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Topic: 84 3.8L Low on Power (Read 7797 times) previous topic - next topic

84 3.8L Low on Power

Reply #15
Quote from: atengnr;459537
Well, I got the code scanner, and gave me 23, 84 (I have EGR vacspooge line plugged), 13, 63.  I ordered a throttle position sensor.  I assume this sensor malfunction could cause the issues that I have had (LOW POWER, hesitation, stall at idle)???  Thanks alot.
Yep... When the TPS failed on my '93 Lightning it had about same power as a 6cyl with two bad plug wires...

84 3.8L Low on Power

Reply #16
Cool thanks.  This low idle speed code, is this related to tps or something else?

84 3.8L Low on Power

Reply #17
In their diagnostics Ford says repair first code given then recheck, often additional issues are corrected or maybe other code(s) were just phantom in nature...

84 3.8L Low on Power

Reply #18
Quote from: atengnr;459428
I did note that vacuum was 16 inches at idle. 


Quote from: TheFoeYouKnow;459455
16 inches is still PRETTY low for a stock engine at idle.  At 16 inches on a speed density car, you'll be spraying more fuel.


Yup 16" at idle on a stock 3.8 V6 is low. It should be around 20" at idle. My Thunderbird (mods in signature) makes 17" at a 700rpm hot idle. A stock 5.0 HO makes around 18-19" at hot idle, and a 5.0 SO makes around 20" at hot idle (from what I've measured over the years).
88 Thunderbird LX: 306, Edelbrock Performer heads, Comp 266HR cam, Edelbrock Performer RPM intake, bunch of other stuff.

84 3.8L Low on Power

Reply #19
Intake Leak?  From my past experience with these motors, my engine has zero blowby up in the air cleaner housing, which tells me that the cylinder bore/ rings are still in good shape.  Vacuum lines are original but Ive found no issues on visual inspection.  Thanks.

84 3.8L Low on Power

Reply #20
Fix the TPS code, then if still a issue worry about low vacuum... My bet is most of you problems/codes will be corrected...

84 3.8L Low on Power

Reply #21
Finally got a motorcraft TPS from rockauto.  Ill let yall know howshe runs.

84 3.8L Low on Power

Reply #22
Hello go figure, I think I need a starter solenoid....I replaced TPS, and wen to start, and got nothing except cabin lights went out when trying to turn over, but no click.  I charged battery, and still does the same thing.  Sounds like solenoid no??

84 3.8L Low on Power

Reply #23
My first step would be to pull the small red wire off the solenoid and stick my meter on the wire.
See if you have battery voltage when you try to crank.
Voltage: solenoid
No voltage: neutral safety switch or ignition switch. Make sure you are in park or neutral.

84 3.8L Low on Power

Reply #24
Quote from: atengnr;459684
Hello go figure, I think I need a starter solenoid....I replaced TPS, and wen to start, and got nothing except cabin lights went out when trying to turn over, but no click.  I charged battery, and still does the same thing. [COLOR="#FF0000"] Sounds like solenoid no??[/COLOR]

NO.... Not likely if cabin lights are going out, you're dropping voltage and solenoid would have to be dead shorted to ground which is going to burn up battery cables... My bet is the battery didn't charge or is bad...

84 3.8L Low on Power

Reply #25
I have had this check your battery cable earth's and live track them back and clean and have a good look at the battery terminals sounds like a bad connection breaking down under load.

84 3.8L Low on Power

Reply #26
oops, my bad. I missed the "cabin lights going out" when cranking part. That kinda proves the solenoid is good.

84 3.8L Low on Power

Reply #27
Quote from: mr glee;459690
I have had this check your battery cable earth's and live track them back and clean and have a good look at the battery terminals sounds like a bad connection breaking down under load.
I'll second this, but all the suggestions are good.

84 3.8L Low on Power

Reply #28
Quote from: TurboCoupe50;459687
NO.... Not likely if cabin lights are going out, you're dropping voltage and solenoid would have to be dead shorted to ground which is going to burn up battery cables... My bet is the battery didn't charge or is bad...

I put on a charger yesterday and initially pulled some decent current, but charged within a few hours (amperage dropped to < 1).  I just drove the  car 2 weeks ago, and pulled negative terminal a few days after parking.

84 3.8L Low on Power

Reply #29
Interestingly, in order to get cabin lights to come back on, I need to pull negative terminal on battery and reinstall.