Engine stalling on heavy accelerations

mouserider

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Basically trying to solve that problem for the last 3-4 month, all have started when we put indy tunnel ram, 2 holley 450 and Edelbrock Performer-Plus Cam 2192.
Since then problem still exist, however
we changed like 3 fuel pumps and 2 regulators
we rebuilt entire fuel line
we moved from holley carbs to Sniper EFI for dual quads
we put entirely new fuel system, high pressure regs, pump, filters
we moved to MSD with CD Box

It just not going away, if i accelerate slowly its ok, but if i floor it, its just feels like stalling for 1-2 sec and then it accelerates, sometime engine can completely shut down

We dont have vacuum gauge (ordered one) but via msd software it looks like 15.

What i also noticed, that when it stalling, fuel pressure also drops, but fuel pump working (and as i said, this was happening with 3 different fuel pumps and with both carbureted setup and EFI

im now thinking, that maybe its because of tunnel ram and inappropriate cam.

Thanks for advise.
 

wagonman

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It sounds like a fuel starvation issue for sure. If the pressure drops and the O2 sensors go high it is lean for sure. What size feed line from the fuel sender 5/16 or 3/8? There is a filter- sock- strainer on the end of the pickup line inside the tank, they are known to plug up. The pickup can become uncovered on hard acceleration and suck air. They make tanks for EFI with the pump inside. First thing I would look at is the sock.
 

mouserider

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It sounds like a fuel starvation issue for sure. If the pressure drops and the O2 sensors go high it is lean for sure. What size feed line from the fuel sender 5/16 or 3/8? There is a filter- sock- strainer on the end of the pickup line inside the tank, they are known to plug up. The pickup can become uncovered on hard acceleration and suck air. They make tanks for EFI with the pump inside. First thing I would look at is the sock.
thank you, will definately check it out. Also, i just took it for a 10 min drive, one of the acceleration i got bursting sound( kind of air explosion). I had it before, and then pump just went completely quiet (usually its pretty loud) and then when i tried to start the engine fuel prime sound was completely different, then it went back to normal.
Damn, this drives me crazy
 

Wietse

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I had it before, and then pump just went completely quiet (usually its pretty loud) and then when i tried to start the engine fuel prime sound was completely different, then it went back to normal.
That sounds like what wagonman said, the pick up is uncovered and the pump loses prime.
When starting again it needs priming which gives almost no sound, until it gets suction again.
 

Don Frelier

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Did you ever check the sending unit sock?
It seems like that is where the problem lies.
 

BSB67

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If it’s at the initial hit, it’s likely not the tank, sock, line, or pump. It takes a lot of fuel to cover the TR plenum volume. I’d make sure there is no vacuum leaks, richen the idle circuits and squirters
 

Geoff 2

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I do not think it is fuel delivery. I take it that you can cruise around ok, no issues, but if you suddenly floor it, it wants to stall.
Not surprised, with a TR intake. Very poor choice for a street driver. Plus, everything I have seen from Indy is huge. The TR probably has a huge plenum & runners with large CSA. Which adds up to a whole lot of air that the 'signal' to the carb has to fight it's way through to get the carb.
I would fix it by fitting a dual plane intake & Edel AFB or AVS carb.
 

mouserider

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Thank you guys, will definitely go check all one by one. But today I also noticed another strange behavior. So car at park, I give it 3k+ rpm, keep it for 10-15 sec checking fuel pressure, all good. Second I release the pedal and rpm goes to idle it starts to stall. Tried like 5 times and every time it’s the same
 

Wietse

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I think you will be better of with a Edelbrock dual quad manifold or similar type.
Just looking online for Indy tunnel ram manifold, I was having something else in mind but obviously as Geoff already mentioned, that is a poor(est) choice for on the street.
That will be good for 6500 rpm at the race track.
 

mouserider

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I think you will be better of with a Edelbrock dual quad manifold or similar type.
Just looking online for Indy tunnel ram manifold, I was having something else in mind but obviously as Geoff already mentioned, that is a poor(est) choice for on the street.
That will be good for 6500 rpm at the race track.
i understand its maybe not the best choice, but its already done, i already have a cut in the hood, it already has bug catcher and there is no way back basically. And still i have seen on forums many people have tunnel rams and they drive it street. i dont want daily driver, i just dont want it stall, i can live with not optimal drivability and throttle response.
 

Wietse

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i can live with not optimal drivability and throttle response.
Well....what to say.....live with it.:lol:

If you can verify fuel pressure while driving you should be able to rule out the fuel supply.
If you floor it and the pressure remains at a sufficient pressure that is not your problem.
Surely that intake would be next to consider.

Edit: What if you gradually increase throttle to WOT? same stalling or pulling nice?
 

69L48Z27

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If you have a Sniper, can’t you see all the fuel data? See if it lean or fat when these thing happen.

Its either real or fat, sounds like lean. That explosion you mentioned is a lean pop. Throw more fuel at when you go WOT, squirter. Fix one problem at a time.
 

mouserider

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Well....what to say.....live with it.:lol:

If you can verify fuel pressure while driving you should be able to rule out the fuel supply.
If you floor it and the pressure remains at a sufficient pressure that is not your problem.
Surely that intake would be next to consider.

Edit: What if you gradually increase throttle to WOT? same stalling or pulling nice?
i know) if i gradually increasing throttle it pulls nicely. any other way around it might dive for a second do some noises and then pulls like crazy or it can stall
If you have a Sniper, can’t you see all the fuel data? See if it lean or fat when these thing happen.

Its either real or fat, sounds like lean. That explosion you mentioned is a lean pop. Throw more fuel at when you go WOT, squirter. Fix one problem at a time.
i do see and its good when it drives, but moment it starts stalling, AF ratio goes lean, but i thought thats obvious, as its stalling
.
 

BB BELLA

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if you really want to keep the tunnel and street drive it, maybe you need to fabricate some sheetmetal baffles and install them in the intake reducing plenum volume and increasing air velocity.
 
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