When it's below 0 degrees F on first startup it will usually flood. I have an '86 TPI setup with the CSI, with a $6E bin, I have disconnected the CSI, and used the default Crank BPW values for engines w/o CSI, until it got colder out, I noticed that it would flood out, making it impossible to start unless I left it sit for a day or two. I tweaked the values a little bit, and it seemed to help up to about 0 degrees, but anything below that and it floods very badly.

Just wondering if there is an easy way to calculate how much Crank BPW I should have at temps below 0 degrees, I can't keep making little adjustments hopeing that it doesn't flood, because once it does flood, it's impossible to start. Plugs keep getting fouled.

Oh yeah, using 24# Svo injectors, and stock pressure regulator.

Engine specs in Sig below.

 

Take your values for the 0 degree table and go ahead and use those all the way down. It should be able to start and run with those settings even if it gets like -20 out. I had the same issues with my car but it turned out I 0'de out the IAC park steps and it was fully closed at start up! That caused all kinds of issues... come to think of it I need to change my plugs!

 

If while tuning the cold start is floods again, hold the pedal to the floor while cranking. This puts the ECM into a clear flood mode. Which has it substantially reducing the amount of fuel.

RBob.

 

I'll try taking the 0 value all the way down, I was just going to ask if there ever can be too little fuel?? Or would that just cause it to crank longer. If that was the case, it shouldn't be a problem, because I've got a brand new 900 cca battery, so it'll crank. Just don't need it to flood out.

I tried holding the pedal to the floor, but at that point it was so far flooded that it would just backfire, I think holding it to the floor puts it @ 20:1 AFR. Took the fuel pump fuse out, and cranked it over til it stopped tring to catch, put the fuse back in and then tried the pedal to the floor trick and it still wouldn't start.

Someone pulled me back to my apartment, and we got it into the garage somehow. Got it plugged in and on charge, have to see if the plugs are too far fouled to even work now. That'll be interesting, i'll probably have to wait a week or 2 til it warms up and I can swap out my plugs to get it to run again.

I'll def. have to try burning a new chip and see if that helps. And if there is too little fuel would it just have to crank a little longer?

Thanks!

-Tyler

 

Yep, I had to drop the tables down on my proms because I used to have a HUGE issue with my burner, I just treated it like a carbed car and would give it a little throttle and crank a few times, quit cranking and let off the throttle then crank again and poof magic start. It was always funny when my friends tried to move the car you would hear it cranking for eternity out there.

 

Well, since I've been doing cold starts in the SERIOUS cold, I'll give my tips/advice:

1) A HUGE amount of fuel is needed when it's cold. In sequential mode, at -30C, the prime pulse is >300ms, followed by 190ms, decaying quickly until RPMs climb enough for run mode.

2) Too little can cause flooding (wet soak). Too much can cause fouling (carbon).

3) Fuel RVP (vapor pressure) really helps cold starts.

4) A proven method is to have a (very) large initial pulse, then about 75% of that, then about 75% of that, keep decaying the PW until it's about 20% of the initial pulse. Do that for each cylinder, such that every 8DRPs on a v8, it decays to 75% of the previous value.

5) The initial huge shot should be calibrated such that it fires on the first cycle of intake. That applies a wall film, and the combustion warms the chamber, which requires significantly less fuel (thus the reduced PW), and so on.

6) After start fuel is required to compensate for un-burned wall film as the chamber warms to a point that is quasi-steady state with the coolant temperature (chamber is much hotter than coolant, except at cold start up).

7) More IAC also helps a lot. In my situation on small engines, a warm start may need 11 steps more than the base of ~70. Super cold likes 70 extra steps on top of the 140 base (total near 210 steps). It's useful to reduce load on the starter and to increase power to get faster run-up speeds.

8) If it doesn't start in 5 seconds, it's probably going to need an open throttle deflood, unless you calibrate a deflooding period into the cranking PW routine. Open throttle until it fires a few cylinders, then close it again to return some fuel.

Steps 4 & 5 can be methodically calibrated such that an ideal decay is achieved (for example, only allow the one injection, and calibrate it such that it fires on the first cycle, then calibrate the next injection such that it continues to fire, and then the 3rd), but that takes a long time. Follow the general trend, and scale it up or down, and get the best cold starts for the quickest starting without flooding or fouling.

