Hi all, today I picked up my new 550, as a stable mate to my 355. I initially bought the car when it did not run , due to the dreaded molten fuel pump rubbers. Car has had a lot of maintenance in the past, and bill to prove it. With the garage's promise to have that pump problem fixed before delivering, I struck the deal. After a very long wait as the garage could not locate the parts ( In the end I helped them, having had the same issue on my 355 before, so I knew what was involved), today I picked up the car. I did not notice anything strange on the car, so started the journey home (like 50 miles). But after say 10 minutes on the highway at 100 km/h ( like 60 miles/h), the SDL started blinking. That I also am very familiar with on the 355, which had the same problem years ago. That one started blinking from startup, which turned out to be a thermocouple delivering only 10% of the voltage of the other one, and the central Motronic concluding that there was a very big temp difference between the cats, triggering the blinking SDL, and sometimes the limp mode. (SDL solid) As I suspected a similar problem with this car, I drove on with 100km/h to finally get home. Stopping and let it cool a bit did not have results, as it did not look warm at all. And as the rain was pouring down and investigating further on the emergency lane was not a nice proposition, I very calmly drove home. Then I discovered that the passenger bank seemed cooler than the driver's side. As the SDL was still blinking, I did not know I had been driving on limp mode, as I drove very calmly. ( limp mode = solid SDL, correct??) I checked the fuel pressure, and the driver's side was like 50psi, and the other was zero! The question now is: is not having fuel pressure on one bank the cause of the SDL , or is the SDL causing limp mode, by shutting down fuel pressure? The SDL now immediately starts blinking after cold start, which my 355 also had as a symptom, but was not consistent with difference in voltage because both TC should be cold and thus giving a low voltage...But changing that low-output TC completely solved my 355 problem... (where the 1.5V batterie-trick did not!!) Where do I start? Can I put 12V on the pumps themselves directly at the tank, to check them? Or should I never ever do that? Or can I jump the fuel pump relays to check? (where are the relays, passenger side?) which terminals to jump? Thanks for your ideas!
Could indeed be fuel shutting off due to another problem, but first thing I would do is check for generic P-codes with a code reader
It is a euro 550 from 1998, so the OBD port is somewhere beneath the steering wheel, correct? (3- pin type, just as my euro 97 355?) I do not have a Check Engine light, so I do not expect codes, or is that not always the case?
I have not played with every aspect of the SDECU system but I have played with a lot of it. I'm 90% sure from a dead cold engine it would take some time to get the SDmil to light. Assuming this is true you would have fuel pressure on both sides at least until the SDmil is lit. I can't remember how the SDECU killls a bank whether it does it electronically or by cutting fuel. I would have a very strong suspicion since the pumps were just disturbed that the shop did not get all the rubber bits out of the system and you got a blockage stopping fuel flow which can lean things out and set an SDmil too. Read this thread I started. https://www.ferrarichat.com/forum/threads/exhaust-ecu-aka-sdecu.328364/ I think this is the one where I tell you how to bypass the SDECU with just a 1.5volt battery. Doing this bypass can also be used diagnostically. If you do this bypass and are still seeing no fuel pressure on one bank I would start cleaning out that line from gas tank to fuel injector. These cars are old now and nowhere does Ferrari have a service interval for the injectors. I routinely at my major services have injectors professionally cleaned. It is cheap for me since I DIY. You may have to add the ground wire to make your OBD port work. It is there and it does work of grounded properly. I would pull codes to see if you had misfire codes p0300 codes. That can imply lean out conditions fuel starvation and possible blockage and give you more reason to consider fuel injector cleaning. I think this is the Ferrari tech bulletin to make sure the OBD wiring is updated so you can read it. Ferrari left off connections so only they could get data. Federal government made them add the wiring in under recall. You may nit have recall in your country but the wiring is there.
