Questions about 16v into pre 85.5 car
09-14-2017, 01:22 AM
#1
Racer
Thread Starter
Questions about 16v into pre 85.5 car
Hey guys, I've all but completed building my 16V engine (a fun, if not expensive, way to learn how to build an engine, thanks everyone for your help), and now I need to start figuring out the differences between an early car and a 16V so I can plan my installation. So far, I have a few questions:
Can the wire harness be made to reach under the steering wheel (as opposed to the passenger side kick panel, where it's intended?) If not, I assume I'll need to make a rather large hole in my firewall.
Is there any reason I can't run my smaller 8V alternator? I have the factory A/C delete bracket and the new alternator is much larger, but I can't think of anything on the engine that would require any more power than the 8V.
Were there significant difference in the HVAC systems? I noticed the heater control valve has moved to the front of the engine and no longer has a cable running to it. Also not sure where to route the vacuum line from the HCV.
Can I leave the power steering pump pulley off the crank? Mine's manual and I don't see any counter weights on the pulley so I doubt it would throw off the balance.
I know there's a difference in the ignition system, but I'm not very familiar with the 8V system to begin with. I assume if I just use the jumper from the distributor to my current coil (? The cylinder next to the headlight motor), the car will not run?
Thanks again for your knowledge.
Can the wire harness be made to reach under the steering wheel (as opposed to the passenger side kick panel, where it's intended?) If not, I assume I'll need to make a rather large hole in my firewall.
Is there any reason I can't run my smaller 8V alternator? I have the factory A/C delete bracket and the new alternator is much larger, but I can't think of anything on the engine that would require any more power than the 8V.
Were there significant difference in the HVAC systems? I noticed the heater control valve has moved to the front of the engine and no longer has a cable running to it. Also not sure where to route the vacuum line from the HCV.
Can I leave the power steering pump pulley off the crank? Mine's manual and I don't see any counter weights on the pulley so I doubt it would throw off the balance.
I know there's a difference in the ignition system, but I'm not very familiar with the 8V system to begin with. I assume if I just use the jumper from the distributor to my current coil (? The cylinder next to the headlight motor), the car will not run?
Thanks again for your knowledge.
09-14-2017, 09:56 AM
#2
Rennlist Member
Unfortunately, the rebuild is probably the easiest part of this project.
There are a couple of questions which would help assess what you're trying to accomplish. 1) What DME will you use? 2) How comfortable are you with automotive wiring concepts?
You can run without the power steering pulley, it won't affect the engine and since you have a manual rack, it won't affect that either.
You can also run the smaller alternator but since you've already got an A/C delete, why not run the larger one?
You'll want to run the early, cable-operated HCV at the back of the block. Your HVAC system is completely different from the later cars and it's not easy, quick or painless to swap over. As far at the coolant pipe running above the headers, try picking up an 8V one and see if it will bolt to the head. I don't know if it will, but if it does just run the 8V hose from the pipe to the water pump. It's far and away the easiest solution.
As far as the ignition system, it's completely different from the 8V cars. There are a couple of threads regarding folks swapping in 16V motors to 8V cars and some of them worked. I bought a project S2 swap into an early chassis and the owner could never get spark. He screwed up so much wiring I opted to part the car out instead of rewiring an entire car.
Good luck!
There are a couple of questions which would help assess what you're trying to accomplish. 1) What DME will you use? 2) How comfortable are you with automotive wiring concepts?
You can run without the power steering pulley, it won't affect the engine and since you have a manual rack, it won't affect that either.
You can also run the smaller alternator but since you've already got an A/C delete, why not run the larger one?
You'll want to run the early, cable-operated HCV at the back of the block. Your HVAC system is completely different from the later cars and it's not easy, quick or painless to swap over. As far at the coolant pipe running above the headers, try picking up an 8V one and see if it will bolt to the head. I don't know if it will, but if it does just run the 8V hose from the pipe to the water pump. It's far and away the easiest solution.
As far as the ignition system, it's completely different from the 8V cars. There are a couple of threads regarding folks swapping in 16V motors to 8V cars and some of them worked. I bought a project S2 swap into an early chassis and the owner could never get spark. He screwed up so much wiring I opted to part the car out instead of rewiring an entire car.
Good luck!
09-14-2017, 10:02 AM
#3
Rennlist Member
I'm not sure about the harness being able to take that route, but if it can't, I was able to find a hole in my firewall (mid-year 83 tub) that I used to run my MS harness. If memory serves, it was located just aft of the fuel rail and had a rubber plug in it. Around 1.25-1.5" in diameter. You may not be able to get some of the connectors through it, though. I terminated all of mine when the flying lead harness was already through it.
