code diagnosis

86jalopy · Jan 12, 2009

i picked up an 86 ranger with the 2.9 v6 for my kid brother and i ran a self test with my scanner and got a few codes,
(not driven but comp reset and allowed to idle for half hour)

koeo
84
89

cm
29

koer
41
33
13
77
74

4x4fun · Jan 12, 2009

cm 29 code is the 5.0 swap code

Wicked_Sludge · Jan 12, 2009

84 - EGR Vacuum Solenoid circuit failure
89 - Converter clutch solenoid circuit failure

29 - Insufficient input from vehicle speed sensor

41 - No HEGO switching detected always lean (right side).
33 - EGR valve opening not detected
13 - Cannot control RPM during KOER Self-Test low RPM check
77 - System failed to recognize brief WOT during Dynamic Response Test
74 - Brake On/Off switch not actuated during KOER test

the last two are from failing to run a KOER self test properly...i wouldnt worry about them.

theres a huge list of things that can be causing all those codes. the top of my list would be to check the engine for vacuum leaks, especially in the EGR system vacuum lines. how does the truck run?

how did you go about clearing the PCM? seems a bit odd to have a VSS code if the vehicle didnt move after clearing the codes... :dunno:

86jalopy · Jan 12, 2009

i pulled the battery cables for a while to reset the comp.

i have fixed the only vac leak i could find was where the upper intake bolted to the lower so i changed the gaskets and the leak is gone.i did this after the test.

is there a thread here for diagnosing the different codes?i can do it on a foxbody mustang but i dont know if the ranger tests the same way.

the truck runs ok'ish but i doubt it will pass the emissions test i need to have/

Wicked_Sludge · Jan 12, 2009

diagnosing the trouble codes will be largly the same as doing the same on a mustang. the computers function the exact same way (EEC-IV) and the codes mean the exact same thing (all EEC-IV computers use the same sets of codes).

if i had to guess, fixing the leak will probably take car of code 41 and MAYBE code 13. id start into the EGR system next. check for valve movement and ensure it holds a vacuum. check for EVR operation. make sure all vacuum lines are connected and not plugged. clean/inspect all EGR passages.

86jalopy · Jan 12, 2009

what is the evr? is it the little black sensor mounted on the intake with a vac line to the egr near where the metal tube connects?i can feel exhaust pulsing when i pull the vac line.

the idle was pretty high so i lowered it some.

should i worry about the code 29 since i dont have a 5.0 swap?

how do i properly run the self test?i just plugged in my scanner the last time.

Wicked_Sludge · Jan 12, 2009

the EVR is a valve with two wires going to it. it has two hoses, one should be manifold vacuum, the other should go to the EGR valve.

the code 29 is a vehicle speed sensor code, 4x4fun was yanking your chain. i would take the vehicle for a short drive and see if you get an ABS light to accompany a new code 29.

theres a good write up on how to properly perform a KOER self test on this page (using a jumper. ive never used any kind of scan tool other than a ford STAR tester, which gives you idiot-proof directions on the screen during the test....i dont know what the proceedure would be with your scanner). theres a ton of other EEC-IV info on this page too...it might be worth your time to skim around on there for a while and soak up some basic info on the computer that controles the truck.

http://www.fordfuelinjection.com/?p=94

86jalopy · Jan 12, 2009

the evr is new

Wicked_Sludge · Jan 12, 2009

then id check the wiring going to it. the PCM seems to think its an open circuit.

86jalopy · Jan 12, 2009

i will look into it,thanks for any advice.

86jalopy · Jan 13, 2009

i lowered the idle,fixed a vac leak,and reset the comp again.

tomorrow i am taking it for an emissions pretest about 40 miles from home,hoping the drive will let the computer learn a little.

i checked that all of the sensors where in place.they all exist.the evr solenoid is new,will check for voltage in the morning.

as for the converter clutch......it's a 5 speed.maybe someone put in a different ecm?anyone know what ecu is stock?

i may just change the o2 sensor in the morning just cause its old.

the truck has a shake at idle.the friend i bought it from stopped by today and drove it after i put the intake back on,he says it never had the shake and it is down on power.could this be from pulling the battery and the truck only being run about 2 blocks?

Wicked_Sludge · Jan 13, 2009

replacing the O2 isnt a bad idea, they do wear out.

if your getting a converter solenoid code and its a 5 speed than either someone switched computers or transmissions at some point in the trucks life. im not sure how you could "trick" it to keep the light on.

i doubt the shaking and power loss is due to restting the computer. have you varified your base timing? what about a compression test? what do the plugs and wires look like?

MAKG · Jan 13, 2009

If it has a rough idle, don't bother with the pre-test. You'll fail.

If you're going to change a HEGO sensor just by guessing, get some hands-on professional help instead (wicked's a pro, but it really is a lot harder to do this stuff over the net). It will be more useful, and cost about the same. While they do eventually get consumed, I've personally run some to nearly 300,000 miles, with operation checked every 6 months. They get fouled or broken, but you would want to know why if that happened.

If you "lowered the idle" on a 1986, you're digging yourself deeper. That's not an idle stop screw. Now your TPS is out of adjustment.

And wicked, some of those code titles are clearly wrong -- there is no BOO switch on a 1986, for instance. This sounds like a case of excessively-abbreviated codes (very common for code readers, even worse for the Haynes book).

86jalopy · Jan 14, 2009

the idle was high and the o2 looks ike hell.the guy at the smog shop is a family friend so i am sure he'll give the truck a once over when i get there.

what is the code on the proper ecu for an 86?

none of the emissions tests here check at idle anymore.

i will adjust the tps in the morning.

86jalopy · Jan 15, 2009

turns out number 3 isn't firing.i got 150 psi compression,spark and i can hear the injector click so i assume its clogged.i'll swap it out and see what happens.

code diagnosis

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