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Bruce, thanks for the info. Just checked again after coming home from work. Gauge reads 30-31PSI at idle. When I removed the vacuum line from the FPR, the gauge jumps to about 40-41PSI. So it appears to be a little low...? I hope my gauge is accurate.
You (and the others) might be wondering why I suddenly started looking at this. I get some hesitation when accelerating before the engine gets to 3000RPM. It's not a lot, but enough to be noticeable and annoying. It's more pronounced now that the summer is here and both the AC is going and the thermal clutch is engaged for the engine fan.
In addition, I've been failing emissions for some reason. The HC and CO readings are high. I have tried running a few bottles of Techron through the system. I removed the intake manifold (not all the way, just enough to replace the intake manifold gasket) and TB. The intake manifold itself looked a bit dirty but I couldn't really reach inside of it to clean it. The TB looked decently clean but I cleaned it again anyway. Then I put it all back together and replaced the gasket.
There do not appear to be any vacuum leaks as I've tried the vinyl-hose-in-my-ear stethoscope trick adn I don't hear hissing anyway. The cat should be good as well; it's less than 4 years old, and there's no rattling. Have also tried a "water" cleaning (dipping a vacuum hose into a small jar of water while revving the engine to keep it going) and also blasting some air cleaner spray into a vacuum line.
Spark plugs are not that old, and the gap is correct as well as the torque. What I did notice is that the spark plugs appear to get contaminated with a bit of oil, which is not good, and I guess it's a leaky seal (piston ring?) But the leak couldn't be that bad though because I'm only losing about a quart every 3-5K miles, so somehow I don't think it should be affecting my emissions that much.
Also, there is no knocking or pinging or misfiring. No smoke from the exhaust. No odors.
And oh yes, a few weeks ago on a hot day (80F+ degrees), my car died. I don't believe it was fully warmed up and the AC was on. I was stopped at a light, and all of a sudden the car starts shaking, the idle starts dropping, and it dies. It wouldn't for about a minute or two no matter how much I cranked it. I just waited, and all of a sudden it started right up again as if nothing was wrong. Later on that same day, it happened again. I tried to catch it before it died by throwing the car in neutral, shutting the AC off and revving the engine, but no good. Same thing. Wait a few minutes, and it fired right back up.
This also happened before on a cold soak (overnight) start (on a warm day ~80F) where the car kept cranking and cranking and wouldn't catch. Took nearly 5 minutes of sitting there before it would fire up. I didn't get a chance to look at the fuel pressure gauge to see what it read. I'm sure that would've been a valuable piece of information.
Anyway, I'm thoroughly befuddled at this point.
I know it's a long read, but I hope someone goes through it.
I've been reading through the FAQ a bit and it sounds like I should definitely be looking at the relays first as someone suggested. Thanks, I will do that this upcoming weekend first chance I can. But would that throw off my emissions? There are no OBD codes being set other than the chronic 3-2-1 of cold-start valve.
Any input from anyone is much appreciated!
P.S. Pump is original as far as I know with 167K miles on it.
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Ken
1990 Volvo 740 base sedan (B230F)
My Volvo 'Project'
Click here for the 700/900 FAQ
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