Wetted manifold question- MS

[malloy1]

I had to take my intake manifold off my engine to do some work on my brake system, and I noticed that the intake/head was saturated with gas (the intake gasket was saturated at the bottom of the ports to about 1/4"). I probably wouldn't think this was odd, but the car sat for 3 days before I started work on it. I've never noticed an intake manifold saturated like this on a stock LH setup. To me, this doesn't seem right.

Every since I switched over to MS, my gas mileage (~21 MPG) hasn't been what I've expected it should be.

Could something with the injectors be part of the problem? Could the injectors be open after the car is off? At first I thought my injectors might be leaking, but I just replaced the injectors with a different cleaned/balanced set a week ago, and the MPG didn't change.

I usually drive the car about 30 miles to work, and it sits there for about 8 hours before I drive home. So if the car is flooding out after I turn it off, the time lag would allow the gas to clear out of the cylinders.

When I do start the car in the morning and the afternoon, I wouldn't say the car starts right up like I hear from other MS users. I really have to open up the throttle and pump it after it starts for about 15- 30 seconds.

The manifold is still off the engine, but I'm planning on checking to see what the injectors are doing when the car is off (check the power to the injectors/relay), MS is powered up (fuel pressure is up, and the injectors are firing during priming), and when the car is powered down (check to see if the injectors are leaking/open).

Just wondering if someone have any suggestions?

Paul

The setup is:
-'65 122 with a B21F/M41 (stocked, not modified normally aspirated engine [4-cyl 2100cc])
-LC-1 WBO2
-MS V2.2 running MSnS-extra (24s13) fuel only - tuning with MT2.25b
-original '79 Bosch iginition setup from a 240
-Bosch 21lbs EFI injectors
-Volvo 850 Bosch TPS
-EGO crossover is set to 2.75v (AFR 15.4:1)
-K&N air filter

[The Aspirator]

the time lag would allow the gas to clear out of the cylinders. ... and drain down into the oil, thinning it out and making you throw a rod bearing.... :-P Might want to change your oil, or at least think about it.

21mpg is NOT bad at all, I'm trying hard with 87 octane, tuned to 16's and 17's on cruise and light decel, decel fuel cut below 25kpa, only running around 8psi and I get 19.5mpg all the time with about 30% freeway 70% city/back roads. All freeway I get 22.5mpg :lol:. I don't know how on earth I can get better mpg than that, I want to, but nothing seems to be working.

About the leakage, you're on the right track. Watch the injectors during power up, crank, and shut down.

[malloy1]

Your getting 22.5 mpg on a turbo engine, I'm running a non-turbo engine in a car that weighs at least 800 lbs less than your car and getting 21 mpg on the highway?

Paul
-'65 122 with a B21F/M41

[linuxman51]

sounds like you're running rich. your cranking pw's might be a little high as well. whats your cruise afr?

[malloy1]

sounds like you're running rich. your cranking pw's might be a little high as well. whats your cruise afr?

I drive about 90% of the time on a pretty good flowing freeway (avg. about 65 mph) for 30 miles each way/twice a day. The strange thing is that I get the same mpg (21-23mpg) if I run from 14.7:1 to 17:1. At 17:1 I feel a lean surge. The last time I drove it, the AFR was set to 17:1 and the mileage was the same (21-23mpg).

Here's a list of things that I thought might be the problem and I'm planning on changing:

Done:
1. Clean K&N filter -> cleaned it and mileage did improve from 21 to 23 mpg (only improvement in mileage).

2. Replace Bosch 711 injectors with cleaned/balanced Bosch 762 -> changed injectors and no change in mpg.



Need to try:
3. Relocating AIT sensor and replacing inlet piping -> Move AIT sensor further upstream of the intake/AIT sensor is getting heat soaked (don't know if this has anything to do with mpg) and replace the B21FT elbow (see picture below) with the rubber elbow and aluminum tubing from a '85 740 turbo (the B21ft elbow might be restricting flow to the engine, the 740T piping is a larger diameter)

4.Relocating the LC-1 WBO2 sensor ->move O2 sensor further downstream (it's located in the original B21F exhaust location(see picture below)), but the car just went through emissions and passed with flying colors (but the car only needed to pass the '81 and older requirements->no NOX, and a stationary test). From the datalog stuff (see datalog below) it seems to be running like it should at the 16.5 AFR that it was set at during cruise.

5.Manifold design (not going to do anything about, just is a alteration that might be the cause) -> Manifold is a B230F intake manifold that was altered by relocating the throttle body about 90* to fit it in the car. I really didn't think this would be a problem, and it was one of the few solutions to fit it in the car (see picture below).

This new observation with the intake manifold being saturated with gasoline after the car hasn't been started in a week is the big question right now.

Paul

http://www.brickboard.com/IMAGELIB/images/5626.jpg

http://www.brickboard.com/GALLERY/images/122-B21/volvo/5208.jpg

http://www.msefi.com/files/afr_o2_3_167.jpg

The setup is:
-'65 122 with a B21F/M41 (stocked, not modified normally aspirated engine [4-cyl 2100cc])
-LC-1 WBO2
-MS V2.2 running MSnS-extra (24s13) fuel only - tuning with MT2.25b
-original '79 Bosch iginition setup from a 240
-Bosch 21lbs EFI injectors
-Volvo 850 Bosch TPS
-EGO crossover is set to 3.25v(AFR 16.5:1)
-K&N air filter

[malloy1]

Also, I thought it might be something outside the fuel injection system like the car's ability to roll. I've checked the brakes for a frozen brake caliper/wheel cylinder and general binding when wheels are turned (everything moves freely), and I've replaced the wheels (no changed in mpg).

Alignment hasn't been checked, but the car drives a pretty straight line. No pulling to either direction. I do know the front end bushings need to be replaced, but again the car doesn't pull.

Paul

[jpbturbo]

I had a dead FPR that was giving me similar results.
I would check to make sure that it's not leaking fuel into the vacuum line it's connected to.

[malloy1]

I do have another FPR I can try.

Paul

Edit: I just remembered that I used a fuel pump from a 740T (and a fuel pump bracket from a 240). I didn't think that would be an issue. Maybe something to replace?

http://www.brickboard.com/IMAGELIB/images/5627.jpg

[The Aspirator]

Your getting 22.5 mpg on a turbo engine, I'm running a non-turbo engine in a car that weighs at least 800 lbs less than your car and getting 21 mpg on the highway?

Paul
-'65 122 with a B21F/M41When you put it that way, you're totally right, should be getting better mpg. :lol:

And the FPR swap is a great thing to try, I've had two blow out on me before. First one popped all at once and filled my engine, intake piping and IC with fuel. Second one popped very slowly, causing richer and richer mixtures till I replaced it.

[malloy1]

Checked out how the injectors operated. I would say perfect.

-When the car is off (check the power to the injectors/relay)
->No power to injectors or relays

-When MS is powered up (fuel pressure is up, and the injectors are firing during priming)
-> No leaks when fuel pump is priming, and injectors are firing perfectly.

-When the car is powered down (check to see if the injectors are leaking/open)
->No leaks. Injectors are closed

The wetted manifold most be normal then. Still doesn't explain my lousy gas mileage.

Paul