P80 hot start stumble and dies Topic is solved

[98v70t5mgonegray]

Good afternoon, reaching out kind of at my wits end.
To start it was a very far from 0 tune 1998 v70 t5 m. Purchased running for a tidy 623.00. Owning a s70, and c70, prevoiusly i know the standard timing belt and itll stay together mentality i was looking for in a commuter. Its either developed, or shown more because of the heat, a hot start issue.
The parameters are cold start every day will start with no fault. (It does always rev higher than other volvos ive had at 2k rpms).
Driving will be no issue, no hesitation, sit at lights in fl. Heat no issues, 1 hour or 8 hours driving no issues. If you go to a store and spend a half hour in the store or more you wouldnt ever notice it. If you stop once, say to get gas, it will start kind of stumble at first, then find idle from too low and you are good. If you stop a second time, or were like 10 min in the store, you are waiting. After a half hour it'll start like it didnt just leave you freaking out. Maybe a bit longer on a really hot florida day.
As far as its almost on-off-ness im thinking at warm start computer maybe looks at a sensor that it doesnt when the temp is less.
As far as getting it up to good order i have replaced timing belt and tensioners, pcv-flametrap, the abs mod for the dash light, fixed several vac leaks in the evap canister system, several motor mounts, suspension components. I can't pinpoint a time when it started to try to trace a connection or something i disrupted.
Now in the end of my wits catergory.... reading posts, knowing what i know.... i tested ect sensor, at hot it was just off of the measurement it should be, like 25 ohms. Replaced it. The iac valve, i cleaned, then replaced. Read something about evap, so replaced the evap purge solenoid back by the rear wheel. Still no difference. Instead of replacing the purge solenoid at the front i disconnected it. Thought process its getting too much air, it seemed to work good for several days, then it did it again. So i started down the other path of the start up equation, replaced the fuel filter, checked for leaky injectors and ordered a gauge to read off the tiny schrader. Gauge read like nearly 40 in the key position 2 , just at 30 running. Its the returnless fuel rail with the fuel pressure reg somewhere by the steering rack i guess. Read its rare for a pressure reg to go bad so i bought a fuel pump. Installed the fuel pump.......took it for a heat up ride and same deal. I'll check the pressure tomorrow its just doesn't seem to me that it will be abnormally low too.

[abscate]

Cap.rotor, plugs, wires?

[98v70t5mgonegray]

Checked the fuel pressure and its close to the same as before 40 on ignition 2, 33psi running.
I have been assembling a tune up kit, lacking a cap at this point. I just dont see, excluding a hot coil not functioning correctly it would be different cold and warm starting.

[scot850]

As you are looing for unusual possible sources here are a couple to check on:

1) You say you are getting 40 Psi fuel pressure. It should be higher, 43 psi minimum.

2) Does you cooling fan run after you switch the engine off to allow it to cool down? If it dies not, then you may be getting fuel vaporisation, possibly coupled to low fuel pressure.

Neil.

[belskee]

I have a known issue on a c70 t5 with the cam position sensor, has thrown a code but the eml comes and goes, I get the same issue with the hot starting and figured it to be related to the sensor fault.

Also I notice you said it fires up to 2k revs before idling on start up? Mine also does this however it bounces up to 2k then drops to 1.5 then down to 900 where it idles without fluctuating.

One thing I know about hard hot starts is it usually points to a problem with the engine getting air in

[98v70t5mgonegray]

New cap, rotor, wires and plugs gapped for turbo. It feels smoother. However no remedy to the warm start.

Can someone verify my recorded fuel pressure is still low for a 2.3 t5 returnless fuel rail? And if so where is the location and possibly p/n of the fpr?
Key 2 40psi
running steady 33psi