Need help with spb no start issue
09-11-2018, 02:00 AM
#1
Drifting
Thread Starter
Need help with spb no start issue
*** SOLVED *** See Post #15
Need some debug help...
SPB cranks, no fire ... however let me explain further.
My first DE with it a year ago, I backed it out of my space and it died as I was putting in first and trying to pull away.
Would not retire... but cranked ok
Put it on a charger and it fired up 30min later.
I continued to charge it all weekend but figured battery was toast so I got a new one Wet Cell Acid .... 16CLB I think.
Worked fine for my club race and 6 months later she fired up coming out of the trailer. Ran 2 sessions on Friday, 3rd session would crank, no fire. Doing some debug, I realized I left my marker lights on. Tried charging, no luck, tried jump starting from my cayenne, no luck. On a whim I decided to disconnect the battery and attempted to start through the jumper cables. Slowly cranked but on about the third revolution she fired up. Remove cables, still ran (alt is putting out juice ~14.2v) Put battery back on, still ran.
Killed it, tried to refire, crank but no start.
Went home charged up the old battery, that one was dead. Bought a new gel cel, played chemist, charged it up, same story crank but no fire.
If I could get enough juice from cables, I could slow crank and fire, did this a couple times.
Went and bought an AGM battery. Same song and dance.
Looks like my kill switch is a 4 pole, 2 big with a junction box and hefty cables while the other two are 16 gauge (ie small)
I’m trying to figure out why the car would fire if all the batteries were bypassed but would not start with battery whether jumped or not.
It rained all today at track, so I didn’t have debug opportunity.
I have a durametruc I could hook to the dme, but not sure what to look for.
Tonite I bypassed kill switch, didn’t matter.
battery only 12.8v, cranking gives me 10.6v, 40psi of oil pressure, but no fire.
Was not able to do jump start tests as I was in my trailer
mike
Need some debug help...
SPB cranks, no fire ... however let me explain further.
My first DE with it a year ago, I backed it out of my space and it died as I was putting in first and trying to pull away.
Would not retire... but cranked ok
Put it on a charger and it fired up 30min later.
I continued to charge it all weekend but figured battery was toast so I got a new one Wet Cell Acid .... 16CLB I think.
Worked fine for my club race and 6 months later she fired up coming out of the trailer. Ran 2 sessions on Friday, 3rd session would crank, no fire. Doing some debug, I realized I left my marker lights on. Tried charging, no luck, tried jump starting from my cayenne, no luck. On a whim I decided to disconnect the battery and attempted to start through the jumper cables. Slowly cranked but on about the third revolution she fired up. Remove cables, still ran (alt is putting out juice ~14.2v) Put battery back on, still ran.
Killed it, tried to refire, crank but no start.
Went home charged up the old battery, that one was dead. Bought a new gel cel, played chemist, charged it up, same story crank but no fire.
If I could get enough juice from cables, I could slow crank and fire, did this a couple times.
Went and bought an AGM battery. Same song and dance.
Looks like my kill switch is a 4 pole, 2 big with a junction box and hefty cables while the other two are 16 gauge (ie small)
I’m trying to figure out why the car would fire if all the batteries were bypassed but would not start with battery whether jumped or not.
It rained all today at track, so I didn’t have debug opportunity.
I have a durametruc I could hook to the dme, but not sure what to look for.
Tonite I bypassed kill switch, didn’t matter.
battery only 12.8v, cranking gives me 10.6v, 40psi of oil pressure, but no fire.
Was not able to do jump start tests as I was in my trailer
mike
Last edited by txhokie4life; 01-23-2019 at 12:49 PM.
09-11-2018, 02:06 PM
#3
Drifting
Thread Starter
its a very strong crank -- enough to build 40psi of oil pressure.
When I bypass the battery -- it barely cranks at all -- theres only so much I can get through the jumper cables -- but it fires.
it's like whirrrrr, pause, whirrrrr pause, whirrrrr --- FIRE. Then it idles just fine for as long as I let it.
