Rb25det Weird spluttering / dying while driving.

[Saul007]

Hey guys, have a weird one here. The car is a r32 with a 25det s2. Basic bolt on mods that has been tuned by previous owner. Power figures unknown. Currently running on 10psi. 

First issue is the car is losing voltage on startup. Turn the key to crank her over and it drops from 12.8v to about 6 or 7v. Only started doing this after I changed the coilpacks and plugs around to new ones but I can't see why they would do this ?

Second issue is the car will randomly hesitate and splutter almost like it's fuel / boost cutting. Hard to explain. On acceleration it'll splutter, die out and come back to life. It's like the car just loses all power and dies down until it jerks itself back to life. Or when I try to accelerate slowly at low cruising speeds it will do it then too. Fuel pump is a walbrough that's a few years old and new recent fuel filter. Haven't check injectors just yet. It also has a new O2 and ecu coolant temp sensor. A few people have told me that AFM going faulty has similar issues. Intermittent hesitation and spluttering then eventually dying out and working again after letting it sit for a while. I've cleaned it but no difference. Again it doesn't always have this issue, it pulls and drives like it should most times then other times itll have this issue. Any info would be really appreciated on what I could try myself before I take it in to a shop and get charged the heaven and the earth. Cheers 

Edited June 1, 2022 by Saul007

[Chopstick Tuner]

If you're concerned about battery voltage, put it on a load tester. If it drops below 9v put it in the bin. Could even have a loose battery terminal (forgive me for starting so basic, I don't know how mechanically minded you are) and therefore losing electrical power and spark etc. 

Start with that before diving in deep, charging problems and lack of voltage will affect spark, how much power the fuel pump gets and so on. 

[Duncan]

I'd check that the earth strap between the chassis and block is good (or check resistance between the block and chassis, should be basically 0)

[Saul007]

Battery is brand new but I'll test it anyways, even new batteries can be duds I suppose. I'll also check the ground wire from block to chassis. Thanks lads