LH 2.2 740 Turbo No Injector Pulse/Ground

[93Regina]

So just use the test light as a probe to manually apply power?

Correct...I thought I saw in a Volvo manual this could be probed at connector, without backprobing wire, or cutting/splicing a wire.

LH2.2 uses the fuel system relay for power.

LH2.2 is sending a small current to ignite fuel pump relay.

LH2.2 Fuse - Clean it up, located here (212)

I assume you inserted another relay at 214?

That fuse might be your issue....clean it and its terminals up...I've never seen it before

[bmdubya1198]

Yes, there is room on the back of the connector on most of the wires. That's how I checked for all correct ECU values.

I am not familiar with that fuse. I don't think the 740 actually has that one, either. I haven't seen it in any diagrams and I certainly haven't seen it on my car.

The main diagram I've been using is the first one at this link, for the 1989 740 http://volvowiringdiagrams.com/?dir=vol ... 20Diagrams

[93Regina]

fuse

Without looking, I think I've seen it on several 240 series Volvos....not sure about 93-940 with Rex/Regina.

My cite came from Dave's site...

LH is LH, and all LHs require lots of intermittent current to fire up those injectors....having a circuit being fused is common sense...without looking at schematics, if Fuel Pump Relay also fires up LH2.2, then that's a heavy draw on some 12volt circuit, if only one power wire is used.

Relay 217 is powering up LH2.2 & fuel pump(s)....fuel pumps alone is what, some 7+ amp draw? I think that relay has two circuits...but is there just one power source? Find its fuse, and clean fuse and terminals.

[93Regina]

Ooops, diagram was for 240....but check fuses on 740...and btw, if you have not replaced that relay, end of discussion.

[bmdubya1198]

Tested once again for injector pulse while using a Y-jumper on the fuel relay, and I now have pulse!
Next problem... I do not have fuel at the rail. I pulled the return line from the fuel pressure regulator and there was nothing. I went ahead and changed the coupler line between the pump and filter, and there was no fuel at all there either.
I don't think my in-tank pump is running. Wouldn't the in-line main pump have enough power to pull the fuel? I checked and there is voltage at the connector for the in-tank pump, so I'm pretty sure it's dead.

[93Regina]

in-tank pump is running

From my recollections and experiences, keeping tank full eliminates dead in-tank issue, with an OEM Bosch main pump. .

I ran for years with a dead in-tank pump. The reason it was put there goes back to 1975-240s, which initially did not have an in-tank pump. In summer time with higher outside temps, vapor locking was the issue, so there was a recall on 1975s.

That said, unless that filter sock is plugged up, fuel should be sucked out of a full tank...unless a newer style "impeller" pump was installed. If my OEM Bosch is replaced, I will install a new in-tank pump.

[bmdubya1198]

I just have a cheap eBay main pump, and not much gas in the tank. That combo kind of explains the problem!