LT1? Can the 96-97 Coil & Module work on a 94-95 LT!

[dave w]

Can the 96-97 Coil & Module work on a 94-95 LT1?

dave w

17453

[NomakeWan]

EDIT: Apparently the problem is going from 94-95 to 96-97, but not vice-versa. Whatever changed in the 96-97 ICM apparently doesn't piss off the 94-95 PCM. But a 94-95 ICM will piss off a 96-97 PCM.

No; unless you are also using a 96-97 PCM. I know the '96 Y-body ICM and 94-95 Y-body ICM are different. Info: https://www.corvetteforum.com/forums/c4-tech-performance/4266898-1996-lt4-icm-issues-and-schematic.html

[LeMarky Dissod]

https://www.impalassforum.com/threads/96-coil-wire-pinout.236214/post-2231206

https://www.impalassforum.com/threads/coil-measurements-94-and-96.1048713/post-10027545

https://www.impalassforum.com/threads/96-coil-upgrade.273055/post-2658534

https://www.impalassforum.com/threads/96-coil-swap-writeup-pics-incl-56k-die.1083617/post-10287569

https://www.impalassforum.com/threads/%E2%80%9896-coil-on-%E2%80%9894.1314550/post-12091466

https://www.impalassforum.com/threads/need-a-quick-hand-from-someone-with-a-96-install-coil-in-95.426345/post-4304513

https://www.impalassforum.com/threads/96-and-on-coil-used-on-95-and-94-icm.1127593/post-10597553

Admittedly, most of these only use the '96 coil, but not the '96 ignition driver module.

[WASyL]

Sure it can be used, just change connectors and you are good to go.

Best regards

[dave w]

I would like to convert a 96 LT1 to the 94-95 PCM. Seems like it's possible with the original 96 ICM and some wiring work.

dave w

[WASyL]

Just swap knock sensor modules, plug PCM to car and you are good to go. Did it couple of times.

[ScottP]

No need at all to touch the coil or ignition module. Swapping a '96 LT1 to the 94-5 8051 PCM is nearly
a plug and play affair. I've done more than I can count over the years, mostly in the days long before
TunerCat '96 LT1 support.

If you're planning to use the Tach output from the PCM, you will need to address the number of pulses.

The knock sensors changed from 95 to 96, as did the number used depending upon the donor vehicle
(F, B, D or Ybody).

Is this an engine swap, or a stock '96 application where you just want to use a '95 PCM? Knowing the
exact platform will help narrow down the answer.

-Scott

[dave w]

No need at all to touch the coil or ignition module. Swapping a '96 LT1 to the 94-5 8051 PCM is nearly
a plug and play affair. I've done more than I can count over the years, mostly in the days long before
TunerCat '96 LT1 support.

If you're planning to use the Tach output from the PCM, you will need to address the number of pulses.

The knock sensors changed from 95 to 96, as did the number used depending upon the donor vehicle
(F, B, D or Ybody).

Is this an engine swap, or a stock '96 application where you just want to use a '95 PCM? Knowing the
exact platform will help narrow down the answer.

-Scott

Hi Scott,
The engine is from a 1996 F-Body Camaro auto trans that will be converted to manual trans. The application is an off-road only Jeep . . . Oregon Sand Dunes playground. https://traveloregon.com/things-to-do/oregon-dunes-national-recreation-area/

dave w

[steveo]

its definitely an easy swap. i believe you can use the knock module from your 1996 ecm in the older ecm and retain your original (twin) knock sensors. i did it once and it appeared fine. the icm part numbers are different but ive never run into issues interchanging them

[ScottP]

That is definitely an easy swap. The knock sensor in the engine block is the only critical difference you
will want to handle. The '96 PCM is expecting a knock sensor with a resistance of 100kohms, while the
'8051 expects 3.9kohms.

There are two ways to address this:

1 - Buy a '95 knock sensor and swap it into the '96 engine.

2 - Install a 3.9kohm resistor inside the PCM on the knock sensor input pin to ground.

I've done both over the years depending upon the circumstances and parts availability - both work fine.

-Scott

[NomakeWan]

its definitely an easy swap. i believe you can use the knock module from your 1996 ecm in the older ecm and retain your original (twin) knock sensors. i did it once and it appeared fine. the icm part numbers are different but ive never run into issues interchanging them
You can retain the twin sensors, but only one sensor will be used by the knock filter unless you wire the two sensors together. The 94-95 PCM only uses a single knock sensor input wire (D22) while 96-97 use two (D22 and D21). Additionally, as others mentioned, the sensors themselves will throw Code 43 if you try to use 96-97 knock sensors on a 94-95 PCM. Either swap to the older sensors, insert a resistor inline with the sensors, or just program out Code 43 since it's a stupid useless code anyway.

[dave w]

I greatly appreciate everyone's thoughts and suggestions.

The 96 engine is on a stand, the 94-95 knock sensor(s) will be installed.

