Help!! No start after pcm write.

[Natejk99]

Hey guys having an issue after I flash my pcm the truck wont start It fires then shuts off then after I play with it for awhile it will start. it happend to me at the track last night I pushed it on to the trailer left it over night then it fired right up. Truck is a 2004 silverado 07 van pcm swapped to DBC added wiring trans is a FMRVB 4l80e none lock up when the truck is running its fine and only happens when I flash the pcm.

[wasyl]

contact support and if you can attach config here

best regards

[schpenxel]

Hey guys having an issue after I flash my pcm the truck wont start It fires then shuts off then after I play with it for awhile it will start. it happend to me at the track last night I pushed it on to the trailer left it over night then it fired right up. Truck is a 2004 silverado 07 van pcm swapped to DBC added wiring trans is a FMRVB 4l80e none lock up when the truck is running its fine and only happens when I flash the pcm.

Mine has had a weird issue lately where if I flash it and just start it it'll cut off. If I start it and rev the shit out of it immediately it will stay running long enough to get over whatever is causing it to die. I still haven't figured out what is causing it but it seems awfully similar to yours

Try giving it maybe 30-50% throttle when it's starting next time and let it rev up.. see if that gets it going

Mine will start fine on a cold start/fresh flash..

[10_SS]

Mine has had a weird issue lately where if I flash it and just start it it'll cut off. If I start it and rev the shit out of it immediately it will stay running long enough to get over whatever is causing it to die. I still haven't figured out what is causing it but it seems awfully similar to yours

Try giving it maybe 30-50% throttle when it's starting next time and let it rev up.. see if that gets it going

Mine will start fine on a cold start/fresh flash..

I just put mine in SD mode, and noticed this, but the cells didnt need much work in that area, it was like the throttle blade was learning airflow or something. What are the odds this is related to what you guys are talking about?

[Natejk99]

Mine is doing the exact same thing only when I flash it I'm contemplating another pcm, mines a cable throttle so I'm not sure on yours 10_SS

[schpenxel]

I went through an old tune vs. a current one on mine and really don't see anything that I think would cause this, so I dunno what it is. According to my WB it's going super rich. I've found that flooring it right after it fires will keep it running long enough to get over whatever hump this is

[10_SS]

I swear I'm having this problem now. It cranks then fires, then stalls. I have to literally floor it right after it starts to kick it into run mode. You can see the injectors bottom out right after it fires up then the flooring action tells something to start working, and injectors work as usual. I dont have a log of the 4 attempts to start before this...

Starts after the first start after flash just fine. It is something like the MAF isnt failed right? I have it set to 0's in the MAF table and the unused VE tables. the check engine light didnt come on until the second start 20mins after this first start.

Seemed to start doing it after putting in SD mode, so not sure if it's the editor or the tune...

125f VE STFT with VE changes from 125e.hpt
125f first start after flash stalling until WOT.hpl

[schpenxel]

Yeah, that's weird and sounds pretty similar to mine. I need to check out inj PW on mine when this is happening.

Looks like it goes way high at first on yours (would be interesting to see how high inj PW goes on a cold start that isn't after a flash just as a comparison). Look like you're idling around 1.3 to 1.5 msec. When it almost cuts off it's down around 0.5 msec. Weird. I wonder if you're right and the MAF isn't failing immediately?

[Stuffs]

I went through an old tune vs. a current one on mine and really don't see anything that I think would cause this, so I dunno what it is. According to my WB it's going super rich. I've found that flooring it right after it fires will keep it running long enough to get over whatever hump this is

same here , goes to 10.5-low 11s on idle stalls and dies... crank it again and pedal it to keep it running after this it wont die

[schpenxel]

I've wondered if flooring it puts it into flood clear mode and cuts the fuel--I need to log inj PW next time it does it and see what happens. It's really weird that three of us are having the same problem though.

