infernosg

If you're keeping it mostly stock I'd stick to established vendors like Racing Beat. Though on the expensive side, their aftermarket parts are well built and offer conservative improvements over stock.

Thanks! The wiring was a pain in the *** but fortunately everything still worked in the end. Basically all that's left of the stock harness are the wires for the lights and fan motor. I got a little overzealous in the trimming and now I'm kicking myself for stripping out the coolant level, oil level, and brake level sensors. Unfortunately, adding them back would be a huge hassle.

chuyler1

iTrader: (1)

Finally got around to reading through your build thread. Lots of great work here. Can you elaborate on your decision to have the custom intake made vs using one of the cast side-draft manifolds? It looks like you may get slightly longer runners.

infernosg

The main reason is port matching to my throttle bodies and intake ports. There would have been a lot of boring/honing of the off-the-shelf manifolds. Another reason is equal runner lengths. The off-the-shelf manifolds usually have slightly longer runners for the rear rotor in order to make the carburetor sit level since the engine is mounted at a slightly downward angle. Also, there is weight. I can guarantee my intake is significantly lighter than the cast aluminum ones. My manifold isn't perfect, though. The biggest change I want to make is to add two more vacuum ports to the tops of the runners.

I've got it running on a pretty conservative tune right now. The air-to-fuel ratio generally sticks around 13:1, which is rich but safe. I'm at around 1300 miles of the 2000-mile break-in and am taking the car up to 7000 RPM currently. I need to lean out the higher RPM/lower MAP points since air-to-fuel rations are dipping below 11:1 up there. The goal is 9000 RPM by 2000 miles and maybe even higher depending on the power curves when it's tuned. One of the things I'm struggling with right now are low oil temperatures due to my cooling system and the cold weather. It's hard to keep the oil temperature above 150 degrees with ambient temperatures at or below 50. So even though coolant temperatures stay around 179-181 degrees the engine isn't really "warmed up." I'm running 10W30 oil now but I'm still apprehensive about taking it to higher engine speeds with such low oil temperatures.

chuyler1

iTrader: (1)

Good stuff, maybe just slap a piece of cardboard over the oil cooler for the winter?

I'd be curious to see your fuel and timing tables. I was struggling with off idle stalling before I parked my REPU for the winter. Have you had any similar issues? I gave up on the MAP tune and resorted to TPS and started over. It drives around fine but every time I pull up to a stop sign and dies on me and I can't for the life of me figure it out. Once I fire it up again I'm good to go. It's like closed throttle high RPM decel floods or leans out the system and it needs to be cleared before it can idle again.

13.bREW

Are you tuning your car yourself? and are you using a MAP reference or TPS reference for load in your tables? I'm slowly figuring out my fuel map using TPS but it looks crazy with large spikes of VE in low RPM and seemingly low numbers in high rpm. I've got a decent vacuum block and a short distance to the ECU but I still didn't think ITB rotaries would make a constant enough vac signal.

infernosg

I've seriously thought about doing that or at least covering part of it. Knowing me I'd forget about it though...

I'm having similar issues. It was worse when I was tuning with TPS but for me it seems to be temperature-related. When I first switched to a MAP tune back in October it would only want to stall when the car was still warming up. I've also noticed it wants to idle better when my oil temperatures are above 150 degrees, which is rare lately. I've been struggling with an explanation too. I don't have any kind of fuel cut since I premix but I have a zero-throttle fuel table so my mixtures go lean off-throttle above idle. I wonder if it's something to do with fuel wetting/not wetting down the walls of the intake manifold or manifold vacuum. I've noticed I pull more vacuum slightly above idle than at idle. At idle I pull -7 to -8 psi but it'll go as low as -10 or -11 psi while cruising under very light throttle or closed throttle at higher engine speeds.

Not completely. I got an initial TPS-based tune and tweaked the fuel curves until the car ran and drove. After that I switched to a MAP-based tune with someone's help and have made some small modifications. I was told the same thing about MAP-based tunes with ITB's but my car has been driving better since switching. I think the biggest issue is idle. See above - I pull less vacuum at idle than I do at low-load cruising. Due to that and a slightly unstable MAP signal at idle I have a zero-throttle fuel map. Otherwise, I think I'd have weird peaks/valleys in the base map as well. On advice from others I am using a 1 bar external MAP sensor mounted as close to my vacuum signal as possible. I think I have less than 12" of total line length.

chuyler1

iTrader: (1)

So far, I've been tuning it myself by reading articles and forum posts on the Adaptronic website. I want to get a decent road tune going before I take it to someone for finer tuning. Tuners get paid by the hour, and they can only do so much in a given time. Of course, putting the vehicle on a dyno makes it a lot easier to hold certain sections of the map so you can dial it in...but I don't want them to spend time debugging mundane stuff only for me to have to fix things later. I'm also planning on street porting the motor in the next year or so, and I don't want to pay for tuning services twice.