You should be able to leave off the PS pulley. Check the PET diagrams to see if the washer is different, or anything else for that matter just to make sure. Getting oil pressure on a fresh engine during it's first start seems to be common issue on these cars, from posts I've seen. Would hate to introduce a new variable into that by overlooking something dumb in the oil pump drive area.
If you're using the PnP Megasquirt still, it should be setup to use the factory external igniter module. But remember that it's a DIY kit still, so you could always add an igniter to the board with an IGBT or FET driver. http://www.megamanual.com/ms2/Ignition.htm
You can use other Bosch igniters too (also called ignition modules). I have 2 from a 928 in my garage, yours for the price of shipping if you want them. The bottom line is that if the ECU is set up to trigger an external igniter, the current flow through the ECU's ignition output circuit will be almost nothing compared to what it takes to saturate a coil. It's comparable to the current used to trigger a relay, versus the current that the relay allows to pass through. Having that external igniter allows the ECU to do a lower-power task so there's less current flowing through its ground and power connections, which is good for sensor grounding integrity.
If assembling the MS and figuring that stuff out intimidates you or is possibly outside of your current skill range, consider getting a Microsquirt and the 8' harness. It's something like $350 all together. It's the size of a deck of cards and is pre-assembed and weatherproof. The downside is that you would have to terminate the engine-side of the harness, but in reality, it's not hard at all and everything is nicely labeled and of good quality. You even get 2 sheathed speed sensor input wire bundles, so you could read the cam and the crank sensor. Unfortunately there are only 2 fuel injector drivers so you can't run sequential injection - but that's not really a giant issue. The factory DME batch fired the injectors even though it had cam position input, and I would assume the PnP MS does the same thing.
You should be able to leave off the PS pulley. Check the PET diagrams to see if the washer is different, or anything else for that matter just to make sure. Getting oil pressure on a fresh engine during it's first start seems to be common issue on these cars, from posts I've seen. Would hate to introduce a new variable into that by overlooking something dumb in the oil pump drive area.
If you're using the PnP Megasquirt still, it should be setup to use the factory external igniter module. But remember that it's a DIY kit still, so you could always add an igniter to the board with an IGBT or FET driver. http://www.megamanual.com/ms2/Ignition.htm
You can use other Bosch igniters too (also called ignition modules). I have 2 from a 928 in my garage, yours for the price of shipping if you want them. The bottom line is that if the ECU is set up to trigger an external igniter, the current flow through the ECU's ignition output circuit will be almost nothing compared to what it takes to saturate a coil. It's comparable to the current used to trigger a relay, versus the current that the relay allows to pass through. Having that external igniter allows the ECU to do a lower-power task so there's less current flowing through its ground and power connections, which is good for sensor grounding integrity.
If assembling the MS and figuring that stuff out intimidates you or is possibly outside of your current skill range, consider getting a Microsquirt and the 8' harness. It's something like $350 all together. It's the size of a deck of cards and is pre-assembed and weatherproof. The downside is that you would have to terminate the engine-side of the harness, but in reality, it's not hard at all and everything is nicely labeled and of good quality. You even get 2 sheathed speed sensor input wire bundles, so you could read the cam and the crank sensor. Unfortunately there are only 2 fuel injector drivers so you can't run sequential injection - but that's not really a giant issue. The factory DME batch fired the injectors even though it had cam position input, and I would assume the PnP MS does the same thing.
09-14-2017, 12:25 PM
#5
Racer
Thread Starter
You'll want to run the early, cable-operated HCV at the back of the block. Your HVAC system is completely different from the later cars and it's not easy, quick or painless to swap over. As far at the coolant pipe running above the headers, try picking up an 8V one and see if it will bolt to the head. I don't know if it will, but if it does just run the 8V hose from the pipe to the water pump. It's far and away the easiest solution.
As far as the ignition system, it's completely different from the 8V cars. There are a couple of threads regarding folks swapping in 16V motors to 8V cars and some of them worked. I bought a project S2 swap into an early chassis and the owner could never get spark. He screwed up so much wiring I opted to part the car out instead of rewiring an entire car.
Thank you!
09-14-2017, 12:48 PM
#7
Racer
Thread Starter
I'm not sure about the harness being able to take that route, but if it can't, I was able to find a hole in my firewall (mid-year 83 tub) that I used to run my MS harness. If memory serves, it was located just aft of the fuel rail and had a rubber plug in it. Around 1.25-1.5" in diameter. You may not be able to get some of the connectors through it, though. I terminated all of mine when the flying lead harness was already through it.
