Execut1ve

Greeting everyone!

In case you had not heard, my 900 mi round trip with the truck pulling a camper was a resounding success - truck ran strong the whole time. I did have to drop down to *gasp* 2nd gear several times in the thickest of the Kentucky mountains and make use of the old big boy truck climbing lane, but aside from that I had no real issue EXCEPT...

About an hour out on the way down, the dreaded CHECK ENGINE LIGHT reared its head once again. I didn't notice any difference in how the truck ran, so I figured it was a bad sensor. I pulled the codes once, reset them, and pulled them again after a bit of driving. Here are the results, along with my best guess as to their meaning:

First Batch:
KOEO
332 - egr not opening
334 - vacuum pressure out of range?
452 - speed sensor issue

KOER
311 - smog system (removed)
332 - egr issue
536 - short in brake switch
538 - missed WOT test
632 - E4OD trans test issue, dont know why i got this as the truck has the 4R70W

Second Batch:
KOEO
332 - EGR valve
452 - speed sensor

KOER
311 - smog system (don't care)
332 - EGR valve
536 - brake switch shorted or open
632 - don't know why the computer thinks the trans is E4OD, it's definitely 4R70W

Any light anyone can shed on these is appreciated - am I correct in thinking not all of these codes will cause the CEL to illuminate? For example, code 311 has been around since long before this trip (since I removed the smog system) and the CEL has not been on.

For now, I'm going to start reading up in other threads to see what the best way to proceed might be

BLDTruth

Check for leaks in the vacuum system, especially the coffee can reservoir on the passenger fender. Also inspect the vacuum lines to the EGR and to the solenoid.

If you keep the emissions solenoids plugged in and capped you will avoid any CEL issues from having the air pump system removed.

Not familiar with the 4R70w but I do think it has an additional speed sensor on the tranny itself? Don't trust me on that one google around.

Glad to hear you made it safely!

Execut1ve

Thanks - I will start with the old starter fluid vacuum line test.

This may be connected - I do regularly get the flashing OD light on the shifter stick. Also, the 4wd shift motor is bad and needs to be replaced. I haven't rushed to do it since 2wd operation is fine.

BLDTruth

^^^Yeah the flashing OD light should serve up one of those codes.

If it were me, I would just replace all of the vacuum lines in the system - it's a pretty quick fix and since you seem to know your way around the engine bay it will be quick. And probably easier than diagnosing a leak.

http://www.fullsizebronco.com/forum/...es-rubber.html

Execut1ve

Well, the starter fluid test was inconclusive! I thoroughly sprayed every vacuum fitting and junction I could reach, and the truck revved nary a single RPM above idle. I pretty much doused the coffee can too - nothing.

I'm not sure why it took me this long to remember this - I replaced the entire vacuum line system (minus the big hose from the brake booster) when I had the engine out for the rear main, which was 4ish??? years ago? The hoses are all still pretty pliable, not stiff, dried out, or cracking.

That was also when I removed the smog pump and emissions stuff. The thermactor solenoids are still in there with wiring harness and vac lines attached, but all the actual plumbing is gone.

I suppose removing the EGR and bench testing it for proper function is the next step?

BLDTruth

Slap a short vacuum line on the EGR...then suck on it.

If you see it move it should be working.

Execut1ve

That doesn't seem at all like the sort of thing that will get me laughed at by the guys!

BLDTruth

The things we do for our trucks....

Execut1ve

I've been hampered by inclement weather the past couple days...hopefully I'll get some time this weekend when things are supposed to be nice and i"ll pull the EGR valve

Execut1ve

Ive experienced a bit of a setback... i discovered today during a regular oil change on one of my other vehicles that the threads of the oil pan are stripped >.< i havent decided how i want to fix it... not particularly pleased