I've been chasing down a warm start issue with a 1988 245 and I'm hoping someone here might be able to coax me in the right direction. Let me set the scene:

• 98.9% of the time, when the car has been sitting for 6+ hours, it starts up beautifully the first time in a fraction of a millisecond! (If it's hot and been sitting in the sun, this is sometimes the exception.)
• 100% of the time, if it ran in the last 10 minutes it starts beautifully
• When it's been sitting for 20+ minutes to a few hours is when I have a long period of cranking before it finally fires up

In pursuit of this problem, I've spent hours scouring the forums and you've been very helpful so far!

• Early on when it was in for an inspection to a trusted specialized Volvo mechanic, he said the fuel check valve is fine but I did not confirm for myself.
• Replaced cap, rotor, wires, plugs
• New air filter and filter thermostat
• Fuse 4 removed: Left side jumped to fuse 6, I hear the main pump. Right side, I hear nothing
• Replaced the in-tank pump...now I hear that when I jump the right side of 4 to 6 with the fuse removed. Excellent! The pump was bad.
• I don't hear the pump prime when I turn the key to accessory *but* I read that the 2.2 system in the '88 may not prime the pump because it has a hall effect sensor instead of a crank position sensor.
• Replaced the fuel pump the fuel pump relay "just in case" but the condition persists. Could have bought a bad new relay...maybe? Unlikely.

The problem is not intermittent, in that I can replicate it precisely. Some questions:

• If the hall effect sensor was bad, would that have an impact on starting and running conditions all the time? Logic makes me think if that was bad, the pulse would never get sent to the relay and thus the fuel pump would not operate, ever.
• Same question as above, with regard to the relay. If it was bad, would the car stay running at all?
• I DO have a new fuel pressure regulator valve that I haven't swapped yet. I removed the vacuum hose and *don't think* I smell fuel...though I read the absence of a smell may not always indicate it's a good valve. Is there any benefit in replacing this considering the above?

Before I continue to "fire the parts cannon" (ha-ha) I was hoping one of you might have a logical next-best thing to look for. I'd hate to swap an otherwise fine distributor if that's not the issue, etc.

Thanks all!

 

Connect a fuel pressure gauge - measure running pressure. Turn car off, measure rest pressure. Report back with numbers.

 

I had the same exact set of symptoms. Most likely your ECT is to blame. You can take readings at the ECU under the glove box. Check out the link here.
https://www.davebarton.com/pdf/Harne...ctions2021.pdf
Or just buy the part and replace lol. It's cheap and not THAT hard to replace.

 

I'd check the the fuel pressure regulator. Cold start good, as extra fuel is delivered prompted by the coolant temp sensor now cold. Then car sits for awhile, still warm so temp sensor is done delivering that extra fuel but the FP regulator has lost pressure thus causing the fuel starvation.

 

As I was preparing to test a couple things related to fuel pressure, I came across this potential culprit. I believe "A" to be the coolant temp sensor for the dash gauge, but "B" has snapped off completely (second photo is the rest of it in my hand.) Searching the parts sites, I see a two-prong temp sensor that sends a temp to the ECU for the fuel injection system but that sensor does not look like this one, and it's just one wire. Anyone know what "B" is? For reference, it's the LH 2.2 from 1988.

 

A is your temp sensor for the gauge. B is the early style single wire knock sensor. Car will run fine without it. Later style is 2 wire and clamps against the block.

The temp sender for the fuel injection is installed in the head near the #3 intake runner - Not too bad to get too. Probably a 1332396. If you replace it - make sure the new one is the same color as the old - there are blue ones and black ones. They do not interchange. I would certainly look closely at the temp sensor for the fuel injection - given the condition of the knock sensor. That temp sensor tends to melt when the cars are overheated - the single wire one for the gauge don't seem to melt at all -

I would still check rest pressure - that's a common cause of hard warm starting if still having problems. When engine is off the fuel pressure is held on one end by the check valve in the fuel pump, and the other end by the fuel pressure regulator.

If you have a new pump with a new check valve - conceivably you could test the fuel pressure regulator by clamping off the return line fully (as long as that hose is still flexible enough to survive that treatment! )

Wait the amount of time you usually suffer from hard warm start and try it.