[10_SS]

I've wondered if flooring it puts it into flood clear mode and cuts the fuel--I need to log inj PW next time it does it and see what happens. It's really weird that three of us are having the same problem though.

I do about 50% throttle and sometimes it kicks right in starts running normal. The initial start sounds normal then it just dies, once I get it to recover it runs perfectly normal. 0.5 is way too low and I think actual injector is less than that, or even 0.0.

It has to be something to do with the MAF not failing fast enough for me anyway, and I put all 0's in the MAF table so makes sense. I'll put my normal values back in the MAF table and let you know if that improves it. I dont get a check engine on first run either. Im messing with the VE table for the next week or so should be flashing allot.

If your not getting a good clean initial start then a good clean run after you hit the pedal once or twice, as if it's too rich or too lean then fueling must be messed up for some other reason. Mine just feels like injectors cut off.

Are you guys in MAF fail mode with either no working/calinbrated MAF or 0's in your MAF table? my MAF Test ERT min delay time is 1sec, along with Test Enable Delay, both for Frequency set for 1 sec... that is two full seconds until the MAF could fail, right?

[10_SS]

Yea, well mine is due to MAF not failing. I just flashed it again, and started right up and had the MAF fail DTC. I cleared it, and now It will fire then stall over and over and over, cant get the DTC to set.

[schpenxel]

Interesting. I'll look into that on mine. There are quite a few settings on what it takes for the MAF to fail, not just the frequency.. I wonder if messing with those will get it to fail quicker

Mine doesn't even have a MAF.. so if it's trying to use 0hz on mine then that really is not going to work. Wonder what logging dynamic airflow will show?

[10_SS]

I lowered some of the settings to make the MAF fail quicker, didnt seem to make a difference. One value I couldnt put less than 1sec. This time I got it running and the DTC for MAF was set, then I cleared it when running and it stalled and wouldnt restart. I had to reflash. This time I populated the MAF table with my old settings and now starts fine every time. I still have the MAF fail, however now I can clear the DTC and I can hear a slight change in the fueling when MAF is active for that 1-3 seconds until it fails again. I would think with it unplugged it would fail instantly.

[schpenxel]

You'd think it'd fail without a MAF pretty dang quick... I'll flash it tomorrow and see what happens DTC wise

[Natejk99]

I think mine is different because it only does it right after i flash the computer. Any other time I start it its fine only when i gladh it is when I have issues with starting like secuirity or pcm maybe im not sure what its deal is but if i sit there and hoss the gas relly fast to keep it running all the sudden it goes vroom and starts running fine.

[schpenxel]

That's exactly what mine does

[ElecTech]

Yea, well mine is due to MAF not failing. I just flashed it again, and started right up and had the MAF fail DTC. I cleared it, and now It will fire then stall over and over and over, cant get the DTC to set.

You need to set your P0101, P0102, P0103 DTC's to "MIL on First Error" to get the MAF to fail immediately. Currently your ECU is waiting for a second failure to throw a code.

[10_SS]

I think mine is different because it only does it right after i flash the computer. Any other time I start it its fine only when i gladh it is when I have issues with starting like secuirity or pcm maybe im not sure what its deal is but if i sit there and hoss the gas relly fast to keep it running all the sudden it goes vroom and starts running fine.

that's what mine is doing too if i have 0's in my MAF table but still have it set to fail, the reason is the ECU is reset after a flash and it erases the DTC for MAF Fail, without the DTC, the MAF is enabled. The reason for the no start is the MAF hasnt failed yet and if it's not setup correctly or 0's in the table, it's using that for airflow measurements until it fails (1-3seconds usually).

I changed my DTC's to fail on first, but didnt help. Get it running and check for the MAF DTC's, and while it's running clear the codes, if it stalls or runs rough, that is your problem for sure.

[Natejk99]

That's how mine is set up right now miles on first error idk what my maf fail is though I think it's zero I know I needed those codes to go into SD mode though