Everything is buttoned up but it wont run, fuel problem, give me your ideas

[Denison636]

It has been a few years since I installed my FAST system.  But if I remember correctly there is a safe mode on the ECU that wont allow the injectors to fire unless everything is programed correctly.  Is you ECU programmable?

All my notes are at home, so once I get there I will check to see exactly what was needed.

Also, you say it runs on starting fluid, have you tried to pour some fuel in to see if it will  run longer once started?

I am sorry you are having these problems....my no start issues with the FAST system turned out to be a software issue when I updated the system. turned out to be an easy fix once we figured it out....and it only took three week. 

I have never delt with mega squirt but if they don't have a tech department maybe a local tunner can help. Most of them around my area are more then glad to help in a situation like this due to they know that a person will want to dyno a car to get it right.

[74BlueFish]

Can you post the MSQ files and I'll see if they are similar to mine.

Also the Megasquirt controls the injectors by grounding them.  Megasquirt does not power them.  I'll say you got that right as you can hear them click.

While cranking the injectors still need power and the fuel pump also and coils.  Check they are still getting 12 volts while cranking.  I lost my fuel pump when cranking and engine won't start.

I hot wired the pump direct to battery and it started,  then figured out the two wires that needed to be hot during on and crank.

[GreenFish]

It didnt allow me to attach the msq file, ill try to pm it to you

[73restomod]

Megasquirt themselves may not have a tech department but their primary distributor, DIYAUTOTUNE does, I have dealt with them and they will help however they can. Also they offer a full GEN 3 standalone kit and a Gen3 piggyback kit.
https://www.diyautotune.com/support/tech/install/chrysler-dodge/megasquirt-your-hemi/

They have other articles on gen 3 as well.
Just out of curiosity after cranking the engine over is there any wet fuel on plugs or paddling in the cylinder?  If so it would indicate that the injectors are firing but at the wrong time.
EFISOURCE.COM is another company that may be able to help.
http://www.efisource.com/efi-source-megasquirt-iii-gen3-hemi-plug-play-gold-box/

[Denison636]

I would pull an injector out and see if your getting fuel out of the rail then try the injectors plugged up in the rail were you watch and see if it's not something els.

[GreenFish]

you guys will never guess WTF was wrong. We all though it would be something stupid and it was.

Had remembered at one point that the injectors cycled properly at one point but didnt remember when that stopped happening. I started going backwards. I had swapped relays, and did some other things. Then I had an idea, all i did was swap the 5A fuses I was using for the injectors for 15A fuses. Soon as I flipped my toggle switch I heard the prime cycle. Turned the key and it fired.

So either the 5A wasnt enough or those 5A fuses were shot. They are non see though so I couldnt see if they were bad and had no reason think other wise. I was running 5A fuses for my injectors. Based on what the diagram for the MS3 said. What size fuses do you guys use for injectors?

anyhow, thanks for your help guys. I'm going to get this thing drive able this week so we can take it down to the show in a few weeks. Hopefully there wont be any new surprises.

[shawge]

  Happy to hear you figured it out.

[70chall440]

  congrats

[67vertman]

   Glad you got it figured out. 

Injectors use very little current to fire, but I don't think that the 15 Amp was to much, like you said I thing the % Amp was bad. . 

[Denison636]

Glad you got it working. Hard to trouble shoot over the web

[HP_Cuda]

You should put an ammeter on the line and see what it draws so you can size the fuse accordingly.

I would assume that 5A is way more than enough for injectors.

B

[GreenFish]

You should put an ammeter on the line and see what it draws so you can size the fuse accordingly.

I would assume that 5A is way more than enough for injectors.

B

yeah I agree, I actually think the fuse itself was crap, both of them.

[EbodyMod]

glad you found it!! now for the fun part, listening to beautiful engine songs

[YellowThumper]

Congratulations.
Now time for the seat of the pants and black stripe tuning...

Mike

[quagmire]

I run 7.5A fuses for each bank.  So if you're only using one, 15A is fine...  Remember, you fuse to protect the wiring from overheating, not to protect the component.  If it's drawing too much it's shot anyways, so you are not going to save it.