Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!





Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Did you get a great deal? Let us know in the Values & Prices Paid section!
Meet your fellow owners in our Owners Clubs

1998 Blazer - I have a Crank /NO Spark condition I need help from someone Experienced in this

stevekruzichstevekruzich Posts: 33
edited April 2017 in Chevrolet
1998 blazer 4.3l engine. 4l60e transmission.
112,000 miles

Old engine blew out a rod bearing so i replaced with a 4.3 out of a 98 blazer
that had been rear ended. Engine is hooked up.
I have a Crank but no spark condition.
After futzing with it for about a month I've gave up tracing the problem with a
vom and test probe being that i have no O-scope to test for a signal.

I have Done the following:
Fuel pressure (everyone insists i have this info for some reason) is 60psi
Checked ECM1 15a fuse and all fuses---Good.
New Computer flashed with my vin number
Ign control Module New
Distributor w/cam positioning sensor New
Crank positioning Sensor NEW
Coil New
Tested Ignition switch at the wire block pink w black stripe as i tried to start.
Got power to that wire when i put into start/run position

Still have a crank no spark condition.
I do have power going to all of the components.
I also have power going to the injectors and am smelling fuel when i try to
start.

To verify i have power to the components i tested the pink wire going to the
coil, ICM, CMP, CKP. They all show 12v

Tested continuity on wires i could not test signals.
Coil was tested for resistance and is within specs.
Coil tach sig wire white/black stripe has continuity no signal from ICD
ICD ign timing wire white going to est output sig on computer chip c2 has
continuity no signal from ecm
Ground wire black/white stripe has continuity
CMP sensor pnk has 12v, pn/blk has continuity to the pcm chip c1. brn/white
wire has continuity to pcm chip1
CKP sensor has power to pink wire. Yellow wire has continuity to ecm chip
c1 Purple wire has continuity to ecm chip 1

Computer is new. Flashed with vehicle vin
This car according to gm does not have passlock or any security to prevent
starting.

I am a mechanic but am 100% disabled and rely on this car to get to my
heart doctor and medical treatments. Sure need to find out what is wrong.
IT ran before i swapped motor.
I'm at a loss on what to check now. It ran before i swapped motors now i
don't get any spark. IF i could solve the no spark issue i believe it would fire
up and start running.
«1

Answers

  • xwesxxwesx Fairbanks, AlaskaPosts: 13,087
    I am having a hard time remembering the names of things when I was last dealing with an issue that seems somewhat similar to this. So, I'll just recount the no-start experience I had and suggest that you double-check the quality of the grounds. Given the extent of the work you performed, this seems a likely culprit.

    Mine was a '98 DGC, but the lack of spark was caused by an automatic shut-down relay. This relay was not getting a good signal from the various parts that had to "check in," such as cam and crank position sensors, etc., and it was due to a bad ground. On that vehicle, the core grounds all terminated at a post located under the battery tray. Turns out, that spot was subject to a fair bit of corrosion. Cleaning up the connections resolved the issue.

    To be clear, all my testing indicated ground continuity on all circuits. However, the resistance level in one (or more) of them was high enough that it periodically tripped the ASD relay. Once the relay tripped, it was not going to start.
    2014 Audi Q7 TDI, 2008 and 2013 Subaru Forester(s), 1969 Chevrolet C20 Pickup, 1969 Ford Econoline 100, 1976 Ford F250 Pickup
  • thecardoc3thecardoc3 Posts: 5,091
    edited April 2017
    If I was going to come over and help you out, the first question that I would ask is "How are you checking for spark?"

    An ST125? http://www.tooltopia.com/otc-tools-6589.aspx?utm_source=bing&utm_medium=cpc&utm_campaign=PLA&scid=scbplpOTC6589&sc_intid=OTC6589

    The next question that I would ask is "With a test light while cranking the engine, do you have power to the ignition coil?"

    If the test light is connected to the ignition coil ground side and cranking the engine (ignition module connection) "Does the test light flash? If not, is it lit or not lit?"

    To get a command to turn on and then fire the ignition coil, the ignition module gets a 5v pulsed command from the PCM. To produce the ignition command the PCM must see the crank sensor input, which BTW is the same signal that is required for the PCM to fire the injectors. An easy way to determine if that signal is present at the PCM or not is to pay attention to the fuel pump.

