sublute Posted November 29, 2007 Author Share Posted November 29, 2007 Here is what I see. The low side of the coil 1 or 3 to gnd dips before the injector dips. I tried to get a photo, but was unsuccessful at getting a clear one. I drained the battery again cranking it.... That sounds similar to what I saw with the timing light. and it flashed pretty close in relation to where the B channels dips... I tried it on both injector 1 and 2 with the respective low coil side. similar results If the timing belt is on right, how can this be? the cam pulley can only go on one way, indexed. The wires and coil can really go on one way... unless you force things... I've gotta tighten the drive belts on the Loyale before I go to the Dr.... My wife is hauling a harpsichord to a gig this weekend... Quote Link to comment Share on other sites More sharing options...
OB99W Posted November 29, 2007 Share Posted November 29, 2007 Seems like you need to get the battery fully charged before proceding. I've attached an ASCII drawing that roughly depicts what you should see as the timing relationship between the injector and igniter pulses. Quote Link to comment Share on other sites More sharing options...
sublute Posted November 29, 2007 Author Share Posted November 29, 2007 That is not what I saw. I ran the sweeps again with a topped up battery I tried to take some photo's. These results seem irratic. The top is the injector and the different durations were my attempt to vary the sweep to see the coil/igniter more clearly. I am going to rig a coax probe to the coil to reduce any interference that might be coming from the spark plug wires. Dr. says bronchitis and gave me happy juice (cough syrup w/codeine) and antibiotics... Quote Link to comment Share on other sites More sharing options...
OB99W Posted November 29, 2007 Share Posted November 29, 2007 That is not what I saw. [...]The first scope photo looks a bit like my ASCII drawing, but the igniter pulse appears to be inverted. (By the way, what was the timebase setting for that first shot?) Is there any possibilty that the scope has a "trace invert" function that was on? On the other hand, the last photo seems to show the correct igniter pulse polarity, but the timing seems wrong. As you said, it does seem to be erratic, perhaps due to triggering difficulties. The ringing on the waveform is typical of a coil, as is inductive kick-back, and are reasons I prefer to use resistive dummy loads when checking these timing relationships. Can a slightly lower sweep speed be used, so that more than one pulse could be seen? Quote Link to comment Share on other sites More sharing options...
sublute Posted November 30, 2007 Author Share Posted November 30, 2007 I'll try again tomorrow with the more shielded lead and slower sweep. The happy juice has got me mellowed for the night... Quote Link to comment Share on other sites More sharing options...
85T-REX Posted November 30, 2007 Share Posted November 30, 2007 I remember reading in one of your previous posts that you marked the cams and lifters with a sharpie. From all I've seen since then is it seems like your crank and cams aren't working together properly. Are you absolutely sure you put each cam in its right place? Are you absolutely sure the intake cams are on the top of each bank and on the correct side of the engine? Are you absolutely sure the exaust cams are on the bottom of each bank and on the correct side of the engine? If they're switched bottom to top, you will still get a compression stroke but the intake stroke will be sucking from the exaust side and expelling through the intake. The injector will also probably fire after the spark. If they're switched d/s to p/s, the compression stroke, intake stroke, and exaust stroke would be in the correct order and you would still get compression. But once again, the the injector will probably fire after the spark. I say probably because I don't know for sure if the notch on the end of each cam is in the same place in relation to the lobes. Since your compression tests are consistant, it would seem that IF one side was switched, both sides would be switched. This may be a hard one to check. It may be worth an extra consideration. Are you able to verify if the intake stroke is pulling air from the intake or exaust? If not, from which one do you smell more fuel? I really hope this helps, I know you're struggling. Quote Link to comment Share on other sites More sharing options...
sublute Posted November 30, 2007 Author Share Posted November 30, 2007 I certainly though of this posssibility. I'd have to take a valve cover off to check... Yikes! 6 bolts and a tight squeeze? I'm pretty sure I got them right. They are marked in the casting and I marked the lifters with a sharpie. I also remember double checking the exhaust from where the Y pipe bolts on. 2 holes instead of 4 (2+ wide space +2) I was spending a bit of time waiting for new cam bearing cap bolts to arrive and such, so I wasn't rushing through anything at this point. Where are the archival digital photo's when you need them? Wouldn't the spark/injection relationship still be the same as the crank and cam shaft would be working as normal and the valves would just be out of sync? I think I smell fuel from the exhaust more... I think I would have smelled it in a strong way when I was messing around the throttle body? I would also smell some half burnt fuel from the coughing. Brain is hazy, think better tomorrow.... seems like there could be an easy way to verify the proper cams are in place. Quote Link to comment Share on other sites More sharing options...
