Scrappy_Brap

Currently am in a pickle, I have a 6 port bridge with 9.4:1 rotors, 550cc injectors, t2 intake port matched to the 6 port, Yukon coils running on ms3-pro, I can currently get the car to start (pouring oil down the intake to build up compression due to fresh seals and used housings) and it'll run for about 10 seconds until it slowly starts to bogg down until it stalls, I'm wondering if the fuel table needs to be upped some, anyone have some insights on what some required fuel values for a bridgeport is?

Aaron Cake

iTrader: (1)

Push start it with another vehicle.

Req'd fuel is the same as another 13B with the same sized injectors.

Based on your description, it sounds like the engine is leaning out after the afterstart. Increase fuel.

Scrappy_Brap

I've push started it previously, (before it wouldn't even start with oil down the intake) before I make another attempt at push starting Id like to make sure I have some decent tables, I've based this build off of your project TiiNa, so I'm very happy that you're on this thread!! The car will be getting a t70 with a .96AR after I get it running NA and get it broken in, aiming for about the 450hp range. I'm attaching some pics of some tables if you wouldn't mind giving me your opinion of any errors you see

Scrappy_Brap

Another

Scrappy_Brap

Ase

Scrappy_Brap

Cranking pulse widths (don't mind the dip in the taper we were messing around with different values and the temp was around that taper)

Aaron Cake

iTrader: (1)

Post your MSQ and a datalog of an attempted start. Do you have any sort of AFR monitoring? A wideband isn't going to read very well during cranking and startup but it can provide some clues.

There seems to be multiple threads about this issue. That's going to make it difficult for people to help if the information is spread around. I will only be replying to this thread.

The ports that you have cut, as I believe I mentioned in one of the other threads, are going to reduce cranking airflow to almost nothing and decrease low RPM air velocity hugely over a less aggressive port. Thus it is going to take a lot more fuel than you think to start and idle the car.

I tuned a car with ports very similar (though the eyebrow followed the RB bridgeport template).

It took about 14MS of cranking PW on 720CC injectors at about 20C ambient temperatures to reliably start the car.

Idle of around 1400 RPM took about 2.4mS for an AFR if roughly 13.5 or so.

Fresh seals on a used housings, combined with high overlap ports, mean that if the map isn't damn near perfect then starting is going to be an adventure. In all honesty a push start is the easiest thing at this point. As soon as it starts, hold the engine around 3000 RPM where it has the best change to stay alive. Then tune the VE table live to keep the engine running until it is fully warmed up. Once it's warmed up, have someone else turn the hard idle stop screw on the throttle body out so that if you let off the throttle, the engine is idling at around 2000 RPM. Keep it there for at least half an hour or so. If possible, try to drive the car (someone will need to work on the VE table while driving) to at least establish a VERY rough tune. Keep it on the rich side.

From there, at least you have a base so that the starting and cranking corrections have a clos enough VE table to work off of. More likely if the cranking PW isn't around 14MS and your idle isn't around 2.5, then the car is lean.

Typically, starting then dying is more a lean issue than a rich issue.

Scrappy_Brap

apologies about the multiple threads, Ive just grown very impatient with the car lately and Im on my last leg with the whole matter... Ive been trying to get it to start for literally 3 months straight now and Ive just run out of ideas so I posted it in a couple of different sections hoping someone will have had the same exact issue and can give me some light on the situation.

I do have a datalog I sent to Matt at DIY but a majority of the datalog is cranking with one fire up if I remember correctly and feel sorry for anyone who asks for it so I will save you the headache of saying you don't have to look at it lol.

My car doesn't have an idle valve, could that be serving as a potential issue as well? The guy who built my engine said I shouldn't need one to Idle... but that seems far fetched IMO.

I posted the tune below. I would show my engine builder but Ive come to find out that his knowledge isn't as creditable as he makes it out to be... So long story short I bit off more than I can chew.

papiogxl

iTrader: (6)

You probably won't need on to idle if you set idle a bit high, the issue is with starting without an idle valve. You may need to crack the throttle to accommodate it.

