'90 Golf faltering for a second. Transfer fuel pump?

Hi,
Checking in with the gurus. I have a '90 Golf (gas engine, 8 valve)
that's been exhibiting short bouts of faltering on acceleration most
times when going uphill. The engine doesn't cut out entirely and
continues running, but power is severely reduced so the car
essentially coasts for up to 1/2 second. Not too long, then the engine
returns to normal power and the car continues to run fine again. The
faltering won't appear again for weeks or months. But today, it was
pretty bad and I moving onto the main road from an alley and was left
exposed without any acceleration with oncoming traffic bearing down.
After faltering for what felt like a full second, the engine came back
to full power. I'm thinking the transfer fuel pump. I believe it's the
original at almost 19 years old with 216,000 km on it. Is that a
logical place to start? The main pump isn't buzzing so I didn't think
it was starved for fuel. If it was the fuel pump relay or an
electrical problem, I'm guessing the engine would just quit. Other
than the infrequent faltering, the engine runs fine.

thanks.

Did you notice any black smoke or smell any unburnt gas coming out of the
exhaust?

With the Digifant FI systems I usually find that the ground wires near the
rear of the cylinder head or intake manifold have broken. That causes a
serious loss of power and gas mileage.
Also I have repaired wiring to the Throttle Body also.

I have also replaced a few Fuel Pressure Regulators too that leaked fuel
through the vacuum hose sporadically.

A clogged catalytic converter or muffler could also cause running problems.

Of course check your distributor cap to make sure that center tip is still
there and I ONLY use BOSCH distributor rotors. I have seen more than one
aftermarket rotor fail causing nasty running problems.

Just some ideas!
--
later,
(One out of many daves)

"tonyw" > wrote in message
...
> Hi,
> Checking in with the gurus. I have a '90 Golf (gas engine, 8 valve)
> that's been exhibiting short bouts of faltering on acceleration most
> times when going uphill. The engine doesn't cut out entirely and
> continues running, but power is severely reduced so the car
> essentially coasts for up to 1/2 second. Not too long, then the engine
> returns to normal power and the car continues to run fine again. The
> faltering won't appear again for weeks or months. But today, it was
> pretty bad and I moving onto the main road from an alley and was left
> exposed without any acceleration with oncoming traffic bearing down.
> After faltering for what felt like a full second, the engine came back
> to full power. I'm thinking the transfer fuel pump. I believe it's the
> original at almost 19 years old with 216,000 km on it. Is that a
> logical place to start? The main pump isn't buzzing so I didn't think
> it was starved for fuel. If it was the fuel pump relay or an
> electrical problem, I'm guessing the engine would just quit. Other
> than the infrequent faltering, the engine runs fine.
>
> thanks.

Thanks Dave,
The faltering is very intermittent, I can drive 1-2 months with
nothing, then a 1/2 second faltering then good for another month or
two. It usually happens when accelerating or under heavy load going up
a hill. My gas consumption is normal, no change at about 6.2 L/100 km
highway and about 11 L/100 km city (38 mpg and 21 mpg per US gallon or
46 mpg and 26 mpg Imperial gallons, respectively). Also I start the
car in the garage and haven't noticed any smell of unburnt fuel.

I just checked if the transfer pump is running and it is when I turn
on the ignition but that's not to say it doesn't stop once in a while.
Will check for broken wires.

thanks,
-Tony


On Oct 3, 3:39*am, "dave AKA vwdoc1" >
wrote:
> Did you notice any black smoke or smell any unburnt gas coming out of the
> exhaust?
>
> With the Digifant FI systems I usually find that the ground wires near the
> rear of the cylinder head or intake manifold have broken. *That causes a
> serious loss of power and gas mileage.
> Also I have repaired wiring to the Throttle Body also.
>
> I have also replaced a few Fuel Pressure Regulators too that leaked fuel
> through the vacuum hose sporadically.
>
> *A clogged catalytic converter or muffler could also cause running problems.
>
> Of course check your distributor cap to make sure that center tip is still
> there and I ONLY use BOSCH distributor rotors. *I have seen more than one
> aftermarket rotor fail causing nasty running problems.
>
> Just some ideas!
> --
> later,
> (One out of many daves)

I had a similar problem with my '83 GTI ... twice. First time it was the
ground strap between the engine and the chassis going bad ...when I
accelerated, the engine twisting in the mounts was enough to break the
ground connection. The second time it was a broken wire in the harness
coming from the hall sensor in the distributor.

"D Wong" > wrote in message
...
Thanks Dave,
The faltering is very intermittent, I can drive 1-2 months with
nothing, then a 1/2 second faltering then good for another month or
two. It usually happens when accelerating or under heavy load going up
a hill. My gas consumption is normal, no change at about 6.2 L/100 km
highway and about 11 L/100 km city (38 mpg and 21 mpg per US gallon or
46 mpg and 26 mpg Imperial gallons, respectively). Also I start the
car in the garage and haven't noticed any smell of unburnt fuel.

