Turbo Buick Forums banner
1 - 20 of 22 Posts

·
Registered
Joined
·
81 Posts
Discussion Starter · #1 ·
It seems I ask 10 different people and get as many answers about this subject. First can a bad or misadjusted cam sensor cause a no spark condition and no starting? And second, how exactly do you check/set the cam sensor? Isn't there a way to check it with a voltmeter or something? Please help, as I am having some serious issues with this Gn. TIA...Mark
 

·
Premium Member
Joined
·
43,735 Posts

·
Registered
Joined
·
81 Posts
Discussion Starter · #3 ·
Steve, thanks for the reply. Yes the crank sensor is ok. I wasnt sure about it, so we replaced it (among other things). Also set it several times and found out about the aftermarket 2 groove deal. Car still does the same thing. I have been chasing this problem for months now.I will check the links. Thanks and any other ideas are more than welcome...Mark
 

·
Registered
Joined
·
81 Posts
Discussion Starter · #4 ·
Ok, took some readings on the cam sensor this evening. The voltage started at 6.6 and stayed there almost one full revolution. Then voltage dropped to 0 and stayed there until the the end of the 1st revolution where it went back up to 6.6 Checked crank sensor voltage and didnt get anything at all. Any ideas from the experts?? TIA...Mark
 

·
Premium Member
Joined
·
43,735 Posts
I don't remember the original story...does the car refuse to start period? Does it cough or spit when you try to start it? Let's start from scratch and try to figure it out.
Any trouble codes in the ecm?
Service engine light burns steadily with key on?

If you plug a small light bulb across any of the injector wiring plugs, does it blink when you try to crank the car? I am assuming the car does not start at all.

If the car does start, then tell us what is wrong with how it runs.
 

·
Registered
Joined
·
81 Posts
Discussion Starter · #6 ·
Steve, thanks I will start from the beginning. The car was showing a lot of knock on Ds. I unplugged the knock sensor, and all hell broke loose. Knock went away, but car was missing terrribly. Like on 2 cylinders. Now, sometimes the car will start, sometimes not. Usually not. Sometimes backfires when trying to start. Last night when trying to start I heard a new noise I've never heard. A clinking noise, thought the timing chain had popped, but the motor still spins over normally and i never heard it again. When it does start it misses like crazy. Fuel pressure is good, but doesnt seem to be getting spark, at least not a very good spark. This is what has been tried:
1. Swapped maf with known good
2. Swapped esc woth known good
3. Swapped coil, but I'm not 100% positive its good. Really should be though.
4. Replaced crank sensor
5. Used noid light to check injectors, they are firing
6. Swapped chip
7. Swapped ecm last night
8. Checked all the grounds i could find
9. Had module tested, it passed
10. Checked voltage on crank and cam sensor last night as stated earlier in this post.
11. Used 3$ spark tester from Autozone, and seem to be getting little to no spark.

Ok, thats the bulk of it I believe. Any help is appreciated as I have been trying to figure this out for months now to no avail. Thanks again for your time...Mark
 

·
Registered
Joined
·
81 Posts
Discussion Starter · #7 ·
Oh and I forgot to mention that its not throwing any codes. I checked with directscan, and manually with a paperclip. No service engine light. It definately coughs and sputters when starting though. Thanks again...Mark
 

·
Premium Member
Joined
·
43,735 Posts
I am only gonna start taking simply requests...

Have you verified that the car is on top dead center when the damper pulley says it is on top dead center? I am thinking of stripped teeth on the nylon cam gear.

Is the knock sensor now plugged in? I don't know why it would run badly when unplugged. Mine runs fine with or without it plugged in.
 

·
Premium Member
Joined
·
43,735 Posts
The weak spark puzzles me, too....crank sensor, cam sensor, and module should determine that...with module and coil determining the intensity. I think.

CAm sensor voltage is usually 6-9 according to the book...since the injector is blinking the light, I assume that the crank and cam sensor are working.

But....?
 

·
Registered
Joined
·
81 Posts
Discussion Starter · #10 ·
"Have you verified that the car is on top dead center when the damper pulley says it is on top dead center? I am thinking of stripped teeth on the nylon cam gear."

Steve, no I havent but I will definately try to do that.

