360 spider won't rev when rolling

Still going, difficult issue. Lack of power can only come from a number of factors, being wrong timing (valves or ignition), wrong fueling, or lack of compression.
I'd go about this systematically, you've already done a lot to cross off the list. I have asked this before, how did the fault occur, out of the blue or gradual?
Since fuel pressure, compression etc can be ruled out, it must be fuel metering or timing. Since the cat sensors are good, the MAFs replaced, and the rolling road indicated proper fuel metering, that to me leaves a timing issue. That can be general timing or valve timing (inlet timing can be retarded significantly without compression loss or valve interference and still perfect fuel metering, but with noticeable power decrease). General timing can be off because of camshaft timing sensing (phase sensor), also a shifted flywheel timing ring can cause problems, as recently happened with someone on a 456.
So I would look into those, see if the firing is correct and don't just check one side, check both individually for firing at TDC. And if it is not ignition timing, I would check the inlet camshafts for timing slippage - not impossible as there have been cases of bad variators on these, with at worst the threaded end breaking off at the camshaft.

EDIT: one other thing you might want to check is the control of the variators. They should not be energised at low revs, but if they are, or the variators are "on" for any other reason at lower revs (solenoid stuck or oil leakage) it will make the car sluggish.

 

Rustybits is one, and he did comment early on in this particular thread.


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He has the car running fine with this clutch switch disconnected, so it must be part of the problem. If the timing , valves or electronic was out the engine would not be running right

 

166&456 has some good and pragmatic recommendations. My only comment is the intake cams don't have a variator only exhaust cams have one.

Have you tried to compare obd2 data with switch open and closed, may give a clue.

For confidence: This is an internal combustion engine for crying out loud it's not a downed UFO. You, with possibly some guidance from someone with more expertise, can diagnose the problem.

Lastly you should have a copy of the workshop manual. Let me know if I can help with this.


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Not necessarily, could be falsely implicated.

As just one example: if the timing is off, and this switch does change the ignition timing, or variable exhaust timing bring it back into spec, may just be masking the real problem.


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Why don't you check the wiring diagram and trace the switch wire to identify the component it is connected to? You should then be able to work out what the switch's function is.

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I wasn't sure rifledriver was around here anymore???

 

I believe it's been traced back to the ecu, and what that thing does with it is the great mystery. I did some less than perfect tests with only obd2 data only at idle (see my prior post). What happens for real and with higher rpm etc...?


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Oops I should have read the rest of the thread . To me it seems that clutch switch is working the way it should (making contact when not pressed in, depending on how it is mounted that is most likely with a depressed pedal?) so the bypass of the switch to me does not sound like a proper fix. It is an important clue though. It is possible that the ECUs are running open loop when it is making contact and use a different fuel map.

 

Maybe we could conjure him up or something. He has a shop in Texas, maybe he would respond to an email with a link to this thread.


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Map may actually be correct with switch working. Like I said in a prior post may be masking another issue by compensating.

Two that my little grey cells can muster:

Unmetered air leak - compensated by reducing fuel trim.

Timing issue - compensated by changing timing advance.


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Also if this is a mapping issue, and the ecu is at fault a new pair may just fix it. Good to have a spare set anyway if u plan to keep the car.

Think about replacing them before doing more tests and possibly pulling stuff off.


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While my comment may not be helpful for the problem Roger is having, from a logical point of view I am amazed that for the <15 secs (x5) that the clutch is depressed, thereby activating the switch, that there will be so much critical information other than load being sent to the ECU. Therefore I was expecting that the car would run close to normal with the switch bypassed as he experienced. Even if fuel/ignition parameters changed with the clutch depressed it will only be for the short periods during gear changes.

I understand the connection of the switch to the ecu for the cruise control i.e. it is dis-engaged during shift changes.

Subscribed.

 

It makes no sense that the ECU would retard the timing to negative. If the ECU does this, wouldn't it stand to reason that the ECU is faulty?

 

sorry I think in Fahrenheit. that's 175f. what's the ambient temp by you? should be ok. coolant temp sensor impedance graph in WSM only goes to 130f I assume after that temp wont make a difference.

 

Normally ignition timing is just prior to tdc at tickover and it is advanced as the revs increase. As the engine speeds up the time available for combustion decreases.
I put an obd tester on my 430f1 and while not the same setup , i have a few readings .
At initial start it was giving -1.3 deg, then went to 11 deg @1300 revs. (shows as negative deg when started)
As it ticked over and warmed up it dropped to 1100 revs and 9 deg
Then 950 revs and 7.5 deg.
If i blip the throttle it goes to 30 deg and drops back to 7.5 deg.
Holding the revs at 2700 gives 22 deg

It makes sense that when you stamp on the throttle it gives a fuel increase initially so it will need a longer time to burn until it gets the required air, hence the timing is further away from tdc. See if the above helps anyway as they are similar engines

 

Roger is this still true?

 

raining here, will be clear later today. I will try get some data to share.