My 550 gave a lot of headaches with limp mode due to high humidity and lack of use in Hong Kong. Most of it was to do with the O2 sensors and bad catalytic convertors. I too started with fuel pumps and a full tank clean. Your tank probably has scaling inside too
Do Euro cars have the OBD 2 port? I'm not 100% sure a 550 ECU cuts off its respective bank fuel pump in response to an SD or other fault, however there is at least one wire coming from the ECU which affects the respective pump control relays. 550 fuel pump control actually uses 3 relays (for each bank). The relays are located in the passenger footwell. Relays D, L and O are the relays for the right bank (1~6 cyl) pump. Relay D is the pump power relay. The other two relays are for controlling the power relay. According to the wiring diagrams, relay L is an extra relay which is controlled by the inertia switch (for safety in accidents). Relay O is the respective bank injector control relay. Some 550 owners have reported the inertia function does not work, so the wiring diagrams may be hiding some secrets. There is only one inertia switch on the 550 anyway, so it's not possible that a faulty inertia switch could shut down only one pump (however, a faulty relay L could). For evaluation, you could try swapping relays. Swap right bank relays D and L with the respective left bank relays C and I. Also check fuse #6. I don't think relay O is faulty. Otherwise you would get more issues. Image Unavailable, Please Login Let me know if you need wiring diagrams.
Looking at your initial symptoms you need to establish if the fuel pump is being cut out / suppressed due to another issue or is it the fuel pump itself. I agree with others but I would do it in 4 steps. a. Remove rear trim and remove the fuel pump connector. Connect a multimeter across and see if there is the voltage when the engine is cranked. You either have voltage or you don't. If you get voltage, the car electrics are fine for the fuel system. If not, you either have a pump relay/fuse issue or some suppression for fuel taking place. In this case, I would use a spare connector and plug it directly to a battery. ALl excess fuel usually comes back anyway so the pump running non-stop will help diagnose the issue. b. Remove the snap-on PVC fuel line on the fuel pump and crank the engine (or hook up with jump batt if there was no voltage in the fuel line connector ) to see if the fuel pump is giving out any fuel at a decent pressure at the pump pipe outlet. If no, you have a pump issue or a blockage in fuel intake from old debris. If yes, then the issue is further up on the injector rail or pressure regulator side. .c.There are 2 plastic caps on fuel injector rails that have valves. I used to release the valve to see if fuel was coming out at similar pressure on both sides while cranking the engine. You can start by checking that rail after putting back the pipes on the pump again. The only other item that caused issues in my car was the Mass Air FLow meters, the green thermocouple control units. (I think similar to the 355 so you can swap them. Good luck
You could jump relay "D", using pins 30 and 87. Note that the pump power relay uses hot battery power, so you may get some sparks when you connect the jumper wire. I would recommend using a switch in the jumper wire or use the battery cutoff switch. Here's the wiring diagram: Ferrari_550_Engine_Service_&_HVAC The right fuel pump is in the bottom, right hand corner. The circuit is quite hard to follow, but the colours and notes help. If the jumper doesn't activate the pump, check the fuse.
Thanks all, very helpful!! I will spend some time tonight and this weekend to follow up all the leads. And will come back with the findings And I really appreciate the time you all spent to add links, and diagrams etc. A small word to FBB about the SDL, my 355 a few years back had a SDL with a dead cold engine, which was solved when I replaced the TC that only gave 10% of the voltage. (when heated with a torch, the voltage output increased , but it was only from (if I remember correctly) 0.05V to 0.2V when I stopped heating the tip. The other TC gave a normal range of 0.5V to 2V, 10 times more. Both values under any threshold value to trigger a SDL normally. So I believe the difference in voltage was considered a difference in temperature by the Motronic, as the SDL ecu's are not connected to each other in any other place and do not know what value the other one puts out. And as it seems the Motronic considers temp difference a harmful condition, it shows a SDL even with a dead cold engine, rightr after cranking. This is all assuming of course, but I know what caused the SDL on my 355, and all was solved with a new TC. Strange thing is that I used the 2 batteries-trick to simulate 1.5V volt TC output , but that did not help, making me initially conclude back then that the TC's were ok. Only when I removed the TC's for testing I found the fault. I understand that these are inconsistent findings, but they were real...must have been a loose wire on the 1.5V battery trick or something...
