I think I figured out the What of his relay wiring. What I know is this:
-He has battery voltage on pin 30, which should be switched 12V.
-There's a fair amount of crisscrossing on the back side of the relay panel.
-Giving fan relays a path to ground made both the fuel pump and fan circuits hot with battery voltage, not switched.
-The wiring that I believe I ID'd is backwards and sometimes upside down.
-He has 2 black wires coming out of pin 86 of the fuel pump relay, 1 goes to pin 85 of ignition relay.
I think that the big, honkin' ignition relay is possibly the only one with switched 12V coming in properly and he used it to close the rest of the relays. I get why the fans were hot, that case is closed (pun intended). I don't know why that same path to ground had the fuel pump hot but, I suspect there is a common ground between the 2 sets of relays. Does this sound like the correct way to put a relay panel together? Cuz it sounds like a hot mess to me and I'm not exactly the most nitpicky with my wiring so that says something.
For reference, my understanding is that pin 86 should be the MS control wire. The MS provides a ground, rather than a voltage, so that's the only sensible place to connect it so that it can control the relay. If I'm wrong, break it to me gently por favor.
What do you mean be "wired backwards"? For just a standard 4 pin relay, 30 is battery, 87 is power out, 85 and 86 are trigger power and ground (and are interchangeable unless it's one of the expensive relays with a diode. ) I usually wire relays for ground trigger.
The MS manual calls for 85 to be switched 12V, 86 ground, 87 battery, and 30 power out. So 86 would be my ground trigger. So 30 and 87 are interchangeable, same for 85 and 86, but he has battery opposite the ground trigger.
I'm not trying to blame anyone, just understand it so I can make it work. :)
So instead of 85 being switched 12v it's actually battery? That would be fine if you're using a ground trigger, otherwise just ground 86 and run your 12v trigger from the MS to 85. More than one way to do it
The MS provides a ground, not a voltage. At least for the fuel pump. I'm less certain about the fan control but it would make sense for it to work the same way.
I think the problem is that he has things crisscrossed with other relays, I don't have the whole system mapped out and I wasn't expecting the relays to share wiring to the extent that they do. Case in point, when I use 86 as the fan ground trigger it makes the fan and fuel pump hot. So yea backwards, at least insofar as what I expected to find. Today was a learning experience, hopefully I'll be able to successfully apply the lessons tomorrow and check off a box that is a little more substantial than I had expected.
Edit: The manual does specify using switched 12V and not battery, they want the relays unpowered when the computer is off to avoid backfeed.
Today I have a small update after some investigative work with a multimeter. The situation appears to be straightforward to resolve, I should only need to switch up 2 wires. I could probably get away with not redoing any but the MS manual calls for switched 12V opposite the trigger ground to prevent backfeed so I'm going to set it up that way while I'm there. I might dig into this today, if the breeze comes back, but it's miserable outside so I might just wait.
The plan is to use pins 86 as the ground triggers to the MS and switch pins 85 on the fan relays to switched 12V.
The relay panel in question:
A handy diagram I made to make sense of it:
Edit: I'm gonna put this here so I don't forget it. The fan relays need to be rewired 3/4, currently they're going to come on as soon as I wire them to the output wires and I will have no way to trigger them. I need the existing out wire to be my ground trigger and I want S12V across from that. The top Battery is fine, but the GND needs to be the new out. I don't anticipate this being difficult so long as I keep things straight. For the fuel pump I will use the upper left as my GND trigger and the lower left as my out to the fuel pump.
I was out of town on vacation last week, a much needed breather, and thusly I ain't got diddly dun. Til yesterday. I have set myself a deadline of driving the car for autotuning purposes this weekend with a hopeful shakedown track day next weekend at The FIRM. I believe that this is attainable, my Must Do list is:
-New gauge cluster
-Bleed brakes (suspected bubble from proportioning valve)
-Install wideband O2s/controllers
-Mount rear view mirror
-Attach throttle cable to throttle body and set pedal position
-Drive and autotune
Yesterday, with the help of some swearing, I finally fixed my fuel pump relay so it is now controlled by the MS instead of being hotwired to switched 12V. I think I got the fans fixed as well but the lappytop I use for TunerStudio is now a large paperweight so it will be a few days until I have the permanent solution integrated. I could have let it run for a few minutes to see if they come on but 1) I didn't want to take any chances and 2) the mosquito squadrons were coming in hot. I hope to verify the fans are good in the next couple days, I expect the only thing I should have to do is set the trigger temp but I am not holding my breath.
