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Topic: 84 3.8L Low on Power (Read 7798 times) previous topic - next topic

84 3.8L Low on Power

Reply #30 –
If you have a  jump lead connect the battery as normal and put one end of the jump lead on the negative  (ground) Terminal the other end to the block.the problem is probably where the cable joins the battery connector .i cut the battery connectors off and replaced problem sorted.

84 3.8L Low on Power

Reply #31 –
Thanks all.  I took off negative terminal and cleaned copper wire with sandpaper and car started.  I ran KOER and got code 48 (in addition to EGR codes bc unplugged).  Whats this??  Car still seemed sluggish on accel.

84 3.8L Low on Power

Reply #32 –
vane air flow high at idle.....what does this mean???

84 3.8L Low on Power

Reply #33 –
Means ECM is giving phantom codes or the scanner missed/doubled a pulse, the 3.8 doesn't have a VAF...

84 3.8L Low on Power

Reply #34 –
Quote from: TurboCoupe50;459758
Means ECM is giving phantom codes or the scanner missed/doubled a pulse, the 3.8 doesn't have a VAF...


Ok.  It's code 48.  Is this correct interpretation of this?

84 3.8L Low on Power

Reply #35 –
Quote from: atengnr;459759
Ok.  It's code 48.  Is this correct interpretation of this?
I don't have my manual in front of me, but 48 seems to be "'air flow high at idle". No mention of VAF.

I'd think 16" of vacuum would trigger that code since a large vacuum leak would cause decreased engine vacuum at idle.

84 3.8L Low on Power

Reply #36 –
code 48 also relates to  electronic ignition-  coil primary circuit failure.not sure if it means its dead(no start) or out of spec(poor performance).might be worth looking with a volt meter.

84 3.8L Low on Power

Reply #37 –
The EEC IV error code charts are a composite of many different years and engines. Unfortunately that means you have to be able to weed out the definitions that don't apply to your vehicle.
The 84 Shop Manual groups KOER code 48 with the "Fuel Control" codes. There nine other codes that fall into this grouping.
The "pinpoint tests" only check the O2 sensors and the fuel injectors. The two EEC related things related to Fuel Control" problems.
Since the O2s have specific codes 41,42,91,92 lets rule them out.

Check the fuel pressure: Engine running pressure 35-45 psi.  Turn engine off, pressure should hold at 40psi ±5psi for 60 seconds after key off.
With engine running: Unplugging each injector one at a time should drop rpm at least 150 rpm.

Your KOEO code 84 indicates a bad EGR vent solenoid. Curious what led you to unplugged the EGR vacuum line?

When you checked the vacuum at 16in at idle did you then rev up to 2000rpm to see if it would hold at 16 at the higher rpm?

84 3.8L Low on Power

Reply #38 –
Quote from: softtouch;459772
The EEC IV error code charts are a composite of many different years and engines. Unfortunately that means you have to be able to weed out the definitions that don't apply to your vehicle.
The 84 Shop Manual groups KOER code 48 with the "Fuel Control" codes. There nine other codes that fall into this grouping.
The "pinpoint tests" only check the O2 sensors and the fuel injectors. The two EEC related things related to Fuel Control" problems.
Since the O2s have specific codes 41,42,91,92 lets rule them out.

Check the fuel pressure: Engine running pressure 35-45 psi.  Turn engine off, pressure should hold at 40psi ±5psi for 60 seconds after key off.
With engine running: Unplugging each injector one at a time should drop rpm at least 150 rpm.

Your KOEO code 84 indicates a bad EGR vent solenoid. Curious what led you to unplugged the EGR vacuum line?

When you checked the vacuum at 16in at idle did you then rev up to 2000rpm to see if it would hold at 16 at the higher rpm?


Thanks a lot. Yes the vacuum did hold at higher revs.  I plugged the egr for the heck of it a while back to see if it helped with hesitation.  Thanks for the help.

84 3.8L Low on Power

Reply #39 –
The rest of the stuff related to Fuel Control error codes. As for which ones could cause a code 48, your guess is as good as mine.

84 3.8L Low on Power

Reply #40 –
Quote from: softtouch;459800
The rest of the stuff related to Fuel Control error codes. As for which ones could cause a code 48, your guess is as good as mine.


Where is the line access to check fuel pressure?

84 3.8L Low on Power

Reply #41 –
Quote from: atengnr;459816
Where is the line access to check fuel pressure?
Schrader valve in the top of the CFI. It will have a valve cover on it.

84 3.8L Low on Power

Reply #42 –
Im confused about these fuel control codes.  Does this mean that the ECM, and sensors are not the issue but some other item is causing A/F ratio to be off? In other words, based on what output is the code 48 being triggered?

Also, to access the valve on regulator, do I pry it off?  Drill?

84 3.8L Low on Power

Reply #43 –
Quote from: atengnr;459819
Im confused about these fuel control codes.
Me too. 
Quote
Does this mean that the ECM, and sensors are not the issue but some other item is causing A/F ratio to be off?
That seems to be what it means. Although I'm not sure that would totally rule out the ECM being bad. 
Quote
In other words, based on what output is the code 48 being triggered?
Well the O2s would indicate whether the A/F ratio is out of specs. Since you have no O2 codes, the only other thing I can think of that the ECM could be looking at is the engine RPM.
The ECM controls the RPM by controlling the throttle position and the fuel injectors. (Of course you shouldn't have your foot in the throttle while the tests are running)

Quote
Also, to access the valve on regulator, do I pry it off?  Drill?
Take the air cleaner off. Unscrew the cap off the valve on the drivers side of the CFI.

84 3.8L Low on Power

Reply #44 –
Fuel pressure check.