Scrappy_Brap

That's what I thought, I've been starting it with the throttle reading 15-20%, sometimes it'll start with the throttle held to the floor as well

Aaron Cake

iTrader: (1)

You don't need an idle vale because an idle with a bridgeport is typically high enough that it is fairly stable (brap brap brap). The PID algorithm in the MS3 is probably going to have a hard time dealing with intrinsic fluctuations from engine cycle to engine cycle. I don't see it regulating a bridgeport very well.

But you would want an idle valve for open loop accelerated warmup. Will make it far easier to start up and idle well cold.

I know Matt at DIY, but I don't know him well enough to have access to his email account. Having that datalog would probably give some clues.

Do you have a wideband?

In cranking settings, you may have better luck setting "Batch fire during cranking".

What is your fuel pressure?

With 550CC injectors, you need more fuel to start the car. If you aren't seeing about 14MS during cranking, it's not enough fuel.

That's why a push start is so helpful. You can immediately get the car up to higher RPM where fuel is less critical, then hold at that RPM while you work the VE table.

Scrappy_Brap

I'll post the datalog later on today, (busy painting my master bedroom I just finished lol)

And what would putting batch fire while cranking help? (New to tuning so please don't flame me for asking)

I haven't checked fuel pressure yet, I plan on checking it and compression once some of this snow melts so I can get into the garage.

I will have to find someone to push start the car because I feel like you made a good point about push starting it and holding it at 3k and start using the autotune feature, what should my target AFRs be? I've always heard bridges love fuel, (yes I do have a wideband, it's an innovate MTX-L)

Scrappy_Brap

Also another stupid question, is there a way to have the ecu control the idle? (I saw your megasquirt write up and I believe you were using an idle valve) I feel like I haven't even set the idle perimeters and if I do it may attempt to stay running

muythaibxr

Closed loop idle will control idle speed, but it isn't going to work well on a brappy high-overlap bridge port that doesn't idle smooth even in open loop.

Aaron Cake

iTrader: (1)

At least you're not mudding and taping.

Doesn't require full sync with the CAS so it just starts firing both injectors when RPM is determined. Also it will tend to set up a better fuel cloud in the intake ports.

There is almost no airflow into the engine during cranking with a bridgeport, so you need to get a lot of fuel in there.


Don't even think about autotune at this point. Autotune is once you have the car moving under it's own power, not trying to get it going. For the initial adjustment of the VE table you will be performing all the changes right after the car has started. It will be a constant adjustment because warmup enrichment will be fighting you until the engine is up to temp.

AFRs are no different from any other engine in most cases. You want to tune for stoich, then leaner during cruise (around 15.5 w/closed loop), high 12s at high load before boost, then in boost tapering down to around 11s until about 15 PSI where I like to go down to mid 10s.

You may find you are able to idle leaner than an equivalent street port for two reasons. One, the wideband is reading wrong at idle due to the misfires. And two, your RPM is higher so the engine will tolerate less fuel. I idle my bridgeport around 14:1 according to the wideband. Streetports typically need around 13:1 or slightly leaner.

peejay

I may be converting my car to MS3Pro this year (I know, I only just got it running in MS2/Extra) and I plan on using closed loop idle control. I think it should be possible if you play with the gain settings. I would be expecting a fight to make the controller accept 300rpm swings as normal but anything outside of that as needing compensation The main reason I'd want to do it is to set the idle speed based on charging voltage, it is happy idling at 800rpm except when the lights or fans are on, then it needs more RPM for the alternator to work.



Really I think I could do everything I want to do with MS2/Extra, but the Pro is SO nice. And I want to play with flex fuel table blending.

Aaron Cake

iTrader: (1)

The MS3 (and thus Pro) does have an idle up feature when it switches on the e-fan. Also has an A/C idle up, so you could connect the input to your headlight signal wire or whatever and use that as an idle up for lights.

Probably with some tuning the PID could be dulled enough to deal with a bridgeport idle but that's going to make its response to loads very slow as well.

