Tweet
I did this swap like 5 years ago and it always had some hesitation after shifting, but would eventually get up and go. Had a slight miss at idle. Over the 5 years, I've flipped between the festiva and 3-4 other vehicles at any given time so I never really looked into it. Plus, my car was a salt belt car and sat a good amount a couple years ago. I swapped everything into a carby shell.
TLDR >> it's fixed, afaik. It all came down to dirty injectors and running the correct ECU... So, I've driven pretty hard on it the last couple of days and it's a thrill to drive. It's 0-60 in 10 seconds (took video, counted time to 60). Actually, I sent that to C this morning, Arty, via facebook messenger
tbh, I might have some details missing. We've looked at SO much the last 6 weeks. I almost tore the harness out a week ago, not even kidding. I was ready to attack it, cut it open and FIND that problem. Also found a slightly weak ground and replaced the TPS.
Since 5 years ago, early on I had the b61k ecu from skeeter. It ran but had some hesitation after shifts. It ran a little worse than a b3, seriosly...lol. busy with life, never had time to focus on it. Last year we did the advanced suspension and it's a blast. I've been considering some autox just for fun and I needed it to run right.
I also had new plugs, new wires, new cap & rotor, from swapping the car for madness 9 (sep '15). We also soldered some shoddy headlight wiring and soldered in a better fusible link box then, as well. I also remember an IAC failing at one point - replaced it. Tried to clean things as we swapped, clean grounds, etc. Couple years ago? Paul sold/gave me an S vaf but no noticeable change? Don't remember.
March, 23 '17, 1st night of diagnosis, we fixed an awful rattle from the exhaust mani banging on a bolt on the block (I think to the water pipe and it was only at like 1800 rpm) - good harmonics, right? We checked fuel pressure (30 w/ vac, 38 w/no vac -- "low" but still in spec), plugs (medium lean with weird hard deposits), compression (120-150), couldn't find any false air / vacuum leaks, started pulling one wire at a time while running (put it to exhaust mani to ground), 1 & 2 reacted.. 3 & 4 did not. pulled injectors and ghetto cleaned them with a vacuum cap, carb cleaner and 9v power supply. #3 cleaned up and #4 did not. Grabbed one out of another b6 we have and cleaned it and threw them back in. Now 1, 2, 4 reacted and 3 did not. We concluded we would check #3 in the coming weeks.
We changed the computer from B61K to B376 at some point, over the course of three thursday nights... might have been this one. It's important because it didn't seem to run any different at idle. We also swapped VAF's and it ran the same. But in the coming weeks, it ran crappy, would occasionally lean out really bad but stay running. Almost didn't make it home one night. It would stutter SO bad and then feather the gas to 3000rpm and then it'd take off like a rocket. IMO it's a combination of mapping, injector size, and clogged injector #3 - likely sticking shut at lower rpm.
We also swapped a coil and no change. Then we quickly swapped in a disty and no change (from optical to halls, too). Forgot to adjust timing and thought I wasn't going to make it home.. realized this halfway but I had to get to work. Took a different car, no time.
Over the coming weeks, started reaching out to Rob, Charlie, Ryal, Jim, Dennis, Alex, Ben, Ryan, maybe some others. Much thanks to everyone, seriously. One week, we cleaned grounds and tried some other things.
So, starting out, we really believed it was a ground issue. I had a ground issue where the pass strut tower ground was weak and it was cutting off the fuel pump under load / call for fuel.
Also bought an AEM wideband with narrowband input for like $160. Con's: $$ semi-spendy Pro's: can watch the meter, heated sensor goes closed loop in like 5-30 seconds (depends on temp) vs maybe warming up by the time I get to work. So, MPG smart. I could watch it blip lean at cruising speeds and then associate that with quarter-half a second before dead spots while driving. Lots of good things here.
We wired it to the cigarette outlet which would be fine except it took me like 2 weeks to find out my accessory circuit has half a volt drop, literally. Headlights would steal some power, but the blower motor stole everything.. so it ran leaner with the headlights on and I didn't know to associate it. And I don't even have a radio installed, PO botched the wiring, complete cluster.
