How to pull codes from a 91 Explorer
- Thread starter Blown&Injected
- Start date
Code 45 is Coil 1, 2 or 3 failure. Code 41 is NO HEGO switching (continuous or "memory" code) or HEGO ckt indicates LEAN.
Even if fuel trims were PEGGED due to a dead sensor, he wouldnt get 50 miles to a tank of gas. The ECM would go into backup mode and it would be rich, but not THAT rich. Code 41 goes to pinpoint test H1.
I personally think that a 6 cyl running on 4 cyls (dont forget, its a waste spark system. If one coil dies, 2 cyls dont fire) WOULD cause extremely bad mileage, and possibly the 50 miles to the tank he got. Considering 30% of the fuel is being spewed out the exhaust manifolds, or worse, being leaked into the crankcase.
The fact it idles like it has a "big cam" in it, it has a coil failure code stored, and "breaks up in N or in gear, but not all the time" would tell me to look at ignition.
Once the ignition is firing on all 6, I'd probably monitor HEGO activity and change them if they seem lazy (contaminated) after a brief cleaning process (2500 RPM for a min or so, or a healthy test drive)
Hopefully the raw fuel hasnt damaged the catalysts either. Fortunately you dont have the cats right up by the exh manifold, or they'd have melted substrate for sure.
He could also have a bad regulator, which is where I think you're going, but that would give a RICH code, which is 42. Which he HAS in the KOER (performed secondly, and of less importance, diagnostic wise, than the KOEO tests. ie: KOEO codes get repaired FIRST, then KOER codes.) test, but I still think that code is being caused by a bad coil/misfire. ON the many bad regs I have seen, it takes a min or two for the upper chamber to fill with fuel and then the pressure goes up....I've seen as high as 90+psi...then he'd have driveability...like puking black smoke, inability to idle, stuff like that.
You could be right with the fuel pressure thing, I just would start with the info the EEC computer is giving me and go from there. Its spitting out code 45 first, which tells me to look at that code first. Fix the ignition problem and I'd almost bet everything else falls into line.
Just my opinion......
Even if fuel trims were PEGGED due to a dead sensor, he wouldnt get 50 miles to a tank of gas. The ECM would go into backup mode and it would be rich, but not THAT rich. Code 41 goes to pinpoint test H1.
I personally think that a 6 cyl running on 4 cyls (dont forget, its a waste spark system. If one coil dies, 2 cyls dont fire) WOULD cause extremely bad mileage, and possibly the 50 miles to the tank he got. Considering 30% of the fuel is being spewed out the exhaust manifolds, or worse, being leaked into the crankcase.
The fact it idles like it has a "big cam" in it, it has a coil failure code stored, and "breaks up in N or in gear, but not all the time" would tell me to look at ignition.
Once the ignition is firing on all 6, I'd probably monitor HEGO activity and change them if they seem lazy (contaminated) after a brief cleaning process (2500 RPM for a min or so, or a healthy test drive)
Hopefully the raw fuel hasnt damaged the catalysts either. Fortunately you dont have the cats right up by the exh manifold, or they'd have melted substrate for sure.
He could also have a bad regulator, which is where I think you're going, but that would give a RICH code, which is 42. Which he HAS in the KOER (performed secondly, and of less importance, diagnostic wise, than the KOEO tests. ie: KOEO codes get repaired FIRST, then KOER codes.) test, but I still think that code is being caused by a bad coil/misfire. ON the many bad regs I have seen, it takes a min or two for the upper chamber to fill with fuel and then the pressure goes up....I've seen as high as 90+psi...then he'd have driveability...like puking black smoke, inability to idle, stuff like that.
You could be right with the fuel pressure thing, I just would start with the info the EEC computer is giving me and go from there. Its spitting out code 45 first, which tells me to look at that code first. Fix the ignition problem and I'd almost bet everything else falls into line.
Just my opinion......
Blown&Injected
Active Member
- Joined
- May 31, 2001
Went to the parts store, no fuel pressure gauge until Friday.
I used a spark plug tester. The type that goes in between the end of the plug wire and the plug. I only checked the easy side - the three on the left side. All three lit the tester with a regular and consistent beat.
Where is the EGR on this thing? The Haynes manual does not show the valve or anything for the 4.0 push rod engine?
I was not considering the possibility of the FPR taking a moment to fill-up on the top. I pulled the vac line to the FPR and no fuel came out, but I am gonna try again after letting the truck run for a few minutes.
The fuel injectors seem to be firing long - as if one were to just move the TPS on a TR engine while idling.
Thanks for hanging in there with me!
I used a spark plug tester. The type that goes in between the end of the plug wire and the plug. I only checked the easy side - the three on the left side. All three lit the tester with a regular and consistent beat.
Where is the EGR on this thing? The Haynes manual does not show the valve or anything for the 4.0 push rod engine?
I was not considering the possibility of the FPR taking a moment to fill-up on the top. I pulled the vac line to the FPR and no fuel came out, but I am gonna try again after letting the truck run for a few minutes.