85T-REX Posted November 30, 2007 Share Posted November 30, 2007 One thing you could try is do the compression test in the cylinder you're testing the injector from and see how they relate to one another. The injector should fire a little before the compression chug. I'm assuming the spark is always going to hit tdc, since the signal comes from the crank sprocket, so no need to check that. Then again, maybe it wouldn't hurt. If it's easy enough to do, why not? Quote Link to comment Share on other sites More sharing options...
sublute Posted November 30, 2007 Author Share Posted November 30, 2007 Couldn't I use the compression guage and timing light as well to establish this? The only thing to watch out for would be the wasted spark... I'm going to try to get a clean scope first to pursue the course OB99W is taking me. OB99W, should I try with a 1K resistor across the open 1-2 on the connector from the ignitor to coil to get a cleaner scope? I have another 1K 10watt around.( a few other value, too) Quote Link to comment Share on other sites More sharing options...
OB99W Posted November 30, 2007 Share Posted November 30, 2007 [...]OB99W, should I try with a 1K resistor across the open 1-2 on the connector from the ignitor to coil to get a cleaner scope? I have another 1K 10watt around.( a few other value, too)Yes, let's try the 1k across pins 1-2, scope hot lead on pin 1 and ground to chassis, as before. (It won't bother the igniter that 2-3 are unloaded.) Quote Link to comment Share on other sites More sharing options...
85T-REX Posted November 30, 2007 Share Posted November 30, 2007 It looks like you have an idea of your spark and injector pulse relation. I believe you would just need to compare both of those to the compression stroke. Make sure the other three plugs are removed. Compare: Compression stroke - spark. Yes, comp gauge and timing light. Compression stroke - injector pulse. Comp gauge and scan. Spark - injector pulse. Already done. Quote Link to comment Share on other sites More sharing options...
OB99W Posted November 30, 2007 Share Posted November 30, 2007 [...]Compression stroke - spark. Yes, comp gauge and timing light.Previous use of a timing light apparently indicated ignition advance of 20-30 degrees during cranking, which would be excessive. Usual base timing until engine start should be closer to 10 deg BTDC. [...]Spark - injector pulse. Already done.Not quite; the scope shots weren't definitive, possibly due to inductive effects of the coil. Sublute already has a dummy resistor in place of one of the injectors, and is going to do the same at the output of the igniter (in place of the coil primary). Quote Link to comment Share on other sites More sharing options...
sublute Posted November 30, 2007 Author Share Posted November 30, 2007 I put the dummy resistor on the coil lead and had a hard time seeing anything from that when I scoped it. I have a question. On the low side of the igniter, 1 or 3 to gnd, I am getting a deflection when I turn the ignition switch on. It might be 12vdc. I will measure it with a DMM. It should be low until it is grounded for spark, right? Battery is charging again... Quote Link to comment Share on other sites More sharing options...
OB99W Posted November 30, 2007 Share Posted November 30, 2007 I put the dummy resistor on the coil lead and had a hard time seeing anything from that when I scoped it.What vertical sensitivity do you have that channel set for? It should be the same as what the channel the injector is connected to is at. I have a question. On the low side of the igniter, 1 or 3 to gnd, I am getting a deflection when I turn the ignition switch on. It might be 12vdc. I will measure it with a DMM. It should be low until it is grounded for spark, right?With the resistor between 2 and 1 (or 3), there should be battery voltage on 1 (3) until the igniter pulls that pin near ground (beginning of dwell period). At the end of the dwell, the pin should go high again, and at that point the spark would normally occur. Quote Link to comment Share on other sites More sharing options...