So one day, I was checking resistance on the injector harness, checking the ECT (good), wanted to check the TPS circuits and found that it had a huge gap in the finger to holder slot. like .025" or more. That's a lot of air getting in and still being on the idle circuit. We had checked the TPS before but didn't see this gap. Shoved a credit card piece in there and it was perfect. Put it back together and went for a drive, figured this was the fix, nope. (It was much more responsive to throttle, though.) I used the blower motor on the highway and it went --- full lean. That's when I dug into the EVTM and started searching other circuits (still believed it would be ground issue - not an electrical pro). I pulled the DASH, dropped the steering column, the community ground behind the drivers speaker was slightly loose but made no change. The ground to the back of the dash was tight. Pulled it and ran a jumper cable to the battery and tested grounds. It was weird. So I'm sitting there checking grounds and the ignition is staring at me and I think, why not. So 12.6, 12.6, 12.6, etc, 12.1. What?! So I switch to positive and started checking the hot side for voltage drop: 20vdc setting, pos for one lead, pos for the other. Sure enough, .48v drop - ideally it should be .00-.02, but apparently .3v is still acceptable? - I can promise you it isn't if it involves your input oxygen sensor competing for voltage. The o2 is so sensitive that you can only check the voltage at the ecu for like 3-4 seconds, then it starts to lean out. It's constantly adjusting from like .2-.8v iirc.
Lots of things were checked between above and a week ago. We eliminated the IAC and tried that for a while. Eventually put it back in place as I verified it was working. I theorized that it was sticking open allowing lean condition. There is a bypass in the VAF that is unmetered, and the IAC does operate in closed loop according to my 91 shop manual. No joy there. I had to wire the O2 to something else that was non-acc, so I went with wiring directly into the safe side of the R.Wiper fuse. headlights, wipers, blower motor, all on, all off, etc and no change to my AFR. That was good. I think my new TPS came in ($20 RA), installed that. Started monitoring sensors, like the ECT, the VAF (rheostat especially - pretty cool stuff), tried to monitor the crank position sensor, any and all source voltages (4.99-5.02v) those were good. So progress is being made, eliminating possibilities, learning, but still not finding the issue. Note, still running the B3 ecu (thought it would give me more fuel, kept it in) and still leaning out. I even found a ground drop of like 3 volts?! Thought that was my problem. that evolved into a serious gremlin hunt that almost sent me to pulling the dash completely and ripping apart the harness. That turned out to be some cali plug for diagnostics....lame. I also tried a different ignition harness and no change. Still stumped...
Now, Saturday night, steve, nate, and myself tear out the injectors. Nate sourced a timer and chopped up an intake, we put together a harness and modified the festy plugs to fit on pretty much any denso injectors, we started flow testing them. 5 years ago, I had bought $150 in injector parts, pump, supplies to rebuild injectors, never happened. Now it happened. Still needs some refining. It proved to show that my #1 and #3 injectors were low on flow. #1 not so bad, #3 like 10%. We put like 10-12 injectors through it. cleaned them, flowed, cleaned more, flowed. One of mine that flowed the best, we used as the match to injector. Finally found 4 that flowed well, put it all back together. Drove home, drove great. idled awesome. no lean conditions, was really watching it at cruising throttle and then call to load for it to richen up. In 35 minute drive home, only twice? did it kind of take some time to richen up. Now, compare, the richest it was going up to Skeeter was 13.0-13.3. Coming home, it was 11.9-12.2, on occasion it would hit 10 for a ms.
Few days later, I notice it kind of miss...don't think much of it. Next few days, it goes back to running crappy. And it was weird, it was kinda surgy on acceleration. like it would incrementally accelerate. And it was bouncing rich-lean, it wouldn't just stay close. Even while cruising. It would still richen up to 12.0 but while cruising it couldn't make up its mind. Yesterday, I measured resistance on the injectors. 13.2 (supposedly 1st gen b6 is 12.7) on all 4. half an ohm can be important but seems to be high spec. Also tried running it with the vac line pulled from the regulator to up the pressure to verified 38psi previously. No joy.