 

Got the oil changed, was about a half quart of fuel in the oil, changed out the spark plugs, they were blacker than night, fouled for sure.

Pulled the chip, and dl'd the current bin, was going through it, and saw that I had 0'd out the cranking SA table, for some odd reason, wondering if that maybe had something to do with it. Put it back to stock, and then took a look at my Crank BPW vs temp table, and subtracted about 30 from each of the colder tables. Figuring that maybe with the #24 injectors it's pushing more than what was intended with teh #22's.

Also changed my Crank PW Multiplier vs Ref Pulse table up a little, used to have .5 in the first 8 pulses, changed it to .5 in the first two and .25 in the rest.

Burnt the chip, went out, was just above 0 degrees F, threw the chip in, and crossed my fingers.

Started up real nice, cranked over a few times and fired right up.

It used to have a little quirk when it started, it would rev up to about 1000 and then stumble and rev up to 1500 and then back down to idle. I'm thinking maybe something to do with too much fuel? Or not having the added SA on startup?

But I'm not sure if this is related to my changes or something else, but it had a hard time trying to stay idling for the first 20 seconds, it was surging real bad. between 900 and 700. ??

I'll have to wait til it gets 40 below again to see if it floods out. We'll have to see.

 

Have you seen were your BLM's are at warn/hot? If there on the way rich side, take another look at your inj size your using and up it an few lb's. SVO's I beleave rated at 40lb's, if your useing a stock reg your going to be way rich

 

I've got my blms 128 +-2to3

 

Tried to cure the surge on first startup by cleaning the PCV valve, cleaned the MAF, and checked for vacuum leaks with a can of carb/choke cleaner. No leaks.

Put everything back on, and started it up in 20 degree weather. Reved up to 1200 and settled down to commanded idle of 800 and then began to quickly surge between 800 and 1000.

It did that for about 15-20 seconds, and then settled back down to commanded idle and it then idled like nothing was wrong?

What possible could be causing this? It only happens on the very first startup in the morning. None after this.

Could too little fuel do this? Since I took a buncha fuel out?

Not sure where to look now. Did a search on surging idles and came up with alot of vacuum leaks, but i'm pulling 18-19 @ 900rpms and 16-16.5@ 550rpms.

Any1 have any suggestions?

 

Put everything back on, and started it up in 20 degree weather. Reved up to 1200 and settled down to commanded idle of 800 and then began to quickly surge between 800 and 1000.
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Pull more fuel, still sounds like your too rich, with to little fuel won't alow you to hit command rpm and IAC will be like 160

 

It would take a friggin ton of fuel to cause rich surging like that. I'd vote too lean. Rich usually won't surge up and down either, just kind of burble and chug, and blow black or brown smoke.

 

But isn't it kinda weird that it only does it on the very first startup in the morning. I went to class and came back out at noon, after it was sitting for 4-4.5 hours and it started up, no surging at all. But I did notice that even though the water temp was still cold, atleast about 20 degrees F, it decided to use the hotter temp idle of 550.

Wondering if maybe my coolant temp sensor is reading funny?? And maybe that's why it was getting funky fueling and flooding out?

But then I was thinking that my fan shouldn't turn on at the appropriate temp if the CTS isn't working. Since it's a single fan. But it turns on right where I commanded it to at 205*

What would cause it to ignore the idle speed vs coolant temp table?

 

The cooling fan and the temp sensor for the ECM should run off 2 different sensors. There were 2 different ones on my 1991 TBI motor and I bypassed the controls when I went TPi so I may be incorrect on this but I believe there are still 2, one in the side of the head and one in the front of the intake, these control the fan and the ECM seperatly.

 

Only the one sensor for my 86 with a single fan. There isn't a sensor in the passenger side of the block. And the one in the drivers side goes straight to my water temp gauge.


I took out the startup SA thinking maybe that was the problem. Didn't help. Started better but didn't help the surging.

I tried just reving it up to 1200 or so and letting off, but as soon as I let off it started to surge again. It'll surge between 1000 and 800 for those 10-15 seconds and then it's fine. Really weird. Any why would it only do it on the very first start no other starts for that day?