Take the cables off its fine, put the battery back on, just don't turn it off and try to restart.
with the battery in the system -- its cranking full speed -- but that's it.
Mike
When I bypass the battery -- it barely cranks at all -- theres only so much I can get through the jumper cables -- but it fires.
it's like whirrrrr, pause, whirrrrr pause, whirrrrr --- FIRE. Then it idles just fine for as long as I let it.
Take the cables off its fine, put the battery back on, just don't turn it off and try to restart.
with the battery in the system -- its cranking full speed -- but that's it.
Mike
09-11-2018, 04:08 PM
#5
Nordschleife Master
Do you have just a single positive battery cable, or you have a cable and multiple positive wires attached to the battery connector? I'm grabbing at straws here, but if multiple wires, could one be grounding out when you connect to the battery?
09-11-2018, 05:55 PM
#6
Drifting
Thread Starter
I bypassed the kill switch -- I still have the ignition (all power) switch, although I cannot crank the starter without that switch "on".
It does run to some sort of larger relay ( I think that's what that round can is).
I haven't been able to figure an easy way to tell if the ECU us getting power -- HOWEVER -- I did connect to it via the OBDII and the duramatic. I could querry ECU information.
I tried asking for live data -- but I wasn't getting RPM signal -- in fact I don't think I was getting RPM indicated on the dash either when cranking -- but that might not be enough RPM to register.
BTW I am an electrical engineer and DEBUG engineer by trade -- so this is being quite perplexive. I haven't had a chance to do more than first or second level triage.
The real confusing thing is -- no setup differences -- why can the jumper cables fire the car -- as long as its enough juice to trigger the starter solenoid -- even if its a really slowwwww crankkkkk,
but only if the battery is out of the loop. My theory is it's an elevated voltage (but lower amperage), and somehow the battery (note I've used 3), averages out the voltage to a slightly lower level and
thus won't allow it to power something (ECU) as there is enough voltage drop some where (or (slightly) bad reference ground).
I have two wires connecting the battery -- One hot, straight to the kill switch then a junction box (now just the junction box), and one ground -- to the normal battery chassis ground.
thanks,
Mike
When I jump it -- I clamp onto the battery terminal, and the chassis ground where the battery cable connects to.
Mike
09-13-2018, 09:15 AM
#7
I would check to see what the voltage drop is in both the positive and negative cables. This is challenging because you need long lead wires for the voltmeter. Disconnect the injectors to keep the car from starting. Get some friends to help you. Put one of the voltmeter leads directly on the battery post and the other directly on the bolt attaching the cable to the starter. Crank the starter for 10-15 seconds. You should measure a few tenths drop (ideally). Do the same on the negative side. I expect that you will find a bad connection, possible one of the crimps in the cables.
I made a lot of money fixing these kinds of problems on the early Audi diesels.
I made a lot of money fixing these kinds of problems on the early Audi diesels.
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09-13-2018, 01:13 PM
#8
Drifting
Thread Starter
I would check to see what the voltage drop is in both the positive and negative cables. This is challenging because you need long lead wires for the voltmeter. Disconnect the injectors to keep the car from starting. Get some friends to help you. Put one of the voltmeter leads directly on the battery post and the other directly on the bolt attaching the cable to the starter. Crank the starter for 10-15 seconds. You should measure a few tenths drop (ideally). Do the same on the negative side. I expect that you will find a bad connection, possible one of the crimps in the cables.
I made a lot of money fixing these kinds of problems on the early Audi diesels.
I made a lot of money fixing these kinds of problems on the early Audi diesels.
I'm suspecting something that allows the starter to get enough voltage, but the ECU or something isn't getting enough voltage -- and yes voltage drop can be on the header or footer of the circuit.
I just solved a ground problem on a buddies Spec944 he's been battling for 1.5 years.
The starting with the jumper cables might have been from the ground post, and not the battery terminal (I can't remember).
What is confusing -- is how can the jump work, but only when the battery is out of the loop -- unless the battery acts like a regulator on the voltage, lowering the jump voltage.
