No output from reference sensor - Page 2

soxnail · 10-26-2006, 07:24 PM

so you have the square wave in to the klr at pin 9 (with the klr installed) but flat 9v at pin 16 ?

mcmahonl · 10-26-2006, 07:31 PM

yes

soxnail · 10-26-2006, 07:37 PM

ok now lets try the limp mode pull the klr off and jump the pin 9 to 16. you will have to use a jumper of some type (piece of wire with pins on the end ?) when you do this put the scope on pin 9 see if the squre wave is still there or did it get pulled down (gnd) or up to 9+volt. If it still shows then go look at the dme pin one and see if the ignition signal shows there..

mcmahonl · 10-26-2006, 07:55 PM

I'm not sure what to make of this. This is pins 9 and 16 jumpered with the KLR unplugged. There is no trickle charger attached.

soxnail · 10-26-2006, 08:06 PM

looks like the dme may be pulling the line down. I don't figure you have any way of only disconecting one pin on the dme? because we need to look at the klr output with out the dme loading it. What we are trying to achive is to have the signal go from the dme to klr's pin 9 but not hav the pin 16 of the klr conected to any thing...let me think for a sec if you have a sugestion fire away but we need to unload the klr output line to check if its a klr output drive problem or a dme input pull down problem

mcmahonl · 10-26-2006, 08:11 PM

BTW the DME is newly rebuilt and I'll void my warranty if I open it. Let's think about it overnight ;-) I'll go catch the last few innings of the game

soxnail · 10-26-2006, 08:12 PM

sorry you have already eliminated the klr by jumping it looks like the dme is pulling the line down...

soxnail · 10-26-2006, 08:13 PM

ok later

soxnail · 10-26-2006, 10:21 PM

Just thinking some more with the help of a few adult bevrages

Looking at the schematic of the DME (wish I had a KLR one hint to any kindly soul in possesion of one) You can ohm the dme pin 32 to gnd it should be a couple of 100 k or more, if it is low like less than 1k then there is a short or partial short in the dme which could be the reason your trace looks pulled down, but some where back you said it was 9ish volts ?? btw how long did the new/rebuilt dme work before it went dead IF its dead

mcmahonl · 10-27-2006, 04:18 AM

When the car didn't start when I got the 1st rebuilt DME I sent it back right away. When I got the current DME the guys at the place I got it from swore they bench tested it. I've no evidence it ever worked other than their word. I don't know exactly how they tested it.

If we're pretty sure the DME is still the most likely culprit I'm happy to send it back (again). It's still under warranty as long as I don't open it.

soxnail · 10-27-2006, 07:37 AM

lets make sure we eliminate every thing else first. Do the resistance check from my last post first. I have superimposed the two traces (as the time base is the same) looks like the same signal but pulled down. There is only one connection to the klr out which is the dme ign in (pin 32). So if we ohm the circuit at pin 32 dme with the klr out but the dme in it will tell us if that line is pulled down. Some things to consider
1) first test with dme in if resistance is high then the problem is else where.
2) if resistance is low then unplug the dme and do test again to separate out the dme and the wire leading to it. if dme measures low R then it is (probably) the culprit.
3) if dme R is high then its the wire(best out come

)
If case 1. above then we are going to have to scratch our heads some more.
Luck

mcmahonl · 10-27-2006, 09:47 AM

OK, I think I understand what I need to test (and why) but I need a little help.

1.) How do I measure the resistance from pin 32 on the DME to ground without opening up the DME and with it still plugged in?
2.) To measure the resistance from pin 32 to ground without the DME plugged in I need to know which pin is ground or if the case is ground.

Does anyone have the pin descriptions for the DME like the one in this thread for the KLR?

Thanks

soxnail · 10-27-2006, 01:12 PM

you can test it at the klr pin 16 with the klr out gnd. is pin 10 or 11 on the klr also pin out for the dme...

mcmahonl · 10-27-2006, 04:16 PM

I'm getting an open circuit from pin 16 to pin 11 on the KLR plug

soxnail · 10-27-2006, 09:58 PM

with the dme pluged in?..and the out put from the klr is still squashed? this is weired...to reetarate ( I can't spell right now)

input to klr is a square wave.
output is around zero.
if you jump the klr 9 to 16 still zero.
dme pluged in klr out pin 16 to gnd (pin 11 or 10 ) is open.

