'91 3.3 barely runs when warm
10-04-2010, 02:27 AM
#16
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As for the gas tank, if I recall correctly it has had a small amount of pressure or vacuum each time I have opened it, although it's been a while since I've used the car so my memory might be faulty.
10-05-2010, 11:11 AM
#17
hi,
for sure not, should be an air ventilation issue and should be solved. don´t think that it causes your problem, but its easy to check, try to run the engine without
filler cap.
as john wrote its a low octane jumper, brown and brown/white wire. should be bridged in country with bad fuel, reduces ignition advance.
as far as i recall its the engine speed sensor, located at the clutch housing, connected to the EZ69 ignition box.
if all fuel issues have been excluded from causing the trouble the speed sensor would be my next favorite.
fritz
I noticed that there is considerable pressure in the fuel tank after the engine has run for a few minutes. There's a big 'whoosh' when you crack the cap open. Is this normal?
filler cap.
here is a plug with two brown wires dangling from the relay panel in the engine compartment. I don't see anything that it would plug into. What's its purpose?
On top of the air pump is a bracket that holds the oxygen sensor connector and another electrical connector (with three conductors). What is this connector for?
if all fuel issues have been excluded from causing the trouble the speed sensor would be my next favorite.
fritz
10-05-2010, 11:34 PM
#18
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You're right, Fritz, the gas tank venting issue doesn't have any effect on the main problem. The engine runs just as poorly with the gas cap off. I suspect that the cap may actually be responsible for the pressure build-up. The cap doesn't look like the one that was on the car when it went into the repair shop - it's got a red handle; the original was yellow.
Is is there a diagnostic procedure for the engine speed sensor?
Is is there a diagnostic procedure for the engine speed sensor?
10-06-2010, 02:29 PM
#20
Rennlist Member
Might be worth checking the below
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The below post helped with my issue. May not be the cause but pretty easy to check.
sounds like an air leak, pretty common. There is an orange o-ring that seals the Intercooler to the throttle body. If you can see any orange at the neck of the IC, this may be it. Its a common problem, especially if the IC has been removed. Its happened to pretty much everyone with one of these cars at some point based on the number of threads on this issue. Good luck.
__________________
94 Turbo 3.6 - 516RWHP
Full EFI Conversion, Garrett GT35R Turbo
2008 BMW M3 - Daily Driver
The below post helped with my issue. May not be the cause but pretty easy to check.
sounds like an air leak, pretty common. There is an orange o-ring that seals the Intercooler to the throttle body. If you can see any orange at the neck of the IC, this may be it. Its a common problem, especially if the IC has been removed. Its happened to pretty much everyone with one of these cars at some point based on the number of threads on this issue. Good luck.
__________________
94 Turbo 3.6 - 516RWHP
Full EFI Conversion, Garrett GT35R Turbo
2008 BMW M3 - Daily Driver
09-12-2011, 02:12 PM
#21
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Because of some other stuff going on in my life, the car ended up sitting for most of the past year without any work being done. Now I'm at it again, and I need more help!
The engine is very hard to start, won't idle, and usually dies if you try to open the throttle. If it doesn't die, there's a huge cough before the revs pick up. The car is not driveable in this condition.
Fuel filter is good and the output of both pumps is fine. Last year I bought gauges and checked the fuel pressures. They're good, too.
I've been looking for an air leak and thought for sure I had found the problem when I discovered a very loose hose clamp. At the connection between the plastic tube that Porsche calls the intake manifold and the rubber elbow on the inlet side of the turbo, the hose clamp was loose and had slipped down on the elbow. When I pulled out the manifold, I found that the metal reinforcement ring had fallen out and was lodged in the elbow (see the first attached picture). Also, the end of the manifold was distorted (not round - second picture). There had to have been an air leak here!
I cleaned up the ring, epoxied it into the manifold and put everything back together. While I was at it, I also replaced the orange o-ring where the intercooler mounts onto the throttle body.
Unfortunately the engine still runs just as poorly. I really don't want to throw in the towel and have the car towed to a shop, but I'm really baffled.
Any ideas what I should try next? By the way, even though my car is twenty years old, it's got less than 25k miles on it!
The engine is very hard to start, won't idle, and usually dies if you try to open the throttle. If it doesn't die, there's a huge cough before the revs pick up. The car is not driveable in this condition.
Fuel filter is good and the output of both pumps is fine. Last year I bought gauges and checked the fuel pressures. They're good, too.
