Ferrari Forums banner
1 - 20 of 20 Posts
G

·
Discussion Starter · #1 ·
I have a 348 that starts and r

I have a 348 that starts and runs fine when cold, but warm it up and shut it down and it is a mother to get restarted. I mean it cranks fine but doesn't start. sometimes it pops out the exhaust, stumbles,
after about 5-8 tries it starts and runs like nothing ever happened. it runs and idles perfectly.
any ideas on what might be the problem?
thanks!
 
G

·
Discussion Starter · #2 ·
This can be a symptom of a dua

This can be a symptom of a dual-mass flywheel starting to fail. When hot, the damping-greease is less viscous. The drive shaft, damping grese and the DMFW are used in place of a heavy balacing weight at the front of the crankshaft in americam V8 engines. The the 348/355 the shaft between the crank and the clutch and the DMFW are used to control crankshaft vibrations.

When the first cylinder fires (successfully) the drive shaft twists, and has plenty of time to reach the DMFW and return that twist back to the back end of the Crank. This end of the crank has the timing position sensors, and a failing DMFW can cause the timing pulses to arrive early (BTDC) and create negative amounts of power input, causing the motor fo fail to catch.
 
G

·
Discussion Starter · #3 ·
Alternately, this could be a D

Alternately, this could be a Digiplex problem.

One can tell a DMFW issue if the 3K-4K RPM range has developed a rattle in the gearshift lever. One can also tell by looking for grey greas seeping from the clutch observation port under the clutch.
 
G

·
Discussion Starter · #4 ·
OK, it starts fine when cold.

OK, it starts fine when cold.

Have you tried re-starting it the moment that the engine is shut off (when hot)?

It takes a few minutes for a failing component like a fuel pressure regulator to bleed off fuel pressure, so a quick re-start will test if you have a fuel pressure leak.

Likewise, you'll want to spray in some starter fluid with the engine off but hot to see if she starts up easily that way.

Until you perform those two tests, you'd just be guessing at your problem/cause, likely costing you money and time while upping your frustration.
 
G

·
Discussion Starter · #5 ·
thanks guys, I'll start te

thanks guys, I'll start testing things.
it's pretty much a solid problem, car just needs to warm up and it happens every time.
Wonder if putting a timing light on #1 plug wire when it's in a hard start mode would help figure out what's wrong.
I'm taking your advice and doing the easy tests first though.
thanks again.
 
G

·
Discussion Starter · #6 ·
I was going to ask if you'

I was going to ask if you've done what we should always start with first, and that's Reprogramming the Computers? So many times we've seen a simple Relearn Run on the Adaptive Logic Chips fix a driveability issue. If the answer is yes carry on with the other suggestions as they are spot on, if the answer is no, back up and start at the beggining.

On the Fuel Pressure Regs....pull the small Vacum Hoses at the Manifold End and Look for Raw Fuel (if you see raw gas that's a bad thing). Then put a lenght of vacum hose on the Reg End & pull a vacum with a cheapy vacum pump, if they hold vacum they're ok.

On the DMFW..that advice is also spot on...and if you hear a strange rattle from the rear on shut down you can bet the flywheel needs grease. About 40K miles best case scenario is about as far as a flywheel gets before it needs attention, especially in light of the fact that the factory has upped the specified amount of grease twice since the 348's were first introduced..
 
G

·
Discussion Starter · #7 ·
No, I didn't do the re-lea

No, I didn't do the re-learn thing???
what do I need to do to accomplish that?
thanks,
tim
 
G

·
Discussion Starter · #8 ·
To run the "Relearn" -

To run the "Relearn" - with a cold engine - unhook the Battery (not the kill switch, the battery itself)Ground Cable for about a few minutes....this clears the computers of stored data...reconnect...turn on key & turn off accesories...radio, AC, etc....then...without touching the gas throughout this entire cycle, start the engine & let "idle only" for approx. 10 minutes...by this time the engine should have gone from all the way cold thru heating up and the fan cycle, then you can shut down the engine and after a few minutes take the car on a road test of normal driving. This process clears the chips & restores the computers to a "Baseline Model" of codes that the computers then use to determine basic driving vs hard driving. What happens with Adaptive Logic Chips is that after many drives without a "relearn" they can become polluted or over run with info...and lose the original baseline parameters. The Baseline is also corrupted if the Battery goes dead or is disconnected and the 10 minute relearn is not run upon restarting the engine. Any corruption of the baseline parameters can & often does cause starting and/or drivability anomolies.