I tried the MAP reference and it didn't work well because it was basically an on/off switch between idle vacuum and wide open atmosphere when I got to as little as 5% throttle. There is also a small hiccup in the vacuum signal. At first I thought it was a change between front and rear rotor so I was mucking with the balancing screws but no amount of changing gave a steady reading at idle. As I recall, the motor always had a bit of a studder with the old carb so it could just be internal, one bad apex seal or something. Anyway, now I'm using the TPS reference and it has made it much easier. It gives me a higher resolution between off and on throttle. The resulting map is relatively flat but slightly increasing as RPMs increase. I gave up on the "auto tune" as it was picking values that were not good for the overall range of the given cell it was changing. I have a few steep hills near me that I can drive up. I start logging, make a few pulls at various RPMs, make some adjustments at the top, then repeat. Of course the truck keep stalling on the way back down....I really need to figure out that closed throttle deccel issue.

13.bREW

Interesting, I may have to try that later down the road. I haven't tried setting up a separate fuel comp table for zero throttle I figured the separate table setup would be for turbo cars. If I cant figure out how to make my car come down off RPM above 3000 after I lift the throttle up there this may be able to solve my problem. The more I learn about tuning the more I think I like it lol.

Chuyler- something I've learned while road tuning is start at the lightest load you can create in your engine without it dying like 2% throttle at 1500 RPM. Then go up the hill trying to hold 1500RPM all the way up to 100% throttle as slow as you can to get many log points, left foot braking will help keep a constant RPM. Adjust that row then move up to 2000RPM and repeat to 5000RPM. its time consuming but it simulates the steady state tuning method that a shop would use on a Dyno.

chuyler1

iTrader: (1)

Yup, that's exactly what I've been doing. I started with letting the adaptive tuning feature make the changes as I held an RPM and throttle position, but it just wasn't picking values that were good for the range of the cell. So I switched to just data logging and checking it afterward.

chuyler1

iTrader: (1)

@infernosg, you're only running 2 injectors right? Do you know what size?

infernosg

That's interesting. I get a smooth MAP curve that runs from about -11 psi up to atmospheric pressure. The only weird thing is my idle MAP is slightly higher (less negative) than my cruising MAP, which I noted before. What type of MAP sensor are you using and how is it setup? I'm using an external GM 1-bar sensor and I was told to mount it as high as possible in the engine bay and as close to the vacuum source with as little hose as possible.

Yeah, Haltech recommends the zero throttle table for anyone who doesn't have a stable idle MAP signal. While that isn't my case my idle MAP is less negative than my cruising MAP. Rather than have a weird dip/bump in my base fuel map I decided to use the zero throttle table.

I really wish I had some good roads for tuning around here. I don't really have any consistent roads - lots of small hills/turns that make it hard to maintain a given MAP/RPM while also paying attention to driving. I do need to work on my tune though. When it was warmer last week I took it out and I'm really rich up top. My wideband was pegged at 10:1 above 6000 RPM and it was noticeably bogging down.

Yeah, just two ID1000's. I'm running 45 psi of fuel pressure and according to Injector Dynamics' tables I should be seeing about 1035 cc/min from each of them. Based on my observations above so far I'm having no issues with fuel delivery up to 7000 RPM and idle is stable at 1000 RPM at 13:1 air:fuel. It might not work any leaner than that though because the injector duty cycle is like 4%.

chuyler1

iTrader: (1)

Well, I've got 4 barrels only slightly smaller than yours and I'm running 4 Edelbrock 425cc injectors on my REPU. They idle around 2% duty cycle at 35psi. I was at 45psi but I figured lowering it would provide a slightly longer cycle. Today I messed with a few more idle parameters and actually made a bit of progress. There were two sections I hadn't really touched on the Adaptronic ECU because the doc said not to mess with them unless the car is fully tuned....well I guess I'm tuned enough to at least start messing with them. The first cluster of settings deals with immediate off throttle usage of the IACV. It opens it up for a period of time specified to ease the drop in RPM. The Nikki carb does this too if you listen closely. The second cluster of settings deals with using ignition timing to stabilize idle. Using some advance also helps "catch" the RPMs as they drop from a high-vacuum (22Kpa) coast down to moderate-vacuum (40Kpa) idle. Again, this is something the old rats nest would have done on a carb'd rotary. The solenoids would have locked the ignition on my 1st gen at 10 degrees for a second or two, then release the vacuum advance allowing it to settle back down to 0 degrees. I still have to dial in the settings, but a quick lap around the block and I saw it holding higher RPM when i pushed the clutch in, so I'm on the right track. Part of what holds me back is the lack of a digital clutch switch or neutral switch. My truck is too old to have those. I can probably fabricate a clutch switch, but knowing when the transmission is in neutral isn't as easy.

