'96 850R Very low mpg, very low power.

[bmessina]

Thanks for asking - I just noticed that I forgot to mention that in my update.

[northernlights]

If you don't have any luck with the MAF you might want to take another look at the fuel pressure regulator and possibly the return line. Some of the later 850's had a returnless system, but I don't know the exact details as to when that happened.

I saw that you said you checked it for leaks, but (again assuming the MAF isn't a problem) I'm a little suspicious of the regulator for a few reasons. As was mentioned before, the plugs look pretty sooty and cars will run even when they are really, really, really rich, but they turn into complete dogs. If the car has a funny regulator, especially if it's a returnless system, then you might be getting very high pressure. The old service manuals warn not to exceed 87 psi while testing the fuel pressure, so that makes me believe the pump is capable of at least that.

You implied that you have been chasing this problem since you bought the car two months ago. Did the previous owner stick some monster 600 cc injectors in because he thought he needed more fuel?

I recently worked on a friend's car that was idling very erratically and running generally poorly, and it turned out to be an incredibly fouled MAF caused by years (and 298k miles!) of deposits from gasoline vapors floating around a supposedly dry, port injected manifold. That car ran the same with the MAF disconnected, and was repaired with brake cleaner. That car wasn't down on power as bad as the way you describe yours even with essentially no working MAF.

The fact that you passed smog is really weird. You mentioned a recurring CEL now - did you get a code for that?

[bmessina]

I've measured fuel pressure at idle, at high(er) revs, and in gear building boost (while stationary, not great for the trans I know). Everything stayed in the 40-44psi range. Do you have any other recommendations for testing? I guess I could try to rig up something to test while in motion...

I don't think it's returnless, as there are two lines coming into the fuel pump apparatus, and one looks like it just dumps into the tank (doesn't go through the actual pump, just the assembly).

The previous owner (the original owner) was an older family guy who told me the car had a problem around the corner from the house (barely ran, couldn't get it above 10mph). They pushed it into the driveway where it sat for 2 years. When I checked it out I found that the hot side turbo hose was off. I thought I had a deal! Oh, how I've paid for it since The car was overboosting, hence the replaced TCV. Long story short, no, the family I bought it from would not have upgraded the injectors.

No codes via OBD for the CEL, but I still need to do the other method... this weekend, most likely.

Thanks!

[rspi]

Hold the phone. If the car is in "limp home mode" it is likely starting in 3rd gear. It will take you forever to get up to 60 mph. You may have a bad PNP switch or something wrong with the transmission that is starting the car in 3rd gear. When you start the next time, see what speed it shifts at. It should shift out of first at about 12 mph, out of 2nd at about 23 mph, out of 3rd at about 50 mph. If you are not seeing the tack drop at those spots, you are likely in limp home mode and may have a transmission issue. The fashing arrow lets you know it's in limp mode.

Other than that, I was thinking that the timing was off. Maybe someone had installed the timing belt and did not align the cams properly, or they pulled the cam sprockets and didn't get them on correctly so the timing is off.

The car has a button near the shifter that says WINTER/SPORT/ECONOMY, what is lit up there? If you select any of the buttons does the switch light up any of the lights?

[bmessina]

No, it shifts well through the gears. Even when the arrow was flashing it was shifting fine. The only trans issue I'm experiencing right now is either with the lockup solenoid or the converter itself, the car tries (and fails) to stall out sometimes when I come to a stop. I'm planning a fluid flush to see if that helps.

Timing has occured to me too. The belt was probably changed when the new(70k mile) motor was put in about 50k miles ago, but there's no record that far back. I guess I'll just check to make sure the cams line up right and go from there.

I'm familiar with the buttons on the car. I keep it in economy mode just because it does rev comfortably up in the range where sport takes it. The winter button functions, it definitely forces the car to start in a higher gear when activated. Selecting winter mode lights the up arrow on the dash (no flashing, just steady as normal), switching between sport and economy only lights up the lights on the switch itself. In other words, both normal operation I believe.

Thanks!

-Ben

[rspi]

So, I would check timing next, then for stuck calipers. Jack the car up and see if the wheels spin freely.

[jblackburn]

No, it shifts well through the gears. Even when the arrow was flashing it was shifting fine. The only trans issue I'm experiencing right now is either with the lockup solenoid or the converter itself, the car tries (and fails) to stall out sometimes when I come to a stop. I'm planning a fluid flush to see if that helps.

Timing has occured to me too. The belt was probably changed when the new(70k mile) motor was put in about 50k miles ago, but there's no record that far back. I guess I'll just check to make sure the cams line up right and go from there.

I'm familiar with the buttons on the car. I keep it in economy mode just because it does rev comfortably up in the range where sport takes it. The winter button functions, it definitely forces the car to start in a higher gear when activated. Selecting winter mode lights the up arrow on the dash (no flashing, just steady as normal), switching between sport and economy only lights up the lights on the switch itself. In other words, both normal operation I believe.

Thanks!

-Ben

I missed the timing somehow by 3 teeth in each direction (although the marks on the cams lined up perfectly, I think the crankshaft moved when putting the belt on - I couldn't see the mark at all) when I did the timing belt on mine. You could floor it, hear the turbo boost up to where it sounded like a truck, etc, but there was very little pickup at all.

FPR would be another major suspect, but my car couldn't idle or do anything but choke when its went bad. The diaphragm had ruptured to the point it was just inhaling fuel into the intake manifold in addition to what the injectors were supplying. Perhaps yours isn't quite as bad if that's the case.

You say you've tested things looking back at the service manual specs - maybe I missed it, but are you able to see O2 sensor readings at all using an OBDII scan tool?

[bmessina]

You could floor it, hear the turbo boost up to where it sounded like a truck, etc, but there was very little pickup at all.

This is pretty much exactly how the car reacts when I floor it. It boosts more than fine, especially with the IPD TCV, but it barely moves.

I've pulled the vacuum hose for the FPR multiple times and have never gotten a whiff of fuel. I'm not sure I've done it while running though, I'll do that next.

Yes, I can see O2 sensor voltage via the OBD interface. That one is harder to say in anything other than general terms, as to whether it's in spec. But the voltage ranges seem to be appropriate for a rich-running car, which is to say max voltage (~1v) under throttle. I've also replaced the upstream O2 sensor recently.

[bmessina]

Ok - Checked timing. Cam marks line up like they're supposed to on the cover.

Hooked up a timing gun and started it up. If I'm supposed to be able to read it off the camshaft mark to the timing scale on the cover like it seems, um... It looks way off. Got a picture:



That's at a dead idle. It advances even more past that point when I rev it. Isn't it supposed to be 4-8 degrees advanced at idle?

[precopster]

Photo doesn't look right to me. Remove the cam sensor and distributor to view the horizontal slots at rear of cams. They should be precisely horizontal with the crank on mark.