After the relearn, if you still have the starting issues then move on to diagnoising the other issues described above.

HTH's
 
G

·
Discussion Starter · #9 ·
To reinforce JRVs message::

To reinforce JRVs message::

After a day or a weekend at the track, my F355 engine (2.7 ECU) is somewhat unhappy running down the interstate at 65 MPH until it gets 50-100 miles under its belt and relearns that the throttle is not being floored every other 5 second interval for 5 seconds. It will idle just fine, run flat out just fine, but it is quite unhappy with the 2000-3000 RPM band, shaking and rattling various things in the exhaust system.

I have followed this over the last 3 years and found out several parameters of the ECU and its learning process.

You, as a driver, can accelerate the relearning process by holding the throttle with extreme precision. You must hold the throttle absolutely still and hold the engine within 250 RPMs of any given point for at least 45 seconds, and repeat this over the whole range from 2000 through 3000 RPMs and most of the lower throttle opening band. If you know of some hills that take those 45 seconds to traverse, you can accelerate the learning at various throttle openings.

You can tell when the ECU has learned any given 250 RPM band, because the engine becomes crisp (and in my car the exhaust vibrations go away) and takes tiny increments of throttle and converts these into immediate thrust. Once the ECU has learned several of these 250 RPM bands, it sort-of automagically adusts the intermediate ranges at least until it gets some learning time in those bands.

If you just drive the car, it might take a bunch of miles for the learning (adaptive) logic to figure out what state of tune the engine is in and adapt to its current state (and the gasoline in the tank).

Note to self: do not try to teach the car ECU new tricks when running 106 octane race gas, it gets very grumpy when you refill with 93 octane!
 
G

·
Discussion Starter · #10 ·
You're Funny Mitch,

Yes


You're Funny Mitch,

Yes guys....you CAN actually "teach the computers new tricks"...as Mitch states,...we should probably start a new thread on this & get deeper into the mechanics behind it all,the advantages & disadvatages, and then put it into the Tech Section after all of our input.

 
G

·
Discussion Starter · #11 ·
Ok guys, I think I found what

Ok guys, I think I found what the hot start issue(s)
were on my car with the help of all of you.
seems both clamps after the MAF sensors were completely loose and after driving the car over 600 miles the engine torque and vibrations loosened those intake hoses to the throttle bodies allowing un-metered air in the intake.... that's first.
secondly doing what JVR mentioned above, checking the fuel pressure regulators, the left bank 5-8 was leaking fuel out the vacuum port. that's bad right??? :))
anyway I didn't even both checking the right one.
I'm looking for replacements for both any suggestions?

symtoms where, car starts cold fine, runs fine, shut it down hot, car starts back up fine and runs fine if you do the restart within say 30 second to a minute. any long after a hot shut down and you'd have to crank the living heck out of it to get it started.

Hope these new parts fix the remaining problem.
Oh, then it time to fix the clock from always reseting and flashing every time you start the car
 
G

·
Discussion Starter · #12 ·
Tim,

the FP Regulators are


Tim,

the FP Regulators are Bosch & have the Bosch P# stamped on them...you can out source them from a Bosch Distributor or call AW Car Parts or Rutlands, or GT CAR Parts.

Yes leaking is a bad thing because it floods the manfold with raw gas after shut down, and the air leaks you found sure don't help matters. Defenately run the "relearn" after all the fixes so that the computers have a new & proper baseline to work from.
 