That leaves the transient throttle issue between shifting gears. The injectors just don't ramp up fast enough when I punch the throttle in the next gear. I get a full lean reading for about 2 seconds and then it wakes up and starts pulling. I'm going to mess with longer transient values. Last time I did that, I flooded the motor at idle revving it to test the changes. There's got to be a happy medium between asynchronous gain and duration, and this mysterious other setting called persistence that is in the software but not in the documentation. Only one thread on adaptronic's website mentions it, and the user suggested a value of 20. I know going higher floods, and going lower causes more immediate lean...but I don't know how it relates to the other two variables. Do I increase persistence and lower asynch gain or vice versa? I dunno, I just need more time...and it's winter so there are few days where the salt is clear. I had this weekend to make some progress but snow is coming tonight so that'll be all for probably the next month.

infernosg

Hmm, that's good news so maybe I do have some room to work with. Back when I first got the car running I had some issues with it idling at ratios above 13:1. It would hold 13.5 or 14:1 for a bit then start to creep lean. I was reading about minimum duty cycles and apparently there is a limit, but it's dependent on many factors. It's possible that at such low duty cycles there just isn't enough time for sufficient fuel to leave the injectors. I don't have any kind of idle control other than a throttle stop. Maybe one day I'll get an IACV if I can't stop the car from stalling but it doesn't seem to be an issue in warmer weather. You also might want to look at bumping up the fuel at lower engine speeds as well. In my case I both fatten up the fuel curve and advance ignition timing at speeds below idle. I lost my clutch switch when I adapted my S5 harness into a S4 car. I didn't realize the clutch switches were different and kept the S4 switch, which isn't compatible with the S5 harness. It wouldn't be too hard to find another S5 switch and make it work. I'm just not sure it's worth it.

I generally don't have too much of an issue with lean spots between gears if time the throttle correctly. I have a lightweight flywheel and clutch so I can shift quickly so there's little time off throttle. If I take too much time I experience what you're explaining. Again, it has to be something with fuel wetting/not wetting down the walls of the intake manifold. I'm still playing with the transient settings as well. No matter how I change them I can't seem to get rid of the initial lean condition. I got to the same point where you were: bumped up everything so high it would flood while revving it in neutral. Right now I can roll onto the throttle with moderate speed and be okay but stabbing it will cause it to go full lean for a second. Like you, I think asynchronous injection is one part of it. I wonder if the "persistence" you mention is similar to "decay" in the Haltech. My basic understanding is it is the rate at which the transient enrichment tapers off. If that's the case, that's not my problem. After the initial lean spike I'll go rich as intended. It just like I need to speed up the initial response of the transient enrichment. One thought I have is it could be a result of my injector position. Like yours, mine are located pretty high up just behind the throttle plate. Perhaps it just takes time for fuel to get from there into the ports. I have a potential solution if that turns out to be the case: I purchased an aftermarket primary fuel rail from Full Function Engineering and I pair of the older ID725's from Injector Dynamics. If needed, I'll run a parallel fuel system where these inject fuel right into the primary ports.

13.bREW

That's strange your having such issues with getting the 1000CC to idle that lean. My car runs well at around 13.5 AFR I'm running ID1050X with 45PSI. I have the idle timing set at 9* I was having idle issues at 15* so I slowly retarded it until it started holding steady RPM.

Lavitzlegend

iTrader: (3)

Where are your injectors located?

infernosg

I haven't tried again since switching to the MAP/zero-throttle tune I have now. That was also back when the car had less than 300 miles on the rebuild. I've been keeping my air:fuel ratio around 13:1 throughout the break-in process to be safe. I think my idle timing was set to 0 degrees back then as well. It's up to 14 degrees now. What kind of injector duty cycles are you seeing at idle?

13.bREW

Lavitzlegend- They are all 4 located roughly 1" below my TB plates. the RB manifold is fairly short also so that may be of some help.

Infernosg- At risk of sounding like a dummy I haven't had my data logs set up for injector duty cycle. I'll change that and look at the logs when I got to do more road tuning today and let you know.