 

Add a little more "Afterstart Fuel Enrichment" at 20F or -7C (depending on your XDF). Try 7% more, and blend it into the surrounding areas. 60% enrichment is a ballpark figure, and will depend on how well calibrated your MAF is, and any other age issues, such as carbon buildup.

More startup spark advance would actually help. Cranking spark is ONLY from the base setting on the distributor. Startup comes in when above 400 RPM. It's to help plow through the cold oil, and maintain a smooth idle until the oil get warms up enough.

The main reason you're seeing it only on the first startup is that engines will heat up from the inside, but cool down from the outside. If you had an oil temperature gauge, you might be able to see this. Also, it's usually several degrees warmer in the afternoon than in the morning. If you live in an area that is never extremely cold, they may be selling some fuel with lower RVP. It may also be a national fuel standard change that can cause this. The more RVP, the better the cold starts, but worse HC evaporative emissions at the pump, and through the purge canister.

If your engine flares up too high on the start, it may also be stripping the wall film a bit, and then, as the RPMs drop, the vacuum drops, and more wall film is needed, and it robs the main fuel charge. With MAF and this old software, there's not exactly a good wall film model, so, just have to over compensate it enough to not surge or stall.

The coolant sensor is in the front of the intake manifold, BTW. A brass sensor with 2 wires (I think Yellow and Black). May also be your old cold start injector there. You DO have that disabled, right??? $6E doesn't use it.

 

I'll have to try the afterstart fuel enrichment but now I'm starting to wonder if it isn't something else.

I was battling this random surge some more and I finally decided to just burn a chip with everything back to where it was before I started taking fuel out and adding spark. And messing with the idle speed/ IAC counts.
I waited til the morning, it was -7 F, started it up, and it reved up and held longer because of higher Idle IAC counts. and then it began to settle, it settled to the commanded 1000 rpms for the cold temp and only surged for 2-3 seconds. and then it quit. idled fine.

This problem started after it flooded out and I had to change all the spark plugs. I gapped the new ones (NGK ur4) at .045 I think my old ones were .035, but I added a long time ago a MSD coil in cap so I thought it woulda been better.

Could too much spark plug gap cause something like this? Or do you still think its a fueling issue.

I was messing with the IAC counts because I was trying to remove the high spike in rpm on startup and I was having a spike when putting it into nuetral from drive to reverse. So I set the "Idle RPM startup postion" to about 120 from 160 and the "idle speed adder to park/neutral" to 0 rpms, Just wondering if that would cause any problems, it got rid of the spike and I liked it, but thought that maybe that was contributing to the surge.
But I reset everything back and the surge is still somewhat there.

 

RednGold86Z, you definatly do know your stuff.

I finally got around to actually re-reading this thread to try and see what I could make of my situation. I read it twice actually, the post of steps to a good cold start.

I went and took my crank pw vs ref pulse, it used to be .35 .35 .35 .35 .25 .25 .25 .25 .25 .20 .20 .20 20 etc. I didn't know that the first 8 pulses were the first crank? Does it correspond to each cylinder? I thought it was 4 pulses per crank but anyways, I took what you said about a huge first pulse and then 75%, and then 75%, so I went .75 .75 .75 .75 .75 .75 .75 .75 .20 .20 .20 .20 .20 .20 .20 .20 .05 .05 etc.

I then went and looked at my IAC values, but I couldn't find where you have the "base counts" but I just added some counts to the -30 -7 values of "warm IAC park counts" to 160, 125

Kept the stock cranking fuel values for ARAP.

Burnt the chip, went out side to a -20*F -48*F wind chill parking lot.



Replaced the chip with the current chip.

Crossed my fingers.

Turned the key, and to my surprise, it fired instantly!

It went verup BOOM. Instant start.

I also noticed that the surge was less of a surge, it still kinda surged a little back and forth but it was very gradual.



I think that this surge might still have something to do with not having the "after start fuel" which you were talking about. But I can't find the items that need to be addressed in the $6E ARAP bin for the afterstart fueling. I think once I get the afterstart fuel in there it'll be the best starting car in the state of ND.