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I recently took in my first ford and I feel as though I should not have taken on this nightmare. I was advised that it backfired occasionally. I drove the 120 miles home in it and made it with little issue. The next day It began losing power at about 1800rpms. It would backfire, smell of gas in the cab and out the exhaust and going up hills is a nightmare if at all. I have ran the codes both KOEO and KOER I will list below. The previous owner said that the person before them replaced the exhaust which I confirmed as a cat back flowmaster. I also discovered someone did not tighten alternator bolt and used the wrong length wires from the cap. I have looked up many images and diagrams to find out where everything is and where it goes. Recently discovered a extra hose where their should be a air rail of some kind which appears in other images. My truck does not have that part present. I will upload the images and hopefully someone can get to the bottom of what appears to be a hack job passed onto me. I bought this truck to hopefully get it in good running order to use for work and falling behind due to not be informed on what I was getting into. Any input would be great.
ok so.
KOEO
114,116,565
KOER
116,126,213,311,332,522,565
I am aware that one or more of these could have popped due to doing the code read solo.
image found online showing a part that is not present on my truck.
The area indicated is the Thermactor manifold w/check valve.
Fresh air injection into the exhaust ports as part of the emissions system. You should see plugs installed in each port top unless the head is incorrect for the MY.
To manage the codes, they generally are addressed in the order they were stored. Coolant temp/ loop status would greatly affect a heated drivability condition if over rich under normal operating conditions, and may set misfires and cause other issues. Misfires, overfueling can damage/ restrict the Cat creating power loss etc but normally if the Cat system is damaged, power loss wouldn’t be intermittent..
It does idle relatively normal with the occasional miss. When giving throttle it bogs down very quickly and seems to "flood" as in the carb days. Initial startup usually dies and then on second try will idle decent. The issue only shows when giving throttle. I feel like something is missing as the picture that I added with the colorful lines is a online sourced photo and my truck does not have said air rail or whatever they call that. But the combo vac/air valve thing has the 3/4in line for it just hanging out in space by itself.
Many of the codes point to vac operated areas including purge valve canister solenoid, egr opening not detected and I think 2 others. Question, are the lines on the vacuum tree supposed to be in particular order? I see photos that do not match mine but didnt think it would have to much bearing on vac supply itself as its not electronically operated.
The Thermactor manifold runs the length of the cylinder head under the intake plenum. The legs of the manifold insert into each exhaust port. With it now removed, there should be 6 plugs present, one on each exhaust port.
It’s certainly not there in your trucks images,, so it could have rotted, broke and was removed, or sometimes if an earlier cylinder head is installed, they weren’t equipped drilled/tapped for Thermactor ops.
No,, the vacuum tree positions other than leg size, have no baring..
That makes sense. I did just take it for a test drive after rechecking vacuum lines which all seem to be appropriately seated. Noticed after returning that the bolts on the exhaust manifold close to the front of the engine were literally smoking. Keep in mind this was a 1/2 mile test drive.
12-13-2018, 12:02 AM
1991 F150 4.9l bucking loss of power backfire