1)check if you have good gnd. With the klr out the gnd is pin 20 so check 16 to 20 (sorry)
if also open then... heck I don't know, does not seem possible. Some where we are mis comunucating.
the signal is present at pin 9 and but not at 16 even with the klr out and a jumper, but the the resistance is open ?
not possible signal into open should still be there.. (no current sink). maybe we shopuld try doing this real time like over the pelican parts chat room ...

ae1969 · 08:43 AM

............slow down guys.

This system is relatively easy to troubleshoot. I am assuming it is JUST a no spark issue. You have confirmed injectors firing, fuel pump running etc. etc etc

Step 5. If you wanted to test if the KLR is bad all you had to do was jumper 9 to 16 as has been said on the KLR connector and the car should still run (without boost-control or knock-detection & ignition retard). No other tests needed. If it worked replace KLR.

Your problem is elsewhere.

I love the scope pics by the way...........

1. I am assuming the spark test was done at the center wire coming out of the coil. If you have spark look at distributor/wires.

2. I cant remember if you tested the ignition switch? I saw a coil test earlier. That you grounded it and had spark?

3. If the reference and speed sensor outputs while cranking at the DME harness are correct. You have a scope...........you should post some nice pics of them for future reference. Then we can assume the sensors, and wiring harness between sensors and dme are good.

4. Wiring from DME to coil. Pin 1 to coil. Make sure its not broken.

soxnail · 10-28-2006, 10:30 AM

"............slow down guys.

This system is relatively easy to troubleshoot. I am assuming it is JUST a no spark issue. You have confirmed injectors firing, fuel pump running etc. etc etc

Step 5. If you wanted to test if the KLR is bad all you had to do was jumper 9 to 16 as has been said on the KLR connector and the car should still run (without boost-control or knock-detection & ignition retard). No other tests needed. If it worked replace KLR.

Your problem is elsewhere.

I love the scope pics by the way...........

1. I am assuming the spark test was done at the center wire coming out of the coil. If you have spark look at distributor/wires.

2. I cant remember if you tested the ignition switch? I saw a coil test earlier. That you grounded it and had spark?

3. If the reference and speed sensor outputs while cranking at the DME harness are correct. You have a scope...........you should post some nice pics of them for future reference. Then we can assume the sensors, and wiring harness between sensors and dme are good.

4. Wiring from DME to coil. Pin 1 to coil. Make sure its not broken."

I love easy...but if you look at the thread in this post it boils down to there is a signal out from the dme as seen on the pin 9 of the klr so:
1) ref sensor ok
2) dme internal signal condition to convert it to a squre wave and out put to the klr ok
3) when you jump the pin 9 to 16 of the klr the signal gets squashed (looking at his scope traces)
4) input of the dme/wire from the klr as checked by resistence between pin 16 and gnd pin 20 is very high.
So whats pulling the signal down ?
enlighten me please ??

soxnail · 10-28-2006, 10:33 AM

sorry the post also contains ref and speed sensor pics I posted earlier

mcmahonl · 10-28-2006, 11:25 AM

I'm reading 14K from pin 16 to pin 20 on the KLR plug with the KLR out.
When I unplug the DME this becomes open.

I'm happy to open up another line of communication... chat room , IM or whatever let me know. Also, I'm very greatful for all the help so far.

soxnail · 10-28-2006, 11:47 AM

mcmahonl ok right now I am on kitchen duties breakfast

. let me finish and I will post again and you should get an e-mail alert. Then we can use the board chat room.
In the mean time 14k seems to be low, but it should only be a 650 micro amps draw at 9 volts (but thats dc). can you check if the car when the ignition sw is on and
1) Is there 10 to 12 volts steady on pin 16 of the klr (with klr in)
2) if not do you get it if the dme is unpluged.
3) if not try this test unplug the klr leave the dme in get a 9 volt battery or any other source of dc at that level put a 1 to 3 k resistance in line with it. feed the positive to the pin 16 f the klr plug (no klr) and gnd to pin 20. See if there is a drop i.e does the dme draw the voltage down. (trying to eliminate the ac coupled current draw if any)
All this means is that I am trying to find out if the dme draws more current at ac (car cranking and producing a square wave) versus straight dc. Let me know.