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Engine Struggling engine

  • Thread starter Thread starter Canadianfox
  • Start date Start date Aug 10, 2020
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Canadianfox

Member
Aug 18, 2019
32
2
18
Montreal
Aug 10, 2020
#1
  • Aug 10, 2020
  • #1
So as many of my previous posts I’m still struggling with a idle surge and no power issue with my MAF plugged in .With the MAF unplugged she runs just fine minus a small idle surge .I bought a smoketec machine and repaired my leaking vaccum line issues ,she now doesn’t have any leaks i can see.

I also ECU swapped it to weed out the computer being the issue and that changed nothing .I have a new TPS properly timed,engine timing is spot on .I have two new O2 sensors and new harness from LMR.New rotor and cap,plugs and wires.I also have new ACT/ECT ,new injectors stock size , EGR delete from LMR,cat deletes.I have a new idle control solenoid ,new alternator upgrade kits installed .New coil .The orange ground seems good on the back of the head.New purge solenoid on the canister , air pump delete with plugged heads in the back.New ignition module on the distribution.New PCV with grommet and hose.New gasket on upper intake when I took it off to do the injectors .MAF was swapper with a new one off rock auto a Delphi,made it 10x worse so I put back on the walker that was on the BBK cold air intake when I bought the car.New fuel pump and filter.

I checked the fuel regulator and no gas leaks or smells .Fuel pressure readings are spot on to factory .Compression test was good,I also use no oil or coolant .No smoking either at idle,start up or driving .I ran codes and I get both side O2 sensors again even after putting new ones on and a harness &egr code because well it’s deleted .I also am running lean the plugs are whiteish .
My two questions that will help guide me are 1: on start up cold she runs fine ,then as it seems the O2s warm up she goes into her bucking and no power ,stalling .Could new O2 sensors have failed?
Second question when the MAF is unplugged and she is drivable with a slight ruff idle (, meaning she’s running off the base closed loop software that Ford puts in the ÉCU, with full power on all rpm’s........ would this mean there is for sure no internal engine issues and no vacuum issues anymore? Given if there were issues they would still be there even if the car was running off base software no? A vaccum leak is a vaccum leak regardless of software? Or a burnt valve is a burnt valve regardless?
 

Boostedpimp

20+ Year Stangneter
May 8, 2003
1,451
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NJ
Aug 10, 2020
#2
  • Aug 10, 2020
  • #2
What year is the car?

Have you put a vacuum gauge on it?

I don't remember the procedure or values but I would search on how to test your MAF and wiring and harness just for piece of mine. I've had a car of mine run better with maf unplugged twice and both times it ended up being the ProM and BBK mass air sensors failing. One car gave a error code for it while the other did not.
 
C

Canadianfox

Member
Aug 18, 2019
32
2
18
Montreal
Aug 10, 2020
#3
  • Aug 10, 2020
  • #3
It’s a 1993 lx convertible manual , I’m also suspecting a MAF .The CAI was on the car when I purchased it ,I’m wondering if the size of the air pipes are standard or not ,as the car never really ran well since day 1.
 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
Admin Dude
Jan 4, 1985
42,878
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Aug 10, 2020
#4
  • Aug 10, 2020
  • #4
I just dug this link up for another thread:

Help me create the "Surging Idle Checklist"

Updated 26-Oct-2019 to clarify creeping idle RPM increase as the car is being driven. Many of you are familiar with the "Cranks OK, but No Start Checklist for Fuel Injected Mustangs" checklist and the No Crank Checklist. They are very effective in finding and eliminating the problems by use of...
www.stangnet.com
 

Boostedpimp

20+ Year Stangneter
May 8, 2003
1,451
493
154
NJ
Aug 10, 2020
#5
  • Aug 10, 2020
  • #5
Canadianfox said:
It’s a 1993 lx convertible manual , I’m also suspecting a MAF .The CAI was on the car when I purchased it ,I’m wondering if the size of the air pipes are standard or not ,as the car never really ran well since day 1.
Click to expand...

The cold air and size of piping doesn't matter with a factory meter honestly.. if it were a c&l maf meter I would say try clocking it a little bit as that has been known to smooth out some issues but I would work your way down that list posted above and google the instructions on testing both your MAF sensors
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
27,826
10,506
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polk county florida
Aug 10, 2020
#6
  • Aug 10, 2020
  • #6
#7 in the checklist deals with the maf.
 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
Admin Dude
Jan 4, 1985
42,878
21,058
234
Box behind Walmart
Jul 11, 2025
#7
  • Jul 11, 2025
  • #7
Closing this thread.

You've not responded to any of these suggestions so, you must have resolved this issue.

If not, you can include current information about this issue in the thread that you created here:

C

Electrical Thread 'New fox body owner little worried'

Aug 19, 2019
I hate being a first time poster with a tech issue but I’ve totally run out of ideas and need some help.Ive done a ton of reading and mechanical work based off the forums on this site trying to solve my issues .

I own a 1993 lx 5.0 convertible and am having idling issues ( sounds like its camed but isn’t) and predetonation ,and à first this last weekend the power lose in 5th,4th where my car just lost speed when I was floored on the highway and all I can watch was my speedo drop .No backfiring ,stalling just power loss until I got to a certain rpm .

Here is what I’ve done based off many...
  • Canadianfox
  • Replies: 30
  • Forum: Fox 5.0 Mustang Tech


 
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