Any other thoughts or part suggestions while the engine is on the stand are greatly appreciated. Maybe the Opti-Spark???

dave w

[LeMarky Dissod]

I greatly appreciate everyone's thoughts and suggestions.
The 96 engine is on a stand, the 94-95 knock sensor(s) will be installed.
Any other thoughts or part suggestions while the engine is on the stand are greatly appreciated. Maybe the Opti-Spark???While on the engine stand:
flush out the block after the OBD2 knock sensors / freeze plugs are out, before the OBD1 knock sensors /freeze plugs are installed.

Obviously now's a good time to go over the following:
oil pan & intake manifold gaskets
exhaust manifold bolts
AIRpump exhaust tubes
rear coolant crossover piping (some replace with AN hoses, for example)
if the intake manifold comes off, clean the EGR, PCV, & idle air paths (separately from the main intake runners)
if the H2Opump comes off, check its bolts
if the Opti-Spark comes off, check gaskets and seals (some are DRY, and/or may need special installation tools)

[tayto]

dave, it's nice to see someone going with a gen1/2 sbc vs LS. i don't have a lot of LS experience, but have been told they lack in the low end torque department. anyway, post some pics of progress if time allows! I have an LT1 on the stand myself, but it has been untouched until I have time thia spring.

[steveo]

I greatly appreciate everyone's thoughts and suggestions.

The 96 engine is on a stand, the 94-95 knock sensor(s) will be installed.

Any other thoughts or part suggestions while the engine is on the stand are greatly appreciated. Maybe the Opti-Spark???

dave w

don't be afraid to take the optispark apart to inspect and clean things, but also to see WHAT the optispark is, you almost never see a GM original these days, make sure it's not some bottom of the barrel chinese garbage. if there's a mitsubishi logo on the optical sensor, put it back together and leave it, it's your best chance of success.
goop the cap&rotor seal of the optispark to ensure the venting system doesn't draw through it. replace the opti vent hoses. a busted opti vent hose could be sucking dirt and air into the opti.

[spfautsch]

I would emphasize removing the water pump, check out the opti as steveo mentioned. If you have a delco-remy distributor base (the aluminum casting) a drop-in replacement pickup can usually be had for a reasonable price from a vendor on Amazon called AIP Electronics. I would probably advise against leaving an original Mitsubishi sensor in if you have no way to know how old it is and if it has the Mistu logo on it, it will likely be 15+ years old.

More importantly, if you don't know the engine's history I'd replace the water pump so you know it won't spring a leak in six days / weeks / months and ruin the opti. Also, replace both oil seals in the timing cover. The water pump driveshaft seal does need a specialty tool, but one can be improvised with the case of a sharpie or a piece of soft copper can be flared to create one. This seal is terrible about letting go early and spewing oil all over the front of the engine and rear of the opti.

[dave w]

Hmmm, https://www.eficonnection.com/home/category/engine-hardware/crank-and-cam-signal-kits/efi-24x-product-line/efi-24x-lt1lt4

Sure has me thinking . . .

dave w

[LeMarky Dissod]

Hmmm, https://www.eficonnection.com/home/category/engine-hardware/crank-and-cam-signal-kits/efi-24x-product-line/efi-24x-lt1lt4

Sure has me thinking . . . EFI Connection's Opti workaround looks more weather-resistant than TorqHead's.
https://torqhead.com/shop-24xlink-products.html#!/24xLink-Signal-Kit/p/53109885/category=23575139

[NomakeWan]

Torqhead's advantage is that they can sell you the entire kit (including the PCM you'll need, the harnesses you'll need, and if you want, the coils and coil brackets you'll need). They also support the digital dash in the 94-96 Corvette, which at the moment no other company does.

EFI Connection gives you the sensors and such, but you'd still need to supply the PCM, wiring harnesses, coils, brackets, etc. And if you have a digital dash you'd have to figure out the fun of making them work together.

Or I suppose you could get really creative and build an interpreter to convert the 24x signal into the opti's high-res and low-res signals, then feed those into both the $EE PCM and spfautsch's DIY coil controller.

[LeMarky Dissod]

Torqhead's advantage is that they can sell you the entire kit (including the PCM you'll need, the harnesses you'll need, and if you want, the coils and coil brackets you'll need). They also support the digital dash in the 94-96 Corvette, which at the moment no other company does.

EFI Connection gives you the sensors and such, but you'd still need to supply the PCM, wiring harnesses, coils, brackets, etc.
And if you have a digital dash you'd have to figure out the fun of making them work together.

Or I suppose you could get really creative and build an interpreter to convert the 24x signal into the opti's high-res and low-res signals, then feed those into both the $EE PCM and spfautsch's DIY coil controller.Thinking more along the lines of using EFI Connection's Opti- replacement (instead of TorqHead's), with the rest of TorqHead's kit.

[dave w]

My daily driver is a S10 with Coil-on-Plug 5.7 liter.

Not my first rodeo.:thumbsup:

dave w

[babywag]

I would like to convert a 96 LT1 to the 94-95 PCM. Seems like it's possible with the original 96 ICM and some wiring work.

dave w

Very easy to swap 96 coil/icm into 94/95 harness, just need parts/connectors and a few minutes of wiring work. Don't forget the coil wire is different for 96.