    When you turn the key on without cranking the engine you should hear the pump turn on for approximately two seconds and then it turns off. The PCM turns the pump off if it doesn't see the crankshaft signal. So then if you start cranking the engine and hear the pump turn back on, that means that the computer IS seeing the crankshaft sensor input. This is also confirmed if the injectors are being triggered which while not directly measured at this point is being suggested as occurring by your description that you can smell fuel.

    Since you don't have a scope but do have a DVOM, Go to the four wire connector at the distributor.
    The pink wire pin "A" should be 12v power.
    The white wire is the EST electronic spark timing signal from the computer.
    The white with black tracer is the coil command.
    The black with white tracer is the ground connection.

    The pink wire should of course be system voltage at all times with the key on and with cranking the engine.
    The black/white should be close to 0v (less than .2) at all times with key on and with engine cranking.
    The white/black should pulse to ground as the module turns the coil on. (A test light should be lit and actually flash off, exactly as seen at the coil)

    The white wire would be mostly 0v and go up to 5v while the module is being commanded to turn the coil on to make a spark. Stetting your voltmeter to measure "dwell" or duty cycle should result in a measurement of the on time that the computer is commanding. One would be a percentage measurement, the other would be in milliseconds.

    If you get 0 in either one, switch your voltmeter to DC volts and tell me what you see both key on not cranking, and then key on cranking.

    Compare what you measure at that the distributor connection to pin 9 of connector 3 at the PCM. FWIW, this is easier to do with a scope, but not impossible to do with a voltmeter.


  • Well, i don't find a relay in the wiring schematics. I have a complete wiring diagram to look at.
    BUT so far heres what i have done since i posted. I got frustrated and just started removing stuff from top of engine. I pulled wiring harness loose, undid the mount for ac compressor and pulled valve cover.

    I checked number one valves for exhaust to open then intake and backed up to set TDC. So that is right! I put that stuff back together last night and am now at the point of checking position on the distributor. I ran out of daylight and got shaky from working. (I have congestive heart failure and diabetes so it affects time working).

    While i had everything removed i checked ground strap and two ground wires that are supposed to go to driver side head but these guys that did the engine swap for me were students at local college and I know they are learning but seriously i am not impressed.

    The ground wires were mounted on passenger side head (no wonder i couldn't find them) and the bolt was finger tight.

    I then felt around as i couldn't see anything and felt the braided ground strap going to the firewall loose. Again, the strap was positioned and a bolt inserted but never tightened down. I remedied that. Meanwhile i felt around some more and found the three top bolts on the tranny were loose. :| Tightened them up.

    At that point it was dark and i wrapped it up and its raining cats n dogs today so i won't be working on it.

    I Did manage to test the coil a diff way. I pulled the connector going into the Ignition control Module and set my spark test tool in the secondary on the coil and then grounded the white wire with black strip or the tach sig wire. It lit up my spark tester. So that works. Since this coil is oem and 18 years old i said screw it and ordered another one and am waiting on one to arrive.

    I replaced the connector on the crank positioning sensor. (i really need to find a good soldering gun cause i almost didn't get wires to heat up enough to wick the solder0, and then did not shrink the tubing over the open wire on the yellow and purple.

    I know it says to turn the crank by hand but that is very difficult for me to do. So i bumped the starter by using my relay that i took apart for the starter and left ignition on and i got around 5 v ac coming off the yellow wire. The purple is ground so i just tested it to see if it was good and not grounding on the wire anywhere other than the computer.

    I went to the connector on the ICM and it appeared to get something on it but i don't know if its supposed to be ac or dc voltage or how much on it. This is the signal wire coming from the pcm to the ICM to tell it to fire the coil.

    I'm telling y;'all this to verify that i am doing it right. It goes against the turn the crank by hand instructions.

    Tomorrow when it warms up and drys up a bit i will go back out and hook up the rest. These guys didn't put the pcv valve in, or hook up the vaccuum line going to that circuit and god only knows what else.

    Once i check distrib to see if it is positioned right i can turn the engine over and see if i get any codes.
    I do have a persistant code which sets immediately after clearing codes, evap code 452 or something like that.

