1998 V70 T5; problem hot starting & occasional brief power loss at speed

clifford06 · Post by **clifford06** » 01 Oct 2019, 19:39

If injectors spray when hot , What could be my next point of focus ? ECU ?

Post by **abscate** » 02 Oct 2019, 05:41

If it fires in ether, and the injectors are delivering fuel, the fuel delivery amount is wrong.

I think you need an oscilloscope to confirm the injector pulse ( more accurately , how long the ECU isnpulling the injectors to ground

An ECU swap is the Mossberg method if you can’t get a scope , but you are getting close, not much else left

Send me your coordinates, TX travel planned soon.

clifford06 · Post by **clifford06** » 09 Oct 2019, 15:04

Dallas. Been busy with work and family . Could injector relay act just like a fuel pump relay ? Meaning , could it stop working or cause a stall when hot ?

clifford06 · Post by **clifford06** » 09 Oct 2019, 15:14

Also , while doing research, I saw something about air pump relay having the same " value " as the injector relay . I guess this means they are interchangeable ? If so , I have a few relays from a salvage run that I could try . Thoughts and helping opinions always welcomed !

Post by **misha** » 09 Oct 2019, 16:05

They are NOT interchangeable and also visualy not the same.
Yes...main fuel injection relay could make problems when it becomes hot....just like any other relay.
Try to swap it with a used one and see if problems go away.

Post by **erikv11** » 09 Oct 2019, 16:35

erikv11 wrote: 17 Sep 2019, 17:41 There's also the gray fuel injection main relay up under the radiator - or maybe that relay is not used on a 98? My 98 is not here or I would check. Someone else will remember.

It's basically guaranteed to be an electrical/electronic part, that when it heats up the resistance gets too high. V = IR so currrent drops and the component stops working and the car stops working. Could be a relay, sensor, or a critical wire that is thin or poorly connected.

clifford06 · Post by **clifford06** » 09 Oct 2019, 19:59

Thanks for the reply .I'll make a salvage run this weekend. You quoted from the same thread I read .

clifford06 · Post by **clifford06** » 10 Oct 2019, 17:12

Hello ! Today I spoke with local Volvo dealer about price of a injector relay ( local salvage yards are bare of S70s ), and the part number matches main relay in main fuse box. I called back and was emailed a schematic showing the location was in the main fuse box , not under radiator cover . Only thing on radiator cover is cooling fan connections.

From the pic , it seems it goes in slot #2 in fuse box , which is labeled Air Pump on the underside of fuse cover . I have no fuse there , never have . Maybe that was to show general location. I think , maybe my problem is the main relay itself ? I have a matching relay from previous salvage run that I'll put in and see what I get . Any input is welcomed !

clifford06 · Post by **clifford06** » 10 Oct 2019, 18:15

Swapped main relay after getting car to temp, and still same result . I'll swap cam sensor next .

Post by **erikv11** » 10 Oct 2019, 22:20

Yeah, I didn't think the 98 had the relay at the radiator. This is a sticky one hang in there ...