'89' 740 GLE AGAIN!

Ho hum,

Back again.

have delight in informing all those who, have any interest in this
mysterious problem at all. Having had the vehicle in to a Carb + Injection
specialist and themselves checking and trying numerous things for me. They
replaced the "warm up regulator" which did indeed fix the crappy cold
running and improved the revving our problem but did not cure the problem
completely.

Now I know that everything has been checked and tested barring the fuel
control unit itself so this MUST be where the problem is lying.

The car is driveable now so now my dilemma is:

Do I keep the car and continue to drive it as it is?

Sell the car to some poor unsuspecting soul who really does not need the
expense and agro of going through what I have gone through. Unless of course
I tell them but then they wouldn't buy it.

Keep the car and purchase a recon unit and fit it myself?


Dilemmas, Dilemmas.

 

Because there's more to the internet than hits alone, Artful Dodger
wrote:

I understand your logic, but in my experience, when I have illiminated
everything else I have simple discovered the limits to my own
ignorance - there is still plenty of other stuff that I haven't
thought of yet.

Fuel control units seldom go wrong, and cost, IIRC, a couple of
hundred pounds or so for a new one. But I got a secondhand one off the
shelf at a local breakes for 20 quid, so it's not all bad news. Go
through the Yellow Pages; some breakers specialise in Volvo parts and
can be quite helpful.

But you could try adjusting the mixture. Did the workshop measure the
exhaust gases? Have a look at Fig. 6.4 here:

http://www.auto-solve.com/mech_inj.htm

The Idle Mixture Adjustment Screw is located inside the Airflow Meter,
but can be accessed via a little hole in the top. Long thin
screwdriver needed. You could try tweeking it a quarter of a turn at a
time to see if it makes a difference. Keep count of the turns so you
can put it back to how it was. An exhaust gas analyser helps too,
though if you are careful you can do it by ear.



--

Stewart Hargrave

I run on beans - laser beans


For email, replace 'SpamOnlyToHere' with my name

 

Okey Dokey.

Here is a list of what the nice man at Carb and Injection tested and carried
out.:

1. Checked air filter and air intakes.
2. Checked all vacuum pipes and connections.
3. Checked all fuel lines and fittings
4. Checked fuel line pressures. Main lines and controlled side.
5. Checked co levels, cam timing and ignition timing
6. Checked coil, leads, distributor and plugs.
7. Checked injectors (Although they seldom cause a problem)
8. Checked all pipework and electrical connections to ALL valves, regulators
and injectors.
9. Checked for blockage in exhaust.
10. Replaced warm up regulator. (which was indeed buggered)
11. Refit new copper washers and 'o' rings where necessary.

The car was on a dyno tester most of the time and when he replaced the
regulator he reset the CO levels.

It seems to be a fairly conclusive looking list and being as they checked
everything barring the fuel control unit and bearing in mind that the warm
up regulator was full of crap. Natural progression leads me to the control
unit being dirty or faulty.

I know the fuel distributor can be removed from it but how easy would it be
to flush out the rest of the unit?
Or is that a big no, no?

 

I've never taken one apart, but I know there's a bunch of very fragile
diaphragms inside it. You can get an idea of how clean it is by
removing it from the air flow meter (3 screws) and taking the control
piston out. This piston is precision machined to match that control
unit, and can fall out the bottom of the unit as you remove it. If it
does, then it's not precision machined enough any more, and you'll need
to buy a new or rebuilt unit. The only thing that kills them is bad
gas, and unfortunately, it sounds like that may have happened to your
car.

 

Because there's more to the internet than hits alone, Artful Dodger
wrote:

IF the fuel line pressures check out OK, AND the CO levels are OK, I
reckon this must cover the functioning of the fuel distributor.

On the other hand, if EVERYTHING checks out OK, then the engine should
run properly. The fact that yours doesn't is a deepening mystery.

The crap in the regulator prompts the question about how it got there.
Is the fuel filter good? If there is more crap in the system, perhaps
partially blocking a fuel line, then it may be restricting maximum
flow of fuel, leading to fuel starvation at higher revs and under
load. This seems like clutching at straws, but you seem to have
eliminated so much else.

I think the best you can do in this regard is to disconnect all the
fuel lines, take them off the car and blow them through with a high
pressure air line. If you are suggesting dismantling the fuel
distributor, the early Haynes manual (black cover) describes removing
the control plunger (the bit the meters the fuel) and the control
pressure regulator to clean them, but warns not to attempt further
dismantling. Normally I take this sort of advice from Haynes as a
challenge, but in this case I think I'd recommend against it - the
internals are fairly high precision engineering. Locate a secondhand
unit first, before you risk damaging the one you've got.



--

Stewart Hargrave

I run on beans - laser beans


For email, replace 'SpamOnlyToHere' with my name

 

Thanks for all your help guys. You have been a HUGE help.

Now I am in the market for a fuel control unit for an '89' 740 gle manual
the one with the b230e 'k' jet red block motor.

Anyone happen to have a spare kicking around in a box in their garage?


Thought I would ask.

 

Isn't this the same unit as any other non-turbo K-jet Volvo uses? Shouldn't
be too hard to find, all the old 240's used them here.