I did try years ago to use closed loop idle with an MS1 on a bridgeport. It did not work.

peejay

I don't doubt it... but I'm partially in it for the learning experience. Trying to make my car drivable like a stocker has played huge dividends in being able to tune relatively sedate vehicles at work.

The fan idle-up would be a nice way to implement BUT I would still want the ability to control the fans manually. I have a sub 160 degree thermostat (has holes drilled for steam evacuation, will run at 150F if it's cold enough outside) and I generally switch the fans on at 200 and off at 180, UNLESS I am at a rallycross, then I turn the fans on full time for maximum pre-cooling of the coolant and I adjust the idle speed up to 1500-2000 so the charging system works. So it's a non simple issue, since the overarching problem is trying to get enough radiator and fan in the nose of an FB.

Scrappy_Brap

Tomorrow I plan on picking up some more oil so I can pour it down the intake so I can start it up (or at least attempt to) and I will datalog this session so I can post it. (I've changed around some stuff in the tune since that datalog was saved, so I doubt it would serve much use now)

After recapping on everything (and watching a couple of videos I filmed of it starting and running) I did notice the temperature outside was a lot warmer than it has been currently which makes me question if I try tomorrow it may want to run a little better than it has been (60° tomorrow rather than the 30° I've been trying to work with here lately)

peejay

30 degree starts are a bitch with a bridge port. They don't build much airflow through the throttle plates, and they need a LOT more fuel than you'd expect. Mine starts on the first or second revolution in the summer, haven't really had time to work with it in the winter since swapping to MS2 also resulted in the car breaking a lot. (Long story. Cumulative effects) It was near perfect on MS1 but MS1 cranks by straight pulsewidth, not a percentage of req_fuel.

I think my cranking figures are near 110% when fully warmed up and over 300% at 20F. But it wants more fuel. Additionally, I'm not 100% certain that my injectors are what they say they are, so my req_fuel may be off.

One "trick" that I do if you have it set to do the priming pulse with key on, is to cycle the key a few times before starting if it's not getting enough fuel. Acts like hitting the accelerator a few times with a carb. Not a good strategy long-term but it can help you figure out if your problem is too much or not enough fuel.

Scrappy_Brap

I am questioning if I've been chasing fairy issues (yes, Fairy issues, ones that don't exist) and that the reason I haven't had much success lately is possibly due to the drop in temp. I felt like it was 2 steps forward and one step back (that one step starting when the winter cold started to kick in)

I've picked up 2 quarts of 20w-50 to pour into the intake to bump up the compression, (figured thicker oil will set on the apex seals better) Im done playing games with this car, seems to be one headache after another (me spending 1 year getting the swap done and trying to fix a junk s4 harness to make it work, and anther 3 months of just dealing with software issues and tune issues after I installed the MS3) So fingers crossed that today I will see a glimpse of hope!!!

muythaibxr

MS1 closed loop idle didn't really work even on engines that ran normally.

Scrappy_Brap

alright so heres an update, just went out to work on it some more and I finally got it to start up by pouring quite a bit of oil in the intake, I set the rev limiter to 3k and mashed the gas, I was able to get a datalog of the events (but for some reason my laptop kept kicking the usb serial adapter and would lose sync with the laptop I cant win to save my life) kept having to disable and enable the usb Drivers to resync it...

anyway I managed to get it going for a little while by mashing the gas, eventually the car just died, as in It was running (not very gracefully but running) and then nothing, rpms dropped and just fell flat on its face?

Datalog is attached

muythaibxr

The laptop disconnecting usually indicates wiring issues on the ECU. Things like noise from coils getting into grounds can cause weirdness like this.

Scrappy_Brap

I believe I took the coil grounds all the way to the battery, will definitely double check though. Having LS2 coils makes me think I may be getting interference (due to location) I also had to make a new connector for the CAS (used a trailer connector I had laying aroind) so I'm wondering if the CAS is getting crap tons of interference. Here's a pic of the engine bay so you can see the setup