    If y'all can verify that the testing i did on the yellow signal line from the CKP and the white sig line from the ecm to the ICM is a good reading then i can probably look at the new icm i got as faulty.

  • If I was going to come over and help you out, the first question that I would ask is "How are you checking for spark?"


    http://contentinfo.autozone.com/znetcs/product-info/en/US/grn/25227/image/4/


    The next question that I would ask is "With a test light while cranking the engine, do you have power to the ignition coil?"
    I don't have anything but a test probe. No noid light. Someone walked off with that a couple years ago.
    Guess i could put VOM on it and see if i get a volt drop.
    It has power when i turn ign on, but in a start condition i don't know.
    If the test light is connected to the ignition coil ground side and cranking the engine (ignition module connection) "Does the test light flash? If not, is it lit or not lit?"
    No i use my test probe which has a pulse detect and it does not show anything. I know its hot when i turn the key on, as when i ground it it lights up the spark tester.
    To get a command to turn on and then fire the ignition coil, the ignition module gets a 5v pulsed command from the PCM. To produce the ignition command the PCM must see the crank sensor input, which BTW is the same signal that is required for the PCM to fire the injectors. An easy way to determine if that signal is present at the PCM or not is to pay attention to the fuel pump.
    Well the PCM is firing injectors because i am smelling fuel.
    When you turn the key on without cranking the engine you should hear the pump turn on for approximately two seconds and then it turns off. The PCM turns the pump off if it doesn't see the crankshaft signal. So then if you start cranking the engine and hear the pump turn back on, that means that the computer IS seeing the crankshaft sensor input. This is also confirmed if the injectors are being triggered which while not directly measured at this point is being suggested as occurring by your description that you can smell fuel.

    Since you don't have a scope but do have a DVOM, Go to the four wire connector at the distributor.

    Yes fuel pump comes on runs a couple seconds then shuts off. I can't hear if it comes on while cranking though. May be my hearing at fault here.
    But i do smell fuel when i do crank. that indicates that the injectors are firing.

  • thecardoc3thecardoc3 Posts: 5,091

    I don't have anything but a test probe. No noid light. Someone walked off with that a couple years ago.
    Guess i could put VOM on it and see if i get a volt drop.
    It has power when i turn ign on, but in a start condition i don't know.

    Well you need to find out. I can walk you through this, but you have to test exactly as I describe and report your findings back.


    No i use my test probe which has a pulse detect and it does not show anything. I know its hot when i turn the key on, as when i ground it it lights up the spark tester.

    Get and use a test light, and voltmeter. Since I cannot see your test probe and how you are using that creates variables that I cannot account for. I can't tell you what s wrong with your car, nobody can really do that. But if you follow my instructions I can tell you how to figure it out.


    Well the PCM is firing injectors because i am smelling fuel.

    Or else you have a fuel leak. I only say that because it is a plausible reason to smell a fuel odor which would have nothing to do with the injectors actually supplying fuel.


    Yes fuel pump comes on runs a couple seconds then shuts off. I can't hear if it comes on while cranking though. May be my hearing at fault here.
    But i do smell fuel when i do crank. that indicates that the injectors are firing.

    Let me know when you are tooled up and ready to do some testing.
    Stop buying and changing parts until we prove what is wrong.

  • I put things back together, dist is set right on time. Get a po452 as soon as i clear codes. then after starting it i get a po336 now.

  • thecardoc3thecardoc3 Posts: 5,091
    P0452 is fuel tank pressure sensor signal low voltage. That can happen if the 5v reference signal for the sensor is missing or is being pulled to ground. It can also happen or if the sensor has failed, or if a circuit issue exists that has the signal back to the PCM from the fuel tank pressure sensor open or grounded.

    The P0336 is the crankshaft position sensor signal is missing. The code sets when the PCM (VCM) sees four or more camshaft sensor signals without seeing a crankshaft sensor signal. With no crankshaft signal you won't get the fuel pump to turn back on after the two second priming pulse as described above, and you don't get injector command.

    CKP circuit at the PCM...

    Pin #28 Purple of #1 connector is the crankshaft sensor signal. You should be able to connect to it with a volt meter and see a duty cycle of 40-60% . Since this is a 5v square wave that means you would see something between 2-3 volts.

    Pin #31 Yellow of #1 connector is the ground circuit for the crankshaft position sensor.