I've been looking for an air leak and thought for sure I had found the problem when I discovered a very loose hose clamp. At the connection between the plastic tube that Porsche calls the intake manifold and the rubber elbow on the inlet side of the turbo, the hose clamp was loose and had slipped down on the elbow. When I pulled out the manifold, I found that the metal reinforcement ring had fallen out and was lodged in the elbow (see the first attached picture). Also, the end of the manifold was distorted (not round - second picture). There had to have been an air leak here!
I cleaned up the ring, epoxied it into the manifold and put everything back together. While I was at it, I also replaced the orange o-ring where the intercooler mounts onto the throttle body.
Unfortunately the engine still runs just as poorly. I really don't want to throw in the towel and have the car towed to a shop, but I'm really baffled.
Any ideas what I should try next? By the way, even though my car is twenty years old, it's got less than 25k miles on it!
09-12-2011, 09:39 PM
#23
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The fuel tank vents though the vent valve on the expansion tank back to the carbon canister. Fuel vapors are stored in the carbon canister when the car is not running. When the car is started, the vapors are purged from the canister, flushed out with fresh air that's drawn from the engine, pulled into the intake to be burned.
The charcoal in the canister can be cycled an infinite number of times. The only time you would replace it is if fuel got into it.
Check the fresh air vent on the canister for obstructions. Check the vent valve in the expansion tank and the line running back to the control valve for function and obstructions. Also, you may need to check the control valve to see that it opens when the engine is started. The canister is in the forward part of the left rear wheel well, behind the plastic wheelhouse.
Last edited by Metal Guru; 09-12-2011 at 10:08 PM.
09-12-2011, 09:45 PM
#24
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The engine is very hard to start, won't idle, and usually dies if you try to open the throttle. If it doesn't die, there's a huge cough before the revs pick up. The car is not driveable in this condition.
Fuel filter is good and the output of both pumps is fine. Last year I bought gauges and checked the fuel pressures. They're good, too.
Fuel filter is good and the output of both pumps is fine. Last year I bought gauges and checked the fuel pressures. They're good, too.
09-12-2011, 11:27 PM
#25
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Thanks for the advice!
I'm going to give this a try.
22 psi cold; 48 psi warm. How do you check the pressure at the boost level?
I haven't checked this, but I'm willing to buy a meter or gauge if it will get me closer to solving this problem. What meter or gauge do you recommend?
Agree with fritz K. Put a new speed sensor on car.
What are the pressures; cold, warm and boost?
What is the idle afr or CO? (spec is CO of 1%). What does your afr curve look like? at steady state? Under boost?
09-13-2011, 05:49 PM
#26
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3.2 bar warm cp. Seems a little low. Spec is 4.5 bar. To check boost cp you need a mityvac pressure/vacuum pump and hook it up to the line in the side of the wur. Energize the pumps and apply no more than 1 bar. The cp should drop to whatever it's set at.
The Innovate LM-2 is a good tool. You'll need to weld a port into the tailpipe for the O2 sensor.
09-14-2011, 06:33 AM
#27
same jear, same mess ...
Because of some other stuff going on in my life, the car ended up sitting for most of the past year without any work being done. Now I'm at it again, and I need more help!
The engine is very hard to start, won't idle, and usually dies if you try to open the throttle. If it doesn't die, there's a huge cough before the revs pick up. The car is not driveable in this condition.
Fuel filter is good and the output of both pumps is fine. Last year I bought gauges and checked the fuel pressures. They're good, too.
I've been looking for an air leak and thought for sure I had found the problem when I discovered a very loose hose clamp. At the connection between the plastic tube that Porsche calls the intake manifold and the rubber elbow on the inlet side of the turbo, the hose clamp was loose and had slipped down on the elbow. When I pulled out the manifold, I found that the metal reinforcement ring had fallen out and was lodged in the elbow (see the first attached picture). Also, the end of the manifold was distorted (not round - second picture). There had to have been an air leak here!
I cleaned up the ring, epoxied it into the manifold and put everything back together. While I was at it, I also replaced the orange o-ring where the intercooler mounts onto the throttle body.
Unfortunately the engine still runs just as poorly. I really don't want to throw in the towel and have the car towed to a shop, but I'm really baffled.
Any ideas what I should try next? By the way, even though my car is twenty years old, it's got less than 25k miles on it!
