K20 project off to a good start, volume 2

So I did some sleuthing to figure out the fuel gauge problem. First, I pulled the sender from the tank and tried it just manually moving the float through its range. At the full position, the gauge only registered a little over 3/4 full. The sending unit was a new one that I bought from MWB about 4 years ago, but this was its first use. I contacted Matt at MWB and he said he would stand behind it and send me a new one, but that he has sold a lot of them with no complaints about them reading low. I then thought it may be a gauge or wiring issue, so I dug out the original fuel gauge from the car that I was not using and hooked up the sending unit to that. It read full at full height of the float, so that meant I probably had a bad gauge or a bad connection that was adding resistance to the circuit.

I pulled the gauge cluster and connected the sending unit directly to the signal post of the fuel gauge. Again, it read full at full float height so I tried the spade connector on the cluster that leads to the gauge. Only 3/4 again. I thought I might have made a poor solder joint when I built my gauge cluster, so I redid those, but no change. That lead me to the connection of the signal post to the circuit board. Turns out that it was corroded under the nut and washer, so cleaned the board, put in a new washer and voila, all fixed. :)

While I had the cluster out, I used the sending unit to test the temperature gauge and it moved through its normal range with movement of the float. I then put the gauge cluster back in the car and connected the sending unit to the signal wire from the Fiat temperature gauge on the engine. Again, the gauge moved through its full range so that ruled out a wiring issue. My assumption at this point is that I did not run the car long enough for it to get warm enough to get the gauge to move. I had mounted the temperature sending unit in the outlet housing off of the head, so it really will not start to register until the coolant starts to move to the radiator. When I was trying to figure out where to mount the Fiat sending unit on the engine, I debated trying to drill and tap a hole in the head into the cooling passage, but chickened out on that idea. I had only run the engine long enough for the radiator to get just slightly warm, so next time I will run it longer and see what happens.
 
How is it coming along? I'm assuming you're not running down the highway with it yet, since we haven't seen a video or you gleefully sprinting down the road :D
 
As much as I would like to, I just haven’t had time to touch it since my last report. Working and then we have been negotiating to buy a new house closer into town. Also starting to downsize. We are on a college visit trip all week with our last daughter.

Cool thing about the new house is that although it is only a two car garage (I have a three car now) one bay is extra deep so room for a workshop area, plus it has a 13 foot ceiling!! I have already gotten a bid to change the garage door to go straight up to the ceiling and I am going to get a four post lift. No more crawling under jack stands plus I can stack the X’s when I am not working on one. :D
 
I have been crazy busy with getting our house ready to put on the market, plus overseeing an interior renovation of our new house, so the K20 project is still on hold. I did finally register the car since I hope to drive it soon and just got my new plates!
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Since the engine came out of an Acura RSX, it seemed to make sense.
 
I have been crazy busy with getting our house ready to put on the market, plus overseeing an interior renovation of our new house, so the K20 project is still on hold. I did finally register the car since I hope to drive it soon and just got my new plates!
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Since the engine came out of an Acura RSX, it seemed to make sense.

Didn't quite get the personalized plate I wanted, it was a trade-off for an $80 five-year registration!


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After a way too long absence due to a move and all of the house projects that goes with that, I finally have gotten back to work on my build. Thanks to COVID-19, I suddenly find myself with no job for the next two months and with a stay-at-home order in place here in Washington. So as bad as this pandemic is becoming, the silver lining is that I now have plenty of time to hopefully finish my K20 project. Of course, I wish this was under better circumstances and I dread what is to come of this outbreak in the next couple of weeks.

I decided to tackle the exhaust system first, because I was very unhappy with how loud my first attempt was with the Magnaflow muffler. There was no way I was going to happy with it that way. Doug Martin had suggested a chambered muffler and a resonator as a possible solution and that is the route that Hussein did with his. Judging from his thread, he was pretty happy with that combination. I ordered the same muffler from Stainless Works and a 9" resonator from Vibrant (I just don't have many Volvo parts laying around ;)). It was hard to cut into the system that I had spent so much time on, but once I started, it actually didn't take took long to cut it apart and fit the new pieces. I was even able to get a bit tighter stretch with the hanger springs this time, so the exhaust system seems to have less movement. Once I got it back on and fired up the car, the exhaust note was so much better! It definitely has presence, but it is much mellower. I haven't taken it out for a drive yet as there are some tuning issues I want to work on, but at least I am happy with the exhaust note at this point.
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I must say, having the car up on lift to do this was such a joy. To be able to stand up and see what I was doing without having to crawl around on the floor with the car on jack stands was amazing. I should have bought one years ago. :D
 
Looks great, Rodger! Welds looking clean :)

What are your tuning issues? I struggled with an idle & part throttle issue that I FINALLY resolved - in my case it was a bad (aftermarket) IACV causing backfeed issues in the system. Had to break down & pay $200+ for a Honda-packaged one to resolve it.