    The third wire at the CKP is a pink wire that brings vehicle power to the sensor. It is the same power supply that feeds the injectors, so you could check for power to them (key on engine off and key on engine cranking) which would confirm power should be available to the CKP but you will still need to confirm that.
  • stevekruzichstevekruzich Posts: 33
    edited May 2017
    Ok no the 452. Not sure why it would happen now. Guess its going to be a wiring issue.

    1.17v on purple wire 1.01 on yellow. 12v on pink

  • thecardoc3thecardoc3 Posts: 5,091
    Yellow is too high.

    This is where a scope is a much better tool than a voltmeter. With a scope you could see if the sensor was actually creating a signal even if the ground circuit voltage is too high for the PCM to recognize it.

    You can watch some of these videos and get an idea of what you need to do.

  • stevekruzichstevekruzich Posts: 33
    edited May 2017
    w3hen i tested it was connected to the CKP and i was cranking the engine.
    This guy tested disconnected. So i'll go back out and retest the wires.

  • Ok i'm sorry but i've watched it 3 times it makes zero sense. i can't do a oscope test because i have no oscope. I have what tools that i have. Is he testing conntected to the CKP or is he disconnected. What voltages am i looking for. This just stressing the crap out of me.
  • thecardoc3thecardoc3 Posts: 5,091
    edited May 2017
    If you don't have the tools and the training to use them, then you will run into situations that you will struggle to solve. What I linked is an excellent description of what your crank signal would look like. You have a code that describes the PCM as unable to see that signal, which means you have to be able to look directly at it yourself to prove if it really is missing or if there is a reason that the PCM just can't see it.

    The yellow wire should be less than .2v to battery negative. If it is over 1v as you described earlier then you are suggesting that you have a ground circuit issue. The problem with a voltmeter is that it averages what it is measuring and updates the screen about four times a second. It doesn't give enough detail to be certain what is really going on in a given circuit. The video at about five minutes twenty seven seconds describes the difference between the scope capture and the multimeter operation.

    You're going to need some help beyond this point. Problems that can cause the system to not create the crankshaft sensor signal could be, but ARE NOT limited to:

    The sensor.
    Clearance between the sensor and the pick-up.
    Connection issues at the sensor or the PCM.
    Wiring issues.
    The PCM itself.

    Proper testing with the right tools which include both a scope and scan tool, would walk you right to the failure no matter what it is.

    See if there is a mobile diagnostic technician near you that can assist. Otherwise look for a shop that is a member of the iATN or has techs working for them that are members.

    http://www.iatn.net/

    https://iatn.net/repair
  • Correct me if i am wrong but this diagram says the signal wire is yellow, not purple.

    http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0996b43f/80/23/2a/20/large/0996b43f80232a20.gif
  • Ok. This is what i have done.


    WITH the ckp connected, i took a tpin and inserted into the signal wire which i think is yellow not purple according to the schematic
    http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0996b43f/80/23/2a/20/large/0996b43f80232a20.gif

    What i did wsa check voltage while turning crank and i got soemwhere around 2-3v off the signal wire.

    I did go and take and touch 5v to the pin and heard the fuel pump engage and the injectors fire. I didn't get a spark though on my spark tester which was in place at the same time.

  • thecardoc3thecardoc3 Posts: 5,091
    edited May 2017
    Mitchell has the circuits switched in the drawing, that kind of stuff can drive us crazy. Use the schematic you have.

    The important part is that the system reacted to the signal you gave it, and it's not reacting to what is coming out of the sensor. At 2-3 volts that suggests that it is doing something but we still have the problem of knowing if the signal is going low enough for the PCM to recognize it. Computers don't look at the maximum and minimum voltages of a given signal. They usually operate on something like a 10%-90% strategy. (could be 20%-80%)
    By looking at the low voltage as something that went below that 10-20% and not actually looking for 0v, that makes the signal more tolerant of faults. The same goes for the maximum voltage. This is why the voltmeter often let's techs down when it doesn't display all of the information.

    Try measuring just from the yellow to ground and compare that from the yellow to the purple while cranking the engine. They should read very close to the same. Re-measure the purple to ground both with just the key on and the engine cranking. It should be below .2 volts in both cases.

