740 GLE '89' Running Problems?

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!

Reply to
Artful Dodger
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Did anyone check the air mass meter? Unplug it and see if it makes a difference.

Reply to
James Sweet

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

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.

Reply to
Stewart Hargrav

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.

Reply to
Artful Dodger

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.

Reply to
Mike F

From a point at sea, to the circles of your mind, this is Artful Dodger:

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:

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Reply to
Stewart Hargrav

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.

Reply to
James Sweet

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.

Reply to
Stewart Hargrav

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

Reply to
volvowrench

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

Reply to
James Sweet

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 aga> > Hi.

Reply to
Artful Dodger

From a point at sea, to the circles of your mind, this is Artful Dodger:

We think we've got your location and engine configuration figured out now.

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.

Check.

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.

It could be. You've certainly had some suggestions pointing to this. You'll have to do the elimination bit, though.

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.

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.

But at least then you can tick these off too.

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.

Reply to
Stewart Hargrav

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

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a number ofguys have installed this on Volvos and you can do so relatively easily usingjunkyard parts from LH Jet equipped Volvos.

Reply to
James Sweet

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

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.

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

Reply to
Stewart Hargrav

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.

Reply to
James Sweet

How does a car Fart, I have never heard a Volvo Fart

Reply to
no

FUEL RESTRICTION BLOCKED FUEL FILTER MAYBE

Reply to
John Robertson

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