| Author |
Message |
Kurt Kjelgaard (Kurtk328)
| | Posted on Friday, April 27, 2001 - 5:52 am: | |
There could be several reasons for your hot start problem.
- Leaking injectors: Remove from manifold (still connected to fuel line), pressurize system, check for leaks, don't smoke!
- Incorrect control pressure: check, that the warm control pressure is correct.(Best done at specialist workshop, requires special equipment).
- Cold start valve: Check for leaking by removing from the manifold, pressurize system and look for leaks. A leaking cold start injector can also be due to a defective thermo time switch.
- The airflow sensor plate should be checked for correct height, centering and no binding. When moving the sensor plate use a magnet on the center bolt. System must be DEpressurized.
Good luck and keep us informed
brgds Kurt |
Ben Lobenstein 90 TR (Benjet)
| | Posted on Thursday, April 26, 2001 - 11:31 pm: | |
My thought....the fuel accumulator would be more suspect of the situation were reversed. Meaning if the car had a hard time starting when dead cold, but not when even remotely warm. Basically the accumilator holds fuel pressure when not running. Have you tried using Ether to start it (Starting Fluid), when I had a starting problem (not 308) I used it to start and it worked %100 of the time...what this ended up doing was showing us that spark was good but not fuel pressure. Turned out I had a bad tachometric relay and a bad throttle control microswtch (again this is NOT on a 308 but may lead you in the right direction) that were both intermittently bad. Both replaced and starts %100 of the time. When you start there are only 3 factors air, fuel and ignition/spark. If you have narrowed it down to fuel you have to make sure you are getting the correct pressure on startup. With the bad tachometric relay we had what should have been running idle fuel pressure during startup (which is much less than startup pressure) therefore not starting first time out, every time.
Hope this helps
-Ben |
Monty Bates (Montybates)
| | Posted on Thursday, April 26, 2001 - 10:39 pm: | |
I appreciate the help everybody is giving me on this problem.
I installed the new fuel accumulator today.
Very little or no improvement. The car still starts easily when cold, but when warm it's a battle to get the car started.
With the new fuel pump and accumulator installed, the pump buzzes (runs) continuously with the blue connector near the fuel distributor unplugged.
Question 1) Is that normal?
Question 2) Any ideas on what could be causing this warm start problem? I am happy to replace parts since these parts are seventeen years old. But I am not sure what else to replace.
Question 3) Could leaking fuel injectors cause this problem? Any chance the fuel injectors are leaking fuel into the cylinders? Which causes the engine to be flooded until the fuel evaporates? |
Paul308qv (Paul308qv)
| | Posted on Sunday, April 22, 2001 - 9:29 pm: | |
Monty, Heath and Erik, even thought the accumulator was not my problem, I have heard others also tell me that this can be the cause. Best of luck. |
Monty Bates (Montybates)
| | Posted on Sunday, April 22, 2001 - 2:55 pm: | |
Wow! Thank you, Erik, Heath, Paul, and Fredrick!
That is fantastic information you posted.
I disconnected the blue safety switch (next to the fuel distributor) and yes; the fuel pump clicked on and never turned off (until I turned off the ignition).
With the safety switch unplugged, the car is still tough to start when warm.
Therefore, I suspect the fuel accumulator is faulty. I will replace it next and report back to this board.
For the record, the fuel pump and fuel accumulator are easy to replace. They are both attached to the same mounting plate and when I replaced the fuel pump; I removed the mounting plate with both the fuel pump and the accumulator from the vehicle.
My steps for replacing the fuel pump and/or accumulator:
1) Try to have the least amount of fuel in the gas tank as possible. Either siphon out as much as possible or do like I do and just don't come home until the tank is about empty.
2) Disconnect the battery. (Very important as any sparks would cause an explosion when working with dripping gasoline!)
3) Raise the driver�s side of the car. (Of course use proper jack stands.)
4) Remove the rear driver�s side wheel.
5) Remove the fiberglass fender well.