I had 15 minutes of time, so I thought, before I dive into the fusebox with relays etc tomorrow, I first have to be sure the replaced pumps are working or not. As I certainly do not trust that garage anymore, they might have bodged the job of replacing the pumps. So I removed the big plastic plate / tank guard, to expose the pump covers with the connections. On the driver's side I get 50 psi pressure on the valve on the injectorrail when I give that pump 12V. But on the passenger side, I still get no psi whatsoever, even if I hear the pump spinning. (I even tried to switch the + and - connections in case they rewired it wrongly. Pump still spinned, but no PSI on the pressure tester) Not sure if that is good or not... In the parts diagram the most logical point to check if fuel is being pumped into the line at all is the fuel filter, so I think that will be my (messy) starting point. And it looks like the SDL warning was not a false positive, that side not having enough pressure creating a lean situation etc...
Obviously not good. If the pump is spinning, either the pump impeller has disintigrated or you have a blockage (either at the pump pickup/exit or in the lines). How did you activate the pump? By turning the engine over or by putting 12 volts directly on the pump? Even though you can hear the pump running, I would still check the fuse and its holder for melted plastic. Also check the brown wire on pin I5 for heat stress. Image Unavailable, Please Login
The fuel filters on 550s can completely fill and block fuel flow from disintegrating rubber fuel pump holders.
@Qavion, the car is in my small (and narrow) garage, up on the 2 post lift I have. Which means I can't open the door far enough to get to the fuse box. Stupid situation , I know. So checking the fuse box for symptoms will have to wait until I get the car down again to push it back far enough to give the door some room. Will report on the findings later. But up on the lift, I was able to remove the bottom aero covers, and noticed that the fuel union connectors at the fuel filters were coroded, and without any wrench signs of being loosened for replacing of the fuel filters. So the fuel filters are still the old ones , and the garage that was supposed to repair /replace the fuel pumps and filters before delivering the car, simply did not replace those filters. Needless to say I do not trust them to do that properly if I would return the car for repair , so I will do that myself. So I ordered new filters, hope to be able to install them myself end of the week. Just have to figure out how the fuel unions screw out of the filters, forgot how it worked from when I replaced the filter on my 355....but that will not be rocket science... And I also ordered new(used) rigid fuel lines that run under the car (2 each side), as I do not like coroded fuel lines at all. And likely to be MoT unacceptable, even if that garage arranged a new Mot for the car the day before I picked it up.
I removed the fuel filter on the passenger side, and indeed it was an older filter. But putting 12V directly on that pump in the trunk, did not work: no fuel came out of the banjo. So there are 2 possibilities left: the fuel line is clogged, or the pump spins but is broken anyway. Or is assembled wrongly by this now proven fraudulent garage. Positive thing is that I can see the whole chassis now the plates are removed, and the car has never been in an accident. To investigate the fuel issue further, I will need to remove the fuel line from the cover to see if it is clogged. Is that possible without having to remove that bolt/nut on the cover, and in fact open the tank up (with a lot of gas flowing out) Or do I need to empty the tank (how?) and open the whole thing up to remove the cover+ pump?
There is a shrader valve on the front of the FI rail. It is not tire sized. It is the size that is used on A/C charging manifold, not the size that is on the car A/C inlet and outlet. Wire the good pump up and run a line off the fuel rail and drain down the tank. Then you can take the pumps out and give a good clean and inspection. There are threads here that tell you what to do. Someone (ferrarifixer dave? or cribbj? ) made a metal cover I think of some other better than factory parts for this. Its in those threads on rebuilding the pumps.
Sounds like a good idea. Hopefully the fuel lines and old pump are not too clogged to get fuel through. Having the old filter in place should help stop any debris getting to the new pump. I would still have a very large bucket under the fuel pump when you take it out.
Yes, I know that valve, (that is where I hooked the pressure gauge on).The driver side has 50psi pressure, so not clogged (at the moment...) I had not thought it would give that much flow to empty the tank in reasonable time.... So I will certainly do that! (and the bucket...) Back problems cause a hopefully not too long a pause in working on it, but I expect that at the end of the week I have drained the tank, and will post my findings. Superformance.co. sells a cover as well, but as these things including VAT and shipping set me back around 1000 usd, I hope the old ones are still good (they do not leak, so are not cracked, and visual inspection did not notice anything strange) Thanks so far!
