'78 Super Beetle engine chugging

I have recently replaced the fuel injectors, and though there is still
about .5mm of o-ring protruding, they seem to be in solidly. The
engine now fires, but after about 40 seconds it chugs painfully and
dies. The coil is new, the rotor and cap are new. The sparkplugs are
new. The mass air flow sensor is new, and I've checked all the vacuum
hoses for leaks or looseness.

I sprayed some carburetor cleaner around the fuel injector openings to
see if they were sucking in air, but no extra power came, as it would
if the Carb cleaner was sucked in. I did not grease the o-rings or the
holes for the injectors before I put them in, should I have? The bolt
holding the injectors in is fastened all the way down snugly. The fuel
pump is new, as is the gas tank and all the gas lines have either been
replaced or blown clear.

I was wondering if it was just an idle speed problem as the engine can
be kept running if you apply the accelerator. The only other thing I'd
guessed was that the fuel injectors are not seating properly and at
slow speeds the gasoline isn't atomizing from them right.

On a different subject, I went to pull out the front strut, according
to the Muir manual, but both bolts holding the bottom end broke off. I
cannot now get these out. I have tried a hammer and punch but it
doesn't move. Is there another way I can get the bolts out, or do I
have to try and drill them?

Any help would be good. Thanks.

I know that the cylinder head temperature sensor is a forgotten part.

Any vacuum leaks at the air flow box boot?
Sometimes that plug might pop out of the throttle body.
Are all of the hoses hooked up correctly?
Oil cap on nice and tight?

Did you adjust the idle speed and the CO screw in the air flow box?
Is the air flow box the one that has that safety valve in the flap that
sometimes pops off?

Is the exhaust rich & dark or ???

Just trying to remember how these FI SBs used to be! ;-)

Good luck,
dave
(One out of many daves)

> wrote in message
ups.com...
>I have recently replaced the fuel injectors, and though there is still
> about .5mm of o-ring protruding, they seem to be in solidly. The
> engine now fires, but after about 40 seconds it chugs painfully and
> dies. The coil is new, the rotor and cap are new. The sparkplugs are
> new. The mass air flow sensor is new, and I've checked all the vacuum
> hoses for leaks or looseness.
>
> I sprayed some carburetor cleaner around the fuel injector openings to
> see if they were sucking in air, but no extra power came, as it would
> if the Carb cleaner was sucked in. I did not grease the o-rings or the
> holes for the injectors before I put them in, should I have? The bolt
> holding the injectors in is fastened all the way down snugly. The fuel
> pump is new, as is the gas tank and all the gas lines have either been
> replaced or blown clear.
>
> I was wondering if it was just an idle speed problem as the engine can
> be kept running if you apply the accelerator. The only other thing I'd
> guessed was that the fuel injectors are not seating properly and at
> slow speeds the gasoline isn't atomizing from them right.
>
> On a different subject, I went to pull out the front strut, according
> to the Muir manual, but both bolts holding the bottom end broke off. I
> cannot now get these out. I have tried a hammer and punch but it
> doesn't move. Is there another way I can get the bolts out, or do I
> have to try and drill them?
>
> Any help would be good. Thanks.
>

The air flow boot, that large black molded boot from the the MAF, is
new and has no holes in it. I would guess that the fuel was rich, due
to the chugging, but the exhaust is fairly dirty but not particulaurly
dark. I did try to adjust the idle speed, but that had no effect. I
did not adjust the idle mixture, even though the service manual says
to when you replace the MAF sensor. I figured that if it was just a
emission adjustment, I would deal with bad burning until it ran okay.
All the hoses appear right, and they are all connected. I've checked
the oil cap.

I checked the temperature sensor, and, with the ohm test, speedy jim
said it was fine. Even after spraying much carburetor cleaner, I could
find no vacuum leaks. The service manual also says that if the idle
speed screw doesn't work for adjusting idle up, that it might be EGR.
I currently don't have an EGR filter on the car (the old one rusted
out) but I did cover the end of the pipe with a plate so there
shouldn't be a leak there. Also, there should be no gas recirculation
at idle.

wrote:

> The air flow boot, that large black molded boot from the the MAF, is
> new and has no holes in it. I would guess that the fuel was rich, due
> to the chugging, but the exhaust is fairly dirty but not particulaurly
> dark. I did try to adjust the idle speed, but that had no effect. I
> did not adjust the idle mixture, even though the service manual says
> to when you replace the MAF sensor. I figured that if it was just a
> emission adjustment, I would deal with bad burning until it ran okay.
> All the hoses appear right, and they are all connected. I've checked
> the oil cap.
>
> I checked the temperature sensor, and, with the ohm test, speedy jim
> said it was fine. Even after spraying much carburetor cleaner, I could
> find no vacuum leaks. The service manual also says that if the idle
> speed screw doesn't work for adjusting idle up, that it might be EGR.
> I currently don't have an EGR filter on the car (the old one rusted
> out) but I did cover the end of the pipe with a plate so there
> shouldn't be a leak there. Also, there should be no gas recirculation
> at idle.
>

Here's one you might try. Hop over to Radio Shack and get a
potentiometer (volume control). A 5,000 Ohm job would be nice,
but a 10,000 will do.

Wire it in place of the head temp sensor. One end terminal to
ground. Center terminal to the ECU connector.

Start the engine with the wiper arm pointing at the terminal
with no connection on it (maximum resistance). This will
produce maximum starting richness. As the engine warms up,
start turning the pot "down" (lower resistance). This will
make the mixture less rich.

The effect is quite dramatic. Play with it a while to get the feel.

See if it is possible to get the thing running somewhere near normal.

Jim

Well how is the Air flow box or MAF?
**** Yes adjusting it should be attempted! 8^) ******

Which spark plugs are you running?
Also what is the fuel pressure? Is there a vacuum hose going to the
regulator?

> wrote in message
ups.com...
> The air flow boot, that large black molded boot from the the MAF, is
> new and has no holes in it. I would guess that the fuel was rich, due
> to the chugging, but the exhaust is fairly dirty but not particulaurly
> dark. I did try to adjust the idle speed, but that had no effect. I
> did not adjust the idle mixture, even though the service manual says
> to when you replace the MAF sensor. I figured that if it was just a
> emission adjustment, I would deal with bad burning until it ran okay.
> All the hoses appear right, and they are all connected. I've checked
> the oil cap.
>
> I checked the temperature sensor, and, with the ohm test, speedy jim
> said it was fine. Even after spraying much carburetor cleaner, I could
> find no vacuum leaks. The service manual also says that if the idle
> speed screw doesn't work for adjusting idle up, that it might be EGR.
> I currently don't have an EGR filter on the car (the old one rusted
> out) but I did cover the end of the pipe with a plate so there
> shouldn't be a leak there. Also, there should be no gas recirculation
> at idle.
>

I checked the area around the plate I put over the EGR pipe. When the
engine began to die, I sprayed some carburetor cleaner in it and it
would rev back up. That seems to have been the vacuum leak. Once I fix
that I'll get back with more questions if there are still problems.