This needs some more diligent debug which wasn't available in the paddock and trailer.
Mike
09-13-2018, 07:22 PM
#9
This is the normal behavior of a failing and/or failed crankshaft position sensor.
I replace these around 10000 track miles and new builds get a new one.
It is about the only thing that allows cranking but not starting (unless the start relay has been bypassed).
Chris Cervelli
Cervelli Technical Service
I replace these around 10000 track miles and new builds get a new one.
It is about the only thing that allows cranking but not starting (unless the start relay has been bypassed).
Chris Cervelli
Cervelli Technical Service
09-14-2018, 02:31 AM
#10
Drifting
Thread Starter
This is the normal behavior of a failing and/or failed crankshaft position sensor.
I replace these around 10000 track miles and new builds get a new one.
It is about the only thing that allows cranking but not starting (unless the start relay has been bypassed).
Chris Cervelli
Cervelli Technical Service
I replace these around 10000 track miles and new builds get a new one.
It is about the only thing that allows cranking but not starting (unless the start relay has been bypassed).
Chris Cervelli
Cervelli Technical Service
i’ll order one, good to have a backup just in case
not sure if the start relay has been bypassed, there’s not to many relays left in the trunk.
why would it start if jumped without battery?
mike
09-20-2018, 12:26 AM
#12
Drifting
Thread Starter
Hauled it to a garage tonight I’ve bartered to share.
will dig into it this weekenf.
have to solve or my first trip to Hallets in the chopping block.
mike
will dig into it this weekenf.
have to solve or my first trip to Hallets in the chopping block.
mike
09-23-2018, 11:47 PM
#13
Drifting
Thread Starter
For push to start cars...
where does the rfid key pill go?
does dme control fuel pump or just furl injectors?
how does immob communicate with dme ?
mike
01-20-2019, 07:01 PM
#14
Drifting
Thread Starter
4 months later still fighting this problem.
what is the bare minimum that allows boxster to fire?
i shipped off dme/immob/key ... tested good, removed the immob req (illegal, but I wanted to take that out of the equation)
Got dme back, still no joy, dme does work as I tested it in I second boxster I bought as test mule.
i have no fuel pump gnd signal
no fuel injector signal at fuel injector
no spark signal at coil pack
i have 5v and 12v at maf.
i do not have a gnd signal to engage starter on the wire that would engage the starter relay
but on this car it’s push to start, so the relay is hard wired to gnd and relay fires and starter
engages.
i have a good CPS signal
wgats the bare minimum needed dme needs to want to start the car?
running out of ideas.
thx,
mike
01-23-2019, 12:48 PM
#15
Drifting
Thread Starter
*** SOLVED ***
The rain, the battery running down, battery cables, kill switches, fuses, relays, DME, Immobilizer, Key RFID, etc
None of that had anything to do with it
Shortly after I bought the car
I installed a traqmate system, including a traqmate USB to control the cameras and data acquisition.
That system had been in the car for nearly a year prior including 2 or 3 event weekends with no symptoms whatsoever.
There was a pin on the traqmate usb labeled 5v with the input analog pins. The documentation. Is poor, so I hooked up 5v off the obdii port after having found you can get 5v off of there (I don't remember how that was determined, probably internet)
I eventually had to buy a street car to have a known good reference. She showed up late last week and was keen to success.
After checking things back and forth between the street car and the Spec Boxster, including triple checking the DME.
I decided some input to the DME must be wrong and is causing the DME not to let the car start.
So I wrote out all 88 pins and made a chart and one by one probed each signal in the street car, and then did the same in the spec boxster.
After probing all the signals between the street car and spb I noticed only a couple differences, one was the software voltage pin which only
connects to the obdii port.
Street car was 0v, spb 5v.Also the durametric could talk to both dmes, but on the spb, all live data was defaults and voltage was 0v, regardless of the DME,
while on the street car with both DMEs I got live data.
I went home and thought about where the 5v could have come from, and I remembered the traqmate usb had a 5v pin.