A thought.... Maybe the corrugated fuel line that connects the pump to the cover has broken or come off the pump and the pump is just pumping fuel within the tank. Did the garage replace those fuel lines when they did the pumps, or maybe they reused the old lines. I remember when I had my pumps replaced, those corrugated lines had become quite rigid and not reusable. Those corrugated lines were the hardest part to find at the time! Image Unavailable, Please Login
Update. The schrader valve -trick worked, thanks FBB. It took me a few hours and 8 jerrycans to come to the point where I was convinced there could not be much fuel left. But completely draining was not necessary, as long as the covers where above the level. I removed the two lines from the cover, and no fuel came out. so the level was lower, great. I made a tool to remove the large ring nut on the covers (sounds easy, but took me 3 attempts and 3 hours to get it welded right in the proper hardened steel) And when the ring-nut came off, I moved the cover, that was only attached to some electric wires... The fuel line from the pump to the cover had come off! Jubilee clip was not moved far enough up the connection and it simply worked itself loose on pump pressure. Incredible that the garage had not checked proper installation of the line... So it was rather easy to remove the rest as well, to inspect and further clean it as it still had some debris in the bucket. So Avimax was right. the line had come off. (I am rather anxious tp let the pump turn on power outside of the tank, one spark and...) So assuming that the new pump is still good , the culprit is known. Question, there was only a fuel line from the pump to the cover, the return line from the cover to the bottom of the basket is missing. As is the white valve in the picture above Do I need that line + valve, or is fuel simply pouring out of the nozzle back down into the tank no problem? Or will not having that valve cause pressure loss in the system after shutting down, resulting in hard starting afterwards? Are those valves easy to find other than at Ferrari prices? It will have to be fuel resistant. Should it be on the supply or return line? Thanks for your ideas!
I’m glad it turned out to be something easy. As far as the missing line and valve, I don’t know if it is absolutely necessary, but I always assume everything I find has a purpose. It may not be critical, but it’s there for a reason. You should ask the shop that replaced the pumps why they removed those return hoses and valves and if they don’t still have them, they should supply you with replacements.
In a normal situationyou would have been right, but the shop that sold me the car and did the repair does not answer my phone calls, nor reacts to whatsapp messages. They know perfectly clear they made a mess of the car , but they prefer to duck then to react the right way : admitting they scr*wed up, and help/compensate.. So even if they still have the valves, I do not know a way to get the parts from them without a court order. But that would certainly spoil any joy I still have left of buying the car, so I prefer to repair the problems myself. (a court order by the way would most likely say that the garage has 3 attempts to solve a problem themselves, and they may take a year for that. I already asked around...) Are there any other 550 owners that have experience with this new setup without internal return line+valve? There are universal valves for sale, but they all are rated for low pressure. Would that work / be safe/ (pressure on return is of course lower than the 50 psi the supply line has, because of the use of fuel in the system, while lines are still the same diameter)
Total understand about wanting to take care of it yourself. Eurospares shows the complete return line with valve as p/n 177353 for cars after assy# 28081. For cars before assy# 28081, they show the valve by itself, p/n 166540 for 14.50 GBP. I'm sure at your friendly local Ferrari dealer, it's a crazy price. I don't know what the difference is between early cars and later cars, but the OEM valve for 14.50 GBP seems reasonable, if available.
Yes, the valve alone list price is cheap, but not available unfortunately ( I order my parts from both Eurospares and Maranello parts, as well as superformance., but nobody has that valve) But maybe an universal one is good as well, as long as I know what the pressure is (opening as well as max pressure)
Ok, I wrote a little tutorial on the pump and how to remove it, renew some lines and reinstall it, it is in the 456/550/575 section. I have not connected the new fuel filters yet, so not really sure if all is well now with the fuel pressure, but I have very good hopes as its problem was clear.
