aspen5

Hey guys, after a long time sitting I've started to refresh my Tercel project. I went through the normal procedures when starting a car that's been sitting for a while. Now I'm having problems getting any crank signal to the Haltech RA10 to enable the M&W to fire. It's running a coil on plug setup with GSX-R 750 coils to the M&W Drag 14 CDI digi ignition box getting converted signal from the Haltech RA10 from the distributor and through an E6X stand alone. I pulled the entire engine wiring harness and checked for any broken connections between the boxes and nothing. There is continuity through all the wiring. The rotor and buttons inside of the distributor are not worn to the point that it wouldn't get a signal off of the pickup. The M&W is getting power on start up but nothing during cranking. If you have nay ideas any help would be apreciated!

Joe

Fabrik8

Nevermind, I think I see what you're saying. First of all, the rotor and button shouldn't have anything to do with the crank position sensor in the distributor that the RA10 is picking up. The rotor and buttons only matter if you're actually using spark plugs and spark plug wires from the distributor. The cam and crank angle sensors (whichever are integrated into the distributor) are completely separate and sense the rotating distributor shaft or some other distributor target. It's possible that the crank angle sensor has somehow been damaged though. It's a variable reluctance sensor, so normally they're pretty reliable but can still have failures. It's really just a coil of wire and a magnetic pole piece, and the coil twangs (and outputs a one-period triangular signal) when the magnetic field at the pole piece is disturbed by a ferrous target. So unless the coil breaks internally, gets too hot and melts the coil insulation, gets moved too far away from the target, or gets bashed by the target, not much can go wrong. There aren't any of the extra problems that digital hall-effect crank angle sensors can have.


I guess I'm wondering how you're determining that the RA10 isn't getting a signal from the crank angle sensor...?

aspen5

Fabrik thanks for the response! I took the distributor apart and the point for the cam sensor seemed to be fine to include the said coil. I'm not sure if there are clearance specs for that, either way by testing for voltage signal under cranking and static states the RA10 wasn't getting anything through the signal wires. I pulled the wiring harness and checked the continuity from the cam sensor plug to the RA10 plug and got the signal with a voltmeter, but couldn't get it with battery power. There weren't any breaks to speak of in the wiring either. The wiring sheet that I have for the RA10 says it is supposed to recieve 12V signal so I'm not sure why there was continuity outside of the car using 12V. I guess it's still an ASSumption that the RA10 is the culprit. I'm just trying to break it down to the basics as far as my understanding goes, which is also very basic lol Thanks again bro.

Fabrik8

You can't check continuity on a circuit that has power applied, so throw out any assumptions you've made because of that. You can only test resistance/continuity on circuits without power. I'm not sure if that's what you were actually doing though, so take that for what it's worth. The signal coming from the crank angle sensor is not a DC voltage, it would be a waveform that has some peak to peak voltage value. That waveform voltage actually changes with engine RPM though, because the faster the target interrupts the magnetic field, the bigger the voltage twang from the sensor coil. I won't bore you with the details, they're not important.


If the stock crank angle sensor hasn't moved from the stock position, and the target hasn't moved, the spacing should be fine. I'm still not convinced that the sensor is working though, so I'd still caution you against blaming the RA10 yet.

I'm still having trouble interpreting how you were testing everything though, which is one of the problems with internet troubleshooting.

aspen5

lol I probably have this thing all bass ackwards in my head :P either way the testing was just to see if the RA10 was seeing any voltage at all during cranking. The "continuity" (only word I could think of at the time) tests were to see if the signal wires were complete from the cam sensor plug to the plug for the RA10. A very good point I never tested for a signal from the actual distributor <----*dumbass Thanks for the advice. I planned on re-wiring the harness at some point anyways to make sure that all the connections are still solid after the years, so what better time than now. I'll take the distributor out tomorrow pending time, and the weather and take a closer look. Thanks again lol something so simple jeebus *fingers crossed

Fabrik8

I'm assuming that you've checked all the DIP switch positions on the RA10? I've never used an RA10 before, but I found this: http://files.haltech.com/downloads/a...structions.pdf

Looks the same as any other VR sensor converter I've seen though.

Some other things that occurred to me:
Is the crank angle sensor only connected to the RA10? If it is, make sure one of the crank angle sensor wires is grounded. That didn't occur to me until I saw that PDF file.
Are you also using a cam position sensor with the RA10, and if so have you checked that sensor?

One other thing to remember: The sensor voltage (when measured with a voltmeter) is not going to be very high probably. The reason for that is the signal is zero volts and then a pulse, zero volts and then a pulse, etc. The multimeter will tend to average the waveform voltage, so even if the sensor pulses are 20V (random value I just made up), the multimeter might average that to a much smaller voltage because of all the dead space between pulses. All you can say with a multimeter is "OK, there's probably something happening" and other than that you'd have to find someone with an oscilloscope or a scope meter (a multimeter with some oscilloscope functionality built in).

aspen5

I'll need to find someone with an oscilloscope when I put the harness back in. I kind of figuered the signal wasn't going to be significant but I thought that I'de still be able to pick up some solid values. The RA10 and E6X is wired to read off of the cam sensor. I'm going to go ahead and take the distributor out tomorrow and inspect it further. I won't be able to get solid test results off of the cam sensor until I get the harness back in and get my hands on the wave sign meter I'm guessing. In retrospect I can't believe that I didn't think to test (or atleast attempt) the cam sensor lol thanks for waking up that sleeping part of my brain. This would explain the lack of signal which is yet to be confirmed to the RA10. Ground is in place as well. The cam sensor is also feeding to the E6X as well. I was guessing that the digital signal that was converted by the RA10 and fed to the E6X signaled the M&W when it needed to fire. I guess that's why I was thinking that there was a problem involving cam sensor/RA10 because the M&W was functioning fine statically but was not getting it's signal to fire during crank through the leads it was supposed to be getting them through. I'm really not great with wiring lol sorry for the lack of technical terms and know how I really apreciate the help. Either way no spark situation

Fabrik8

I'm just getting more confused as we go along.. LOL..

So I'm assuming that this setup worked at one point before the car sat for a long time?

aspen5

You got it, the setup was running fine. I put it into storage before last winter and decided to revive it for a trip to the track before the season ended but meh it's turning into a little bit of a PITA. The car was getting progressively harder and harder to start as the winter set in. I didn't think much of it at the time though.

Fabrik8

Maybe the sensor was dying. Well, whatever it is sounds like it was probably dying.