MSefi.com read only forum (Jan.15,2018)

The x-tau is triggering a big burst of fuel while I'm cranking. Its flooding out the engine. I have been having to pull the plug and dry them and start the car in clear-flood while using the nitrous....its getting old. IDK why...shouldn't the only thing that adds fuel be the prime pulse and the cranking pusle under my set cranking rpm?


Where is the list of engine codes? I can neverfind them. I know 1 is a warm-up and I think it 17? it accel.
What 3? It sets just as x-tau steps in and pumps the the fuel.

I attached a datalog, but this is on a warm engine. It will start warm, but bearly start from being so rich.

Also, attached is the msq. I have been changeing stuff the last three days as this has been happening, but IDK what went wrong. I have been trying to get the x-tau better in the lower rpm, and I have I feeling that is why Its flooding, but I don't understand why its engauging under my set craking rpm (I have tried as low as 100 and as high as 600 rpm)

The x-tau algorithm needs to start as soon as the first squirt so it can keep track of how much fuel is on the port walls. If it doesn't there will be a glitch when it kicks in. When you start the car it is assumed the walls are completely dry. So when you do the first squirt it assumes that a lot of the squirt ends up on the walls. To give you the amount of fuel you ask for, it squirts extra. So when you bring in x-tau, you may need to cut back on the prime and maybe the cranking pulses, especially at the colder temperatures.

Prime is setto 1.0ms.
Cranking set at 1.2ms

I think what I'll need to do is to turn x-tau down at 600 rpm, move the next point lower in rpm (say 900) so I can still have the x-tau in low rpm, but not as much in cranking.

I just thought of something. I have x-tau set for acc/decel only, It gave me issues beofre set as warm-up and acc/decel.
How does ith work then? Does it just use the x-tau numbers as if the system was warm already? I was under the impression that it did start to take action while the engine is in warm-up. Based on the statement about it kicking in as soon as it cranks, I have been forced to rethink my theory.

I think I fugured it out. I turned the puddle down under 600 and it started fro me when I left for luch today. The real test will be tomorrow when I need to get to work. I think the next project I do will have a set of 40-50's for primaries and save the 95lb injectos for secondaries. These garden hose injectors can be pesky at times.

Do not use the x-tau warmup option. It should be possible to change x-tau based on coolant temp as the car warms up, but the algorithm goes nuts when you do this and we have not been able to find a reason for this. I haven't given it much time because the existing warmup control is very extensive, but it is on my list of things to do.

I haven't been using it...it WAS accednentily set a few days ago for some reason. At first, I thought that was my problem. I tried it out a year or so ago it it flipped out like you said, so I just switched it to accl/dec only and had been running it like that since.

Well, I turned the puddle (x) down in the cranking range, and it has been starting up like it used to. So I guess this is ironed out. Thanks for straightening out the part about x-tau having to turn on at first spray...that was the little peice of info I needed.

Well...it flooded out on me again this morning. Its really starting to piss me off.

With x-tau off, its still giving me cranking pulse higher then it should. Cranking is set to 1.2ms, its despensing 2.4-3.0ms.
Its like its pulling from the VE table and not the cranking table. Normally it will start and be really rich right after it fires. I think the problem I'm haveing has to do with the summer gas, the poor atomization of the large injectors, the cool weather we have been having...and the very high humidity from it raining for the past 4 days.

With the later versions of the code, cranking PW is corrected for baro, air temp and battery voltage. This was done because it is the correct way - these things affect the pw requirements, especially the battery correction.

Well, I figured it out. It had NOTHING to do with the tune. In fact it was just something stupid that was easily thought to be ok....it was the damned spark plugs. Even thought I dried the out and cleaned them off with a glass beader, they where not firing until they for hot. There must be somthing internally wrong with the. I didn't feel like cleaning and driing the plug last saturday afternoon, so I got a new set of plugs out of my tool box, fired em in there and she fired right up...no hesitation, no sputter...just fired right the eff up.