Just a quick session today that I decided to end in a high note before the rain rolled in. I'll let the pictures tell the story.
Edit: So I really ought to talk about this a bit. In the process of rebuilding the trans and swapping engine management I realized that pretty much none of my gauges were going to work right. I set out to put together a set of gauges (trying to stay on a budget) and began to see just how much custom work I was in for if I was set on physical gauges. Normally, I would take actual gauges over a screen any day and this is no secret. In the course of my research I saw the various digital dash systems, like the one offered by Holley, but they were all $$$ and still required additional work. I'm not sure what search criteria I used but I came across DD EFI and realized that it looked familiar, I had seen the original build thread for this system on (I think) the 'corral' forums. The price is hard to beat and it comes with the full version of TunerStudio to interface with my MegaSquirt. The printed bezel is a direct fit for my car, I just needed longer screws to mount the assembly. It did arrive damaged (UPS, am I right?) but that's not a big deal, I glued it up yesterday and did most of the install today. The hardest part was making sense of my in-car wiring to make sure this would be on its own circuit. Kurtis was a pleasure to deal with over several emails from my initial 'prospective customer' email to my 'it's broke what do?' email. My dealings with him and DD EFI have been entirely positive and I strongly recommend his product for anyone looking for one, you know who you are.
On the subject of the shipping damage, this was packed in bubble wrap in a box that was then bubble wrapped and boxed. If it had been shipped with FedEx or USPS I feel comfortable saying that it likely would have arrived intact. As it was, the lower left tab was dangling and some Gorilla Glue and overnight clamping set it right. I have not yet begun to play with this, I am pushing for the aforementioned shakedown day at The FIRM next weekend, but this should provide many hours of tinkering joy.
*This is only a positive review combined with a helpful word for anyone that might be in a situation similar to mine, no money changed hands, etc...*
Patientzero said:
Very nice
Thank you. I look at this as a transitional period wherein I am wrapping up the work done by the PO and beginning my own leg of the project. Once I get through the "reliability and trackability" phase I have my eye on some minor fab work for seats, some door panels, and an all around neatening of everything so it appears to be a little less like a junk heap on loan from Florida Man. Long term, I might experiment with some time trials for *its and giggles.
It's car day here and the Mustang battery is dead. 12V was measuring at 10 during the initial install, 3.6 today. It's not a large battery but it should not have dropped so far so fast, I think the computer needs to fully shut down much faster and not stay idle. I hooked up a jump pack, the car needed to move for garage access, but no crank. I'm hoping it's as simple as the computer not coming on or possibly needing the firmware redone after the battery being disconnected a few times. Weird but that's my MS I guess and I haven't changed anything else.
The TunerStudio is not talking to the MS because it wants a config file and my internet is not letting the computer have internet access. It's a frustrating afternoon that I will revisit after the battery has charged up enough to turn things on. Hopefully that works out and then I'm going to see about getting some wideband sensors installed once I can drive it into the garage
Edit: Either my charger isn't working or the battery is shot. The result is my battery is not charging or us being drained faster than the charger can keep up with. I'm going to try disconnecting the dash and seeing what happens.
Battery is shot, it lost .6V on the charger and the charge indicator light is not coming on. Yay! Battery shopping...
Long story short, the relay panel is a mess. The fan relays were putting battery power to the switched 12V line and royally messing things up, probably due to the way everything is daisy chained and intertwined. Getting functional fans is going to require rewiring of the fan relays and isolation from the "Ignition" relay. This mess messed up the fuse to the MS that was being fed battery power and probably didn't take kindly to my hooking a jump pack to the battery. It wasn't blown (50 Ohm), still passed a visual check, but when I replaced it the MS powered on. I still think that my battery needs replacement, the charger that has worked previously is not charging the battery and the charge light is not lighting. It's a tiny battery, as mentioned previously, and it has been discharged a few too many times. If I replace it I will likely be looking for something that won't die if I turn my lights on for more than a handful of seconds and I'll probably try to shift it further back.
