DougM

After getting my car running again, I still have the "bucking" at around 2000 rpm. Idle is steady and acceleration is smooth. My MAF is rebuilt. After researching, and an earlier post on the subject when I got the car, I have learned that some EUro S cars run lean. Some have had success with an AFPR installed on the passenger side with a dampener on the driver side. From a donor car I had, I have an AFPR. Looking through all my spare fuel parts, I have extra regulators and noticed I have a dampener with the Bosch # 0 280 161 008. At least it googles to show it as a dampener. After researching the vendor sites, it does not show this to be the dampener sold for this application that has a 930 part number. Is this a correct part with a superseded number?

Mrmerlin

did you readjust the MAF to get the correct co ?
there are 2 dampers and one fuel pressure regulator ,
the FPR is on the right rear fuel rail ,
the other 2 parts are fuel dampers.
Also check the ignition wires and the coil wires for corrosion
check the twin dizzy for the correct timing,
remove both caps with the engine at TDC and verify the rotors are both pointing to the hash marks in the dist body.
mark the coil wires to the caps if they get swapped the engine wont run,
verify the plug wires are infact going to the correct plugs

byrdman454

The 85-86 uses 2 diaphragm dampers, one on the front and one on the drivers side. The drivers side is the one you want. This part number is 930 110 601 00. The Bosch equivalent to this number is 0280161021. The damper on the front is 928 110 202 00. The Bosch equivalent to that number is 0280161008.

I am not sure if the damper function itself is different, but one reason for the different part number is the mounting. The 930xxx damper has a threaded hole for mounting and the 928xxx damper has a threaded boss sticking out. This is what I can see from looking at the PET diagram.

It may function the same, not sure. You could always try it and see what happens instead of buying one from $130 from RockAuto.

John Speake

A 1984 Euro S with MAF uses 1 damper at the front of the engine and 2 FPRegs in each of the return lines after the rails.

Suggest you have the injectors ultrasonically cleaned and flow tested. Then adjust idle CO to be 1.5% at the tail pipe. I assume the car has not been "federalised" in any way ?

DougM

It was once federalized but no longer has the cats. There is an o2 sensor on the exhaust but the wire was cut when I got it. I don't know where it went to but I have been through all of the electrics and there is nothing unoriginal in the panel area.

Mrmerlin

84 Euro wont support an O2 sensor. IE there is no provision for it in the computers

John wasnt the FPR and dampers updated to 2 dampers and one FPR

IIRC the last 84 Euro i worked on had 1 FPR on the RR and then 2 dampers one on the center and one on the LR fuel rail

IcemanG17

my 1st thought is the car should run normal with stock parts BEFORE changing anything.....if you have a rough running issue something is wrong......increasing fuel pressure might "hide" it...but won't fix it....it could be lots of things......I would search for the cause of the rough running before dumping fuel on it to fix it....

Landseer

I have the 84 Euro 5 spd with AFPR. Recently we tuned it using an O2 sensor in the tailpipe. Increased the pressure from wherever it was set. Gave very nice increase in performance -- it had been sluggish from a standing start. It reduced the low speed surge, which had become frustrating . Still surges some, but less pronounced.

So I think its a good idea. Jadz928 made the installation on this car a few years ago, so search a bit and you will find his thread on making the changeover. I was just resetting / adjusting the AFPR of that old installation. Best idea is install wide band sensor that will display an A/F ratio so you can monitor. That's what Jim had done, but the gauge had broken by the time I got the car.

Jim piped it to have single regulator, single damper. His thread shows it.

DougM

Is your surge more like bucking at a particular RPM? Mine happens at a particular point @2000 RPM maybe a little less. At this point, my car jerks and bucks as long as I hold it at this particular point. As soon as I let off or push the throttle, it smooths out and disappears.

PorKen

Sounds like it's lean.

What is the MAF CO adjusted to? IE. ohms between 14 and 25 on the LH connector - (EZF_LH22_16V.pdf)

Range is (lean) 0 - 382 - 1000 (rich) ohms. 382 is the 'zero'. Adjusting CW richens.

John Speake

It would be useful to see if it has the original Euro LH 928 618 123 00 or has been retrofitted with the USA Version 928 618 123 04 or 05.

But yes the hesitation is due to a weak mixture. You need to get the idle CO to 1.5% on a Euro.

John Speake

Hi Stan,
I wasn't aware of any change on the 16v Euro. I checked PET from 84 to 86 and it is shown as one front damper and two rear FPR on all years.

DougM

My LH is the 928 618 123 00 .
Measures my ohms across pins 14 and 25 on the connector and got 386.
What is the optimal setting for it?

Leaving for vacation now but will continue testing when I return. Should have the new plug wires then.

John Speake

386 is the facory setting for a MAF in calibration. For your car, the correct value is the one that give 1% CO at the CO test ports. at idle Or measure at the tail pipe at idle if you have no cats.

PorKen

1% CO is ~14.1 AFR.


Try turning the CO screw CW until the stumble is reduced. If you hit 1000, then you have other issues.




WBO2s are pretty cheap now. Get one! Then you can also test my 16V LH adjustable WOT chip, once I get around to the code, again.