Topic: 93 22RE EFI issues

[fzj40]

looking for some help.  I have a 93 22RE with a consistent code 25 (lean condition) and an intermittent high-idle issue.  The engine runs fine but idles a little rough at 800 RPM.  If I pull the EFI fuse to reset the ECU the code 25 will come back within 20 min or so of driving.   The high idle condition is intermittent and will sometimes go high enough to cause the fuel cut to interrupt it resulting in the typical bouncing idle.  I have replaced the Idle Air Control Valve (twice with used, once with new valves).  I have replaced the MAF/AFM.  I have replaced the injectors with new RC Engineering.  I have reset the base timing.  I have cleaned the TB. I have replaced the thermostat.  I am tired of replacing parts with no success.  Has anyone run into this?  Any suggestions?  Could fuel pressure be an intermittent low?  It really acts like an intermittent vacuum leak, but I cannot find any.

Any help is welcome.

Happy New Year!
 

[unclejpl4x4]

wow thats a lot of things 2 replace.
  ? whens the last time you replaced the fuel filter.
   have U checked the vac lines  I really check them  for a off hose, cracked?
    how about temp senders?
     fuel pressure?  fuel reg ?
        I would look for info on doing test  with a meter and not just throwing parts at it.


I am having problems with my93 efi   but i got no code and are runinng rich   high idle, surging, hesitation, crappy gas miles.  as is a few others  we where talking about it in the chat box.

I wonder if it's the winter  gas?

o well im hoping 2 look in 2 it in a day or so im on vaca.

[fzj40 [OP]]

I have replaced the fuel filter also.  I have checked the vacuum lines.  I have not checked the temp sensors, not really sure how?   I have checked the fuel regulator, but not fuel pressure.

[Tallchevy]

I also cleaned the throttle body on mine & still had the same problem. The idle/air control valve on my 89 is built into the throttle body. I had to remove the throttle body & open up the valve to clean the ball & seat. That fixed the problem. If your is built in like mine be sure to count how many turns it takes to back the seat out cause it is adjustable & can go further down. Also check the coolant hoses that goto the idle/air control valve. Mine were clod & not letting the valve to warm up to bring the idle down.

[fzj40 [OP]]

I replaced the AAV/IAC twice with used ones, now replaced it with a brand new one.  No dice..

[fzj40 [OP]]

I forgot, I also replaced the o2 sensor.

[fzj40 [OP]]

I also replaced the temp sending unit on the right as you look at the intake from the front.

[unclejpl4x4]

well i just checked both my water sensors black and green  and compared them with my spares.

black in truck: was .04 ohms  at the sensor  ( the book tells u 2 check from relay 2 sensor)
black out of truck: same
green in truck: was 4.9 ohms     
green out of truck: 4.3 ohms
( book says 4ohms @ 40 )  and its 44 out side. note: 6 ohms at 60   


I say at this point u need 2 grab a manual  like haynes   the one i have has the tests for circuit opening relay,  sensor and so on.  ( i got do mine 2)
it's cheaper and more time efficient  threw testing and so on then just throwing parts at it.

 

[fzj40 [OP]]

I just tested both too.  I had replaced the green one already.  They are OK.   I have the FSM.   No doubt if I ever find it, it is something incredibly simple...

[THK Matt]

it may not be that you have Vacuum leak, but that your vacuum lines are mixed up.

if you have a diagram... id do each line one-by-one.
I had that problem too.
and make sure your TPS is on correctly, it is very easy to put it on wrong.
that will cause your high idle.

[fzj40 [OP]]

I will go over the vacuum lines again thanks.  Right now the idle is holding.  I have had the TB off so many times I am pretty adept at setting the TPS.  Wonder which vacuum lines would cause the lean condition?  That bugs me more than the idle issue, but I think they must be related.

Thanks.

[THK Matt]

they are related.

mine was doing the same thing.
if you don't have a diagram. I can snap a picture of the one on the underside of my hood.

[Tallchevy]

Adjust the valves. Mine were tight & the engine would run rough after it warmed up.

[THK Matt]

that will help too.

if none of this helps....
and you have high mileage, you may have bad rod bearings and its causing you to have poor pressure and your valves to clack and causing the knock sensor to throw your timing off and its throwing the whole thing in a spin.

personal experience.

[93tonkatoy]

The Lean condition is caused by the computer not correctly determining the amount of air/ fuel going into the cyl's. This is possible by admitting unmetered air into the mix (vacuum leak), insufficient fuel (pressure low - bad pump,clogged screen,clogged filter), reading the burned mixture wrong (bad o2 sensor). With the high idle and surging, I would suspect a vacuum leak, as well. If you have a vacuum leak, you should be able to turn the idle adjustment screw on the throttle body all the way in, or almost, and it will still idle. Make sure you check the egr system. Especially from the egr valve to the attachment to the intake and the compression nut in between. Frequently that nut is loose, and it becomes a vacuum leak.

[THK Matt]

good info Tonka

[fzj40 [OP]]

Tonka, when it is having the high idle issue, I can turn the idle set screw in all the way and it will still idle.  After a while the issue will subside and it will die instead of idling properly.  I too am suspicious of the EGR, though the FSM has not mentioned that as a potential code 25 issue. Thanks!

[93tonkatoy]

Just passing on personal experience. When I bought my truck, I could pull up to a red light, and with the brake pushed, the Idle would rev from 800 to about 1300, cut off and die down until it hit 800 and run again. If I let off the brake, it wiuld idle at about 1200 rpm (that was as low as I could adjust it. Finally one day I started trying to eliminate different systems. when I pushed the penny into the gasket for the EGR to intake connection, I had to open the idle adjuster, or it wouldn't run. drove it for a few days, and the problem was gone. I got to looking at the egr system and just happened to try tightening the compression nut on the EGR line, and turned it about 3 full turns before it tightened up. removed the penny from the gasket, and it ran normally. I hope all this helps.

[fzj40 [OP]]

Thanks, I will try looking into the EGR.  Sometimes I think I can hear it, kind of a hollow exhaust sound from the intake side when the symptoms appear at idle.  Could be just wishing I heard something too.

[unclejpl4x4]

I found my problem" i think  "i feel like a    when i did my injectors i hook up my vac lines wrong  well the 3  C-can,  fuel reg, pair valve.  I only found it because i have a spare  tube assembly with hoses   manual  is fuzzy with 90+ efi hoses   

[93tonkatoy]

manual  is fuzzy with 90+ efi hoses  

And it is kinda difficult to trace the lines thru the metal grid beside the intake.

[unclejpl4x4]

I had a idea and i should of did it   

:hint/tip:   IF you ever pull off the tube assemble paint it black.  then paint the ends  say red, blue, green, yellow,  and the corresponding end

[THK Matt]

I had a idea and i should of did it   

:hint/tip:   IF you ever pull off the tube assemble paint it black.  then paint the ends  say red, blue, green, yellow,  and the corresponding end

Not a bad idea Joe.

[gnob]

a sticking egr could cause the symptoms. and just because you replaced the 02 sensor, doesnt mean the signal wire isnt screwed somewhere and is giving a false reasing.
put a vacuum pump on the egr and see if you can actuate it and maybe get it unstuck.

also an easy way to chase those vacuum lines is by blowing air in one end ad finding it on the other side.