    Another little trick you may have to try is to remove the sensor and use a wrench to simulate the tone ring. Pass the wrench across the sensor and see if the PCM reacts by turning the pump on. If it does, make sure how far away from the tone ring the sensor is when it is installed in the engine. The clearance should be .020"-.040"
  • weather took a dump will be a couple days before i can go back out and work on it. Just letting ya know
  • Ok.
    While cranking
    Pink voltage 12v
    yellow to ground voltage 3.74
    Purple to ground voltage 1.74
    yellow to purple .001

    From computer to white wire on ICM
    2.01volts

  • thecardoc3thecardoc3 Posts: 5,091
    edited May 2017
    If the purple is the ground, it's too high. It should be .2 or less.

    Jump that to ground and see what happens to the signal on the yellow.
  • Ok will do tomorrow. Its getting too dark for me to see.
  • thecardoc3thecardoc3 Posts: 5,091
    BTW, be careful just in case it happens to be the problem and starts.
  • I was thinking of that. LOL Thanks. I will make sure nothing is in the way.
  • Ok, i got tired of this crap and went and cannablized a wiring harness i had in the garage that came out of a s10.
    I took same guage and color wires out of it about 5' long and wired into my connector then inserted the oem connector pin terminal into the computer plug and connected it up. Still no spark.

    I've eliminated any issue with those wires being broken or chaffed or anything.The three wires going to the CKP are good and solid.

    Still get 336. That leaves according to the book only the ckp or the pcm.

    It's raining now so i can't do anything i'll have to wait til it drys up. I'm waiting for a VOM meter that can measure hz. if i can get a hz reading between the yellow and purple wire i should be able to determine if the signal is good. The service manual says it needs to be between 40-60% value.
    Heres what it says.....

    1. turn off engine.
    2. install gray wire jumpers from the j35616-a connector tester kit between the engine harness connetor nd the ckp sensor igniton positive voltage circuit and ground circuits.
    3. install a j39200 dmm set to the duty cycle position (select AC voltge and press Hz button twice to display duty cycle) between the ckp sensor signal circuit and the ckp sensor ground. Yellow and purple.
    4. crank the engine.

    Is the duty cycle within th specified value. 40-60% IF yes go to step 8 which says repair short to ground. If no it says go to step 9 which says

    Step 9
    check the ckp sensor and the reluctor wheel for damage. refer to diag aids.
    if yes (damage) go to step 10 which replaces either ckp or reluctor wheel.
    IF no go to step 12 which says inspect mounting surface clean if necessary,
    1. replace ckp
    2. perform ckp relearn
    IF yes it says go to 17 which is use scan tool start engine etc.
    IF no it has no further solution.


  • thecardoc3thecardoc3 Posts: 5,091
    Now you are seeing why the oscilloscope is so important.  As far as checking the sensor and the pickup,  I mentioned how to do that earlier. 
  • thecardoc3thecardoc3 Posts: 5,091
    This is not a recommendation of a given product, if you decide to invest in an oscilloscope for your cell phone or tablet or even a laptop, choose wisely. If you didn't know that things like this are out there and pretty affordable you do now. Just don't expect it to perform like a $4000 PICO.

    http://www.geeky-gadgets.com/100mss-open-source-smartscope-oscilloscope-for-your-tablet-video-29-01-2014/
  • xwesxxwesx Fairbanks, AlaskaPosts: 13,087
    $249? That's fantastic! I need to get something like this for my son. He is very much into electronics, and this would probably help him in his "tinkering" tremendously.
    2014 Audi Q7 TDI, 2008 and 2013 Subaru Forester(s), 1969 Chevrolet C20 Pickup, 1969 Ford Econoline 100, 1976 Ford F250 Pickup
  • Wellllll I went back through my thought process on why i wasn't getting signal through the icm and looked at my schematic for the 100th time and i tested the pink wire which is 12v the white wire which is ignition signal and the white with black stripe which is tach signal and the black with white stripe which even though i've seen it for a month says goes to ground at the ground point of left drivers side head.
    Welll i went out to take the harness off the engine and go through every wire on it. I started thankfully at the left side and had to wrestle the metal hose going from the exhaust manifold to the egr out from behind the head. Not the proper position for it and reached back behind the head feeling for wires connected to the head.
    I FOUND the ground wire (2wires in a connector) and it was cut or broke. The knuckleheads (students) that pulled the old motor out and put new one in broke it pulling the old one out and i guess they didn't want to put a new connector on it and bolt it back down or something. It was broken for sure cause the insulation was stretched where it had snapped.