In addition to copying your exhaust layout I also copied your plate idea with my license plate - I went with TSX19 :D
 
:cool::cool:
Looks great, Rodger! Welds looking clean :)

What are your tuning issues? I struggled with an idle & part throttle issue that I FINALLY resolved - in my case it was a bad (aftermarket) IACV causing backfeed issues in the system. Had to break down & pay $200+ for a Honda-packaged one to resolve it.

In addition to copying your exhaust layout I also copied your plate idea with my license plate - I went with TSX19 :D

Thanks! They say imitation is the sincerest form of flattery. :cool:

Right now, the tuning issue is it runs rough, like it is only firing on three cylinders. It is also running rich but I never had time to mess with it before we moved. I have to spend some time figuring out the Kpro software as right now it is just running on the stock program. I also have to turn off the IACV as I deleted that in my build so the ECU is looking for that. Lastly the tach is reading way too low.
 
Much of it could be related to the IACV - it seems to have a broader impact than I would have expected. I'd do that first

If I recall you put the Marshall gauges - so perhaps like me you didn't do the calibration prior to installing it in the cluster - that will do it.
 
Much of it could be related to the IACV - it seems to have a broader impact than I would have expected. I'd do that first

If I recall you put the Marshall gauges - so perhaps like me you didn't do the calibration prior to installing it in the cluster - that will do it.

According to Karcepts, who makes the delete kit for the IACV, the K20a runs just fine without it, but there is a setting in Kpro to turn it off. I just need to find it. Turns out that you were right about not setting the calibration switches on the back of the tach. I reviewed the install directions and there it was plain as day, I just forgot to do it. It is reading correctly now. So glad it wasn't a wiring issue to trace. :rolleyes:
 
So I took some time out to get more educated about Kpro and EFI systems in general. I just posted a thread in the Discussion Forum about Evans Performance Academy. https://xwebforums.com/forum/index.php?threads/fuel-injection-kpro-education.38409/#post-342000. Highly recommended.

I decided to try and figure out why the engine was running rough because when I bought the donor car, the seller had started the engine and it sounded fine and very smooth. I was pretty sure it was not firing on all four cylinders but was not getting any error codes related to that. I first started by unplugging each connector to the fuel injectors to see if that would affect the RPMs. I quickly found that #3 cylinder was not firing. At first, I focused on the injector and the wiring to the injector as I had done a lot of customizing of the K20 harness to tie it into the Fiat. Once I determined that there was nothing wrong with the injector, I moved on to the ignition. I removed the #3 coil and noted that it felt pretty warm even though I had only run the engine for a minute. I pulled the #4 coil and it was cool. I decided to swap the #3 and 4 coils and started the engine again. This time the coil on #3 got pretty hot very quickly and the engine ran even worse so I figured there was something wrong with the wiring to #3.

After some sleuthing with my multimeter to check my wiring, I found that the #3 signal wire was going almost to ground even with the harness unplugged from the ECU. The other cylinders were all open, so that narrowed it down to the signal wire. I started to unwrap the tape from the ECU end of the harness and in about 6 inches, found the problem. I had spliced in another wire to the signal wire to #3. I looked back at my notes for my custom wiring and did a dope slap! :eek: I had tied in the wire to the alternator light on the dash to the signal wire from the alternator to the ECU which was a white/blue wire. The wire to #3 was also white/blue. What happened is I was looking at the wrong connector. The white/blue wire I wanted was in the B connector and I had tied it into the white/blue on the A connector which was the signal wire. Once I corrected that mistake, everything was fine, except that I fried the #3 coil from it being basically on all the time I was driving it like that. I swapped the #3 and 4 coils and now #3 fires fine, but #4 doesn't work. I ordered two new ones as I am not sure how much I may have damaged the #4 for the short time it was on #3 before I corrected the short.

Nothing like eating a little humble pie, but I am glad I was able to figure it out. Doug Martin was also a big help as we were emailing back and forth about it the past couple of days. So far, that was the only wiring error I have found. Also, no leaks of any fluid anywhere. :)
 
Nice sleuthing Rodger! Now that it runs better, we're all looking for a report on the following:
  • How does the Vintage Air A/C work? You did a lot of work there to keep your wife happy.
  • How about the sound system (custom bass, units in the footwell) sound? The design is amazing but does it sound good?
  • Is the upgraded thermostat think from K-Tuned working as expected?
    • Also, how about your very interesting "constant flow" heater core setup?
  • Sway-bar setup: you have a rear option, using it? Corner feel vs. your silver stocker?
Good to hear you're getting back into 'the game'. Take care friend!
 
