Thanks Graham, what I don't understand is that with fuel pump only I have steady flow in the fuel rail and thus constant pressure reading (needle stable)
Then when I turn on the engine the needle is jumping and I can feel the pulse in the hose when I press it.
There might be an electrical gremlin but it doesn't look like a typical electrical disconnect as it is pulsating... therefore I thought maybe the damper is dead. But why should this damper go bad?

The other option is that the feed from the pump is bad when the injector take away the fuel. So either the pump is bad and has not enough flow or
there is some resistance in the line.
How can I measure fuel flow?
I could test the return line and measure the flow there?

I'll check fuse and relay... fuel pump relay some where hidden behind the ECU I think.

I changed regulator and damper and pressure readings are much better, steady needle. I adjusted 32.5 psi...well the precision of my meter is limited...need to find another one or I am trying the MPS next round. I am going for a ride now and will report back.

New AFR numbers. I adjusted with new regulator/damper set: 32.5 psi..and measured

50mph: 14.8
60mph: 14.0
70: 13.0
75: 13.2
80: 13.4
90: 13.0

Idle: 12.0

What do you think?

Just a smidgen rich at idle and upper rpm's but those 3.5's always seem to like being a little "fat". I'd put some miles on it Martin before I messed with it too much more. You did just replace the valves you know.

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Thanks
yes 'new' heads, I mean a machine shop did the guides and cut valve seats.

I can adjust idle separately on the ECU. Would you?
So you are saying I should go with it for the time being and probably revisit some time later?

What amazes me (I didn't really measure but it must be) that with stock pressure (29/30psi) my 3.5 engine must run too lean. Why is this? I know Graham did perfectly explain it.

Martin

Those look good to me. But important thing, is how the car runs.

Where you are car probably gets up to temperature quickly, but in our cooler climate, I get all sorts of AFR readings depending on if weather and engine are cool or really hot. But once warmed up and driving on highway, the numbers are similar to yours. I would leave idle AFR as-is. It helps with hot starts if you are rich at idle.

You asked about measuring fuel flow. I doubt you need to check it now except just out of interest (I did!) Just disconnect return hose from damper, add a longer hose and lead it into a container with markings at say 1/2, 1.0, 1.5, 2 litres. Jumper the fuel pump relay so pump runs when you turn key. (Don't put power directly to pump, because pump flow is affected by voltage. Things like bad grounds, weak battery, bad connections can affect pump flow) Just turn key and time how long it takes to get to each volume mark. Then calculate litres/min or litres/30sec and compare with spec which is 1L/30sec or 2L/min. Engine is not running when you do this!

I really glad to see you got this sorted out. Everyone with a D-Jet needs a reliable AFR meter otherwise they are shooting in the dark. The permanent AEM meter I installed was about $250 installed including having shop weld in bung. Not a lot of money to get the engine running well.

May be time to move on to the transmission problem I am still away from home and don't have my references here. Do you know which transmission you have and if it is 3-speed? I have some info on my computer, but don't know if it is applicable.

__________________
Graham
85 300D,72 350SL, 98 E320, Outback 2.5

Thanks a lot Graham,
really great to have people with experience and character.
My transmission makes me almost cry, next to my rear shocks. I am very hesitant to push hard from a stop..I can't stand the noise of slipping trans. Also shifts are tooooo slow. Feels like grandma.

Transmission model is: K4 A 040, 4- speed... I think...modulator pressure is 3.8 kp/cm2 (max. pressure)
Slipping means modulator pressure too low
or/and regulating valves (modulator and working regulating pressure valves...don't know where these 2 are located)
or/and vacuum pot are binding...

Modulator pressure is adjusted down at the vacuum pot by screw driver when removing the vacuum metal line from intake.

I'll measure tomorrow and report what I find.
Martin

Martin should have the 4-speed since the car is a 3.5. The 4.5's have the 3-speed, though if I remember correctly, both transmissions have the same top gear ratio.

Best Regards,

David

__________________
_____________________________________________

2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

_____________________________________________