850 loves cold start, hates warm weather start

[Warren Watson]

My 1994 Volvo 850 will start up like a pro in sub 20 degree F. weather. Above 50 it is a hard start. In either case I get it started and if I kill it, it will start up no problem within 5 mins. of killing it. 20 minutes later, i try to start it and takes for ever. Note: i have a new fuel pump relay, cleaned MAF, new cam sensor, temp. sensor, rotor and distr. cap,,new plugs, fuel filter, vacuum elbows, and, if i check fuel at schraeder valve, i have fuel squirt out. What is left?

[erikv11]

The symptoms almost match a heat soak situation, which would be strongly suggestive of an electronics issue. Temp goes up, resistance increases, system behaves differently.

What brand is the MAF? At any rate I would unplug the MAF, then see how that affects the starting behavior. Of course this test will set a CEL for the MAF, so you will need an OBD reader to reset that.

Cleaning the MAF does no harm when the right product is used so it was a good move doing that, but FYI it is rarely useful unless the filament is super dirty (like visibly oily, etc).

Also I would check the condition of the wiring inside the ECT connector, the metal can get corroded and the wires frayed etc.