Hi Darin! Not much to report on your questions yet. I haven’t charged the AC yet as I wanted to make sure everything was running well for a while. I would hate to have charged the system and then have to take some of it out to access something hidden underneath. Now that I have solved the missing cylinder problem, I will probably charge it up in a month or so. Still have to put all the innards of the doors in before it will be a daily driver.

The sound system sounds really good. Very happy about that.

So far the cooling system works fine but I haven’t had it out for a long drive yet. The longest was when I drove it from my old house to my new place last summer, about 15 miles. That was the only time I have seen the temperature gauge move much and it only went up about a third. I drove the car around the other day with my computer plugged in and data logging so I could see the engine temp from the Honda sensor and there was no issue at all but still not a long drive. The engine temp got up to about 155 but the dash gauge had hardly moved. I want to find a better place to put the Fiat temp sensor or see if the Honda sensor will also drive the dash gauge. Where I have it right now, it doesn't really register until the coolant starts to flow to the radiator. It needs to be closer to the flow of the recirculation circuit. The MWB builds I have seen put the sensor on top of the outflow connector, but in my build, nothing comes out of that connector until the thermostat opens to flow coolant to the radiator. The flow to the heater comes out the bottom end of that, so that flow is not near enough to the sensor to register. I moved my recirculation circuit to utilize the outlet that went to the heater core in the Acura, so none of that hot coolant goes near where I have the dash sensor.

As far as the handling goes, again, I haven't driven it enough to really get a feel for it. I only just recently got the toe-in set correctly on the car. It was way off before, but I didn't have a lot of time to mess with it before I had to move. I had tried to do it with the car on the garage floor of my old house, but that was very difficult to do adjustments, as I would have to measure, then jack up the car, make an adjustment, then drop the car, roll it back and forth to get the suspension to settle, then measure again, repeat, etc. Very time consuming. Now, with my lift, it was a piece of cake. I remembered seeing a post on the forum by someone who mentioned using wax paper to sit the tires on so they would rotate as the toe in was adjusted. I still had some one foot square sheets of ABS plastic that I used when I had to hand form the manifolds for my AC ducts. I dug those out and took two sheets, sprayed some Pam on them and put them together to make an almost frictionless pivot under each tire. So easy and quick. The drive I took while data logging was with the new alignment and I could tell it felt really nice. I only have a rear sway bar on right now, so I was not pushing the car at all, but I like it so far. Much tighter than the stock silver one, but this one has Koni coilovers as well as nice 15 performance tires so that has a lot to do with it of course. Future project is to connect up a front bar, but that will be a custom one as well, ala Doug Martin.
 
The engine temp got up to about 155 but the dash gauge had hardly moved. I want to find a better place to put the Fiat temp sensor or see if the Honda sensor will also drive the dash gauge. Where I have it right now, it doesn't really register until the coolant starts to flow to the radiator. It needs to be closer to the flow of the recirculation circuit. The MWB builds I have seen put the sensor on top of the outflow connector, but in my build, nothing comes out of that connector until the thermostat opens to flow coolant to the radiator. The flow to the heater comes out the bottom end of that, so that flow is not near enough to the sensor to register. I moved my recirculation circuit to utilize the outlet that went to the heater core in the Acura, so none of that hot coolant goes near where I have the dash sensor.

I think I put mine in the same place as you - forward face of this housing is what you are referring to, yes?

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I have found much the same - the (124) gauge doesn't obviously move off the stop (120º) until it's over 150ºF - I've sat and watched the temp rise to normal op in the KTuner logging window. It is pretty accurate when the car gets into the normal operating range though. On mine, that is closer to 200ºF than 190ºF, even on the highway, but I don't have a heater core at all.

I checked on some forums and that temp (approx 200ºF) is not abnormal, and that is when the rad fans kick on. I thought maybe it was higher due to the mid - vs.- forward placement of the drivetrain. I still don't have my system completely bled yet, I'm still getting some air out after longer drives. Not sure where a better placement would be - I'm not drilling into the head where the stock Honda sensor goes :D I haven't investigated alternate locations at all myself.

Sensible not to charge the AC yet. I will have to discharge mine when I do do the heater core :(

The niggling suspension/drivetrain thing I have is that on sweeping or hard right turns over uneven roadway (which is everywhere here in NY) there is a knocking from the rear. It's either the corner of the trans hitting the arch that you recommended I relieve further outward (clearly I didn't) or.. it's the oil pan hitting the cross brace of the subframe where the junction sleeve is welded - there is very little gap there on mine.

Shifting the drivetrain a smidge to the right will require lifting and drilling all the engine mount flats oversize, to allow a 1/4" or so shift away from the brace and inner wheel arch. I'm not prepared to deal with that at the moment.
 
I think I put mine in the same place as you - forward face of this housing is what you are referring to, yes?

