| Author | Message | ||
| Jeff Edison (Euro308guy)
Member Username: Euro308guy Post Number: 315 Registered: 7-2002 |
I've considered adding resistor(s), to the sensor input line. Since this sensor is most likely 15 years old and the problem seems to be getting worse, I'm starting with a new sensor. After I know the sensor is definatley not the cause, then, I'll consider modfying the signal. | ||
| John_Miles (John_miles)
Junior Member Username: John_miles Post Number: 51 Registered: 7-2001 |
With a hot engine, too many volts put out by the crank trigger sensor. I certainly wouldn't tackle this by reducing the number of teeth on the wheel! That will only reduce the frequency of pulses received by the ignition, not their amplitude. A series/parallel resistor combination would likely be a better approach. If this is a basic inductive pickup with no active components in it, you might look for a couple of resistors with a value of 100 ohms each (or 4-5X the DC resistance of the sensor winding, whichever is higher). Put the two resistors in series with one end of the pair grounded, and the sensor feeding the other end. Then connect the ignition pickup lead to the junction of the two resistors. Assuming infinite (or at least very high) DC input resistance at the ignition module, this will drop the voltage it sees by about half. Moving the sensor farther from the trigger wheel will have the same effect, but fooling with resistor values (even to the extent of using a potentiometer) may be easier. | ||
| Jeff Edison (Euro308guy)
Member Username: Euro308guy Post Number: 314 Registered: 7-2002 |
Billy Bob, Thanks for the post! I started by confirming no spark. It is certainly a fact. Bob Norwood himself used to own this car and is aquainted with the problem. He has diagnosed it via Motec, (as did I for my first Motec diagnostic experience, it was cool!). The Motec shows bad sensor signal. Bob has actually scoped the problem. With a hot engine, too many volts put out by the crank trigger sensor. In the "sensor set-up" screen on the Motec the Ferrari sensors are listed an a compatable option, as is the 60-2 tooth wheel. Bob says it doesn't respond well with this combination, even though the Motec makes itself available to it. Bob should know, he's one of the countries largest Motec dealers and uses it on all his race cars. I'm going to replace this sensor first before considering altering the voltage via a resistor inline, until the next engine pull. I'll keep everyone posted. | ||
| billy bob (Fatbillybob)
Junior Member Username: Fatbillybob Post Number: 245 Registered: 8-2002 |
Jeff, What makes you think the motec can't handle the stock Ferrari wheel with 60 teeth? I am 90% sure the motec should ahndle this. Did Norwood tell you this was the prob? Did he explain why this is a problem. I do not understand why less teeth would be better? Also how much of the old stock stuff do you have? Have you really been though your diagnosis like gas or spark first then isolating your systems? If you have any old Ferrari sensors running and wire harness like MAP sensors and coolant sensors you could have a mixed Ferrari/Motec nightmare | ||
| Jeff Edison (Euro308guy)
Member Username: Euro308guy Post Number: 312 Registered: 7-2002 |
I looked this up in my Mx manual. I saw the TWO sensors as you say. However, I believe mine has just one. You've got to remember, I have no Motronic ECU's. Mine is a MOTEC controlled car. I'm going to pull the hall effect cam sensor tomorrow and have it tested at an electronic shop. I think it COULD be a bad sensor. Pulling the trigger wheel has become a Non-option  | ||
| Tom Bakowsky (Tbakowsky)
Member Username: Tbakowsky Post Number: 312 Registered: 9-2002 |
There are 2 sensors on that crank. One for the left side computer and one for the right side computer. Somtimes if you spary cold water on these sensors when the engine is hot it can make them work. Then you know 100% that one of the sensors is crapping out. I would give that a try. I realize what a pain in the ass it would be to do but, they are a heck of a lot easier to cahnge then the crank pully!! | ||
| Jeff Edison (Euro308guy)
Member Username: Euro308guy Post Number: 307 Registered: 7-2002 |
Thanks, Tom. I decide earlier today to try to avoid removing or regrinding the crank trigger wheel. I deepend the null spot on the trigger wheel and reasoned this might be a good first bandaid to throw at it blind. I ground it down, (quite cleanly I must say), with a dremel and grinding wheel. I did it in about 15 minutes. I had the same problem again later after driving the car home from a ride. I hooked up my laptop to the MoTeC and it said "bad sync status". I think I'll replace the sensors first, before modifying the trigger wheel. I understand the hall effect sensor normally quits first. What do you think? | ||
| Tom Bakowsky (Tbakowsky)
Member Username: Tbakowsky Post Number: 310 Registered: 9-2002 |
I'm 100% positive on this one. No you can not remove the pully in the car. UNLESS..you want to try and shift the engine and tranamission assembly back a few inches to get the extra clearance. I have never tried to do this before, but it could be done. You maybe able to modify the pully in the car as you can see the teeth on the reluctor ring. But how you would do this I don't know. Maybe with a carbide tipped grinding bit on a straight air grinder might work. | ||
| Jeff Edison (Euro308guy)
Member Username: Euro308guy Post Number: 306 Registered: 7-2002 |
Thanks Tom. I'd wait except the car recently had a major. It was done by Norwood's less than 6000 miles ago. I'm frustrated at the car not starting EVERY TIME I want it to start. You are SURE this can't be removed with the engine in the car? If this is indeed the case, I will have to wait, or, I wonder if it would be possible to remove the evtra teeth on the wheel with it still attached to the pulley? Any ideas here? | ||