G

·
Discussion Starter · #13 ·
JrV,
I pulled the FP regulato


JrV,
I pulled the FP regulator and fuel just dumped out of the vacuum port.
took it to an auto store and they crossed the Bosch number with one made in the states.
I believe that has fixed the hot start issue! Seemed fine yesterday when I let the engine heat soak after a run. the car started back up easily! Time will tell as I use the car more.

thank you, no_doubt and all that help me.
I took pictures for anyone else that might need to DYI. not too bad a job about 2 hours.

while trouble shooting this problem I did notice that the flywheel does rattle some, though probably not enough to cause a problem. I've posted another thread to ask questions related to that.
thanks again!
tim
 
G

·
Discussion Starter · #14 ·
Hey Tim, my 348 suffers from e

Hey Tim, my 348 suffers from exactly what you've described in this thread. Could you post the details of your replacement FP regulator so that I can try Bosch here in Australia.

Also, let me know if you solve the blinking clock problem. My 348tb doesn't seem to keep it's time either.

Cheers
Warren
 
G

·
Discussion Starter · #15 ·
Warren, don't just blindly

Warren, don't just blindly replace parts.

Test first.

If your car is normally having a hard time starting when hot, then Start your 348 cold, drive it until hot, kill the engine. Wait 20 seconds (but not longer than 1 minute). Now Re-start it (while still hot).

If it easily re-starts after 20 seconds, then you've probably got a fuel pressure leak (e.g. failing fuel pressure regulator).



It takes a few minutes for a failing component like a fuel pressure regulator to bleed off fuel pressure, so a quick re-start will test if you have a fuel pressure leak.
 
G

·
Discussion Starter · #16 ·
I'll try that at lunch tim

I'll try that at lunch time (7:42am right now). Every morning it starts perfectly. After driving to work, parking it all day (usually 9-10 hours) starting is a serious pain in the ^%$#. What makes little sense is that parking overnight is only for about 12-13 hours.

After some testing my mechanic and I think the problem lies somewhere in the fuel system. The car is simply not getting the message to pump fuel. He sprayed something into a fuel line (I think) and the car started fine. After one try (no accelerator pedal), and no start, we try a second time but with the accel. pedal flat to the floor, ie trying to force the computers to deliver fuel whether they think it's needed or not. The car starts, not quite as perfectly as in the morning, but 100 times better than a normal hot start try.

My mechanic has noted that (I think) the O2 sensors are disconnected, or not in use somehow. Sorry, I'm a complete novice here so am probably not explaining it right.

Any ideas?

Cheers
Warren
 
G

·
Discussion Starter · #17 ·
Try the quick re-start test wh

Try the quick re-start test when hot, but it sounds as though you've got a leaky fuel injector that is flooding a cylinder or losing fuel pressure. Could still be one or more bad fuel pressure regulators (easy to check, just pop the rear hatch and pull the black rubber hose off of each fpr; if you see gas it's bad).

In the meantime, spend $2 on some starter fluid. just spray it into your air intake box to make your hot starts easy until you get the problem solved.

No reason to be cranking like a wild man on your ignition key after work every day!

Anyway, would love to hear what your quick restart test points out.
 
G

·
Discussion Starter · #18 ·
I will post this DYI on the FP

I will post this DYI on the FP regulator once I get them downloaded tonight. I wasn't that bad of a job if you need to do it.

I would have the same problem after work too,,,, didn't understand what and over night wait and an 10 hour
wait after work would be but I'd have problems starting the car. At min 4 attempts after driving
but one bump of the switch in the morning.

the Nodoubt test is what I used, it helped.
It sounds like you need to add fuel to the engine to get it started though.
I'm not sure how this fuel system works yet but but if the regulator (or something) is leaking does that let the fuel out of the fuel rails? How long does it take to build the fuel pressure back up at the injectors?
I'm new at this car, and trying to learn it.
One other thing Warren added fuel to get the car started.
On Porsche motronics the fuel pump won't stay running unless it sees a TDC pulse at certain intervals and time when starting.
does the 348 do something like that.
 
G

·
Discussion Starter · #19 ·
update on hot start issue.
se


update on hot start issue.
seems the new fuel pressure regulator has corrected
the problem.
thanks,
all.

now on to the other issues......
 
1 - 20 of 20 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top