Air speed meter, How to evaluate?

backkraker · #1 (**permalink**) 09-19-2006, 06:32 AM

My v6 runs well, idles well, starts well, however it accellerates slow compared to my friends v6. Tune up has been done. When cruising in 3rd at about 3200 you can feel a slight variation or surging in the rpm range?

Help Joe K

**kredden** · #2 (**permalink**) 09-19-2006, 08:08 AM

I have some starting issues to work out but I've noticed I have the same surging problem as you at an indicated 2500 RPMs (my tach is off so it may be 3000-3200 like yours). Mine doesn't only do it in 3rd, but also 4th and 5th. I have a feeling I don't see it in 1st and 2nd as the revs are usually a lot higher than that :-).

I've been trying to debug this issue for a while now. I was leaning towards a faulty pressure regulator but have no proof of that. I've swapped air flow meters and it seems to do it for both.

Hopefully someone will know, this is really annoying me!

Kevin

MrT · #3 (**permalink**) 09-19-2006, 08:38 AM

Anyone think of possibly a plugged fuel filter? There are flow tests for the fuel system, involving diverting the fuel return flow into a bucket and measuring the volume transferred in a given time, but I don't remember the numbers. Swapping a fuel filter seems like good maintenance, because it's probably time anyway.

[well, maybe if this were the problem, it would show up in spades at lower gears and high RPMs, but maybe not....]

Nipper · #4 (**permalink**) 09-24-2006, 05:37 AM

I'm sorry for being a little off topic but after recently changing my fuel filter I noticed another filter, a little smaller in diameter than the fuel filter, on the other side of the car. can anybody tell me what this is?

**Alfisto Steve** · #5 (**permalink**) 09-24-2006, 07:53 AM

Fuel pump? Does it have two wire going to it?

**kredden** · #6 (**permalink**) 09-24-2006, 12:37 PM

When was the last time your O2 sensor was changed? I've been trying to debug my surging problem and took the car out for a drive today with my Autoforce tester plugged in. Forcing the O2 reading into open loop mode seemed to smooth things out. I just did some poking around on the Bosch web site and found the following statement about O2 sensors: "# Can cause engine performance problems, such as surging and hesitating ". (http://www.boschautoparts.com/Produc...sors/PremiumO2) I have no clue when mine was last changed so I'm going to give that a go.

Now I just have to figure out which one to buy (Bosch direct fit $$$, Beck Arnley, NGK, Bosch generic 3 wire...)

Kevin

slyalfa · #7 (**permalink**) 09-24-2006, 12:46 PM

Bosch generic 3 wire.. if you can solder.(use heat shrink tube) but they are easy to check. I can tell just by the motor sound.
at idle it wile go lean/rich back and forth. so there will be a slight hi/lo as it does this.
all L-jet seem to do this not just Alfa. if you have a scope you can look at the green wire.
you will see a sine wave as it goes lean/rich

Nipper · #8 (**permalink**) 09-25-2006, 01:22 AM

Quote:

Originally Posted by Alfisto Steve

Fuel pump? Does it have two wire going to it?

**kredden** · #9 (**permalink**) 09-26-2006, 04:37 AM

I just bought this O2 sensor, the price was right, hopefully it works well!

http://cgi.ebay.com/ebaymotors/ws/eB...m=190033706586

The guy actually shipped it out less than an hour after I hit the buy it now button.

Kevin