740 GLE '89' Running Problems?

  • Thread starter Thread starter Artful Dodger
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A

Artful Dodger

Hi.

I have owned my 740 gle Manual estate for over 2 years and until recently
has been bomb proof. It has 214,000 miles on the clock so far and I would
like to add some more but.

The car has developed a fault:
It will start just fine in the cold, hot or wet never fails. Thing is, if I
try to give it any gas it will pop, fart and mis-fire. Seemed a pretty
simple problem to diagnose I thought it was the fuel boost injector.
Only when the engine is warm it will run fine until it gets to around
2,500-3,000 rpm then it sits there it will not improve, clear or pick up but
if I back the gas off a little it WILL pick up.

You haven't got a clue I have had it to 3 different garages including a
Volvo main dealer each of them did little things to it, no real progress and
none of them fixed it.

So far I have had a new distributor cap, plugs, rotor arm, injectors,
exhaust and the coil and leads tested.

ANY IDEAS? Please!
 
Artful Dodger said:
Hi.

I have owned my 740 gle Manual estate for over 2 years and until recently
has been bomb proof. It has 214,000 miles on the clock so far and I would
like to add some more but.

The car has developed a fault:
It will start just fine in the cold, hot or wet never fails. Thing is, if I
try to give it any gas it will pop, fart and mis-fire. Seemed a pretty
simple problem to diagnose I thought it was the fuel boost injector.
Only when the engine is warm it will run fine until it gets to around
2,500-3,000 rpm then it sits there it will not improve, clear or pick up but
if I back the gas off a little it WILL pick up.

You haven't got a clue I have had it to 3 different garages including a
Volvo main dealer each of them did little things to it, no real progress and
none of them fixed it.

So far I have had a new distributor cap, plugs, rotor arm, injectors,
exhaust and the coil and leads tested.

ANY IDEAS? Please!
Click to expand...

Did anyone check the air mass meter? Unplug it and see if it makes a
difference.
 
From a point at sea, to the circles of your mind, this is James Sweet:
Did anyone check the air mass meter? Unplug it and see if it makes a
difference.
Click to expand...

I have a feeling the poster is UK based, in which case it'll probably
be fueling by K-Jet.

I'd start by checking the ignition and valve timing. But it could be a
fueling problem. Maybe the warmup regulator, or the airflow meter.


--

Stewart Hargrave

A lot faster than public transport


For email, replace 'SpamOnlyToHere' with my name
 
Thanks Guys!

Have already checked ingnition and valve timings, ignition was slightly out
but correcting made no difference.

The nice man at Volvo, said he had the diagnostic unit check the ignition
and fuel system.

I shall try and unplug the flow meter to see what happens but I thought that
it would just stop if I did that.. I am in the UK. I know that the emmisions
and fuel systems would differ a little. So for reference I have the B230E
motor with the continuous injection system fitted. In theory it should be a
simple system, in practice it is proving otherwise.

Thanks in advance and thanks for replies already recieved.


If i
 
Artful said:
Thanks Guys!

Have already checked ingnition and valve timings, ignition was slightly out
but correcting made no difference.

The nice man at Volvo, said he had the diagnostic unit check the ignition
and fuel system.

I shall try and unplug the flow meter to see what happens but I thought that
it would just stop if I did that.. I am in the UK. I know that the emmisions
and fuel systems would differ a little. So for reference I have the B230E
motor with the continuous injection system fitted. In theory it should be a
simple system, in practice it is proving otherwise.

Thanks in advance and thanks for replies already recieved.
Click to expand...

It is a simple system, the biggest problem is that it really is affected
by vacuum leaks. Start with the injector seals. And the K-Jet has no
air mass meter to unplug.
 
From a point at sea, to the circles of your mind, this is Artful
Dodger:
I shall try and unplug the flow meter to see what happens but I thought that
it would just stop if I did that.. I am in the UK. I know that the emmisions
and fuel systems would differ a little. So for reference I have the B230E
motor with the continuous injection system fitted. In theory it should be a
simple system, in practice it is proving otherwise.
Click to expand...

Err... Unless you have the turbo version, there is no unpluging to be
done. The version of the K-Jetronic continuous injection system that
we got on the UK market was only ever a purely mechanical system
without any electronic enhancement. If you have the turbo model
(B230ET engine) then you will have Motronic fueling, which does have
an airflow meter that can be unplugged, but is not a continuous
system.

But it would be a good idea to check if the flow meter arm is able to
move through its full range unobstructed. Undo the big clip that hold
the rubber boot over it, push the boot to one side and lift the flap
up through its arc.

For K-Jet, other things to consider are the fuel pump fuses and relay
(there are two fuel pumps; if one of them stops working it displays
some of the symptoms of fuel starvation), the pumps themselves, and
the fuel filter.