85T-REX Posted November 30, 2007 Share Posted November 30, 2007 Previous use of a timing light apparently indicated ignition advance of 20-30 degrees during cranking, which would be excessive. Usual base timing until engine start should be closer to 10 deg BTDC. I mentioned using the light just to indicate the spark not necessarily the degrees, sorry. Not quite; the scope shots weren't definitive, possibly due to inductive effects of the coil. Sublute already has a dummy resistor in place of one of the injectors, and is going to do the same at the output of the igniter (in place of the coil primary). I know the shots weren't definitive, but most of them did show the spark just before the pulse. It should be the other way around, right? Or am I not reading them right? Quote Link to comment Share on other sites More sharing options...
OB99W Posted November 30, 2007 Share Posted November 30, 2007 I mentioned using the light just to indicate the spark not necessarily the degrees, sorry. No problem, but I want to clarify that I didn't say the above, although the way it was quoted might make it look that way. However, I did say something very similar in post #63, when the issue was a bit less defined. I know the shots weren't definitive, but most of them did show the spark just before the pulse. It should be the other way around, right? Or am I not reading them right? Yes, the injection-spark relationship seems wrong, which is why we're investigating it further. If we can get a clean scope shot, I'm hoping not only to verify the order, but perhaps the actual time difference; that could be even more revealing. Quote Link to comment Share on other sites More sharing options...
sublute Posted November 30, 2007 Author Share Posted November 30, 2007 I've been trying to get something usable...I've been having a hard time getting the sweep to show a long line showing more than one blip. When I slow the sweep up they become dots that move across the screen dipping, but I can't see their relationship as they are just dots. I could try a time exposure of this with the camera... Is there something I'm missing here. I'm not a scope power user.... The photos show a rise (lower trace) at the point that the injector is dipping(upper trace). I also tried a video on my camera. I tried slowing it down to be able to go through it at a slow rate. The previous observation holds. Quote Link to comment Share on other sites More sharing options...
OB99W Posted November 30, 2007 Share Posted November 30, 2007 [...]When I slow the sweep up they become dots that move across the screen dipping, but I can't see their relationship as they are just dots. I could try a time exposure of this with the camera... Is there something I'm missing here. I'm not a scope power user....Different scopes have varying functionality (delayed sweep, adjustable delay time, horizontal multiplier, adjustable trigger level, etc.). I can't readily advise without knowing the scope. Seeing a train of more than one pulse would be very useful; if practical to do, a time exposure might help. You could try switching the triggering to whichever channel you're not currently triggering from. You could also try adjusting the sweep variable control, rather than the timebase switch, or experiment with both. It may even be that the scope isn't functioning correctly. Perhaps if you gave the scope make/model, I might get a better idea. The photos show a rise (lower trace) at the point that the injector is dipping(upper trace)[...].Yes, and that seems to verify what was seen and anticipated before -- namely that the spark (which would happen when the igniter waveform rises, if the coil were attached) is occuring at the start of the opening of the injector, not after. It certainly seems to be a timing problem. Quote Link to comment Share on other sites More sharing options...
sublute Posted November 30, 2007 Author Share Posted November 30, 2007 I just pulled out the 35Mhz version of this scope. It seems to be in better operational condition than the 15Mhz scope I was using. That one was a curb shop but was functioning OK with audio Hz until I found this other one. I just took a pic of it... I was looking at the .1v cal sig. with 10X probe, so that is why the setting is there... I'll try this one and also try a time lapse photo if I can't make it clear. Quote Link to comment Share on other sites More sharing options...
