Dear F-Chat friends, I have a 1995 F512M (Euro) that I have had for about 4 years now and since I have had it, there seems to be a constant issue I just cant get my head round. My dealer says its normal, but it just doesnt feel right to me. I also had a 512TR before for about 5 years and never had this kind of issue. So the issue I face comes up when I start the car up after a few days of it sitting (the longer it sits the worse the startup). When I come to crank the car up, the engine would barely start to turn but its like it is trying to fire up (after releasing the starter motor - i.e. on its own fire) and it would maybe do one or two small turns and shut off. On a second start it may do the same but slightly longer but barely turning and cant keep it going to rev higher and idle. On a third it would start up and the revs would pick up a burst to say 1500 (higher than normal) for the initial fire and then idle normally. If I am lucky (usually if it sat for a shorter period) it would fire up after the second try - but usually still taking a few slow turns on its own fire till it picks up steam. My initial suspicion was check valve - but I had recently replaced the original bosch fuel pumps (which I believe have an internal check valve). Second suspect was fuel regulator, so replaced both with new ones. No fuel leaks visible anywhere in the lines. My injectors are original to the car and were serviced by bosch recently. wondering if this is something “normal” or should I be looking through things for issues? I am inclined to just change out the injectors, but in struggling to find new ones of the original bosch units. To note: car has had fresh and regular servicing, timing belt change is around a year old now, had new crankcase sensor and camshaft sensors in. No melting or any issues with the fusebox. Coils are working fine. one issue that crops up randomly and infrequently (resolves itself spontaneously too) is when I would be driving the car and revs go up to say 4k rpm (partial or WOT) it would behave like its hit the rev limiter (like a cutoff) at like 4k rpm. Not sure if this is related, but thought I would share. Appreciate any help or guidance from you guys as I am hitting walls with my dealer and other mechanics telling me its all fine, when it doesnt seem so to me.
I wouldn't say that 1500 RPM is unusually high for a cold start-up idle if the ambient temp is fairly low, but what you report is certainly not "normal" behavior. The two banks are so independent that you must have some sort of upstream problem that affects both banks (otherwise the engine should fire up on the "good" bank and at least run even if at lowish RPM). I know it's hugely frustrating when the manufacturer's service people can't seem to fix it, but it won't be easy your telling them how to fix it . Based on your description of the symptom, it sounds to me like the fuel pumps are running correctly during starter motor cranking (so the fuel pressure builds and the engine fires up), but then, when you release the key to run, the fuel pumps shut off and the fuel pressure starts to fall (so the engine will run for just a very short while). Consequently, it sounds to me like they/you should: 1. Confirm/deny if +12V power is reaching the fuel pumps during starter motor cranking and during that period after you release the key to run where it "would maybe do one or two small turns and shut off". Alternatively, measuring the fuel pressure would tell you the same thing -- does it always stay at the correct value up to the point the engine stalls, or does it go to the correct value during starter motor cranking and then fall when you release the key to "run" and then the engine stalls when it gets too low? 2. If #1 is OK, I'd measure the duty cycle of the signal going to an injector to confirm/deny if it is reasonable during the cold cranking period and after you release the key to run. Good Hunting!
""""""one issue that crops up randomly and infrequently (resolves itself spontaneously too) is when I would be driving the car and revs go up to say 4k rpm (partial or WOT) it would behave like its hit the rev limiter (like a cutoff) at like 4k rpm. Not sure if this is related, but thought I would share.""""" Could this be a lazy tach ..basically you are truly hitting redline but the tach isn't displaying correctly.. check speed and gear and compare ..I don't have manual in front of me but look for max speed in each gear and compare to when you "hit" that wall Btw .. this happens to me Sent from my moto g power using Tapatalk
I cannot help in terms of diagnostic but my 512M, which I only use every 2/3 months (I turned it into an art car) gets started very easily . It is 100% stock (apart from the painting, obviously) and very well maintained. I am always surprised to see how strong it feels when I drive it. No issue whatsoever since I purchased it some 6 years ago.
Its not the tach for sure, as the RPMs are where they are supposed to be. The startup issue seems to happen only on cold starts. Im now suspecting maybe a vaccuum leak. Will run some tests. i had a valved exhaust fitted that uses a vaccuum like for the valve mechanism - could this be causing? Recently drove it and accelerated WOT in 4th gear from about 3k rpm. At about 5k rpm there was a slight hesitation and the check cyl 7-12 light came up for a split second and went away on its own and the car continued to accelerate. On subsequent runs this did not occur. i have a video of the startup to demonstrate the startup issue, but the file is too large. May need to post it on youtube and share link. Will service my injectors too. Jack - not surprised that it runs well. Thats how I recall my 512TR being. This has just got me scratching my head, particularly as my dealer keeps telling me its normal and refuses to recognise an issue.
I am not familiar with the testarossa but this sounds similar to an issue I had with my 400i... In my case this was related to the thermo-time switch (triggers the cold start injectors) that was flooding the engine. Maybe you could try to disconnect one cold start injector and see if one of the cylinder banks will fire up? In my case disconnecting only one bank did the trick. If this improves the situation you know the thermo switch is your problem...
