. If the ECT is bad the ECM will not know how much fuel/spark to give the engine.

If the issue is not the ECT but rather a thermostat being bad the ECM will be getting a reading it knows is not normal. The ECM will continue to give x amount of fuel/spark based on the temp. If the computer thinks the engine is cold it will keep giving it more fuel.

Also, contrary to what some believe it isn't a good idea to reset codes until AFTER you have fixed all issues you believe to be causing the codes.

Each time you reset codes, you delete the tables in the ECM so now it must relearn its fuel ratios and what not after several miles of driving.

It has been experience that if you have fixed the problem there is no need to clear codes. The CEL will just go off because the ECM no longer sees the problem when it compares current info being received to it's current data logs.

Yes and no, engine temp is critical to proper engine operation but it would have to be way off to cause the problem described.
While it is true that (many) DTC's will clear themselves it requires several "trips" to do it, if you want to know if the problem is fixed clear the codes.
This one is not correct, clearing obd codes does not reset the keep alive memory, only an intentional KAM reset or disconnecting the battery power will do that.

Colovette take the air cleaner out so you can spray some throttle body cleaner in the intake when the engine is about to die, you need to find out if the problem is fuel related or what and look hard (and listen) for vac leaks as well.

 

[steadyhand]

Yes and no, engine temp is critical to proper engine operation but it would have to be way off to cause the problem described.
While it is true that (many) DTC's will clear themselves it requires several "trips" to do it, if you want to know if the problem is fixed clear the codes.
This one is not correct, clearing obd codes does not reset the keep alive memory, only an intentional KAM reset or disconnecting the battery power will do that.

Colovette take the air cleaner out so you can spray some throttle body cleaner in the intake when the engine is about to die, you need to find out if the problem is fuel related or what and look hard (and listen) for vac leaks as well.

By resetting codes I took it disconnecting the battery is probably how he went about it. Maybe I missed something but I am assuming this is how since many seem to do that.

In regard to his engine temps, I would be curious to know what the temps are running at or if it changes at all when running. I mean if he is getting a low coolant code and it's correct for any reson I would think the engine would be running hot. It could have gotten overheated. A cracked head (hopefully not) would certainly cause the issues he described. I had the same problem on an old 97 Taurus. There was a slight crack by an intake valve from the previous owner letting it overheat one too many times.

 

[colovette]

Didn't mean to offend with the "Exploder" comment. A friend of mine owned a body shop and he got me started on that - it won't happen again. Sorry.
I have a small engine diagnostic code reader that I used to read and reset the codes. Since I can't get the engine to run more than 15 or 20 seconds at a time, I doubt that I fried the O2 sensor and there is no possible way the engine has been warm enough to send the proper temp to the ECM. The engine won't run long enough to get it out of the garage.

 

[justin82]

have you checked fuel filters? i would assume if you changed the pump you would change the filters.

 

[steadyhand]

If it just will not stay running, I would do a fuel pressure test and compression test before going further. If you have done these, what were the results?

 

[MNgopher]

The way read the original post, you had an issue and found the fuel pump was bad. At that time, the only code was low coolant temp and you reset that and didn't troubleshoot or correct the issue that may have caused that code.

The explorer was then driven for some time, when it broke down again. This time it had the low coolant temp code and an oxygen sensor code. You've replaced the oxygen sensor. You have not been able to troubleshoot the temp code (or the oxygen sensor code) because it won't stay running this time.

Time to look into the basics: Got fuel? Run your fuel pressure and volume tests. Fuel pumps (especially cheap parts store ones) can be bad out of the box. Got good, consistent compression? Got spark? How do the plugs look?

 

[colovette]

I'll double check the fuel pump. I didn't go with the cheapest one, I went with Bosch, which I thought was a decent brand, but who knows.

 

[budwich]

clean or replace the IAC and in general, and if you haven't done so, do some overall routine maintenance... check / change plugs / wires, air filter, fuel filter.

 

[colintrax]

As the others have said, check fuel pressure, don't forget to check spark, and compression. An engine will run if you got compression, fuel, and spark... to certain degrees.

Can you post a video of the truck starting and dying? Are you blimping the throttle as it's dying or are you letting it die?
BTW, bosch isn't the best. But it isn't the worst. For something like the fuel pump, I'd always suggest going oem. Spark plugs, shocks, ect is what the aftermarket is for.

 

[colovette]

Update: I finally had a few minutes to check some things out. Almost no fuel pressure at the rails. So, when I get more time, I'll see if I have either a bad filter or fuel pump, both of which are new - I know, probably the fuel pump.

Thanks for the help - I'll post what I find.

Again, Thanks!!

Greg

 

[colintrax]

What's almost? I'd say it's the pump, unless it's just low the filter can't do much. Wouldn't hurt to check before the filter though, MUCH easier to replace a filter than a pump. If it is the pump, just go to the ford dealership and spend the money to be sure you're getting the best part and save your self the time/money of having to fix this again. The oem should last until that motor poops out. Got 152,x.. on my truck, no major parts have failed yet other than ball joints.
Also, DO NOT start driving it around assuming it's fixed until you fix whatever is causing the low coolant code

 

[colovette]

Update: I was just under the truck and checked the fuel filter - again! The filter was fine, and the pump runs for about three seconds when the key is turned on, then it stops. With the filter out I see the fuel coming out of the line (of course) but then it all stops after about three seconds. With the filter out I would think the pressure switch wouldn't be shutting things down, but I'm at a loss.

Any further ideas?

 

[colovette]

Another update if anyone is interested: I took the throttle body off and cleaned the hell out of it. It was a gunked-up mess. I cleaned all of the little ports on the throttle intake as well. After reassembling, I started the engine and it ran - for awhile. It idles great, but it won't accelerate. I let it run for about 15 minutes and checked the error codes. The only code being displayed now is 402, which is a problem with too much exhaust in the intake?!?! I'm guessing it needs a new EGR feedback sensor, but before I spend the bucks I was hoping to get some confirmation from someone that has seen that error before.

Any ideas?

Thanks!!

 

[budwich]

that's how it is supposed to work... the system only runs for a few seconds when the engine isn't turning ... its a "crash event, stop the gas" feature.

 

[colintrax]

If engine isn't cranking the fuel pump isn't going to pump.

To much exhaust in the intake?? Ummm, guess you should go to the junk yard and get a whole new egr assembly. Better to replace everything than try to guess what's wrong with it.
Is it running now with just the one error code?