Engine Was 4 Cylinder...high Rpm Breakup...advice? Thoughts?

Bb1100yankees

Member
Oct 21, 2016
42
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Ridgewood, NJ
A few months ago, I was looking for something to break up the routine of Work, Eat, Sleep, Kids...so I impulsively bought a 92 5.0, 5 speed Vert. It checked a lot of boxes...fairly inexpensive, lots of parts and upgrade availability, wifey will like the vert, and I should be able to get my kids in it too.

I am learning that you have to be a bit of a sly Fox to own a Fox, and they require a bit of detective work! I've been doing a lot of reading and homework here, and I created a 35 page document of information I have collected, good stuff!

I ordered the build sheet and turns out the car was originally a 4 cylinder AOD car. Not what I was hoping for, but it's a nice little car, and now I have what I have so here it goes.

I have a few issues. One is the car has a 3500 RPM breakup (seems to be hot or cold), and I would like to get some input to on the 4 cylinder conversion, what gremlins I should look, what to upgrade, etc.

Things I have purchased to replace (not on car yet):

Ford Racing Wires
Motorcraft Plugs
Motorcraft TFI (grey one)
Motorcraft Coil (some kind of aftermarket coil on it now, can't tell what it is)
GT40P Heads
Cobra Upper&Lower Intake, MAF, and TB

Things I need to do: Check/Set TPS and clean MAF

Here is some information and attached are some pics:

Planned use of the car is a weekend cruiser with the family, and every now and again I hope to get out and run thru the gears.
Top End looks 100% stock with the below exceptions
Smog and AC Equipment were deleted (EGR is still there)
Dizzy-Motorcraft Part #E4ZE-2151-AA with an MSD cap and rotor
BBK Shorty Headers
K&N air filter
2.5 inch Cat-Less Exhaust with Flowmaster 40's mufflers (exhaust is a little saggy, needs to be pinned up and I plan to swap the mufflers to something quieter)
Idle: 1k RPM (I have the surging idle checklist from jrichker)

Fuel Pressure: KOEO=34lbs, Running=33lbs, Running with Vac Line Removed from FPR: 44lbs

KOEO Codes:
O Codes: 67, 81, 82, 85
CM Codes: 29, 32, 41

67 Makes sense as the NSS is hanging off the transmission
81&82-Air Diverter Solenoid/IAC fault, Integrated Relay Control Module...Clean the IAC or is this Smog related?
85-Canister Purge Solenoid...I think this makes sense as Smog stuff is gone
29-VSS...makes sense as the VSS is not plugged into the transmission...looks like the male/female plugs do not match up, one is larger/smaller than the other, I will have to check when I get it on a lift and see if I can make the combo match so I can plug it in
32-EGR valve (I have jrichkers how to check EGR valve notes)...possibly the EGR vacuum sensor?
41-O2 sensors...makes sense as it does not have any

As for the 4 cylinder conversion, I believe it has an 8.8 rear end (see pics, still drum brakes), but looks like the front end brakes and suspension are still 4 cylinder (10 inch rotors with plastic shield).

So my overall questions/thoughts are the following:

1. I can't run a KOER test until I clear up these codes particularly 67. I assume the NSS hanging off the transmission plugs in somewhere. With the 4 cylinder and manual conversion, I could use some wisdom and guidance here on how to clear this up.

2. I assume I am on the right track with solving the engine breakup with the new plugs/wires/TFI/coil , but thoughts here also would be appreciated as maybe this has something to do with the 4 cylinder swap, and knowing what to look for would be helpful.

3. In my limited time behind the wheel, even with the 10" discs the car seems to stop very well and the steering is responsive. Is it necessary to swap out the spindles/Springs/calipers/lines/MC/Steering Rack/Brake Booster?

4. The pics show front end parts, Master Cylinder, and rear end...not the best pics but if anything looks like it is 4 cylinder parts and should be upgraded that would be helpful.

5. I am debating where to start...get it running right as it sits, or swap the Intake/Heads/TB/MAF, which will allow me to see more and swap out vac lines along the way, then work on getting it running properly. Thoughts here would be helpful.

Lot of stuff here, so thanks for your input in advance, much appreciated!

Brian
 

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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Nice looking vert. Congrats on doing your homework too, too many won't do what it takes to get the advice they need.
There are many issues when swap'n stuff as you have found,
@jrichker and several others can help you, I think there is a thread here where someone is do'n a 4 to 8 swap, check it out and soon you will get it straight.
Don't pay too much attention to me, I'll have you zip tie'n a leaf blower on it.
 

Noobz347

Stangnet Facilities Maint Tech... Er... Janitor
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Run the car in total darkness with the hood open. Look over each plug wire for any arcing.

Pull codes.

2. I assume I am on the right track with solving the engine breakup with the new plugs/wires/TFI/coil , but thoughts here also would be appreciated as maybe this has something to do with the 4 cylinder swap, and knowing what to look for would be helpful

This is a great idea too.


1. I can't run a KOER test until I clear up these codes particularly 67. I assume the NSS hanging off the transmission plugs in somewhere. With the 4 cylinder and manual conversion, I could use some wisdom and guidance here on how to clear this up.

You can short the contacts to run your tests.


Code 67 - clutch not depressed (5 speed) or car not in neutral or park (auto) or A/C in On position when codes where dumped. Possible neutral safety switch or wiring problem. This code may prevent you from running the Key On Engine On tests. You can generally ignore this code, since it has no effect on engine performance.

The computer wants to make sure the A/C is off due to the added load on the engine for the engine running tests. It also checks to see that the transmission is in Neutral or the clutch depressed (T5, T56, Tremec 3550 & TKO). This prevents the diagnostics from being run when the car is driven. Key On Engine Running test mode takes the throttle control away from the driver for several tests. This could prove hazardous if the computer was jumpered into test mode and then driven.

The NSS code 67 can be bypassed for testing. You will need to temporarily ground computer pin 30 to the chassis. Computer pin 30 uses a Lt blue/yellow wire. Remove the passenger side kick panel and then remove the plastic cover from the computer wiring connector. Use a safety pin to probe the connector from the rear and jumper the safety pin to the ground near the computer.
 

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
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Being a former AOD car, the trans harness more than likely needs to be swapped to a 5-spd harness as the Auto cars lack the two wires for the NSS on the t5.

Wire harness runs from drivers kick panel, under drivers seat (under the carpet) and out to the trans tunnel.

To bypass it in the meantime, look at the clutch switch under the dash. Should be two plugs under there. Grey and a white one I believe. One is for the starter, the other will clear code 67 when jumped.

You'll neee to identify which is the starter plug by removing one, and trying to start the car by pressing in clutch. Once you identify which plug is for the starter circuit, leave it connected to the clutch switch.

Take the other plug, and jump it with a 5Amp blade fuse or whatever you have.

That should eliminate the code 67.

If it doesn't, we will need to talk you through repinning your o2 sensor harness
 

Bb1100yankees

Member
Oct 21, 2016
42
1
8
49
Ridgewood, NJ
Awesome ty, I am taking notes, not sure when I will get working on it but I appreciate the information, will be very helpful when I get it on a lift in the spring, and gives me the winter to study and make a good plan.