You should hear the main pump whirring briefly from under the car a
few seconds after a cold start. With the engine running, open the fuel
filler and put your ear to it - you should hear the in-tank pump
whirring. If not, he fuse is easy enough to check - sometimes it just
needs pulling out and replacing to clean the contacts a little. The
relay can really only be checked by substitution. The fuel filter is a
metal can on the near side scuttle under the bonnet, or possibly under
the car with the main pump, and should be replaced every couple of
years or so.

After this you are into measuring flow rates out of the injectors.

A good overview of how Bosch K-Jetronic works is here:

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


--

Stewart Hargrave

A lot faster than Royal Mail


For email, replace 'SpamOnlyToHere' with my name
 
I shall try and unplug the flow meter to see what happens but I thought that
it would just stop if I did that.. I am in the UK. I know that the emmisions
and fuel systems would differ a little. So for reference I have the B230E
motor with the continuous injection system fitted. In theory it should be a
simple system, in practice it is proving otherwise.
Click to expand...

Uhg, K-jet, nevermind my advice then, it didn't even occur to me that they
might have used K-jet on the 16v motor. Check very carefully for vacuum
leaks, this is quite a common issue with K-jet.
 
From a point at sea, to the circles of your mind, this is James Sweet:

Uhg, K-jet, nevermind my advice then, it didn't even occur to me that they
might have used K-jet on the 16v motor.
Click to expand...

In the UK, the 'E' engine was always an 8 valver. 16 valves came later
with the 'F'. As this also had a cat, it wouldn't have had K-Jet.




--

Stewart Hargrave

A lot faster than Royal Mail


For email, replace 'SpamOnlyToHere' with my name
 
Hi.

I have owned my 740 gle Manual estate for over 2 years and until recently
has been bomb proof. It has 214,000 miles on the clock so far and I would
like to add some more but.

The car has developed a fault:
It will start just fine in the cold, hot or wet never fails. Thing is, if I
try to give it any gas it will pop, fart and mis-fire. Seemed a pretty
simple problem to diagnose I thought it was the fuel boost injector.
Only when the engine is warm it will run fine until it gets to around
2,500-3,000 rpm then it sits there it will not improve, clear or pick up but
if I back the gas off a little it WILL pick up.

You haven't got a clue I have had it to 3 different garages including a
Volvo main dealer each of them did little things to it, no real progress and
none of them fixed it.

So far I have had a new distributor cap, plugs, rotor arm, injectors,
exhaust and the coil and leads tested.

ANY IDEAS? Please!
Click to expand...
K-jets will spit back if:
Fuel pressure is too low: (line pressure from the main pump is below 4.5
bar--spec is 4.7-5.1 depending on model--control pressure from the warm
up regulator is higher than 3.9 bar--spec is 1.4-1.7 bar cold to 3.7 bar
fully warmed up). Or the pre-pump connecting hose in the tank has
biodegraded or the prepump has quit. Either condition will introduce air
bubbles into the fuel stream prior to the main pump raising the fuel
column to full pressure and volume. (Common, most likely, causes.)

The bellows between the airflow sensor housing and the manifold is split.
(Rare)

The counterweight on the end of the airflow sensor plate control arm has
come adrift. (Arcane)

The airflow sensor plate is off center, binding in the venturi, and
failing to cause sufficient enrichment during high flow, low vacuum
conditions in the manifold. (Not unusual if backfiring has occurred due
to some other problem.)

Bob
 
Stewart Hargrave said:
From a point at sea, to the circles of your mind, this is James Sweet:



In the UK, the 'E' engine was always an 8 valver. 16 valves came later
with the 'F'. As this also had a cat, it wouldn't have had K-Jet.
Click to expand...

Hmm somehow I got the idea we were talking about a 16v engine, don't mind me
then.
 
Okay guys

I am getting a lot of, sometimes conflicting information.

No I have not got an air flow meter, yes it is single ohc 8valve no it
hasn't got a turbo.

What I REALLY need to know is:
How do I fix it?
Could it be the the air control unit? I believe that is the doohickey that
controls the amount of fuel flow through the fuel distributor by using a
plate that the incoming airflow deflects from.
If I have no joy and the Volvo dealer is next to useless, where do I go to
get it fixed?
I am always assuming of course that my nice Volvo dealer (who also told me
it could be the air flow meter as well as wanting to charge me £200+ for a
rear and mid section of exhaust.) Has already checked BOTH fuel pumps I have
replaced the fuel filters within the last 14 months.
For now I shal check the bellows and fuses but I won't be holding my breath.

Thanks again, I am really getting in a jam with this one!
 
From a point at sea, to the circles of your mind, this is Artful
Dodger:
Okay guys

I am getting a lot of, sometimes conflicting information.
Click to expand...

