Dies while driving2 - the whole story - so far

I am experiencing grief from my 95 Explorer Limited 4.0 V6. It?s got @

150,000 miles. It was about 130,000 miles when the Check Engine initially came on and began intermittently. No consistencies as to what was causing it. At first it wouldn?t come on until several hours into a long trip or at all. Also, it might come on and then go off after 100 miles on the same trip. Since, it now comes on consistently and sooner and remains on longer. You could shut the engine off and it may take awhile to come back on. One thing I have noticed about the light is that is seems to consistently come on after a de-acceleration event like coming into a town with a lower speed limit, but this doesn?t always hold true (an increase in exhaust gas ? makes sense). I never paid much mind to it as the vehicle never ran bad. I was monitoring my mileage and was getting Avg. of 20 ? 24 MPG. Then within the last month, we were making another long trip (400 miles). I was driving about 70 mph when it just died, I shouldered the car and thinking I lost the fuel pump, I managed to get it started after about 10 minutes and drove to the destination and then all the way back home with no troubles. I can here the fuel pump initiate when turning the key so, I promptly changed the fuel filter. However, while making another trip the following week, same story this time in the middle of rush hour traffic in the city. Had a little harder time getting it restarted and managed to limp home with a significant loss of fuel economy 14 MPG. Borrowed a diagnostic computer (AUTOXRAY EZ Scan 6000) from my neighbor performed all the KOEO and KOER tests and got several codes, however this was after he removed the ICV while the test was going because of the moose horn noise and the engine died. Thinking some of the codes were generated from this event, I erased the computer codes and reran the diagnostic test and a 332 Code (insufficient EGR flow) remained as the only code. Also, thinking some of my problem may have been associated with a very dirty throttle valve sticking from carbon deposits, I cleaned it as well as the opening to the throttle body. I also changed the EGR valve and removed and cleaned all the aluminum tubes to the plenum and exhaust manifold. Took a short drive and light has remained to come on as before, but engine did seem to run better and was getting 20-24 MPG. Thinking the dying problem was cured I started on another long trip, went about 30 miles and the truck died as before. The engine ran rough after restart and turned around and returned home only getting about 14 MPG just as before. I ran the diagnostic and received two additional codes - 113 (Intake Air temp sensor above maximum voltage) and 556 (Fuel pump relay primary circuit failure) that were in the initial scan. Since this we only drive it around town, and it runs fine as before. One common factor is that all days the engine died, the outside temperature was above 90 degrees F. I am thinking that the Intake Air temp sensor triggers the fuel pump relay to shut the fuel pump off as a safety and that is what causes the car to die. However, I am not a professional mechanic and all the cars I have worked on in the past had no computers. I forgot to mention that was experiencing the same noise from the ICV that has been previously mentioned in other postings. I cleaned it, and the problem seems to have subsided temporarily, but this was done prior to the last dying episode. So to my dilemma - are all these factors related somehow or are they individual problems? Is the poor Exhaust Gas Flow causing the Intake air temp to elevate somehow or is the sensor just failing? The solenoid that operates the EGR valve seems to be working as per the sound of air from vacuum coming out of it. It may just not be totally effective (unsure). If there was a problem with it, I don?t have a vacuum gauge to assess it. Is there another way to diagnose? Also I saw in other postings that the DPFE sensor may be compromised. Where is that? Is that what I?m calling the solenoid with the vacuum line to the EGR valve? Is the ICV part of the problem equation as well - I kind of ruled it out but may remain to be replaced. Furthermore, I noted in an online code manual that the Powertrain Control Module is involved with these processes. If it were the culprit of my problem would there not be a code generated for it as well? Is the fuel pump relay failure due to the Intake sensor or are they independent? Man I hate intermittent problems!!!!! Any help would be appreciated as I?m stuck with this vehicle for a while, I don?t have a grand to spend on parts or would just change them all. Thanks for your input.

Bryan

Reply to
BryanS
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Not sure if you have a OHV or SOHC but its that thing where the 2 hoses from the egr tube are going too.

Thats the dpfe sensor.

Reply to
johanb

The idle air control valve can be cleaned, but once it begins making the moosehorn noise it should be replaced. 50 bucks at the parts house.

The dpfe is probably your EGR issue. it puts out 1 volt at idle, and increases to 5 volts at maximum EGR. If it is not working right, the computer does not see enough of a voltage increase from the dpfe, and sets an insufficient EGR code, even though the EGR valve is working fine.

If the engine is idling normally with a new IAC, and you pull a vacuum on the EGR valve, it should cause the ebgine to idle very poorly or die. The engine cannot handle exhaust gas in the intake stream at idle. So find a way to pull a vacuum at idle and if the engine dies, you can be pretty sure your EGR valve is ok. DPFE is about 80 bucks.

After you have solved those two issues, see if the other codes return.

Reply to
ross via CarKB.com

Greetings,

I've seen the behaviors you described in a friend's 93 XLT 4.0L. Turned out to be a bad fuel relay. Seems that when the motor heated up the relay failed, the engine fuel starved, and died. Waited a couple of minutes and the engine would restart. The condition got progressively worse over time. We flopped the fuel relay and the A/C relay (since they were the same type) and the problem disappeared. Then the A/C begin to cut out. Replaced both relays (fuel and A/C) and the problem went away. Old vehicle , tired electronics.

Good luck, kroe

Reply to
kroe

I had an intermittent problem with my Explorer dying and it turned out to be the fuel relay. It wouldn't fail often enough to let me troubleshoot it and one day, it finally failed hard and I swapped relays with something else (A/C clutch, I think) and the truck started right up. I promptly bought 4 relays and just replaced 'em all.

Reply to
Tommy Wood

Whacking a dead relay with a screwdriver handle often fixes it (for a while) in an emergency or if you're real broke.

Reply to
Bob

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