You should be able to leave off the PS pulley. Check the PET diagrams to see if the washer is different, or anything else for that matter just to make sure. Getting oil pressure on a fresh engine during it's first start seems to be common issue on these cars, from posts I've seen. Would hate to introduce a new variable into that by overlooking something dumb in the oil pump drive area.
If you're using the PnP Megasquirt still, it should be setup to use the factory external igniter module. But remember that it's a DIY kit still, so you could always add an igniter to the board with an IGBT or FET driver. http://www.megamanual.com/ms2/Ignition.htm
You can use other Bosch igniters too (also called ignition modules). I have 2 from a 928 in my garage, yours for the price of shipping if you want them. The bottom line is that if the ECU is set up to trigger an external igniter, the current flow through the ECU's ignition output circuit will be almost nothing compared to what it takes to saturate a coil. It's comparable to the current used to trigger a relay, versus the current that the relay allows to pass through. Having that external igniter allows the ECU to do a lower-power task so there's less current flowing through its ground and power connections, which is good for sensor grounding integrity.
You can use other Bosch igniters too (also called ignition modules). I have 2 from a 928 in my garage, yours for the price of shipping if you want them. The bottom line is that if the ECU is set up to trigger an external igniter, the current flow through the ECU's ignition output circuit will be almost nothing compared to what it takes to saturate a coil. It's comparable to the current used to trigger a relay, versus the current that the relay allows to pass through. Having that external igniter allows the ECU to do a lower-power task so there's less current flowing through its ground and power connections, which is good for sensor grounding integrity.
If assembling the MS and figuring that stuff out intimidates you or is possibly outside of your current skill range, consider getting a Microsquirt and the 8' harness. It's something like $350 all together. It's the size of a deck of cards and is pre-assembed and weatherproof. The downside is that you would have to terminate the engine-side of the harness, but in reality, it's not hard at all and everything is nicely labeled and of good quality. You even get 2 sheathed speed sensor input wire bundles, so you could read the cam and the crank sensor. Unfortunately there are only 2 fuel injector drivers so you can't run sequential injection - but that's not really a giant issue. The factory DME batch fired the injectors even though it had cam position input, and I would assume the PnP MS does the same thing.
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09-14-2017, 12:51 PM
#8
Racer
Thread Starter
09-14-2017, 12:54 PM
#9
Racer
Thread Starter
I forgot one question (I'll find the 16V -> Pre 85.5 threads mentioned and see if I can dig up more info there), does anyone know of a bolt on fuel line that would reach from the 16V rail location to the driver side pre 85.5 connections? I haven't measured yet but I imagine something in the 944 family used one that was long enough, and LR has some nice stainless ones.
09-14-2017, 12:55 PM
#10
Rennlist Member
Since you're going with a stand alone EMS, many of the wiring issues most people face won't be something you'll have to deal with the same way. In fact, I think it will be quite a bit easier than trying to adapt a 16V DME to play nicely with the 8V engine bay harness.
Mike O'Donnell successfully converted to Megasquirt on his early 944 and he's got some great videos on YouTube. I'd check them out because there's a wealth of knowledge on there.
I soldered together my DIYPNP Microsquirt and it definitely wasn't hard. Just takes time and a decent soldering iron.
Mike O'Donnell successfully converted to Megasquirt on his early 944 and he's got some great videos on YouTube. I'd check them out because there's a wealth of knowledge on there.
I soldered together my DIYPNP Microsquirt and it definitely wasn't hard. Just takes time and a decent soldering iron.
10-05-2017, 11:09 AM
#11
The worst part of the conversion is making the Late 3.0l ECU work with the early chassis wiring harness. The wiring for the S2 ignitor is in the chassis harness, not the ecu loom, so you rarely get that portion of the harness when you buy a 3.0l motor. Since you're using MS you won't have that problem.
There are some changes that have to be made for pin-outs on the 14-pin connector by the firewall for the stock ecus, not sure if that will be true with the MS ecu.
I did not have good luck running the factory ICM (S2 Ignitor) to switch the coil on my car. The S2 has a substantial heat sink on the front fender to prevent the ICM from overheating. I tried multiple setups to mimic the factory, but they would all fail within a short period of time (or not work at all brand new). I ended up ditching the whole system and getting LS2 coils with built in ignitors for a coil near plug setup. They're not that expensive, readily available, and wouldn't be that difficult of a change since your using MS.
