For your existing rental property, the net rental income from your Schedule E on your most recent return will be used in your DTI.

@Ryon PaxHave you considered cutting some of your personal expenses to pay for the HELOC or find another way to generate added income?

Tools like Roofstock and local property managers can make remote investing manageable.If you prefer to stay local, explore adding an ADU to your property for rental income if zoning allows.

You get to make offers on your own and potentially save on buyer's commission.I wouldn't recommend if you already have an active income that is serving you well because it would be better to invest time in that endeavor if that's the case.

The income (rent minus management) should cover the costs (principle, interest, taxes, and insurance) depending on the property's price point. 

Presumably the 100% owned properties throw off some cash for income. 

We just bought a house in a highly desired older neighborhood.The owner agreed to owner finance it with 5k down over 5 years at 0% interest.We did put some money into the house to fix it up some.The rental income will cover the payments.Always ask for owner financing, the answer might surprise you.Work with money partners to do more deals.Join your local Real Estate Club and learn new techniques and grow your network.

You’re generally working with tenants who, by definition, have lower income and often less favorable credit.

To evaluate Real esteate deals for creative financing, start by identifying seller motivations i.e. financial distress, desire for passive income, do they need a downpayment on their next house, etc  and property factors like equity or existing financing terms.

Go down to the bone as long as you have consistent income.