Starting problems when hot, 94 Jetta

I frequently have a problem starting my 94 Jetta, Multi-port fuel
injection when the car is hot and has sat for about 5 minutes. The
engine turns over fine, but will not fire. It sounds like the car is
starved for gas.

I've recently tuned the car up: plugs, rotor, cap, but the problem
still exists.

Sounds like vapour lock. Check how rapid the fuel pressure drops after you
shut down.

SFC

"Mark Kyprianou" > schreef in bericht
m...
> I frequently have a problem starting my 94 Jetta, Multi-port fuel
> injection when the car is hot and has sat for about 5 minutes. The
> engine turns over fine, but will not fire. It sounds like the car is
> starved for gas.
>
> I've recently tuned the car up: plugs, rotor, cap, but the problem
> still exists.

>From: (Mark Kyprianou)
>
>I frequently have a problem starting my 94 Jetta, Multi-port fuel
>injection when the car is hot and has sat for about 5 minutes. The
>engine turns over fine, but will not fire. It sounds like the car is
>starved for gas.
>
>I've recently tuned the car up: plugs, rotor, cap, but the problem
>still exists.
>

fuel pumps working?
fuel filter new?

you need to double check for spark at the plugs.
I have had an ign coil make an engine hard to start. Spark was there but very
weak!

later,
dave
Reminder........
Before you criticize someone, you should walk a mile in their shoes. That way,
when you criticize them, you are a mile away from them, and you have their
shoes. Frieda Norris

NTISPAM (dave) wrote in message >...
> >From: (Mark Kyprianou)
> >
> >I frequently have a problem starting my 94 Jetta, Multi-port fuel
> >injection when the car is hot and has sat for about 5 minutes. The
> >engine turns over fine, but will not fire. It sounds like the car is
> >starved for gas.
> >
> >I've recently tuned the car up: plugs, rotor, cap, but the problem
> >still exists.
> >
>
> fuel pumps working?
The car does run, it's just hard to start when it's hot. Would a fuel
pump perform differently if the engine is hot?

> fuel filter new?
Yes, I replaced the fuel filter.

>
> you need to double check for spark at the plugs.
> I have had an ign coil make an engine hard to start. Spark was there but very
> weak!
>
> later,
> dave
> Reminder........
> Before you criticize someone, you should walk a mile in their shoes. That way,
> when you criticize them, you are a mile away from them, and you have their
> shoes. Frieda Norris

This is almost always a vapor lock issue.


"Mark Kyprianou" > wrote in message
m...
> I frequently have a problem starting my 94 Jetta, Multi-port fuel
> injection when the car is hot and has sat for about 5 minutes. The
> engine turns over fine, but will not fire. It sounds like the car is
> starved for gas.
>
> I've recently tuned the car up: plugs, rotor, cap, but the problem
> still exists.

>From: (Mark Kyprianou)
>
>> >I frequently have a problem starting my 94 Jetta, Multi-port fuel
>> >injection when the car is hot and has sat for about 5 minutes. The
>> >engine turns over fine, but will not fire. It sounds like the car is
>> >starved for gas.
>> >
>> >I've recently tuned the car up: plugs, rotor, cap, but the problem
>> >still exists.
>> >
>>
>> fuel pumps working?
>The car does run, it's just hard to start when it's hot. Would a fuel
>pump perform differently if the engine is hot?
>

Yes it is possible to have a problem starting the engine if the transfer pump
is not functioning well and especially if the fuel has been heated up slightly
by the heat from running the vehicle.
This would be similar to Vapor Lock.
A fuel pressure test should tell you something.

Don't forget about a weak spark causing problems too! ;-)

later,
dave
Reminder........
Before you criticize someone, you should walk a mile in their shoes. That way,
when you criticize them, you are a mile away from them, and you have their
shoes. Frieda Norris

In article >, SFC > wrote:
>Sounds like vapour lock. Check how rapid the fuel pressure drops after you
>shut down.

That only happens with carburators from what I can remember.

--
Jeeps and dubs and everything's nice...
Replace nospam with jetta for e-mail

>>Sounds like vapour lock. Check how rapid the fuel pressure drops after you
>>shut down.
>
>That only happens with carburators from what I can remember.
>

Kinda true, but the fuel lines are still protected against heat for the fuel
injection systems. I would assume that heat might cause problems like they had
with the carbs and vapor lock.

That fuel should recycle back into the tank heating up that fuel slightly and
possibly the lines around the engine or exhaust components may heat up the fuel
when the engine is off.
Heat is what basically causes vapor lock.
I would think it is possible that vapor lock could occur with FI systems also,
or maybe I should say that it is possible that the fuel at the injectors might
have turned into vapor while the hot engine is off.

I would still suspect an ign coil problem though! ;-)


later,
dave
Reminder........
Before you criticize someone, you should walk a mile in their shoes. That way,
when you criticize them, you are a mile away from them, and you have their
shoes. Frieda Norris

"Biz" > wrote in message >...

Any suggestions on how to solve this on a Jetta?

> This is almost always a vapor lock issue.
>
>
> "Mark Kyprianou" > wrote in message
> m...
> > I frequently have a problem starting my 94 Jetta, Multi-port fuel
> > injection when the car is hot and has sat for about 5 minutes. The
> > engine turns over fine, but will not fire. It sounds like the car is
> > starved for gas.
> >
> > I've recently tuned the car up: plugs, rotor, cap, but the problem
> > still exists.

You need to check the fuel pressure. Residual fuel pressure, when the
engine is off, should remain at a certain psi for a certain period of time.
The Bentley manual should explain how to test this.

If the residual pressure test fails then the problem could be the fuel pump
check valve or the fuel pressure regulator or leaking injectors or ???

You should also check the ignition to make sure the plugs get good spark. I
have seen some new ign. coils fail, they would send spark to the plugs but
the spark was too weak to allow the plugs to fire under compression.

later,
dave

"Mark Kyprianou" > wrote in message
m...
> "Biz" > wrote in message
>...
>
> Any suggestions on how to solve this on a Jetta?
>
> > This is almost always a vapor lock issue.
> >
> >
> > "Mark Kyprianou" > wrote in message
> > m...
> > > I frequently have a problem starting my 94 Jetta, Multi-port fuel
> > > injection when the car is hot and has sat for about 5 minutes. The
> > > engine turns over fine, but will not fire. It sounds like the car is
> > > starved for gas.
> > >
> > > I've recently tuned the car up: plugs, rotor, cap, but the problem
> > > still exists.