I just checked if the transfer pump is running and it is when I turn
on the ignition but that's not to say it doesn't stop once in a while.
Will check for broken wires.

thanks,
-Tony


On Oct 3, 3:39 am, "dave AKA vwdoc1" >
wrote:
> Did you notice any black smoke or smell any unburnt gas coming out of the
> exhaust?
>
> With the Digifant FI systems I usually find that the ground wires near the
> rear of the cylinder head or intake manifold have broken. That causes a
> serious loss of power and gas mileage.
> Also I have repaired wiring to the Throttle Body also.
>
> I have also replaced a few Fuel Pressure Regulators too that leaked fuel
> through the vacuum hose sporadically.
>
> A clogged catalytic converter or muffler could also cause running
> problems.
>
> Of course check your distributor cap to make sure that center tip is still
> there and I ONLY use BOSCH distributor rotors. I have seen more than one
> aftermarket rotor fail causing nasty running problems.
>
> Just some ideas!
> --
> later,
> (One out of many daves)

"tonyw" > ha escrit al
...

> Checking in with the gurus. I have a '90 Golf (gas engine, 8 valve)
> that's been exhibiting short bouts of faltering on acceleration most
> times when going uphill. The engine doesn't cut out entirely and
> continues running, but power is severely reduced so the car
> essentially coasts for up to 1/2 second. Not too long, then the engine
> returns to normal power and the car continues to run fine again. The
> faltering won't appear again for weeks or months. But today, it was

I sort of have the same problem with my VW Golf, but mine is a 1995 Golf TDI
90HP.

Hi,
Some more diagnosis and a possible fix. I checked the ground straps
and checked for vacuum leaks. Nothing obvious. The distributor and cap
are relatively, new, maybe 6 months and I only use Bosch parts, they
looked good. I changed the transfer fuel pump (about 18-19 years old)
but that didn't help, engine still faltered. In fact stalled right
away after starting. Doing some reading, someone mentioned the fuel
pump stops if the coil isn't sending out pulses on the high voltage
terminal. The idea is if the engine stops running, say in an accident,
the fuel pump doesn't keep pumping fuel into a potential fiery
situation. The coil connectors were a bit corroded so I cleaned them
and applied dielectric grease. Since cleaning the coil contacts, I've
driven 1,200 km over the long weekend and there hasn't been one
instance of faltering. The coil contacts may have been the problem.
Will report back in a couple of months. Good mileage this trip too,
5.6 L/100 km or 42 mpg (US Gal) or 50.4 mpg (Imperial) on a gas
engine, with a fairly full load with mountain passes topping out at
1,240 m and some 11% grades.

> away after starting. Doing some reading, someone mentioned the fuel
> pump stops if the coil isn't sending out pulses on the high voltage
> terminal. The idea is if the engine stops running, say in an accident,
> the fuel pump doesn't keep pumping fuel into a potential fiery
> situation. The coil connectors were a bit corroded so I cleaned them
> and applied dielectric grease. Since cleaning the coil contacts, I've

Could you please point out where those connectors are situated at so I could
search for any rust traces there? Thanks in advance!

Congrats on your finding the problem and thanks for posting the solution!
;-)


"Tony49122" > wrote in message
...
> Hi,
> Some more diagnosis and a possible fix. I checked the ground straps
> and checked for vacuum leaks. Nothing obvious. The distributor and cap
> are relatively, new, maybe 6 months and I only use Bosch parts, they
> looked good. I changed the transfer fuel pump (about 18-19 years old)
> but that didn't help, engine still faltered. In fact stalled right
> away after starting. Doing some reading, someone mentioned the fuel
> pump stops if the coil isn't sending out pulses on the high voltage
> terminal. The idea is if the engine stops running, say in an accident,
> the fuel pump doesn't keep pumping fuel into a potential fiery
> situation. The coil connectors were a bit corroded so I cleaned them
> and applied dielectric grease. Since cleaning the coil contacts, I've
> driven 1,200 km over the long weekend and there hasn't been one
> instance of faltering. The coil contacts may have been the problem.
> Will report back in a couple of months. Good mileage this trip too,
> 5.6 L/100 km or 42 mpg (US Gal) or 50.4 mpg (Imperial) on a gas
> engine, with a fairly full load with mountain passes topping out at
> 1,240 m and some 11% grades.

On Oct 13, 8:22*pm, "dave AKA vwdoc1" >
wrote:
> Congrats on your finding the problem and thanks for posting the solution!
> ;-)

Hi Dave,
Thanks. But wait for the longer-term results to see if I really fixed
it!!!
cheers

On Oct 13, 1:32*pm, "Wao" > wrote:

> Could you please point out where those connectors are situated at so I could
> search for any rust traces there? Thanks in advance!

Hi,
Our cars have gas engines and yours is diesel so you won't have an
ignition coil. I haven't worked on diesel VWs so don't know the lay of
the land. If the engine falters, it could be one or more of three
things: air supply for combustion, fuel supply, or maybe a worn out
ignition switch which causes the engine to think it's turned off. In
the gas engine, the 4th element is fire which was our problem--no
spark at the spark plugs for a brief moment.

What are your symptoms? Stalls? Or falters but eventually keeps
running? Very predictable or very intermittent?