6) Remove the gas line at the rear of the fuel pump. Since the tank is nearly empty, only a small amount of gasoline spills. Simply elevate the hose and gas will not come out. Cap the open end with a plastic plug or tape to keep particles out of your gas line.
7) Remove the three nuts that secure the mounting plate, which holds the fuel pump and accumulator. (The fuel pump negative power connector is connected to the vehicle frame with one of these nuts.)
8) Disconnect the fuel line from the accumulator. This is the fuel line that connects to the fuel filter.
9) Disconnect the positive power connector on the fuel pump.
10) Disconnect the fuel accumulator return line to the fuel tank.
11) Simply lift out the mounting plate with the fuel pump and fuel accumulator.
12) Replace the desired unit(s) and reinstall everything in reverse order.
As soon as I replace the fuel accumulator, I will report back with the status.
Thank you very much for your help.
Monty Bates |
Erik Jonsson (Gamester)
| | Posted on Sunday, April 22, 2001 - 1:27 am: | |
Marky had the same problem with his, it was the accumulator. Cost was about 95 from Bow Wow auto parts in Boise, Idaho(208 area code)
It is a standard Bosch part, and any VW shop can order it/may have it in stock. |
HEATH VAUGHN (Heath)
| | Posted on Saturday, April 21, 2001 - 9:54 pm: | |
MONTY
I HAD THE SAME KIND OF PROBLEM. WHEN YOU UNPLUG THE SAFTEY SWITCH NEXT TO THE FUEL DISTRIBUTOR LISTEN TO THE FUEL PUMP IF AFTER A FEW SECONDS YOU HEAR A CHANGE IN PITCH THAT WOULD INDICATE YOU ARE HAVEING TO REBUILD PRESSURE IN YOUR SYSTEM IF THAT IS WHAT IS HAPPENING IT WILL PROBABLY BE YOUR FUEL ACCUMULATOR (A WHOLE IN ITS DIAFRAM ALLOWING PRESSURE TO ESCAPE TO THE FUEL TANK. AROUND $125.00 DEALER ITEM BUT CHECK WITH MARANELLO AUTO PARTS 800-233-7820. HOPE MY I HAVE BEEN OF SOME HELP.
HEATH |
Paul308qv (Paul308qv)
| | Posted on Saturday, April 21, 2001 - 9:27 pm: | |
Monty, my 84QV also had the same problem. In my care, it was the Fuel Distributor plate position sensor. This is the device that cuts power to the fuel pump when the car turns upside down (like in a wreck). When my car got hot, the thermal expansion was just enough to make the sensor 'think' it should shut down the fuel pump.
One way to test my scenario on your car is to unplug the little 'blue in my case' plug on the back of the fuel distributor unit. This will not hurt anything to just leave it unplugged while you drive around and try to recreate the problem. If your hot start problem goes away, then you have diagnosed the problem. You will need a competent Ferrari technician to provide advice about whether it can be adjusted or if it needs to be replaced. Good luck. |
Frederick Thomas (Fred)
| | Posted on Saturday, April 21, 2001 - 7:58 pm: | |
Monty,
My 83qv had the exact same problem. It turned out
to be a wiring problem with mine. Now when it is
hot I still have to push the throttle down but it
fires right up when I do. It made a huge difference.I forget the exact details. I will talk
to my mechanic on monday or tommorow if I can get
a hold of him and see if I can get specifics for you.
Fred |
Monty Bates (Montybates)
| | Posted on Saturday, April 21, 2001 - 4:18 pm: | |
Does anybody know what would cause an '85 308 GTS QV to have a warm start problem?
When the car is cold, it starts almost instantly.
After the car has been driven and then sits for 10 minutes to 2 hours, it is very tough to start. In fact, the only way to get it started at that point is to hold the throttle wide open for ten to thirty seconds while engaging the starter.
Somebody recommended replacing the check valve in the fuel pump. So I replaced the whole fuel pump. No improvement.
Any ideas would sure be appreciated. |
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