IMG-20191211-145045.jpg


I have found much the same - the (124) gauge doesn't obviously move off the stop (120º) until it's over 150ºF - I've sat and watched the temp rise to normal op in the KTuner logging window. It is pretty accurate when the car gets into the normal operating range though. On mine, that is closer to 200ºF than 190ºF, even on the highway, but I don't have a heater core at all.

I checked on some forums and that temp (approx 200ºF) is not abnormal, and that is when the rad fans kick on. I thought maybe it was higher due to the mid - vs.- forward placement of the drivetrain. I still don't have my system completely bled yet, I'm still getting some air out after longer drives. Not sure where a better placement would be - I'm not drilling into the head where the stock Honda sensor goes :D I haven't investigated alternate locations at all myself.

Sensible not to charge the AC yet. I will have to discharge mine when I do do the heater core :(

The niggling suspension/drivetrain thing I have is that on sweeping or hard right turns over uneven roadway (which is everywhere here in NY) there is a knocking from the rear. It's either the corner of the trans hitting the arch that you recommended I relieve further outward (clearly I didn't) or.. it's the oil pan hitting the cross brace of the subframe where the junction sleeve is welded - there is very little gap there on mine.

Shifting the drivetrain a smidge to the right will require lifting and drilling all the engine mount flats oversize, to allow a 1/4" or so shift away from the brace and inner wheel arch. I'm not prepared to deal with that at the moment.
Glad to know that you have the same issue with the temp gauge. Yes, your sensor is similar to mine, right where the output to the radiator takes off. I debated tapping into the head at one point when I had the engine out of the car but I wasn’t sure how thick the casting was near the Honda location. Too scary for me as well. I thought about tapping into the recirc circuit which would give good warm up readings but once it switched over to the radiator that would probably cool down.
 
Got the new coil packs today. I replaced the known bad one from #3 and fired it up. What a difference to have all four cylinders.:D Idles smooth and much quieter. Live and learn.
 
After being inspired by Hussein's amazing Dallara transformation and especially the addition of the body stripes and Hot Wheels decal, I decided that maybe mine was too stealth. So, I decided to go for broke and add a couple of decals to mine. :)
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One of the last things to deal with that I have put off until the end are the doors. There was a lot of refurbishing to do regarding the trim pieces, replacing the window fuzzy strips and channel felts, etc. I also wanted to add the mirrors through the vent windows on both sides. This car was an '81, so it only came with the driver's side outside mirror that was through the window. I was able to source a passenger side glass as well as some NOS mirrors for both sides from Henk a few years ago as the original one on the car was severely sun damaged.

I put a layer of Dynamat inside the doors, then added another thin layer of Dynamat insulating foam. Probably not really needed for a car with no roof most of the time, but it gives the doors a much more solid feel when you close them. It will hopefully help with sound during days that I drive with the roof on.
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The next thing I tackled was polishing the bright stainless trim pieces. Polishing stainless is one of my least favorite tasks, so I decided to get it over with and did both the '81 as well as my '79 trim.
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I sourced replacement "fuzzy" strips for the inside door trim from Fiat Plus. Here is the new strip compared to a worn out one.
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I had also gotten some replacement window channel felt from Fiat Plus a few years ago, but found that it was much larger than the original and doesn't really fit in the window channels. On the Fiat Plus website, it says that the ribs need to be trimmed off, but it is still much too big in my mind and the window would not even fit in the channel with that felt. The fuzzy strips were a perfect replacement, but I was disappointed in the felt channels. I thought of trying Auto Ricambi and found that they have a felt replacement for the 124's. The picture looked close to the original on the X so I ordered four strips, two for the '81 and two for the '79. It came yesterday and I found it was a nearly dead on replacement for the original. :) Here is a photo of the original in the middle, the Auto Ricambi on the left and the one from Fiat Plus on the right.
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I used some 3M weatherstrip adhesive to glue the felts into the channels. This photo shows the replated rear channel parts, one assembled, compared to the old one from the '79. There was tons of old undercoating that the dealer had squirted into the doors and it was all over the bottom of the window tracks.
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I started working on the vent window assembly. For those who have never taken one of these apart, the part that puzzled me for a while was how the rubber piece at the top of the window channel comes off. It took me a while of struggling with it before I figured out that there is a hole through the rubber piece and the top of the window channel. Fiat holds the rubber to the channel with some type of plastic rod or pin through the hole that I had to drill out to get the rubber piece off.
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I cut a small piece of 1/8" rod I had laying around and used some of the window urethane to fix those into the holes of the rubber pieces, then used that to glue in the vent windows to the channel.
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Here is the channel assemblies ready to glue the windows in and one with the window in place. Definitely a messy job. It is much harder to keep the urethane off of your fingers with this than when doing the windshield. :( But, just give it a day to set and it cleans up easily.
Vent window channel assembly 01_resize.JPG
Vent window channel assembly 02_resize.JPG
 
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