• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Side Effects Of Wrong Computer?

  • Thread starter Thread starter FastDriver
  • Start date Start date Jan 29, 2018

FastDriver

I was uncomfortably high & wearing a helmet
SN Certified Technician
Sep 5, 2001
6,123
2,735
224
Vass, NC
Jan 29, 2018
#1
  • Jan 29, 2018
  • #1
So, the fox-bodiest guy in my area besides me is a buddy of mine. He's actually got a nice collection. Gen 1 and Gen 2 lightnings, a Harley Truck, and a built mod motor coupe in addition to this car.

He's putting together an SSP 1993 CHP coupe I haven't seen, and I was helping him look for an A9L. In fact, I've sent him several links that he missed out on. Anyways, this weekend he told me that he pulled a computer off of a '90 Grand Marquis and installed it. He was pretty happy about it and said it ran fine. I didn't think anything of it, but today it hit me that a G.M. should have the same firing order. I assume that means that the injector phasing is going to be out of whack on cylinders 3,7,5, & 4. I know sometimes computers are run in batch fire without issue. So, that's got me wondering if he's likely to have a lean condition. What other things should he be thinking about?
 
Last edited: Jan 29, 2018

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,275
17,964
224
Massachusetts
Jan 30, 2018
#2
  • Jan 30, 2018
  • #2
I'm pretty sure that's a batch fire ecu. I'd probably pull the pinout of both ecus and compare wiring to see if any differences
 

vristang

15 Year Member
Mar 31, 2005
4,933
101
124
Seattle
Jan 30, 2018
#3
  • Jan 30, 2018
  • #3
fire order should be the same, right?
batch fire vs sefi could cause some issues though, depends on setup and what he is willing to accept as 'ran fine'
Wire diagram is a great place to start when swapping ecus.
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,275
17,964
224
Massachusetts
Jan 30, 2018
#4
  • Jan 30, 2018
  • #4
It's batch fire with the non HO firing order. Not sure if that really matters with batch fire though.

It's probably not running ideal. I also think its speed density and the pinout may differ from a mass air harness
 
Last edited: Jan 30, 2018

FastDriver

I was uncomfortably high & wearing a helmet
SN Certified Technician
Sep 5, 2001
6,123
2,735
224
Vass, NC
Jan 30, 2018
#5
  • Jan 30, 2018
  • #5
FastDriver said:
I didn't think anything of it, but today it hit me that a G.M. should have the same firing order.
Click to expand...
Meant to say *shouldn't*: non-HO firing order 15426378, I think.

Batch fire, hmm? I guess that would be not ideal. Thanks for the heads up on the the speed density vs. mass air issue, as well. I wonder if he just cranked it without driving it. If SD depends on a MAP sensor he doesn't have, then I would expect the car to run like dog dung.
 
Reactions: General karthief

billison

I like tinted tail
15 Year Member
Feb 27, 2006
2,607
1,094
184
stl
Feb 1, 2018
#6
  • Feb 1, 2018
  • #6
Any updates? I’m really curious about this
 

FastDriver

I was uncomfortably high & wearing a helmet
SN Certified Technician
Sep 5, 2001
6,123
2,735
224
Vass, NC
Feb 2, 2018
#7
  • Feb 2, 2018
  • #7
I'm gonna take a look at the car this weekend. I don't really know what I can do other than check the firing order, which I assume must have been set up in the HO order, and pull the model # off of the computer.

I sent him a link to this thread and he responded that it came out of a GM with mass air. I looked it up and AFAIK the 90 Grand Marquis did not come with Mass Air. Perhaps that motor was a transplant.

If the car's running and driving, I'll report back with my impressions.
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,275
17,964
224
Massachusetts
Feb 2, 2018
#8
  • Feb 2, 2018
  • #8
Computer code?
 

FastDriver

I was uncomfortably high & wearing a helmet
SN Certified Technician
Sep 5, 2001
6,123
2,735
224
Vass, NC
Feb 4, 2018
#9
  • Feb 4, 2018
  • #9
He never got back to me. I had a couple issues with one of mine that kept me busy, this weekend. I'm probably gonna let it rest unless he has issues with it and brings it up.
 
You must log in or register to reply here.

Similar threads

J
Progress Thread Family member 1989 GT- Backstory and updates
  • JRC99
  • Apr 19, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
15
Views
1K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Oct 26, 2025
JRC99
J
New daily driver help needed.....not a mustang but mustang drivetrain.
  • Wayne Waldrep
  • Jun 17, 2024
  • Other Auto Tech
  • 3 4 5
Replies
80
Views
6K
Other Auto Tech Jul 28, 2024
manicmechanic007
I
Progress Thread Exorcising a '76 Coupe
  • IICrew
  • Oct 12, 2020
  • 1974 - 1978 Mustang II Talk & Tech
  • 2
Replies
31
Views
5K
1974 - 1978 Mustang II Talk & Tech Jul 3, 2022
2Blue2
  • Locked
“Doing stuff the wrong way for the right reasons”: A related stupid story.
  • CarMichael Angelo
  • Apr 26, 2020
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
7
Views
4K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Apr 27, 2020
a91what
R
2014 mustang gt roush stage 3...02 sensor issues
  • RS3NLV
  • Jan 20, 2019
  • 2010 - 2014 Specific Tech
Replies
1
Views
4K
2010 - 2014 Specific Tech Feb 3, 2019
shaneyusa
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?