you know, I don;t think I did that during the test. Because I wasn't sure that I had the E40D. I did the brake, the wheel turn, and the goose the gas. But I don't think I turned of the OD. That might explain that code. Tonight I am going to try to track down the voltage signal from the Comp to the TPS.

 

Does your engine have a mass air flow sensor? That will give you much of the same problems that you are experiencing. Just a thought

 

OK, guys.. Do you really think that it is likely that all of those failure codes occurred all at once? I still think the most likely problem is the MAP sensor or the vacuum line going to it. Also, check ALL vacuum lines and EGR connections. You may be erasing the codes and they are coming back when you crank the engine again.

 

Sounds like the knock sensor!
Acceleration gone, mileage gone, erratic problems. Had it replaced and much improvement.



So I got pissed and decided to take it for a drive and pound the crap out of it. I couldn't get the truck over 30 mph and when I would slam on the throttle it would bog way down and then buck and jump around until I let off. It was like this for about 10 min. Then it died while I was turning around. I restarted and it still ran like junk. Then I heard a whine come from under the hood for about a second and then the truck ran great. Ran like a watch, idled great! No misses! I was excited! Then I got home and let it idle some more in the driveway. With everything looking like it was fixed I shut her down.

 

never known a knock sensor to cause all that only prob that i had that caused that much was a coil pack on a distributorless ignition
and yes i know that his truck doesn't have distributorless ignition

 

As stated before ,check MAP sensor. Vacuum going to, when the sensor fails it will suck a gel like product into the vac hose and plug it up. Good luck.

 

Yes, the MAP.
I had the exact same problem. Wouldn't idle without feathering the gas, ran like crap. I had to replace the MAP AND the O2 sensor.

 

68Ford~No mass air Flow. It is a MAP system. Anyone have a good picture as to where the MAP sensor is/what it looks like?

davidb~ it did set all those codes at once.

carpe~ I thought about the knock sensor. In the Haynes manual it says it retards the ignition when it detects a knock. My theory was that it was bad and retarding the ignition all the time. But, after doing the hammer test (banging on exhaust manifold to see if it will retard) it didn't do a darn thing. I still may replace it, since it is throwing a code.

I am digging the MAP sensor idea, someone give me a good picture! I am still going to check why I am getting a low voltage reading at the TPS. Maybe I have a short in that feed wire.

We shall see, I will keep you all posted.
Mike B

 

Don't have a picture of it but it's square with an electrical connector and a vacuum line from the intake manifold. Should be on the firewall on the pass side.

 

95 black f150 has it right - you have to stop the flashing of the codes while it is in the middle of reading them out to erase it. Then drive it for a while and see what codes you get. One thing - sometimes one bad sensor will cause a long chain of others to throw codes.

I usually check the easiest one, erase the codes, and drive the truck until they are all gone.

I thought that 32, 33, 34 all have to do with the EGR system. You may want to double check that.

Good Luck

 

My point was not that all of the codes did not appear at once. That is apparent. My point is that all of the failures that the codes indicate did not occur at once. Go to a vehicle that is running perfectly and disconnect the map sensor. Run it for a few minutes and "pull the codes". Wanna bet that it will run similar to yours and show similar codes. Save yourself a lot of time and grief. Sub the MAP sensor. If that does not fix it, you have a lot of really serious problems.

 

There are 3 sensors that I am going to replace. One at a time. If these don't cure it, I am going to sell the truck to my dad and have him mess with it. This is the order I am planning on replacing. MAP sensor. IAC valve. Knock sensor. Before I do that I am going to make sure that I have good juice going to each of these sensors from the EEC.

We shall see if anything changes.

Mike B

 

Discovery made, well, maybe...

Well last night I replaced the IAC valve. No Change. I then replaced the MAP sensor. I had the truck running while I was testing/messing around with the old MAP sensor, I pulled the vacuum hose and the trucks idle jumped up and smoothed out, I jumped in the truck and rev'd it up, NO MISSES!!! But the exhaust was BLACK and I could smell unburned fuel pretty strong. So at that point I thought I located the root of the problem. I replaced the old one with a new one, but after I hooked it up It went back to missing all the time. By the way, it does pull a ton of air down the vacuum hose when it is disconnected, so I don't think it is plugged. The truck now will start and idle though, so I made some progress.

After all of this I cleared the codes, "drove" it up and down the street and then repulled the codes. This is what I got now,
KOEO
23 TPS out of range
34 PFE/EPT sensor fault/high exhaust pressure

continuous
34 see above

KOER
23 see above
25 no knock sensor
41 running lean
34 see above

The guy at Autozone is convinced that it has to do with the EGR or the EGR positioning sensor or the EGR vacuum switch. When I unplug the EGR position switch while the truck is running there is no change in idle.

give me your thoughts,
Mike B

 

OK, good job. Looks like the MAP sensor was definitely bad. Now you have a smooth idle and most of the trouble codes are gone. If you have not already done so, I would disconnect the battery again for a few minutes (5 minutes is long enough)to clear the old bad codes. The recrank and let idle for a few minutes for the computer to read all of the sensors and reset things. Now pull the codes again and see what you have. I wouldn't worry too much about the code 34. There are thousands of vehicles out there that are running great with a code 34 showing. I would try clear all of the KOEO codes first. If you are still getting a code 34, you might want to check the EGR connections, electrical and vacuum. You can disconnect the EGR valve and use a manual vacuum pump to check to see if it will open. If not, pull it off and clean thouroughly and retest. If you cannot get it to open, replace it. If all connections look good and it will open with a manual vacuum pump, skip over the 34 code and concentrate on the others. You can test the sensors rather than replacing them. The EVTM manual shows how or you can get a cheap sensor testor at one of the auto parts stores. Don't sell the truck, you almost have it fixed. Good luck and repost what you find.

 

thanks for your support!

Well this morning it was back to no idle on start up with out the throttle. I am getting to my last nerve. I have been testing the sensors and they have been coming in bad. So that is why I have replaced what I have.

I will check the EGR stuff this weekend. There has to be something to that vacuum on the MAP sensor. It seems like it is keeping the injectors open longer while the hose is disconnected, thus the black exhaust and smell of fuel, so what other sensors tell the injectors how long to stay open?

This weekend or bust!

Mike B