OB99W Posted November 30, 2007 Share Posted November 30, 2007 Thanks for the front panel photo. Assuming everything on this scope is functional, I can probably talk you through setting it up for our puposes if you aren't successful yourself. First thing I'd do (assuming you're not using EXTernal TRIGgering) is put the TRIGGERING SOURCE switch in one of the INT positions. Quote Link to comment Share on other sites More sharing options...
sublute Posted December 1, 2007 Author Share Posted December 1, 2007 OK, I'm getting frustrated. I hooked up the other scope and lost the injector signal. I switched leads and the ignition followed, so both channels are working. I tried to switch to a higher sensitivity on the injector channel and still nothing! In the movement of wires, the 1K resistor on the injector harness slipped and yellow hit ground. It drew a bit of current!!!. It wasn't cranking at the time. It still has 12v on it but it freaked me and it's time to step back. Could I have damaged anything? It must go to the + of the batt. thru a 10a fuse or something.... Quote Link to comment Share on other sites More sharing options...
WAWalker Posted December 1, 2007 Share Posted December 1, 2007 Over thinking a diagnosis can make it impossible to get to the solution. Me thinks this problem is being WAY over thought. Do you still have the timing belt covers off? How many reluctors do you have on your crank sprocket? Pulling the valve covers to check that cams were properly installed will take very little time compaired to what you are attemting to do at this point. As said before, the car ran before. Most likely your electronics didn't go south while working on the engine. I don't want to say you did something wrong, but in the grand scheam of things it's not going to be a big deal to go back and check. Careful you don't let the magic smoke out of any of the magic boxes. FWIW Quote Link to comment Share on other sites More sharing options...
sublute Posted December 1, 2007 Author Share Posted December 1, 2007 Yes, they are still off. 6 Sensor making a blip on each one... Yes, I know. I really don't want to see any magic smoke.... I just want to hear the puff-puff of exhaust out the tail pipe.... Quote Link to comment Share on other sites More sharing options...
Cougar Posted December 1, 2007 Share Posted December 1, 2007 Well I hate to jump into the middle of all this fun since I haven't been looking into this problem until now but I wanted to find out something. I didn't read all the posts real carefully but near the beginning you stated that the cam pulse voltage was only about .03 volts. I think this is too low if that is the case and you may have a bad cam sensor if that is correct. Can you verify that voltage using the scope? Quote Link to comment Share on other sites More sharing options...
OB99W Posted December 1, 2007 Share Posted December 1, 2007 OK, I'm getting frustrated. I hooked up the other scope and lost the injector signal. I switched leads and the ignition followed, so both channels are working. I tried to switch to a higher sensitivity on the injector channel and still nothing! In the movement of wires, the 1K resistor on the injector harness slipped and yellow hit ground. It drew a bit of current!!!. It wasn't cranking at the time. It still has 12v on it but it freaked me and it's time to step back. Could I have damaged anything? It must go to the + of the batt. thru a 10a fuse or something.... Sublute, I'm sorry that you're having difficulty with the procedure I suggested; sometimes things that I do on a regular basis aren't easy to have others accomplish. It did seem we were making progress, and that there appears to be an electrical timing issue between injector pulse and spark. That can be due to the ECU not getting proper sensor data (among other things), which could be caused by something as simple as a poor connection or improper mounting/spacing of a sensor or what it's sensing. The ECU may then go into a default mode, "assuming" parameters like timing. You should probably recheck the contacts at any and all connections that were removed or disturbed during the engine work, as well as relative positioning of sensors or possible damage to them (tips, for example). Since you're frustrated over my approach, if you don't mind I'm going to extract myself from this. I hope that nothing was damaged by the "slip"; I can assure you that using 1k-ohm resistors as loads and monitoring the pulses as I described wouldn't in themselves cause a problem -- I've done that many times without difficulty. Perhaps you should just reconnect the injector and coil wiring, and try suggestions offered by others. A set of "noid lights" may be useful to verify injector "signal". I wish you best of luck in rapidly resolving the problem. Over thinking a diagnosis can make it impossible to get to the solution. Me thinks this problem is being WAY over thought.[...]By all means please help Sublute resolve the problem. If you've followed the situation from the beginning, you know there were numerous issues that were dealt with during the work, making diagnosis of the no-start more difficult than usual. I leave it in your capable hands, and those of others who may be able to direct him with good result. Note to Skip: Is this where I insert some self-deprecating comment? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.