Engine EEC-IV Problems

EDDIEM75 · Jun 13, 2025

93 306 all bolt-ons dyno tuned
Ill try to make this brief initially....Was going through the process of chasing a high idle issue with the typical solutions. It got better. Went to connect a snap on brick to eec-iv port and no power to scanner. Tried another nothing. Assumed bad gound. Have an actron that powers off cig plug. Connected it and idle immediately rose and would hard start with actron plugged in. Unplugged actron and engine still hard starts and idles at 3k then 1300. Unplugged battery for hours. Issues still persist. Unplugged spout and iac and base idle is good. Plug spout and iac and issues back. Any thoughts?

General karthief · Jun 13, 2025

Is there a chip?
You said it was dyno tuned.

EDDIEM75 · Jun 13, 2025

General karthief said:
Is there a chip?
You said it was dyno tuned.

Not my car but there are splice connectors on maf, O2 etc so I'm assuming. Haven't checked out pcm for eeprom yet to say for sure. Glad you asked because that's the direction I've been thinking.

General karthief · Jun 14, 2025

Make sure those splices are good..

EDDIEM75 · Jun 14, 2025

Yeah I'll certainly double check. And for clarity they're taps no so much splices. But again things were headed in the right direction until I plugged up the powered "scanner".

I'm quite comfortable in the obd2 pass thru/program world but eec4 are not my jam. And it's been a good minute since I invested my time, money etc in Fox bodies. Are most or all tunes performed with a chip? Is it common or possible to rewrite ecm? If so how common vs chip? Thanks

General karthief · Jun 14, 2025

I think there is a system that you can piggy back (?) Quarterhorse come to mind but I have not built stuff that needs 'tuned', the computer in our rides are not 'plug into' fiddle with some keys, flash and play.
Some install chips because they can't make their junk run right with miss matched parts.

EDDIEM75 · Jun 14, 2025

Like I said all bolt-ons including tfs heads intake can't remember which cam but have it written down msd ignition, pro-m etc.
How are these vehicles dyno turned? Is there any programming or all mechanical: timing, fuel psi etc?

gkomo · Jun 14, 2025

With the stock ECU yes you can tune the computer with an external chip like the Moates quarter horse.

EDDIEM75 · Jun 14, 2025

Gotcha. I'm mostly asking bc I'm concerned something might have happened to the chip if it has one or the ecm. The scanner shouldn't have caused any issues. But it did. Not so much thinking it was the scanners fault. More something was/is not "wired" properly being the snap on bricks wouldn't power up when connected. Due to that incorrect wiring and/or short when I plugged in the powered scanner in something got damaged or erased. I'm obviously getting a little dramatic and still haven't dug in to it yet but I am concerned.

gkomo · Jun 14, 2025

If it does have a chip, and you have access to the ECU, look on the sides of it as the chip gets plugged into one of the sides. If it’s just the ECUs metal case, then probably no chip.

EDDIEM75 · Jun 15, 2025

Yes sir. I do understand where the chip is connected. I just thought I'd read that there is the ability with the connect hardware and software to rewrite/program the eec4. Any clue?

GOvert · Jun 15, 2025

Pictures?
Maybe you mean the MT-2500?

EDDIEM75 · Jun 15, 2025

Sorry pics of what exactly?

EDDIEM75 · Jun 15, 2025

"snapping on something to something on your ecm?" was a reply i received. No I'm not snapping on something to ecm. It's a Snap-on scanner referred to many as the Snap-on brick. Snap-on's first scanner that's red and shaped similarly to a brick. I plugged it into the eec4 port and it would not power up. They get ground from the port. Then i plugged a 12v cig lighter powered Actron scanner and that's when the issues began. Even once I unplugged it.

gkomo · Jun 15, 2025

Maybe you blew a fuse with the cigarette lighter somewhere?

nickyb · Jun 15, 2025

I'm confused where did you plug that brick into?

General karthief · Jun 15, 2025

Every 'clip on' connector, the type that clips on a wire without cutting, that I have encounter was a failure, need to go over all those connections and pull the computer out and have it checked out.
ECUExchange is my 'go to' for computer repair.

EDDIEM75 · Jun 17, 2025

nickyb said:
I'm confused where did you plug that brick into?

The data link.

General karthief said:
Every 'clip on' connector, the type that clips on a wire without cutting, that I have encounter was a failure, need to go over all those connections and pull the computer out and have it checked out.
ECUExchange is my 'go to' for computer repair.

Yeah I've spent some more time with it now that I'm back at work. Again there's the hard start issue. If it sits for say an hour or more it'll start. If i immediately turn it off and try to start again it'll hard start or not start at all. Can immediately smell gas. But when it won't start it has strong spark at spark plug and the injectors are firing. But still won't start even with starter fluid. Have also tried pedal to the floor to clear a flooded motor but doesn't start or even try. So has strong spark at plugs and injectors are firing but won't start even with the addition of starter fluid.

I'm just now going through the ecm/wiring but it appears pin 46 ground is bad. Resistance OL to 40 & 60. Will these things still start and run alright with pin 46 open?
At least one looks like two capacitors have open.

nickyb · Jun 17, 2025

You know when the ignition. Module gets hot it usually craps out,you can pull it off the dist. And put some heat sink grease on it.

GOvert · Jun 17, 2025

Did you look at the spark plugs today?
I didn't catch the shop slang "brick". When I purchased my scanner, The Snan-On guy referred to it as the Snap-on MT2500. A Mech/Tech friend called his, a Snap-on Scanner. I'm in a partnership (very small) garage and there is already something else in the shop that we call "the brick". I'm sure that in the big garages/shops and dealerships, a lot of slang is thrown around.
Where in TN are you?

Engine EEC-IV Problems

EDDIEM75

New Member

General karthief

wonder how much it would cost to ship you a pair

EDDIEM75

New Member

General karthief

wonder how much it would cost to ship you a pair

EDDIEM75

New Member

General karthief

wonder how much it would cost to ship you a pair

EDDIEM75

New Member

gkomo

now i can hopefully expect to receive the shaft

EDDIEM75

New Member

gkomo

now i can hopefully expect to receive the shaft

EDDIEM75

New Member

GOvert

EDDIEM75

New Member

EDDIEM75

New Member

gkomo

now i can hopefully expect to receive the shaft

nickyb

I gotta say i never painted my nuts, Never Ever

General karthief

wonder how much it would cost to ship you a pair

EDDIEM75

New Member

nickyb

I gotta say i never painted my nuts, Never Ever

GOvert

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Engine EEC-IV Problems

New Member

wonder how much it would cost to ship you a pair

New Member

wonder how much it would cost to ship you a pair

New Member

wonder how much it would cost to ship you a pair

New Member

now i can hopefully expect to receive the shaft

New Member

now i can hopefully expect to receive the shaft

New Member

New Member

New Member

now i can hopefully expect to receive the shaft

I gotta say i never painted my nuts, Never Ever

wonder how much it would cost to ship you a pair

New Member

I gotta say i never painted my nuts, Never Ever

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