The engine is very hard to start, won't idle, and usually dies if you try to open the throttle. If it doesn't die, there's a huge cough before the revs pick up. The car is not driveable in this condition.
Fuel filter is good and the output of both pumps is fine. Last year I bought gauges and checked the fuel pressures. They're good, too.
I've been looking for an air leak and thought for sure I had found the problem when I discovered a very loose hose clamp. At the connection between the plastic tube that Porsche calls the intake manifold and the rubber elbow on the inlet side of the turbo, the hose clamp was loose and had slipped down on the elbow. When I pulled out the manifold, I found that the metal reinforcement ring had fallen out and was lodged in the elbow (see the first attached picture). Also, the end of the manifold was distorted (not round - second picture). There had to have been an air leak here!
I cleaned up the ring, epoxied it into the manifold and put everything back together. While I was at it, I also replaced the orange o-ring where the intercooler mounts onto the throttle body.
Unfortunately the engine still runs just as poorly. I really don't want to throw in the towel and have the car towed to a shop, but I'm really baffled.
Any ideas what I should try next? By the way, even though my car is twenty years old, it's got less than 25k miles on it!
this mess sounds like the one i am going through with my 91 turbo. bought the car with about 48thousand miles from second owner that had it for a year. all records till he bought it. he drove about 7 thousand miles and sold it. i thought i got a very, very good price. i decided to drive the car for a season and find out if ( or what ) kind of trouble is waiting for me.
the car only drove really well under full boost. idle was ok - but not great. muffler too dark. but ran as hell so far.
so i started with fuel preasure to find out the wur did nothing. fixed to 3,5 bar for full load - no electrical power there.
i bought a good used and found system preasure too low, too. next: fuel distributor dead - while trying to adjust fuel preasure i fluted two cylinders (the black rubber sealings of two cylinders inside had gone) and noticed that when trying to start. so god will my engine did not get any invisible damages! |-@
to reach that point i sit now i had to change: wur, fuel distributor, engine wire (complete), cold start valve, turbo (worn), lambda-sonde, injectors, fuel pumps, fuel accumulator, etc. etc. - and every sender mounted to the engine: cold start, oil themperature, sealings, etc.: all new!
i only did not change that electrical items under the seat and the ez69. i have a complete spare set here and will now go in this mess.
the engine so far is great: fully mainenanced. valves adjusted, leak down test, etc.
it is unbelievable that this car passed emission test. it drove that good i never never had believed there could be such mess with this. but we all grow with the things we love ...
now, after spending all that money and time in my garage i ended up whit a non drivable car like yours. idle cold is great, when it gehts warm it stalles and runs only from 3000 up (reched by pumping the pedal few times). and it runs hard, not the way it should. so the mistake seems to sit somewhere else! let me know if you find the mistake.
i will post if i am successful.
(-:
stefan
09-14-2011, 05:20 PM
#28
Rennlist Member
I think you are close.
09-14-2011, 05:22 PM
#29
Here's a few things to look at:
Check and clean your ground, check and replace the battery negative cable if needed.
Check and replace the throttle position switch, enrichment of the fuel is also dependent on this switch.
check volume of fuel deliverd from the fuel pumps, with both pumps activated it should deliver a min of 1170 cc's of fuel in 30 seconds, if they deliver less, you have bad pumps or a flow restriction in the fuel system. And yes a pump can deliver proper pressures reading and not be able to deliver the proper volume under load.
Also could be the fuel pressure accumalator.
Check and clean your ground, check and replace the battery negative cable if needed.
Check and replace the throttle position switch, enrichment of the fuel is also dependent on this switch.
check volume of fuel deliverd from the fuel pumps, with both pumps activated it should deliver a min of 1170 cc's of fuel in 30 seconds, if they deliver less, you have bad pumps or a flow restriction in the fuel system. And yes a pump can deliver proper pressures reading and not be able to deliver the proper volume under load.
Also could be the fuel pressure accumalator.
Last edited by fastmover; 09-14-2011 at 06:11 PM.
09-17-2011, 01:16 PM
#30
Rennlist Member
check volume of fuel delivered from the fuel pumps, with both pumps activated it should deliver a min of 1170 cc's of fuel in 30 seconds, if they deliver less, you have bad pumps or a flow restriction in the fuel system. And yes a pump can deliver proper pressures reading and not be able to deliver the proper volume under load.
Also could be the fuel pressure accumulator.
Also could be the fuel pressure accumulator.