Edit: The good news is that after connecting to my phone hotspot the dash was able to do its verifying and updating. After replacing the fuse the MS started talking. So I'm just waiting on the jump pack to charge, my brothers Focus almost stalled with jumpers cables hooked up when I turned the key.
I was talking with an EE today and it turns out that there is a right and wrong way to power the coil side of a relay due to an internal diode. The correct way is to power 86 and have ground on 85, so I will be swapping the terminals around on my relays to match this. Leaving them as is means a constant current draw and causes fan problems. That is my main target tomorrow, starting mid-morning. The secondary target is the throttle cable and then IAC/idle tuning.
There is a trailer I can borrow, so that the gf and I can trackday without the whole group. What is the best Class 1 hitch to put on an '89 Mustang? Nobody seems to sell purpose built ones anymore so that means universal but there is a wealth of knowledge here that I would be remiss to not take advantage of before buying.
Also, I have added yellow tire lettering to my long term aesthetics plan.
I know trailer hitches are available for SN95's. Might try adapting one of those.
Patientzero said:
I know trailer hitches are available for SN95's. Might try adapting one of those.
That's the way I've been leaning. The '94-'95 Mustangs are Fox uunderneath, so I can't imagine that it would be hard to adapt.
Moving on! I have taken a breather from the Mustang, and all car related things, for a bit. I needed to step away and renew my enthusiasm for the project and relieve some exapseration with the project. Looking at the very first picture in this thread just now was helpful and a little invigorating. Tomorrow, weather permitting, I'm getting back at it. The punch list remains the same but I have a much better idea of my fan problem and a new battery.
The fan problem:
The MegaSquirt is providing a constant ground on the fan control circuit. I triple+ checked that the pin is in the right place and that everything is good, the line is just grounded with everything off so the battery12V on the coil side and switch side of the relay powers up my fans. More than likely this is the same thing responsible for killing my battery. My initial plan was to put the coil power wires on the switched 12V bus of the engine fuse panel but if the MegaSquirt is providing constant ground then my fans would be always on rather than computer controlled. I'm not sure what input I'm going to use but I'm going to have to swap from the designated "Fan" input to another that will allow me to properly control the fans. Unless someone knows of a setting in TunerStudio that might be telling the MS to short that line straight to ground.
I'd like to say I plan on tackling most of my punchlist tomorrow but I think the only thing I want to get done is the fan circuit. If I'm feeling frisky I might set up the input for the fuel gauge to my sweet DigitalDash setup or futz with the throttle cable. More than likely, weather permitting, I'll wash cars if I can get notable progress on the fan circuit. Going into Sunday with good fans and clean cars would really be a wonderful thing, that would let me really relax and smoke a pork butt with a clear head rather than having lingering car worries.
Any thoughts?
Today I switched the coil side power for the fan relays from the 12V battery bus of the fuse block to the switched 12V. Combined with a new battery to replace the one that the old wiring killed my Mustang is now running and the fans are working the way they should. I'll check the voltage tomorrow, just to make sure but so far this looks promising.
I did let it warm up to about 190° to test the fans and played with the throttle preload and idle settings. Idle VE led to a smoother idle but also a bit lower RPM and it didn't like when the fans kicked one, 850 RPM (1.4% throttle) might be a little low for idle but it sounds so good. I'll bump the preload up a bit and research my next moves for idle tuning on the side, the obvious one is to install the wideband sensors so the computer can really dial in on the VE maps.
IAC is enabled but I'm not 100% that it's functioning. Any thoughts on how to test it?