TOO LONG?! LOL 10000 characters
TLDR >> it's fixed, afaik. It all came down to dirty injectors and running the correct ECU... So, I've driven pretty hard on it the last couple of days and it's a thrill to drive. It's 0-60 in 10 seconds (took video, counted time to 60). Actually, I sent that to C this morning, Arty, via facebook messenger
tbh, I might have some details missing. We've looked at SO much the last 6 weeks. I almost tore the harness out a week ago, not even kidding. I was ready to attack it, cut it open and FIND that problem. Also found a slightly weak ground and replaced the TPS.
Since 5 years ago, early on I had the b61k ecu from skeeter. It ran but had some hesitation after shifts. It ran a little worse than a b3, seriosly...lol. busy with life, never had time to focus on it. Last year we did the advanced suspension and it's a blast. I've been considering some autox just for fun and I needed it to run right.
I also had new plugs, new wires, new cap & rotor, from swapping the car for madness 9 (sep '15). We also soldered some shoddy headlight wiring and soldered in a better fusible link box then, as well. I also remember an IAC failing at one point - replaced it. Tried to clean things as we swapped, clean grounds, etc. Couple years ago? Paul sold/gave me an S vaf but no noticeable change? Don't remember.
March, 23 '17, 1st night of diagnosis, we fixed an awful rattle from the exhaust mani banging on a bolt on the block (I think to the water pipe and it was only at like 1800 rpm) - good harmonics, right? We checked fuel pressure (30 w/ vac, 38 w/no vac -- "low" but still in spec), plugs (medium lean with weird hard deposits), compression (120-150), couldn't find any false air / vacuum leaks, started pulling one wire at a time while running (put it to exhaust mani to ground), 1 & 2 reacted.. 3 & 4 did not. pulled injectors and ghetto cleaned them with a vacuum cap, carb cleaner and 9v power supply. #3 cleaned up and #4 did not. Grabbed one out of another b6 we have and cleaned it and threw them back in. Now 1, 2, 4 reacted and 3 did not. We concluded we would check #3 in the coming weeks.
We changed the computer from B61K to B376 at some point, over the course of three thursday nights... might have been this one. It's important because it didn't seem to run any different at idle. We also swapped VAF's and it ran the same. But in the coming weeks, it ran crappy, would occasionally lean out really bad but stay running. Almost didn't make it home one night. It would stutter SO bad and then feather the gas to 3000rpm and then it'd take off like a rocket. IMO it's a combination of mapping, injector size, and clogged injector #3 - likely sticking shut at lower rpm.
We also swapped a coil and no change. Then we quickly swapped in a disty and no change (from optical to halls, too). Forgot to adjust timing and thought I wasn't going to make it home.. realized this halfway but I had to get to work. Took a different car, no time.
Over the coming weeks, started reaching out to Rob, Charlie, Ryal, Jim, Dennis, Alex, Ben, Ryan, maybe some others. Much thanks to everyone, seriously. One week, we cleaned grounds and tried some other things.
So, starting out, we really believed it was a ground issue. I had a ground issue where the pass strut tower ground was weak and it was cutting off the fuel pump under load / call for fuel.
Also bought an AEM wideband with narrowband input for like $160. Con's: $$ semi-spendy Pro's: can watch the meter, heated sensor goes closed loop in like 5-30 seconds (depends on temp) vs maybe warming up by the time I get to work. So, MPG smart. I could watch it blip lean at cruising speeds and then associate that with quarter-half a second before dead spots while driving. Lots of good things here.
We wired it to the cigarette outlet which would be fine except it took me like 2 weeks to find out my accessory circuit has half a volt drop, literally. Headlights would steal some power, but the blower motor stole everything.. so it ran leaner with the headlights on and I didn't know to associate it. And I don't even have a radio installed, PO botched the wiring, complete cluster.