There are some changes that have to be made for pin-outs on the 14-pin connector by the firewall for the stock ecus, not sure if that will be true with the MS ecu.
I did not have good luck running the factory ICM (S2 Ignitor) to switch the coil on my car. The S2 has a substantial heat sink on the front fender to prevent the ICM from overheating. I tried multiple setups to mimic the factory, but they would all fail within a short period of time (or not work at all brand new). I ended up ditching the whole system and getting LS2 coils with built in ignitors for a coil near plug setup. They're not that expensive, readily available, and wouldn't be that difficult of a change since your using MS.
10-05-2017, 05:44 PM
#12
Racer
Thread Starter
The worst part of the conversion is making the Late 3.0l ECU work with the early chassis wiring harness. The wiring for the S2 ignitor is in the chassis harness, not the ecu loom, so you rarely get that portion of the harness when you buy a 3.0l motor. Since you're using MS you won't have that problem.
There are some changes that have to be made for pin-outs on the 14-pin connector by the firewall for the stock ecus, not sure if that will be true with the MS ecu.
I did not have good luck running the factory ICM (S2 Ignitor) to switch the coil on my car. The S2 has a substantial heat sink on the front fender to prevent the ICM from overheating. I tried multiple setups to mimic the factory, but they would all fail within a short period of time (or not work at all brand new). I ended up ditching the whole system and getting LS2 coils with built in ignitors for a coil near plug setup. They're not that expensive, readily available, and wouldn't be that difficult of a change since your using MS.
There are some changes that have to be made for pin-outs on the 14-pin connector by the firewall for the stock ecus, not sure if that will be true with the MS ecu.
I did not have good luck running the factory ICM (S2 Ignitor) to switch the coil on my car. The S2 has a substantial heat sink on the front fender to prevent the ICM from overheating. I tried multiple setups to mimic the factory, but they would all fail within a short period of time (or not work at all brand new). I ended up ditching the whole system and getting LS2 coils with built in ignitors for a coil near plug setup. They're not that expensive, readily available, and wouldn't be that difficult of a change since your using MS.
Question 1. I realized that I have the resistor pack for the injectors, but that it hooks up with the body harness, which really threw me for a loop. Now, the very very nice part is that I actually have the entire body harness from the 16V car. This should help me right? I can strip the wires I need from it so I have the right connectors, but I have no idea where the wire should go to in the body.
2. Can I use the coil that's in my car currently to fire the plugs? I know it was mounted in a different location but other than that I don't think it was a different part.
3. For the ICM, assuming I can get it not to overheat, it's the same story as the resistors for the injectors? Are these the only two things I will need to run the engine that aren't on the ECU harness?
Last but not least:
UPDATE: MS was taking their sweet time with coming out with the 944S computers, so I have ordered a 16V DME and AFM. I'll attemt to get the car running with the stock parts, and then I'll have something to compare to and help trouble shoot when the MS comes out.
10-05-2017, 09:32 PM
#13
My resistor pack was in the ecu harness. I took a photo of it, but when I try to link, the site crashes. It looks like it gets 12v from the ecu (soldered joint) and the other wires run back to the injectors, via the injector harness. I'm not positive, so you should confirm on a wiring diagram.
You can use the coil that is on your car. Its just the igniter(ICM) that you won't have, and need to install. The stock 16v ECUs do not have one built into the board, it generates too much heat and fried the surrounded bits. So the ecu sends out a low power signal to the external igniter, which grounds the coil (generates spark at the coil) through the ICM. All that power runs through the igniter, and if it doesn't have an adequate heat sink it will eventually fail.
If you have the chassis harness, you should have the connection/wiring for the stock igniter too. IRC you can move the pins around in the 14pin connector, and wire in the ICM while reusing the stock 'signal' wire in the 8v harness to trigger your stock coil.
Or as the others have said, you can get an aftermarket ecu that has the ability to fire the coils without an external igniter. and then just fire the coil directly from the ecu.
I had really bad luck with the stock Bosch ICMs on my S2 swap. If you check out my thread you'll see it was an endless battle with no clear 'problem'. The only cure was the injection of technology from the last decade.
You can use the coil that is on your car. Its just the igniter(ICM) that you won't have, and need to install. The stock 16v ECUs do not have one built into the board, it generates too much heat and fried the surrounded bits. So the ecu sends out a low power signal to the external igniter, which grounds the coil (generates spark at the coil) through the ICM. All that power runs through the igniter, and if it doesn't have an adequate heat sink it will eventually fail.