The fuel injectors seem to be firing long - as if one were to just move the TPS on a TR engine while idling.
Thanks for hanging in there with me!
We will fix yea!!!!
I wanted to know what fuel pressure was as i have had allot of these regualtors go bad and shops replace wires, plugs, coil and same problem.
When i get to the shop in the morning, i will type out of the Ford shop manual word for word of what you need to do yourself to check all these itiems. I believe me and Jim are on same track and close to fixing your problem vie internet.
I wanted to know what fuel pressure was as i have had allot of these regualtors go bad and shops replace wires, plugs, coil and same problem.
When i get to the shop in the morning, i will type out of the Ford shop manual word for word of what you need to do yourself to check all these itiems. I believe me and Jim are on same track and close to fixing your problem vie internet.
How are you checking? A DSO? What is the cranking and idle PW?
As for EGR, I cant remember is 91 used a DPFE sensor or a potentiometer screwed to the top of the EGR valve. A DPFE sensor would be on the LS of the intake, aluminum in color, between the throttle body and distrbutor. It will have a 3 wire plug and 2 fat vacuum hoses going to it that it uses to sense vacuum differential generated by EGR flow. Follow it down to the EGR pipe, and follow the pipe to the EGR valve. Cant seem to place it in my head. I keep wanting to say RS of throttle body, but I know thats a 5.0/5.8 and not a 4.0. Sorry.
Blown&Injected
Active Member
- Joined
- May 31, 2001
Not really checking, just going by the sound of the injectors. Like the way the injectors will get much louder when one just moves the TPS on our TR engine while at idle.
I know that some non firing cylinders would cause rich condition by dumping raw fuel in the exhaust, but something seems to be causing lots of extra fuel to be added.
It seems like the coil is firing, but I need to put the spark tester on another car to see what the light should look like on a known good coil - It does however, seem to show a proper spark
I know that some non firing cylinders would cause rich condition by dumping raw fuel in the exhaust, but something seems to be causing lots of extra fuel to be added.
It seems like the coil is firing, but I need to put the spark tester on another car to see what the light should look like on a known good coil - It does however, seem to show a proper spark
Again you need to start with the basics!!!!! lets not go looking at pin point test.
If you checked 3 cylinders then coil is good as it fires 2 cylinders at the same time. With the poor fuel economy do you have black smoke out exhaust?
Here is what you need to check first before we get any deeper.
1) Check for vaccum leak intake, pcv valve L/S of engine vaccum tree where the PCV goes to and the vaccum caps on the vaccum tree always falls off, check that.
2) Did you take plugs out are they all black, are some black. A spark plug could tell us allot.
3) We still need fuel pressure reading very important.
If you checked 3 cylinders then coil is good as it fires 2 cylinders at the same time. With the poor fuel economy do you have black smoke out exhaust?
Here is what you need to check first before we get any deeper.
1) Check for vaccum leak intake, pcv valve L/S of engine vaccum tree where the PCV goes to and the vaccum caps on the vaccum tree always falls off, check that.
2) Did you take plugs out are they all black, are some black. A spark plug could tell us allot.
3) We still need fuel pressure reading very important.
Blown&Injected
Active Member
- Joined
- May 31, 2001
Got some FP readings:
36 PSI
Vac line off jumps to 46 PSI
Engine off sits at 40 PSI
Several minutes later still holding - 39 PSI
All pissed off - WTH is going on here?!?!?!?
Check it again for... I don't know why, perhaps that it runs fine sometimes for a couple of minutes.
All of a sudden, bamn! 90PSI!!!!!
Turn off engine and it holds at about 85 PSI.
Repeat test 46 then jump to 90 to 100 PSI.
I think, I hope, just a new FPR and the problem will be solved
I will report the results of the new part and must say again THANK YOU ALL VERY MUCH. Cant wait to meet you at an event sometime - the beer is on me!
36 PSI
Vac line off jumps to 46 PSI
Engine off sits at 40 PSI
Several minutes later still holding - 39 PSI
All pissed off - WTH is going on here?!?!?!?
Check it again for... I don't know why, perhaps that it runs fine sometimes for a couple of minutes.
All of a sudden, bamn! 90PSI!!!!!
Turn off engine and it holds at about 85 PSI.
Repeat test 46 then jump to 90 to 100 PSI.
I think, I hope, just a new FPR and the problem will be solved
I will report the results of the new part and must say again THANK YOU ALL VERY MUCH. Cant wait to meet you at an event sometime - the beer is on me!
Blown&Injected
Active Member
- Joined
- May 31, 2001
Sorry to drag you all through what turned out to be a relatively simple problem - the parts store did not have a fuel pressure tester in stock - I bought it and used it the same day it came in.
Kinda needed one any way, the rail gauge busted on my GN, again.
New FPR did it.
You guys are great!
Kinda needed one any way, the rail gauge busted on my GN, again.
New FPR did it.
You guys are great!
