Need help/advise with 90' 348 idling/running after major

Back story: Purchased 348 from forum member AirBarton in March. Car has 94K miles over $39k in receipts since new and I paid $24K for it. Test drove car when I bought, ran it hard and other than leaks it ran fine, no CEL's. I also knew it was time for major. The car has one of the mufflers removed and the previous owner changed over to the Bosch O2 sensors. He said he had over the previous 14 years sorted out the gremlins in the car. Not sure what all those could be. He told me some at the time of purchase, electrical, window motors, stuff like that.

Note: I am done with the independent that performed the major and prefer to sort out the issues myself. I also have a friend with Ferrari experience that is going to help if needed.

Just before taking the car in for the major it cut off a couple times at stop light and CEL's came on, but still ran fine and I did not notice any missing when driving.

After I got it back from the Indy shop it had a rough idle but drive-able. Then the starter went in their parking lot after I came back from the first test drive. I had the car towed to my house(again, I am done with the shop ), orderd a new starter and installed myself this past weekend.

Now when I crank it the idle is horrible. Just after cranking - it wants to idle around 600-700 rpm's. Then it slowly increases after a minute or two. Then occasionally races to 2-3K rpms for a few seconds. Then, backfires after about 5 minutes idling (trying to let ECU's relearn for 10 minutes as I've read on F Chat) then at around 8-10 minutes the backfiring happens every 5 seconds or less. I then shut it down. The constant back firing was unnerving to say the least. Also, I noticed the engine temp gauges are not working. They were the other day.

Since I am new to Ferrari ownership I don't know where to start. Here are some thoughts.

• Old gas? (It has been in there about 6 months)
• O2 sensors
• ECU(s)?
• MAF?
• vacuum leak(s)
• burnt valve?

Where should I start? Also if there are any threads that can guide me through the process of checking and elimination please let me know. Thanks to anyone with constructive help.

Vince

 

You can rule out old gas....

 

1. make sure EVERY sensor got plugged back in. if you have to unplug and replug them all do so.
2. make sure every vacuum line got plugged back in.
3. coils are plugged in and plug wires are correctly run?
4. other stuff...

it's almost like it can't find the crank position so its hunting. (this is not from experience with ferraris, just other cars)

 

May want to try disconnecting the catalytic exhaust sensors and see if it runs better. The ECU's will shut banks down, causing a bad idle. I know one of the ones I have will shut bank down without giving me a slow down light. Unplugging them will not cause any running problems, just a thought.

 

How do the spark plugs look? Bad maf will coke plugs.
Check crank sensors for shavings (they are magnetic), crud, bad wire. Old ones get bad wiring, crumbling plugs.
Check plug on phase sensor. The bracket will crack the plug.
All those wires were reconnected at major, so something good before may be bad after. Drives you nuts.
Not a burnt valve. They are very consistent in pops if burnt.

 

Thanks for the replies, I plan on starting with the first recommendation of unplugging sensors and replugging them in and then move down the list of replies. Honestly yes I'm trying not to let this get to me and look at it as a Chance to learn about my car.

 

No trust of shop = 1st verify timing. start at basic and work out from there.

 

I don't disagree but I don't think he is going to pull the subframe out to do this

 

Ha! I think I'm done for the day or two. I've checked some of the sensors to make sure they're plugged in and that's about it. May give it a couple of days to think about how to attack this thing. Putting it on a trailer and taking it to Ferrari of Atlanta that has done a lot of the work on it in the past is on the table as well.

 

As a 355 owner, I can't help much with a 348 but lot's of guys here know them well. Those guys can walk you through the easy stuff. Hang in there, be patient and you might get this resolved on your own with the help of guys here.

 

Don't need to do that for basic verification. I should be more accurate and say verify assembly vs. timing. pull valve cover. #1 at TDC. move crank via flywheel teeth. verify all cams very very close to on marks to caps. do not use plastic cover holes they can be way off but cams perfect for a number of reasons. 348's run 97% perfect just on assembly marks. will pass california smog and not backfire. Then you go after connectors. LdM called the 348 the worst Ferrari ever. The car is fine and bullit-proof. Problem is Ferrari could not build a basic wiring harness for this simple beginning step into modern electronics

 

Could be cam

I could recommend another shop if you'd rather not use the dealership. Send me a PM.

Certainly sounds like crank or cam sensors to me.

 

I'd suspect that perhaps the "relearn" procedure has not been performed correctly after the service, or after the most recent disconnect of the battery. If you push your throttle pedal during the procedure, it may not reset at the base setting, and tend to "hunt".

The proper procedure should be described in the archives, hopefully that's all you need to do, and no money to spend doing it.

 

Since I have a battery cut off switch can I just turn it off there or do I still need to disconnect the positive cable from the battery?

 

Did the independent shop have any experience with a 27 years old 348? You someone with specific experience on your model, not just anyone.

1) cut off the ground, plug it back in
2) make sure idle valves are plugged in
3) Coolant temp sensor plugged in
4) Throttle position sensor plugged in
5) MAF plugged in, and none of the wires are messed up
6) Spark plug wires are not mixed up
7) Coil connectors all plugged in

You cannot verify cam timing with the engine in the car so ... in the end, you might need to yank it again.

 

I agree, I need someone with 348 experience. The previous owner texted me this morning and said Wade at Ferrari of Atl was who had worked in the car over the past few years. Think I'll be calling him.

 

Forgive my ignorance.
In addition to the above you mentioned the temperature gauge and oil gauge are not working now. Where can I go to find the location of the sensors and listing of the fuses.
Thanks from Mr overwhelmed and confused

 

Thanks for all the replies. I've decided to have the 348 picked up and taken to Ferrari of Atlanta and have them sort out the issues. I'll post back when it's back and I finally get to finally experience the car.

 

And, he knows his stuff

 

OK, there is a 9 pin (round)connector in the left engine bay, just in forward of the shock tower. The plastic outer ring unscrews, allowing disconnection of engine gauge sensors/starter motor, ignition etc. Some of the pins may be corroded/ or not making contact. The feeds range from Charging, Speedo, Oil, Temp, Starter, and others, that slip my mind. This connection is Always disconnected during an engine out. Start the car, wiggle the connection, and see if your gauges in trouble fix themselves... take appropriate action....
I believe there is a proper fix by 'Miltonian" for this connector.....

 

Thanks Dave

 

As I mentioned after I saw the photos from your service debacle, you are probably going to have to have someone that knows what they are doing redo the service. The will have to be extra careful in order to correct all of the wrongs that were done by the last shop. The beginning is to check compression and cam timing/valve adjustment and then go from there.

 

Sadly, you need to start a dialog with the prior shop now and see what they are willing to do (if you decide you wish to pursue financial recourse - which you should)

 

Yes that is in the works now. I probably should not comment on that part for now until I get a resolve. But, I am looking forward to Wade getting the car and getting it back on the road.

 

I agree - but just let me add this: You may legally need to give then the chance to make it right first before going elsewhere. Might be worth chatting with consul on this before doing much..