If you have the chassis harness, you should have the connection/wiring for the stock igniter too. IRC you can move the pins around in the 14pin connector, and wire in the ICM while reusing the stock 'signal' wire in the 8v harness to trigger your stock coil.
Or as the others have said, you can get an aftermarket ecu that has the ability to fire the coils without an external igniter. and then just fire the coil directly from the ecu.
I had really bad luck with the stock Bosch ICMs on my S2 swap. If you check out my thread you'll see it was an endless battle with no clear 'problem'. The only cure was the injection of technology from the last decade.
10-06-2017, 11:36 AM
#14
Racer
Thread Starter
My resistor pack was in the ecu harness. I took a photo of it, but when I try to link, the site crashes. It looks like it gets 12v from the ecu (soldered joint) and the other wires run back to the injectors, via the injector harness. I'm not positive, so you should confirm on a wiring diagram.
You can use the coil that is on your car. Its just the igniter(ICM) that you won't have, and need to install. The stock 16v ECUs do not have one built into the board, it generates too much heat and fried the surrounded bits. So the ecu sends out a low power signal to the external igniter, which grounds the coil (generates spark at the coil) through the ICM. All that power runs through the igniter, and if it doesn't have an adequate heat sink it will eventually fail.
If you have the chassis harness, you should have the connection/wiring for the stock igniter too. IRC you can move the pins around in the 14pin connector, and wire in the ICM while reusing the stock 'signal' wire in the 8v harness to trigger your stock coil.
Or as the others have said, you can get an aftermarket ecu that has the ability to fire the coils without an external igniter. and then just fire the coil directly from the ecu.
I had really bad luck with the stock Bosch ICMs on my S2 swap. If you check out my thread you'll see it was an endless battle with no clear 'problem'. The only cure was the injection of technology from the last decade.
You can use the coil that is on your car. Its just the igniter(ICM) that you won't have, and need to install. The stock 16v ECUs do not have one built into the board, it generates too much heat and fried the surrounded bits. So the ecu sends out a low power signal to the external igniter, which grounds the coil (generates spark at the coil) through the ICM. All that power runs through the igniter, and if it doesn't have an adequate heat sink it will eventually fail.
If you have the chassis harness, you should have the connection/wiring for the stock igniter too. IRC you can move the pins around in the 14pin connector, and wire in the ICM while reusing the stock 'signal' wire in the 8v harness to trigger your stock coil.
Or as the others have said, you can get an aftermarket ecu that has the ability to fire the coils without an external igniter. and then just fire the coil directly from the ecu.
I had really bad luck with the stock Bosch ICMs on my S2 swap. If you check out my thread you'll see it was an endless battle with no clear 'problem'. The only cure was the injection of technology from the last decade.
10-06-2017, 02:36 PM
#15
Maybe the pre-85.5 cars are different, but the 14pin on my car is a black rectangular connection by the fuse box. Male end goes to the ECU, female end is the connection to the chassis harness. the male end is split (top/bottom) so you can pop it apart and move the pins around inside.
I bought a heat sink for a GM ICM, that was 95% right (I had to drill different holes for the nubs on the back of the ICM so it would fit flush). But that was after I had gone through 4/5 of the stupid things. Some of the 'NIB' ones that I purchased would never start the car, they would give me spark, but my only conclusion was at the wrong time. I wasn't happy with how I had wired everything, I used my own wires not a factory harness and suspected that was contributing to the high failure rate, so I ditched all of it. They get stupid hot very quickly, like don't touch it when the car is running/after it has run. I think your best bet is to find the biggest chunk of aluminium you can find, possibly with some fins on it, mount it in a place with good airflow, and use some of the arctic silver heat compound between the ICM and heat sink.
I bought a heat sink for a GM ICM, that was 95% right (I had to drill different holes for the nubs on the back of the ICM so it would fit flush). But that was after I had gone through 4/5 of the stupid things. Some of the 'NIB' ones that I purchased would never start the car, they would give me spark, but my only conclusion was at the wrong time. I wasn't happy with how I had wired everything, I used my own wires not a factory harness and suspected that was contributing to the high failure rate, so I ditched all of it. They get stupid hot very quickly, like don't touch it when the car is running/after it has run. I think your best bet is to find the biggest chunk of aluminium you can find, possibly with some fins on it, mount it in a place with good airflow, and use some of the arctic silver heat compound between the ICM and heat sink.