The punch list remains the same and I'm hoping to knock out 1 or 2 small things, like rear view mirror and throttle cable, during the week. I've mentioned before how my side mirrors aren't really functional with the internal cables stretched, I would like to keep them on the car and I don't really want to go power mirrors ($ and added complexity) for a while. My current plan is to find/print some blocks to wedge between the mirror and housing to pin it where I want it, then apply a moderate adhesive or RTV. This is a bit of a side project, the rear view, open interior, and good ole fashioned lack of factory installed blindspots means that I can generally see just fine and I always headcheck.
I attempted a throttle cable install on Saturday and made a few missteps with it, hopefully I can salvage the cable. I might order another, just to be safe. I also learned that my Lokar pedal is not gonna work without more custom work, the height difference between the cable attach point and the firewall pass-thru has the cable rubbing and it's gonna fray. I could try drilling a hole lower but it would be blind and I really don't want the cable passing that close to the headers, the sleeve would probably do some ungood things next to that much heat. I could throw some heat shielding at it, a thought that just occurred to me, but I think the best thing to do is what I should have done in the first place. That is, I need to get my butt over to the local LKQ pick 'n pull and yank a go pedal out of a 90's Mustang. If I get lucky it'll have a throttle cable attached, if not I might just order one as the Lokar attachment does not appear easily compatible with the OEM style.
The plan is to be on the road this weekend, at least for a victory lap around the block, to reinvigorate me for the work to come. That should give me enough time for autotune to work before Roebling Road in 3 weeks.
Anyone have a use for 2 good shape foxbody seats, grey w/blue headrest? What about 2 GI green seats for a HMMV with integral harnesses? I'm thinking these would probably be sweet in a jeep. Alternatively, what would be something nifty to do with a pair of seats?
Reading your previous update, 190 deg F is kind of a cool temp to turn on the engine fan. 205 to 210 would be more to my liking. 195ish for a turn off point would be my preference as well. As for the 850 rpm idle, that sounds about right if not a touch fast, but not by much if so.
Turn the seats into garage seating? No good suggestions really.
In reply to pres589 (djronnebaum) :
I only had the fan turn-on that low so that they would turn on a bit sooner and, if they didn't, I'd worry a bit less. I'll have to check the OEM spec but I think this engine likes to hang out around 200-205. I've also been thinking about turning the seats into garage seating but I probably need to put them up for sale and clear some space. Thanks for the input
The junkyard trip was a full success, I picked up a stock pedal and throttle cable for less than $23, both are now in the car. The cable needed a bit of shortening and modifying but I expected it. I did not expect the shielding around it to be made of adamantium, I had to shorten it with a cutoff wheel, probably a solid 2mm of steel surrounding the cable. Either way it's in the car and the battery is almost charged up, I should have the car running tonight and might go for a brief trip around the block. I have 2 weekends left before the track and, assuming my throttle is now solid, the remainder of my list should be very attainable in the time frame.
I have been feeling the desire for a bit of beautification and, while I am holding off on door panels and other items, I think I am going to DIY a USB charging panel to go between the seats. I bought a panel last year that I never installed and my thought is to use some sheet metal I have on hand to mount the switch, USB ports, and hatch release button on the trans hump between the seats. The car has no USB power right now so this will be a nice QoL addition while also cleaning up the area and putting the hatch release in a good place. I'll do a cardboard mock-up tonight, hopefully, and work on this as a side project when it's too late to have the car running in my quiet neighborhood.
An at work, finger drawn mock up.
What track are you going to? I'm sure you've mentioned it already.
In reply to Patientzero :
Roebling Road, we're usually there twice a year. We also like The FIRM and I'm hoping to get a Sebring visit next year.
So I mocked up the charging panel in cardboard last night and converted it to plywood backed sheet metal this afternoon. I'll drop a picture below and edit to a better one in the daylight tomorrow. Gonna use the 12V line that used to go to the OBD port to power it as well as tucking some retained wiring underneath it for tidying purposes. I'm not exactly sure how I'll manage the angle with a drill but the wings fold down and will screw to the seat cross-member over the trans hump. 1/2" screws so no over-penetration or splash-up worries.
I also re-reattached the rear view mirror so, if it holds, the car is technically streetable. My hope for tomorrow is to get the wideband O2s plugged in and hooked up so that I can do a little auto-tuning with TunerStudio.