We think we've got your location and engine configuration figured out
now.
No I have not got an air flow meter,
Click to expand...

Yes you have, but not one that can be unplugged. It sits under the
inlet manifold; a black rubber boot connects it to the underside of
the manifold (stricktly speaking, the throttle body); a crinkly pipe
connects it to the air filter box; the fuel distributor sits directly
on top of it, next to the rubber boot thing, and has lots of fuel
pipes connected to it.
yes it is single ohc 8valve no it
hasn't got a turbo.
Check.

What I REALLY need to know is:
How do I fix it?
Click to expand...

All we can do is offer suggestions based on the symptoms you have
described. Inevitably that will include some guesswork. The rest is
down to you.
Could it be the the air control unit? I believe that is the doohickey that
controls the amount of fuel flow through the fuel distributor by using a
plate that the incoming airflow deflects from.
Click to expand...

It could be. You've certainly had some suggestions pointing to this.
You'll have to do the elimination bit, though.
If I have no joy and the Volvo dealer is next to useless, where do I go to
get it fixed?
Click to expand...

An independent workshop? A good mobile mechanic? Ask around. Obviously
helpful to find someone who knows about Volvos. Tell us which part of
the UK you are in; you might be lucky and find someone here who can
recommend somewhere. Post it as a new thread so that everyone sees it.
I am always assuming of course that my nice Volvo dealer (who also told me
it could be the air flow meter as well as wanting to charge me £200+ for a
rear and mid section of exhaust.) Has already checked BOTH fuel pumps I have
replaced the fuel filters within the last 14 months.
Click to expand...

Tick these off the list, then. Do you know how they tested the pumps?
Did they measure line pressure at the fuel distributor? If so, this
would cover various other suggestions.
For now I shal check the bellows and fuses but I won't be holding my breath.
Click to expand...

But at least then you can tick these off too.
Thanks again, I am really getting in a jam with this one!
Click to expand...

We all do that from time to time. Remember there is *something*
causing your problems. In other words, if all the systems of the
engine are working correctly, then the engine *must* work properly.
It's not witchcraft causing your problems. You just have to work
logically, and thoroughly, and eliminate stuff untill you resolve it.
Experience sure helps (and so do some diagnostic tools) but there is
no reason why you can't get there in the end.



--

Stewart Hargrave

A lot faster than Royal Mail


For email, replace 'SpamOnlyToHere' with my name
 
It could be. You've certainly had some suggestions pointing to this.
You'll have to do the elimination bit, though.
Click to expand...

Has anyone ever had one of these fail? They seem to get a hair out of
adjustment frequently as they age but rarely this much. I'm really leaning
towards a vacuum leak somewhere, otherwise perhaps it's the control pressure
regulator. If you get really sick of messing with it and want a cool project
you could have a look at http://www.bgsoflex.com/megasquirt.html a number of
guys have installed this on Volvos and you can do so relatively easily using
junkyard parts from LH Jet equipped Volvos.
 
From a point at sea, to the circles of your mind, this is James Sweet:
Has anyone ever had one of these fail? They seem to get a hair out of
adjustment frequently as they age but rarely this much.
Click to expand...

It's possible that something could be obstructing the movement of the
air meter arm - without it actually having failed.

But I've had a fuel distributor fail, and boy did that take some
figuring out. I'm in two minds about what the primary cause was, but
it became evident following a big backfire during the setting up of
the LPG system that I fitted. The backfire was big enough to blow the
air filter box into several pieces (miraculously, the air meter flap
was undamaged). Following this the engine would only run on petrol
when the throttle was fully open, and was obviously hugely over rich.

Fortunately the LPG system worked properly, so I ran it on that until
I figured out the petrol problem. Turned out that the underside of the
fuel dist. had cracked in such a way as to allow the fuel metering
barrel to drop by about 2mm; this meant that way too much fuel was
being delivered. At first look, the crack, around the circular collar
that held the barrel in place, was so clean and even that I thought it
was made that way.

Given that the dist. is a thick piece of cast iron I feel sure that
there must have been an existing weakness in the casting that the
backfire simply exacerbated.

you could have a look at http://www.bgsoflex.com/megasquirt.html a number of
guys have installed this on Volvos and you can do so relatively easily using
junkyard parts from LH Jet equipped Volvos.
Click to expand...

That really is cool. I'm tempted to swap my car for a carb. model just
so that I can fit this.



--

Stewart Hargrave

A lot faster than Royal Mail


For email, replace 'SpamOnlyToHere' with my name
 
That really is cool. I'm tempted to swap my car for a carb. model just
so that I can fit this.
Click to expand...

You don't need a carb model, you can fit it on K-Jet by just plugging the
injector holes in the head or leave the injectors in place.
 
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