F355 Cold Starting Difficulties

This should be an easy fix for a competent mechanic. Started mine this morning, 25 deg F. and it ran just like any fuel injected modern car should. Should also be a fairly easy fix with someone who is familiar with fuel injection diagnostics. Keep us posted and when it is all fixed, DRIVE IT!!!

 

I'd think fuel flow issue or temp sensor problem. Check your coolant level. Pull a spark plug (or all of them) to see if you have fouling (so, it could be a spark issue, too).

Check your fuel pressure regulators by pulling the little black vaccuum hose off of each one (presence of fuel in that hose indicates a failed regulator).

 

HERE's a FIX I Found.

I too have a 95 355. From the time I got the car I noticed that at cold it would start on the second turn of the key but not the first. I searched on fchat and this seems normal for some people and so I thought it was a 'ferrari trait". Some people suggested pressing the gas pedal to the floor before starting and some letting it sit for 30 seconds after turning the key on etc etc, but I would just turn it over for a few seconds, stop and then it would fire up on the second try. Also whilst cold it was a tad lumpy on the idle and then for a few minutes until it found some heat and all would be well.

This kind of bugged me as I know it shouldn't be the case and in all honesty I found the fix by pure accident, so rather that lie and make up a story I'll just tell the truth.

So one day I'm detailing the engine compartment and I wanted to clean out the airboxes and check the air filters whilst I was checking the fluids and doing the cleaning. Whilst I had the boxes off I vacuumed them out and cleaned the inside of the tubes going to the intake ports. If you take the air boxes off you will notice that you can see the mesh cover on the MAF's (Mass Airflow Sensors). These are the two black boxes on either side that meter the air for the engine fuel management. I noticed some slight dust/oil film residue on the inside of the MAF tubes (on the little sensor tips) and since the mesh is there you can't just wipe it away like on some other cars.

So I got a can of carburettor cleaner that I keep for my truck and gave a couple of second squirt onto the sensor tip and into each tube in a circular motion. I held a rag underneath the tubes and after spraying pushed down on each MAF slightly to drain the carb cleaner residue into the rag. The MAF can be pushed down as the rubber flex hose allows it to bend. I left the tubes alone whilst I finished my detailing to make sure the cleaner had evaporated and then reassembled everything.

When I came to start the car about 3 hours later and not having been run in a week to my suprise she fired on the first turn of the key. The next suprise was how smooth the idle was compared with before. Ever since then the car has always started first time and runs fantastic.

There you go then, ten minutes of work with only a couple of dollars spent to make a night and day difference.

This was the only thing I did other than cleaning the engine bay and so unless Enzo's elves came in the night with magic 355 potion I think its worth a try.

 

Great post, Mark!



Another thing to check are the idle air regulators. Like the MAFs, they too can need to be cleaned with starter fluid or carb cleaner.

 

I have had the same problem on my 95. I have cleaned the MAF sensor last summer and did not help. I it almost like not getting enough fuel on the first crank when cold temps. Maybe the cold enrichment is not enough. Can this be ajusted or is it only controlled by the ECU? Where is the air temp sensor?

 

On the 5.2 355s the temp sensor is about three inches after the MAF (in the direction of flow) on the bottom side of the plastic 'Y' tube.

 

You will also want to have a look at the cleanliness of the connections for the MAFS. Be sure that those are also clean and hooked up properly.

 

I am no Motronic expert, but that intake air temp sensor (I believe) makes minor adjustments to the mixture...it is not part of the cold start or cold idle enrichment circuit. That temp sensor is located (on a 5.2) to the right of the oil filter. It is screwed into coolant jacket and has a blue Amp junior timer connector on it.

 

2.7 has two seperate MAF sensors, and the requisite dual electronics and plumbing. Do a thread search there are many threads with pictures showing the visual difference.

 

Sounds great, congrats!


...but, if your problem "mysteriously" returns in a few months, instead of replacing that same fuel pump again, replace the fuel pressure regulators. A new fuel pump can appear to "fix" a failing FPR for a while, simply because the new fuel pump has so much power.

 

I would rather have it start on the second try than the first. Even though this is a sump oiling system it still needs to pressurize...that first try at crank speed atleast gets some pressure in the system before it fires up to 1K+ rev's. All our race cars had a pin-out switch that killed spark to the plugs....just crank over the engine until the oil pressure gauge needle showed pressure.....push the pins in and then fire it up.

Another problem that does show up in the start sequence is inadequate line pressure at the injectors.......this can be caused by fuel pump/s or regulator/s....not common as much would be a restriction in the fuel filter or fuel return.

 

The easy, free way to test FPRs is to pull off the small black rubber hose that slips onto each one. Fuel in that vacuum hose is a certain indicator of an FPR failure (which makes starting the car problematic, though might still enable the car to run once started).

Each FPR will have the same Bosch part number on it, by the way...go to Google.com and type in the part number to comparison shop on price.

 

You've got 2 FPR's, and it just takes one to cause a hard-start problem.

Spray some starter fluid into your intake when your motor is off and car is cold, then see if she starts right up.

Yes, she starts immediately with starter fluid?
No, she still takes multiple cranks to start, even with starter fluid?


The answer to the above will tell you to look at either fuel pressure points like FPRs or else at sensors such as your crank sensors.

 

There is a real easy fix for this...... Move..... It's too F-ing cold up there.