I still need to test the blower motor (for defrost) and I want to replace the weatherstripping on the doors but that comes after brake bleeding or possibly rebuilding.
Here is the mock-up in the car
And here is the improved version, on my poorly lit bench
I took some construction pictures but my phone was being funny and didn't save them. I had a scrab piece of 1/2" plywood from building my workbench so I cut that size, cut the front and back of the sheet metal a little over, superglued the plywood to the underside of the sheet metal and then hammered the extra flaps over the plywood. 1 1/8" hole saw bit for the (duh!) holes but I got carried away and did 4 when I should have made the 4th smaller to accomodate the thinner hatch release button. Oh well, something to improve on in Rev B. It feels good to get this side project done, even at the cost of maybe getting something more "important" done in the car. It's a small thing but it's a step towards having a track car that's less 'janky' and more 'neat-o'. It's also actually a little important was it will help ensure that my phone stays charged for the long drive back Sunday night. Last time I had no way to charge and was really milking my phone to provide navigation, speed, and music the whole way. In short, I'm getting excited about being back on track with the gang.
Edit: While idling in the driveway the IAC appears tobe doing just fine, sitting at about 15% while the throttle body entirely closed and TPS zeroed. When I initially add throttle, though, the RPMs drop and the engine sputters. It will do this if I blip the throttle lightly or if I hold pressure. Is this a function of having the throttle body entirely closed or something else? If I preset the throttle body between 0% and about 5% throttle, it shreaks like a banshee at idle so I am trying to avoid the ear splitting noise.
I've been on an enforced break from the project car thing myself--the fixation needed some separation. I've also been dealing with massive voltage drain from my current LS swap, which I'm pretty sure is from a non-key-on power source powering my radiator fan (needs an alternate switch anyway). While I'm not familiar with using anything but a GM computer (E38) on an LS swap, I do have familiarity with not using the computer to control things like fans and fuel pumps. Generally, the computer is only used to trigger the pump, so the priming effect is in place and the computer, I guess, can have a reference point for static pressure. Many will power the pump separately, like straight from a post on the alternator (with 10-gauge wire), which can help to make sure of full voltage; definitely never use existing wires for powering a pump.
The same goes for powering electric fans. I've seen countless people struggle for months trying to get the stock computer to run fans and really, it's far easier to just buy a $30.00 controller from Summit or Autozone and rely on a radiator temperature probe. Anyhoo, you've probably already figured these things out by now . . .
Widebands are in! And now the engine dies under even the thought of a load. Took me 20 minutes to go 2 car lengths up the driveway. 30% and the slightest clutch release and I get about 2 feet and it stalls regardless of throttle input. Previously, when I had no pedal but the same throttle body, I could set the throttle to about 8% and go up the driveway no problem. I am hot and tired and I will deal with this headache tomorrow. In the meantime, if anyone has any thoughts, I am all ears. AFR shows 15.00 on gauge 1, I didn't check gauge 2, and the exhause gas voltage is way in the red. Whatever that means...
Edit: So I did some reading and found this this http://www.tmproductions.com/repairs-and-maintenance-blog/2019/1/3/tunerstudio-settings-and-tables
It appears that I skipped a few mildly important steps in the process so I will be working on that tomorrow after work
I think I got the idle sorted out a good bit more than yesterday, much more stable and tolerated light throttle better. I did not leave the driveway, I let autotune work it's magic on the Warm Up Enrichment and Idle VE and definitely noticed a difference. The plan tomorrow is to back it down the driveway and see how long it takes to go around the block. Short trips and the electrical for the charging panel are probably all that I'm going to get done until the weekend, then I'm hoping to tackle brakes.
There is a subaru performance shop within minutes of my driveway. I remembered this earlier today when I also remembered the benefit of hindsight regarding not buying the Plug 'n Play MS option at the start. They will likely want ~$500 for tuning work but they have a dyno and are very close. Presuming they would take on my car (not quite a subi) and had time this weekend, is this the kind of hindsight thing that I might regret not doing the easier way? Put another way, is all this tuning work maybe a problem better solved by throwing money at it? What would you do?