I also remember sourcing that 5v from the OBDII connector as that is what I had found online to do. My spidy senses
were tingling -- was I on to something?
About midnight last night, I found some documentation online on the old traqmate system. It wasn't very good, but I could see a photo of the pins labeled on the USB box
and blew up the picture. , It wasn't clear, but it looked like 5v was an output
Not an input!!! I had figured at the time that the 5v was needed for the analog data acquisition, not the other way around. Surely it couldn't be that simple.
After a sleepless night
I ran out to the shop this morning, unconnected the traqmate usb
And she fired right up
Motherf@cker!!!
I think the 5v put the dme into some sort of program mode or something, disabling its ability to start the car.
Why did jumping it work without battery?
I think once you got 14v, the 5v wasn't high enough to put it in the program mode...
I also think that once you get running, the DME just does its thing -- OR, the Boxster's alternator put out 14v, and once again
the 5v input was read as a low, not an assert.
Further complicating the matter was the small fuse box that was added for accessories that I had tapped off of for the traqmate 12v hookup
is janky, and I don't think it has a good internal connection. That's getting yanked and a new, and more accessible unit will be installed.
Just diabolical....
Now I have to put it all back together and get my medical done and sign up for NOLA.
Thank you very much to all who supported my efforts and responded to my posts -- especially Ahsai. If nothing else,
the moral support allowed me to just keep plodding along.
The rain, the battery running down, battery cables, kill switches, fuses, relays, DME, Immobilizer, Key RFID, etc
None of that had anything to do with it
Shortly after I bought the car
I installed a traqmate system, including a traqmate USB to control the cameras and data acquisition.
That system had been in the car for nearly a year prior including 2 or 3 event weekends with no symptoms whatsoever.
There was a pin on the traqmate usb labeled 5v with the input analog pins. The documentation. Is poor, so I hooked up 5v off the obdii port after having found you can get 5v off of there (I don't remember how that was determined, probably internet)
I eventually had to buy a street car to have a known good reference. She showed up late last week and was keen to success.
After checking things back and forth between the street car and the Spec Boxster, including triple checking the DME.
I decided some input to the DME must be wrong and is causing the DME not to let the car start.
So I wrote out all 88 pins and made a chart and one by one probed each signal in the street car, and then did the same in the spec boxster.
After probing all the signals between the street car and spb I noticed only a couple differences, one was the software voltage pin which only
connects to the obdii port.
Street car was 0v, spb 5v.Also the durametric could talk to both dmes, but on the spb, all live data was defaults and voltage was 0v, regardless of the DME,
while on the street car with both DMEs I got live data.
I went home and thought about where the 5v could have come from, and I remembered the traqmate usb had a 5v pin.
I also remember sourcing that 5v from the OBDII connector as that is what I had found online to do. My spidy senses
were tingling -- was I on to something?
About midnight last night, I found some documentation online on the old traqmate system. It wasn't very good, but I could see a photo of the pins labeled on the USB box
and blew up the picture. , It wasn't clear, but it looked like 5v was an output
Not an input!!! I had figured at the time that the 5v was needed for the analog data acquisition, not the other way around. Surely it couldn't be that simple.
After a sleepless night
I ran out to the shop this morning, unconnected the traqmate usb
And she fired right up
Motherf@cker!!!
I think the 5v put the dme into some sort of program mode or something, disabling its ability to start the car.
Why did jumping it work without battery?
I think once you got 14v, the 5v wasn't high enough to put it in the program mode...
I also think that once you get running, the DME just does its thing -- OR, the Boxster's alternator put out 14v, and once again
the 5v input was read as a low, not an assert.
Further complicating the matter was the small fuse box that was added for accessories that I had tapped off of for the traqmate 12v hookup
is janky, and I don't think it has a good internal connection. That's getting yanked and a new, and more accessible unit will be installed.
Just diabolical....
Now I have to put it all back together and get my medical done and sign up for NOLA.
Thank you very much to all who supported my efforts and responded to my posts -- especially Ahsai. If nothing else,
the moral support allowed me to just keep plodding along.