    Its too dark to see so i am going to pull it up tomorrow get me a circle connector and solder them into it then reroute that wire to the block where i can get to it easier. THen i'll go back through and retest everything and see if i get spark.
  • This is not a recommendation of a given product, if you decide to invest in an oscilloscope for your cell phone or tablet or even a laptop, choose wisely. If you didn't know that things like this are out there and pretty affordable you do now. Just don't expect it to perform like a $4000 PICO.

    http://www.geeky-gadgets.com/100mss-open-source-smartscope-oscilloscope-for-your-tablet-video-29-01-2014/

    Well i haven't had a oscope in 20 years when i gave my tectroniks away to a struggling student going to electronics school. I have a deg in electronics design and shortly after i graduated the market went from a repair market to a throw away and replace. I moved from there into I.T. and became a unix system administrator.
    I ran my engine shop in my spare time building 383's and transmission rebuilds after work.

    So i haven't had a need for one since then. But apparantly its getting so that if you want to work on your car you have to have one. :/

    Sheesh.

    You know I am 100% disabled, just got a defibrillator put in because my ejection fraction went down to 20 on my heart. Yet....I am working on my car so that i can get to the doctor, I just got a 1999 pontiac firebird sitting out here that i have to install new lifters in, fix coolant leak in the 3.8l where the egr tube cooked the gasket and at the back corner of the intake gasket due to dexcool, and a s10 pickup with loss of power eats gas and i have t determine whether or not it has piston slapping or if its a rod beaing gone out. I think the power loss is from a catalytic converter. So i'll disconnect that one day next week and drive it down the road and see if the power increases and pull plug wires to see if that light knock sound goes away.

    I am working more now than i was before i became disabled only it takes me 5 times as long to do anything.

  • Unfortunately still a no spark situation. BUT when i connected that broken groundwire i rerouted to a bolt hole on the block where the spark plug loom bolts in, i got different readings on the sensor.

    while cranking
    1.07 on the yellow wire. Yellow wire to ground.
    .002 on the purpe wire Purple to ground
    1.17 on the yellow wire with ground lead on purple wire.

    Wires ohm'd out around .012 resistance Which is normal and shows no breaks

    I'm trying to find a car with the same oem sensor in it thats running and test with that ckp sensor
  • thecardoc3thecardoc3 Posts: 5,091
    I still have my Tektronix two channel digital storage scope that I got in '94. That was an expensive tool at the time but a must for top technicians. My 4434 PICO is now going on ten years old and if I was going to return to full time work I'd likely be upgrading.

    People often tell someone to "check the ground connections". It doesn't mean look at them and maybe take them apart, clean them and put them back together. It means measure the voltage drop which is what I got you to do. The result of you finding that broken ground is the voltage on the purple wire went down to under .1v and now that also brought the voltage on the yellow down as well to just over 1v. That's how you have proof that it was part of the problem, otherwise referred to as "a problem" and quite often misidentified as "not the problem". In our world when a vehicle actually (and quite often) has multiple failures only the last problem that is found and solved is regarded as "the problem" and everything else is treated as if it was a mistake and wasn't really an issue.

    Now the yellow signal wire at 1.07v. That sounds too low and reveals the problem with using a voltmeter, it doesn't tell you the whole story. It's fine for confirming known steady state signals, and it does work with digital signals when you already know what the signal voltage should to average out to, but it cannot show you the detail that you really need to see. A scope would show exactly what is going on in the circuit, live. Static tests, which are what traditional trouble trees have techs perform leave holes that turn into significant traps that only live complete testing.

    Remove the crank sensor from the engine.
    With the sensor unplugged connect the voltmeter between the yellow signal and the purple ground using back probe pins. What do you see?
    Plug the sensor back into the harness.
    Now what do you see?
    Now take a wrench and swipe it across the pick up portion of the sensor, what do you see on the meter and do you hear the PCM react? (aka turn the fuel pump on etc)
Sign In or Register to comment.