So one day, I was checking resistance on the injector harness, checking the ECT (good), wanted to check the TPS circuits and found that it had a huge gap in the finger to holder slot. like .025" or more. That's a lot of air getting in and still being on the idle circuit. We had checked the TPS before but didn't see this gap. Shoved a credit card piece in there and it was perfect. Put it back together and went for a drive, figured this was the fix, nope. (It was much more responsive to throttle, though.) I used the blower motor on the highway and it went --- full lean. That's when I dug into the EVTM and started searching other circuits (still believed it would be ground issue - not an electrical pro). I pulled the DASH, dropped the steering column, the community ground behind the drivers speaker was slightly loose but made no change. The ground to the back of the dash was tight. Pulled it and ran a jumper cable to the battery and tested grounds. It was weird. So I'm sitting there checking grounds and the ignition is staring at me and I think, why not. So 12.6, 12.6, 12.6, etc, 12.1. What?! So I switch to positive and started checking the hot side for voltage drop: 20vdc setting, pos for one lead, pos for the other. Sure enough, .48v drop - ideally it should be .00-.02, but apparently .3v is still acceptable? - I can promise you it isn't if it involves your input oxygen sensor competing for voltage. The o2 is so sensitive that you can only check the voltage at the ecu for like 3-4 seconds, then it starts to lean out. It's constantly adjusting from like .2-.8v iirc.
Lots of things were checked between above and a week ago. We eliminated the IAC and tried that for a while. Eventually put it back in place as I verified it was working. I theorized that it was sticking open allowing lean condition. There is a bypass in the VAF that is unmetered, and the IAC does operate in closed loop according to my 91 shop manual. No joy there. I had to wire the O2 to something else that was non-acc, so I went with wiring directly into the safe side of the R.Wiper fuse. headlights, wipers, blower motor, all on, all off, etc and no change to my AFR. That was good. I think my new TPS came in ($20 RA), installed that. Started monitoring sensors, like the ECT, the VAF (rheostat especially - pretty cool stuff), tried to monitor the crank position sensor, any and all source voltages (4.99-5.02v) those were good. So progress is being made, eliminating possibilities, learning, but still not finding the issue. Note, still running the B3 ecu (thought it would give me more fuel, kept it in) and still leaning out. I even found a ground drop of like 3 volts?! Thought that was my problem. that evolved into a serious gremlin hunt that almost sent me to pulling the dash completely and ripping apart the harness. That turned out to be some cali plug for diagnostics....lame. I also tried a different ignition harness and no change. Still stumped...
Now, Saturday night, steve, nate, and myself tear out the injectors. Nate sourced a timer and chopped up an intake, we put together a harness and modified the festy plugs to fit on pretty much any denso injectors, we started flow testing them. 5 years ago, I had bought $150 in injector parts, pump, supplies to rebuild injectors, never happened. Now it happened. Still needs some refining. It proved to show that my #1 and #3 injectors were low on flow. #1 not so bad, #3 like 10%. We put like 10-12 injectors through it. cleaned them, flowed, cleaned more, flowed. One of mine that flowed the best, we used as the match to injector. Finally found 4 that flowed well, put it all back together. Drove home, drove great. idled awesome. no lean conditions, was really watching it at cruising throttle and then call to load for it to richen up. In 35 minute drive home, only twice? did it kind of take some time to richen up. Now, compare, the richest it was going up to Skeeter was 13.0-13.3. Coming home, it was 11.9-12.2, on occasion it would hit 10 for a ms.
Few days later, I notice it kind of miss...don't think much of it. Next few days, it goes back to running crappy. And it was weird, it was kinda surgy on acceleration. like it would incrementally accelerate. And it was bouncing rich-lean, it wouldn't just stay close. Even while cruising. It would still richen up to 12.0 but while cruising it couldn't make up its mind. Yesterday, I measured resistance on the injectors. 13.2 (supposedly 1st gen b6 is 12.7) on all 4. half an ohm can be important but seems to be high spec. Also tried running it with the vac line pulled from the regulator to up the pressure to verified 38psi previously. No joy.
TOO LONG?! LOL 10000 characters
Comment