| Tom Bakowsky (Tbakowsky)
Member Username: Tbakowsky Post Number: 309 Registered: 9-2002 |
Jeff. You do not need a puller to remove the crank pully. Just a slight pull with a screw driver is all that should be needed. I have had engines out of 348's lots of times and have tried to do somethings in the car that is just not possiable to do with the engine in the car. The best thing to do like Martain said is to wait until the timing belts need to be changed, and then have the modification done. | ||
| Martin - Cavallino Motors (Miami348ts)
Advanced Member Username: Miami348ts Post Number: 4271 Registered: 5-2001 |
why not wait and do it when you pull the engine for the next major? | ||
| Jeff Edison (Euro308guy)
Member Username: Euro308guy Post Number: 305 Registered: 7-2002 |
Thanks guys. Before proceeding any further, I'm going to make a call to Norwoods. I'm sure James can shead some light also. I'll decide what happens and then post the forum again. Pete: Have you done this? It sounds from your concerns that you have specific experience here? A puller to remove the trigger wheel? I wasn't prepared for that. Are you sure the bolt won't clear the frame? If so, there's no reason for me to proceed. Tom: Same questions. Have you ever removed yours? The space between the pulleys and the cross frame is TIGHT. Fortunately, the tool I made to access this bolt seems to work. I'll let you all know what happens. Thanks again. | ||
| Tom Bakowsky (Tbakowsky)
Member Username: Tbakowsky Post Number: 307 Registered: 9-2002 |
Jeff. To remove the crank pully with the engine in the car will be an exercise in frustration. The pully will not slide off the crank shaft far enough to clear because it will hit the frame. You could try to slide the engine and trans assembly back but this will require alot of extra work. I have never tried to slide an engine in a 348 car. I you really want to try.. Remove the little sheild under the clutch housing at the rear of the transmisson. You should be able to see the ring gear for the starter. Using a large screw driver or pry bar, hold it against a tooth on the ring gear and slowly trun the engine until it wedges against the trans housing.(have a friend help with this). With the ring gear locked try to undo the front pully bolt by applying gradual pressure to the tool. Be very careful not to put to much strain on the transcase, it could cause damage. This method is not recomended, but in this case you could give it a try. | ||
| pete (Pete_peter)
New member Username: Pete_peter Post Number: 22 Registered: 12-2002 |
couple of concerns ...even if you get the bolt off, i doubt you have the room to slide it off, you'll also need a puller to get it off. are you sure there's room to clear the neck of the pulley from the crank shaft end and frame ? you may want to take some measurements you may be spinning your wheels | ||
| Jeff Edison (Euro308guy)
Member Username: Euro308guy Post Number: 304 Registered: 7-2002 |
Sorry, Tom for being unclear. I'm removing the crank wheel sensor to have it machined, (from 60 teeth to a lessor #). Once it is reinstalled, I'll reprogram the MoTeC to comply. You see this car has always had a very unusual problem. Since it was upgraded to MoTeC, once it gets warm, during regular driving, and after it has been shut down for 10-20 minutes, it refuses to start, until it has cooled back off for 20-30 minutes. This problem has been diagnosed and re-diagnosed. It is for sure that the MoTeC does not perform well in this unique situation in this car. A lessor # of teeth will fix the problem. It will show, "sync sensor status: not ok". This has been scoped by Bob Norwood, himself. He has verified that this IS the cause. This was one of his earlier 348 conversions so he didn't include a different wheel at the time of the upgrade, now he does. The problem has not been previously fixed because it is a rare occurence, noone else cared enough to make it 100% perfect ALL the time. I WILL! I cut off a socket, (36mm), and ground the sides flat for grip. I can access the bolt, just haven't been able to break it loose. Suggestions? Sorry to be so long winded. Jeff | ||
| Tom Bakowsky (Tbakowsky)
Member Username: Tbakowsky Post Number: 306 Registered: 9-2002 |
Why are you removing the pully? Even if you get it loose you will not be able to remove it from the car. Are you trying to change the front crank seal? If you are it's an engine out job. | ||
| Jeff Edison (Euro308guy)
Member Username: Euro308guy Post Number: 302 Registered: 7-2002 |
No the engine is IN the car. No way to get an air wrench on it. This space is TIGHT! | ||
| Tom Bakowsky (Tbakowsky)
Member Username: Tbakowsky Post Number: 304 Registered: 9-2002 |
You have the engine out of the car right? You can keep the engine from turning by removing the the small sheild under the clutch housing and using a prypar or long heavy duty screw driver to hold the ring gear. However this is not recommended. The best way like Pete said is to use a 1/2 inch air impact wrench. The thread is not a reverse type. Just undo it like you would anyother fastener. | ||
| pete (Pete_peter)
New member Username: Pete_peter Post Number: 21 Registered: 12-2002 |
you need to use an air impact | ||
| Paul Hill (348paul)
Junior Member Username: 348paul Post Number: 213 Registered: 12-2002 |
Jeff, In the manual it states a torque of 196 Nm which is pretty damn tight!! Not 100% sure on the other questions, so will leave it to those who know!  | ||
| Jeff Edison (Euro308guy)
Member Username: Euro308guy Post Number: 301 Registered: 7-2002 |
How tight is this thing? I can't seem to break loose the securing bolt, (36mm). Is it a reverse thread? Also, what is the best way to "lock" the engine in place? Thanks in advance. |