1st thing I would look for is a vacuum leak.

Rufus68 wrote:

Just curious... are you still loving the EFI or do you wish you would have stayed with your carb?  I'm only asking because I had thought that EFI would be nice before reading threads from so many with EFI issues.

Hi, well ,  it's a little time efi is on my car , so to be honest i dont have enough feedback . 
yes , there are some odds , and issue but nothing impossible to solve , by now for the time i used it , no i wont back to carb .  
I never solved rich issue and clothes smell of gas . With efi all is disappeard and it run always at perfect afr . 
By now i m still in the learning zone , and the issue i got now i think is related about " chocke " and settings or idle screw or even the fuel pump that become noisy . 
anyway now the efi is working better than carb 
bye 

Rufus68 wrote:

After doing a little searching, I found this article that might help you:
https://www.efisystempro.com/efi-pro-hangout/holley-sniper-installation-startup-troubleshooting

thanks Rufus , this open source is one of the best i read ever !      i have read it weeks ago , during installation . 
Btw today i set again idle step and wizard  and seems there no more rpm problem ...but i need to try it 

At the end if i dont touch too much settings is way better . That was my first mistake cause i try some secondary linkage rod and touch TPS AND IAC position settings . This let efi learn wrong , and when i go back to basic linkage, efi still use some wrong info . that's why i started again with wizard .
. 
Brief : havent found big issue to solve ,
           efi can be really ready out of the box , (after you have prepared everithing for the first start ) 
           instructions are very limited and somehow difficult to understand ( american is not my first language ) 
           with efi is a new beginning , need to study , search , understand , trial and error . 
           cheap fuel pump can deserve some issue with hot temp .
            no more gas smell in my clothes . This is a goal for me
            The handhold  allows tuning with a finger . 
           need more miles to know about mileage . . 
BTW you are using efi or carb ?
bye !
                                                                                       
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
 

It's important to note that the IAC can only control the idle by opening up or closing down to a certain point. You still have to use the throttle plate adjustment to get "close". So if there is no vacuum leak then also look at the manual adjustment screw.

 

Rufus68 wrote:

I'm running an Edelbrock 1403 carburetor sitting on a 1 inch phenolic spacer on a Summit aluminum intake.  I have an AEM 30-0300 AFR gauge providing the AFR reading.  I modified my fuel system to be a return style so that the fuel has a constant flow through the line to reduce heat buildup.  I did this using a Holley bypass regulator set at 5.5 psi.  I changed my mechanical fuel pump for an 8 psi higher flow pump to open the bypass regulator.  The stock fuel pump would not produce enough pressure to actually open the bypass.  And to further remove heat from the fuel line, I don't have it routed across the front of the engine.  It routes from the pump, back along the fender and then across the firewall before feeding the carburetor.  The bypass regulator with pressure gauge is mounted near the carb on the firewall.  I installed an inline electric fuel pump near the fuel tank wired to a momentary switch.  I use this pump to fill the line and carburetor before starting the car if it has been sitting for a while.  This prevents the excessive cranking of the engine needed to fill the carb while still allowing a mechanical fuel pump to be the normal source of fuel when the engine is running. 

With the setup described above, my Mustang starts and runs fine.  I can tell by my AFR gauge that the Edelbrock carburetor can not be tuned to be at the ideal AFR under all running conditions and load.  That said, my current tune seems to be a good compromise.  For now, I'm happy to have a reliable car that I trust.
 

   Im kind of doing the same thing this winter on mine with this fuel filter.   $8 Cure For Vapor Lock - YouTube

 

well , Rufus link is  a focus on this issue  , but i  need time to elaborate .  once you act on one setting , other are involved and i m worry to do worst . TPS /IAC /RFI  are involved : Anyway a good point because seems a common issue .
BTW  other than issue , sniper is running like hell and revv up quick and powerfull . When this rpm issue will be solved i think i will have a big smiling face 
 

Rufus68 wrote:

The article explains what extra you need to do if you are using the sniper to control timing.  I say be brave and follow the instructions in the article.  They seem to be detailed enough to set your idle.

yes , that's what i will do after understand all the step needed , sometimes happen that a step provide more question to me . exemple :  my IAC works from 0 to 20 , but i dont know if is the correct range or not . 

so ... do the homework step by step following Chris IAC setting , and then take a ride . All settings was upper the 160 f . As first i see idle wont go lower than 950 at garage . 
take a ride and for first minute goes well , than start to act like was before . 5th gear 2500 rpm dont drop .
At beginnin just a touch at pedal and rpm drop at 1300 , but try after try the double touch on gas was no more effective and idle stay at 2500 always . need to stop and restart , and anyway idle was higher that setted . 
Driving with car that pulls without foot on gas  pedal is not what i suggest even to my enemy , so i come back at garage . Trying to navigate handheld i found TPS disabled  and IAC at 20 .  set up tps enabled and iac at 0   i want to see what happen 
Another thing i notice is when was working it was so slow to lower IAC . 

Keep reporting your experiences to us.  Maybe sometime in the future I'll still consider EFI but only if the system will work reliably.  Thank you, Alessandro.

josh-kebob wrote:

Rufus68 wrote:

Keep reporting your experiences to us.  Maybe sometime in the future I'll still consider EFI but only if the system will work reliably.  Thank you, Alessandro.

That may take awhile....these EFI systems are problematic. Seems for every one that works, ten more have issues.

 

yes , you are right , by now i'm happy . The huge sniper forum and the variety of issue let me think this holley is problematic . I want give a chance . Once for all i solved some gas smell in clothes , super easy start and always afr correct . now is more faster and powerful at low rpm .For sure who is handy with computer and ecu are step forward ! 

will be a pleasure keep informed who needs .