Best fuel pump/carb option

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MARCH374

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I have MSD ATOMIC EFI on my 1989 AHB Diplomat, want to go back to Carb too many issues. What Brands do you recommend for Fuel Pump and Carb ?

Thanks
 
Was the 4-bbl intake already on engine before the change over?
What was you using before fuel injection?

Where about do you reside at?
Mind if I ask what kind of issues you were having with the FI?
The reason I ask is I want to make sure you are not chasing the wrong problem (and I'm not saying you are).
After you get the fuel system working like you like, are you planning on selling your old system?

As far as which 4-bbl to install - the sky is the limit (Holley and Edelbrock might be the two bigger aftermarket names - but there are a lot more). I would get get one with Chrysler linkage or get the Chrysler adapter - if going aftermarket. If going with a factory carburetor, I would look for one made between 1968 to 1975 (Carter AFB, Carter AVS, Carter Thermoquad or Holley (square or spread-bore).
Chrysler went from a square bore pattern (primary and secondary barrels were about the same size) to a spread bore configuration (front barrels were much smaller and rear barrels were huge) in '71/72- but if you have an aftermarket intake it will use either design. The factory '89 4-bbl intake will only take spread-bore carburetors - and that intake will not have a provision for a factory designed divorced choke - so hopefully someone had changed it to an older Chrysler or to an aftermarket intake.

If you have no fuel pump, I might recommend using a low pressure electric pump (5 PSI), mounted either by fuel tank or mounted on the engine where the original fuel pump was located at.

You might want to shoot a couple of underhood photos and post here. Sometimes I can see a problem - depending on the view.
BudW
 
I've got a Thermoquad on the 360 in my 88 and whatever parts store fuel pump was installed last. If I was after a new carb I'd go edelbrock because I've never been overly happy with hollys.
But I'd probably try to stick with fuel injection since you already have it.
 
Mikes5thAve said:
I'd probably try to stick with fuel injection since you already have it.
Click to expand...
If he (or someone) paid for FI, I would too.
I suspect there might be something underlying causing his problems (like timing chain jumped time or blown head gasket, IDK).
 
Thanks for the response. Put on Edelbrock manifold for EFI. I have had the Atomic on for almost 10 years so i have no complaints but tired now of the breakdowns etc. Having issues with fuel pressure, car starts run great at 1st abt 50psi fuel pressure then after 2-3 minutes
it falls to single digits and then stalls try to feather pedal etc to keep running but no luck. Call MSD and the techs haven't helped. They are all focused on the installation of system. Even though i tell them its been that way for 10years so how could it be installation issue.
Handheld tool shows no problems on diagnostic settings.
 
BudW- I believe that there is underlying cause not the Atomic System. I am having the Cap/rotor/p.u coil/coil changed this week. I asked MSD if the fuel pump is affected by anything else within the car's system since the Fuel Pump is powered by the Atomic's power module. They could not answer that.
Thats why i am going to change the previously mentioned parts and then call it a day with it.
 
Does it go back up to 50 if re started? I'd be wondering if it's a pump or fuel regulator problem. But it also sounds like the type of thing that could be caused by a bad sensor or module that's doing something after that warm up type period. I guess there's no diagnostics to it or you would have been able to check it by now.
 
No it does not. Its starts then shuts down immediately. I am hoping its in distributor.
Mikes5thAve said:
Does it go back up to 50 if re started? I'd be wondering if it's a pump or fuel regulator problem. But it also sounds like the type of thing that could be caused by a bad sensor or module that's doing something after that warm up type period. I guess there's no diagnostics to it or you would have been able to check it by now.
Click to expand...
 
Is there a relay you can bypass to see if the pump can make 50 psi on its own after that first few minutes? I don't know that system but would have thought it should keep the fuel pressure high regardless of what the distributor is doing. The distributor would however probably double as the sensor to fire the injectors.
 
Thats what i was trying to find out from MSD. No relay to try to bypass. I was thinking same thing. Thanks
 
I'm thinking the same as mentioned as above - but if you are already at wits end, then I won't say anything more to add to that.

Using the Edelbrock Performer or Performer RPM?
Edelbrook Performer 2176-3776.png

Performer 2176 (or 3776 of with EGR)
Edelbrook Performer RPM 7176.png

Performer RPM 7176
The RPM version sometimes is too tall for a carburetor to fit under the hood.

Personally, I think the Performer is a great intake for a stock or slightly warm 318 - and it does allow for most carburetor usage.

Are you using a Chrysler ignition system?
Ignition Module B.png

This can be black, blue or orange.

If not using a Chrysler ignition system, what system are you using?
BudW
 
I'm guessing there may be a venting problem in the tank and the pump is creating a vacuum in the tank so it can't pump the fuel?
 
I'm guessing the pressure drops after a few minutes even if it's idling?
 
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