13.bREW

Injector Location

infernosg

13bREW - is that an EFI Hardware throttle body? It looks really similar to mine. Are you running 4x IDx1050's? Your injectors are closer to the intake ports than mine. I'm guessing 4-6 inches closer. If transient throttle still proves to be an issue after the car is broken-in and tuned to the best it can be I have a FFE primary fuel kit and some older ID725's I can install. I was really hoping to avoid parallel fuel lines and staged injectors though. With that setup are you finding fuel/oil in your vacuum lines?

I took the car out for a spin yesterday. It's being a bit of a basket case with this crazy weather. Last week, with temperatures in the mid-60's it wanted to run rich and I was really bogging down above 5000 RPM. Yesterday, with temperatures near 60 it ran pretty well at or near wide-open-throttle but the cruising air:fuel ratios were leaner than I remembered. It also wanted to stall out constantly in the first 5 minutes of driving. The only difference between this week and last week other than ~5 degrees of ambient temperature is a slight bump in sub-idle ignition timing in an effort to prevent the stalling.

chuyler1

iTrader: (1)

I know 13bREW's build isn't finished in this photo but I see two major issues.

1) The heat shield is actually blocking airflow across the header. The front edge (closest to the front of the car) should be bent upward, not downward. When your car is moving, air is passing through the radiator and makes its way toward the back of the engine bay. The idea of the shield is to catch that airflow, direct it across the header, and dump that hot air out the back. Your setup breaks the natural flow of air and probably contributes to engine bay temps rather than preventing them.

2) You are using a heat shield as a mount for your vacuum manifold. As infernosg has pointed out, he gets fuel mixture in his lines, as have I. You will too. The nature of the ITBs with vacuum ports below the injectors is that as the engine pulses, it will pull a small amount of air from the other side, air that is filled with fuel. Over time, the fuel left in the vacuum line will condense and pool to the lowest location in the line. In your case, that's the vacuum manifold sitting right on top of a hot heat shield. What do you think is going to happen if one of those vacuum lines pops off or cracks under the extreme heat?

If you want to pull vacuum from both throttle bodies, I don't think there is a way to prevent the lines from getting filled with fuel. It's just best to make sure that when the fuel condenses it trickles back into the intake manifold. Another option could be to connect an IACV to the vacuum manifold so that it will pull fresh air through the lines when activated.

13.bREW

Good thinking I haven't been following any guidelines and this is my first true "figure **** out" build so the advise is well received. I'll put those items on the to do list.

infernosg

Still been slowly putting miles on the car. Over 1300 now and regularly ringing 1st and 2nd gears out to 7000 RPM. I bumped up the sub-idle ignition timing and that seems to help somewhat. Although, after the one day of it running rich it suddenly started running leaner. Cruise air:fuel ratios went from ~13:1 to ~14:1 and it was noticeably leaning out between shifts. The only good thing was it leaned out up top so I wasn't bogging down with fuel above 5000 RPM. I found the culprit today: my IAT reading was pegged at 176 degrees. I'd noticed this high reading after a previous drive but assumed it was because of the warmer ambient temperatures and nature of my intake. Regardless, 176 degrees at startup isn't right. After digging into ECU Manager I discovered that's the value assigned to the IAT input if the voltage falls out of the expected range (approx. 0-5V). Since I'm using volumetric efficiency to tune, which uses IAT, this affects more than just my air temperature correction tables for fuel and timing. Makes sense. The ECU thought the incoming air was hot and so it was pulling fuel, which explains the lean(er) condition. I checked the sensor when I got home and have no continuity across the terminals so I assume it's dead. I just need to verify I'm still seeing ~5V in the wiring harness to confirm that's not the problem. Seeing as IAT sensors only run ~$30 I'm not too concerned. This is my second sensor to fail since getting the car to run last August. The first was an oxygen sensor in December.

chuyler1

iTrader: (1)

I had the same thing happen, sort of. In my case the connector pins weren't making a solid contact, but it was the IAT and it was jumping around causing the AFRs to bounce around. Only noticed it from the log.

infernosg

I confirmed it's the sensor itself. I get no continuity across its pins and I've confirmed the harness is getting 5V on one side and continuity to ground on the other. Hopefully I'll have a new one in a couple days. There's at least one benefit of Haltech using readily-available GM sensors.

infernosg

I got a replacement IAT sensor, plugged it in and everything is running like normal again. The first thing I noticed about the new sensor was I could clearly see the sensor element (a thermistor) inside its protective plastic "cage." Upon further inspection this was nowhere to be found in my old sensor, which would confirm why I was seeing no continuity across the pins. Based on the new one I'm not sure how it could have escaped the cage if it's a similar design. I'm also not liking the idea of a piece of sensor breaking off and going through my engine. The car doesn't seem to be running any worse-for-wear but I suppose at least a compression check is in order.