Swapped out my 4.0 of a 302 in a 91 Ranger XLT. When the engine gets warm (above 150) it starts to pop and sputter. I can’t put it in gear and more her too far (AOD Trans) any answers?

600 Edlebrock Carb
RPM intake
MSD 6a
MSD Distributor
MDS Blaster Coil
Two 600 CFM pusher fans
2 ¼ dual exhaust with dinomax two in two out
4.0 HD RAD
Molly fuel regulator off the original 4.0 EFI pump

timing ? but most of what fireing order did you use ?

is it 302 or a 5.0 and what year?was it out of a car ?
was it EFI or carbed we need more info :flipoff2:

Sounds like you need to advance your timing a bit...

Its not timing. If it was, the motor would run like crap all the time, not just when warm. I got my money on an o2 sensor, or another sensor.

Dimitri

O2 sensor? It's got an Edelbrock carb. But I know what you mean about being warm. Perhaps he drives it easier when it's cold and when it warms up he winds it out a bit more. Could be that the timing is only a bit off.

Choke not releasing?

Damn, I gotta learn to read. You are right, no O2 sensor. hmm, it could very well be a bad choke, or you can just get rid of the carb, and swap on a 2 barrell motorcraft.

Dimitri

Thanks for all the input, I will check it out when I get back, right now I can’t get to her, over sea’s doing the three month rotation.

It might be the timing or it might be the pressure in my Molly reg? I have it set up to down grade my PSI from my original fuel pump, 40 to 7 lbs….I can’t seem to get my gauge to set at 7?

Tim

my vote is for a vaccum or intake gasket leak. Mine did the same thing, the intake bolts had loosened- letting in relatively cold air causing backfiring and lugging.

hth

My vote, is exhaust manifold leak :D Hot pipes, spent gas pourin in and extra air and.. POP!

The engine is a 302 HO vin # E, The timing is right and I have used carb cleaner to check for any vacuum line leaks. The exhaust is sealed with no leaks, I am still betting on the fuel PSI is too low. Not enough fuel and it backfires and dies out…

What is the best way to check the PSI out of my Reg? Plug the hose going to my carb and then check the gauge?

BTW I've had vac leaks inside the crankcase. Impossible to find with carb cleaner or propane. They'll drive ya nuts. Is it an exhaust backfire or is it coming up the carb?

Pop off your valve covers and check your lifters, and rocker arms. Make shure that they are bolted tightly, and that you have some play in the hydro lifters on cil. compression.
If you have vacume advance, then your engine might be advancing itseld w/o you knowing. Once its nice and hot, adjust your timing on the fly, while its in gear and somone is there with thier foot down on the brake.
Check your choke, it might be messed up. If its electronic choke, make shure its grounded.

I have the same carb on my engine, and stock, it dosent like to be mutch above 5 psi on the fuel line. You may have to change metering rods, or jets to fix the problem.


Keep on wheelin!
SMC

I'm not sure if it's got hydraulic lifters or not but when it warms up the oul thins out and you might not have enough pressure to pump them up. I've got a motor (6 cyl) in a 67 Bronco that's doing that. 40 psi when cold and as it warms up the pressure drops to almost nothing and you would swear its got bad intake valves.