Former VWDieselParts.com Forum

after checking my pressure with my version of a pressure gauge (initial was 20psi at 500rpm) i tried to adjust the reg. to find that the steel check piston rattled in the housing. i took it apart and stretched the spring, after reinstalling, the pressure is up at 40+ is there a way to get a new spring? or is it that whole reg. that has to be replaced?


this site has been great for clearing things up on the little diesel!

vwsprite wrote:after checking my pressure with my version of a pressure gauge (initial was 20psi at 500rpm) i tried to adjust the reg. to find that the steel check piston rattled in the housing. i took it apart and stretched the spring, after reinstalling, the pressure is up at 40+ is there a way to get a new spring? or is it that whole reg. that has to be replaced?


this site has been great for clearing things up on the little diesel!

.

I'm currently of the opinion, that an elderly pump with low internal pressure is not neccessarily a bad thing, as long as it's graph of pressure to rpm, is parallel to original; my reasoning being, that if the advance spring is also weak, you are still getting the same dynamic advance...
Too much pressure and the pump uses up some of it's advance range, hence my 'My pump' actually only gives 2 degrees advance with the cold start@700rpm crank, compared to 5 degrees with engine static. That equates to a loss of 3 degrees maximum advance, if engine timed[tuned] correctly...
Additionally more strain on old pump seals.

I was told by the bosch tech that I'd have to buy the whole regulator,.. I think it was $65 new.

well after reading this thread...
1. i need a digital/laser tach
2.a means to check pump pressure ie out banjo bolt with a guage on it.
3. a hammer and a small punch to adjust regulator pressure.
4. a custom socket to remove the regulator.
5. increase my smileage.

would anyone be willing to make and sell me an out banjo pressure tester actually all i would need is for someone to drill and tap it i have guage i could use.

Sometimes you can break the regulator loose with a 10mm wrench, if it's sitting right so you can grab it.

Rather than adjusting the regulator, it is possible to put a metering valve on the out bolt.... I haven't seen anyone do it yet, but Bosh says it is kosher:

Bosch, on page 12 of Diesel distributor fuel-injection pumps wrote:Some of the fuel flows through the pressure regulating valve and returns to the suction side. Some fuel also flows through the overflow restriction and back to the fuel tank in order to provide cooling and self-venting for the injection pump (Fig. 2). An overflow valve can be fitted instead of the overflow restriction.

adjustable pressure regulator like on air compresor,nice thing you say.
Is better place is UNDER outbolt somehow,nidle valve?

mtran wrote:adjustable pressure regulator like on air compresor,nice thing you say. Is better place is UNDER outbolt somehow,nidle valve?

I imagine so.

What would be nice is a valve before a standard "banjo-bolt". The injector return lines need to be on the low-pressure side of the valve.

JUst male/female 12X1.5 neddle valve,what is best that we get by this?

I would expect a valve setup to reduce the output flow, as if I were reducing the output orifice size... or not, depending on results.

Seems less brutal than whacking a pin with a punch.

Not sure where to find a needle valve that fine, tho. Maybe hacked from a carburetor?

TylerDurden wrote:I would expect a valve setup to reduce the output flow, as if I were reducing the output orifice size... or not, depending on results.

Seems less brutal than whacking a pin with a punch.

Not sure where to find a needle valve that fine, tho. Maybe hacked from a carburetor?

So if I understand it correctly an adjustable output valve, would be an attempt to 'improve' the internal pressures of the pump to alter the advance.
I don't think that you would get the desired effect, because:

1) Someone very recently posted somewhere that they had experimentally stuffed a blank bolt into the output banjo. Results were no change. No exploding of pump, and no internal pressure rise. Input regulator dominates and regulates.

Thus:
2) Why not make an input regulator with a screw adjuster.

But,
3) No benefit other than opportunity for earlier seal leaks in raising internal pressure, once internal pressure is sufficient to start dynamic advance.

And,
4) Any increase merely alters the start position of pump advance and robs the maximum effective advance [you run out of advance, earlier at higher speeds], but does not alter the dynamic advance rate.

But,
5) More importantly it robs the cold start of the 2.5 degrees pump advance, at cold idle. Most pumps start advancing at about 700rpm, so by idle of 900ish, is naturally eating into the advance.

So,
A) Better IMO, to try and match start of dynamic advance to your car's idle speed.

And,
B) A stiffer spring in the input regulator would alter the advance rate

Hello to puzzle man,again great info,
Because of another fuel than D,do I get better swich/adjust for different fue and I have sometimes different viscosity on as also.Right now I am on 40 psi on idle.Just for record I am NOT looking in hp etc,just for better combustion.
ps. I know you use/know Fiat,I have Ducato with 0 460 4640189 stock 0.94 mm I did 0.99mm,but Croma same engine only IP is 0 460 494 173 and stock 1.17 mm is it possible with only minor change betwen pumps-aka can I go more than 1.1 that I plan to do,or even more?

mtran wrote:Hello to puzzle man,again great info,
Because of another fuel than D,do I get better swich/adjust for different fue and I have sometimes different viscosity on as also.Right now I am on 40 psi on idle.Just for record I am NOT looking in hp etc,just for better combustion.
ps. I know you use/know Fiat,I have Ducato with 0 460 4640189 stock 0.94 mm I did 0.99mm,but Croma same engine only IP is 0 460 494 173 and stock 1.17 mm is it possible with only minor change betwen pumps-aka can I go more than 1.1 that I plan to do,or even more?

Hi,
I can't find any info on either pump to hand. However the difference in timing may well be down to break pressures of the injectors.
These are 1.9 engines aren't they?
My father has a FIAT 1.9TD in his Talbot camper, and uses about 1mm.
Best to time by ear, and under acceleration up a local incline.
Mark