And also, when we got those readings on the cam and crank sensor they didnt seem to be correct from what we have been told. The voltage never really raised on the cam sensor, but went to 0 at one point almost like it may have a dead spot or something. Then checked the crank sensor voltage and not getting anything there so Wtf?? The guy that sold me this car looked at it when this all started several months ago and seems to think the problem is somehwere in the harness. Does that sound reasonable? After all this I'm beginning to wonder, but I sure hope not...Thanks again for taking the time to read my post...Mark
 

·
Registered
Joined
·
81 Posts
Discussion Starter · #11 ·
And yes the first thing I did was plug the knock sensor back in. The problem continued of course. I guess it was just coincidental these problems started at that time. No one has ever indicated to me that a knock sensor could do that. Will be glad to replace if theres a snowballs chance it would help. Thanks...Mark
 

·
Premium Member
Joined
·
43,735 Posts
If you read the cam sensor adjustment links given above, you will see that the voltage is supposed to drop to zero at a certain point.

I am still puzzled by the poor spark...sounds like the module is bad....that would be my normal reaction.

Do the leds on the tach jump when you try to crank it?

The noises you heard bother me as it would seem that something is either strange with the timing chain or the cam sensor...too many symptoms!

Do you have a fax machine? I will fax you the trouble shooting tree if the tdc seems to be correct.
 

·
Registered
Joined
·
81 Posts
Discussion Starter · #13 ·
Steve, as far as I know tdc is correct. I'm not sure exactly how but I will try to verify that. I'm not the most mechanically inclined person, but my best friend is a mustang guru and he has been helping me with a lot of this stuff. Its at his shop. That would be great if you could fax me that info, I would really appreciate it. You can fax it atten to Mark Lee at 601-936-4482. Thanks for all your help.
 

·
Premium Member
Joined
·
43,735 Posts
okay, hopefully, I sent you six pages-I wrote page numbers on the bottom of each so you can see what you got and, if any are missing.

Your friend should verify top dead center is actually top dead center at this point in time. These things are very bad about losing teeth off the cam gear after a 100k, and sometimes before, if equipped with the factory timing set. if it does this and the chain jumps, then it ain't gonna start.
 

·
Omnipotent Poster
Joined
·
728 Posts
Sounds like how my NA 3.8 ran when the timing chain jumped. It must have jumped a few times because it would barely run somtimes and a little better sometimes. CHECK THE COMPRESSION. Mine bent 8 valves. That may explain the weird cam sensor voltages???

BTW: After replacing the timing set, it still would barely run or not at all (I don't remember which) because of the bent valves. So check the compression again if you do replace it.

[This message has been edited by FastwClass (edited January 11, 2002).]
 

·
Registered
Joined
·
81 Posts
Discussion Starter · #16 ·
Steve, thanks I got your fax but according to the page numbers you wrote at the bottom pages 1 and 5 didnt come thru. I will scrutinize this information over the weekend and check on that tdc issue as well. I will say this, the motor was rebuilt just before I got the car, only has probably 500 or so miles on it tops. Did a compression before all this because thought I had a blown headgasket during another issue. Numbers were really good at that time like 161-165 on all cylinders. Fastwclass I will do another test and see what I get now. That noise I heard is really concerning me too now. Thanks very much guys and have a good weekend...Mark
 

·
Premium Member
Joined
·
43,735 Posts
okay, I just resent pages 1 and 5 without a cover page so if that was an office number..go look for them when you can.

It keeps giving me line errors..not sure what the problem is
 

·
Registered
Joined
·
81 Posts
Discussion Starter · #18 ·
Steve, that is an office number so I will check that first thing Monday morning. Meanwhile I will just keep trying to figure this out. Thanks for all your help buddy, I really appreciate it...Mark
 

·
Premium Member
Joined
·
43,735 Posts
I think you will have between two and four copies waiting on you...like I said, no cover sheet.

If they are readable, they should walk you thru the process. Probably better than me trying to shortcut you thru..
 

·
Registered
Joined
·
81 Posts
Discussion Starter · #20 ·
Okay I will follow these steps and see what we get. I'm so glad you sent that because I am pretty much lost, nobody works on these things around here. And I will check on the tdc concern and see what we can figure out there. Thanks a lot dude...Mark
 
1 - 20 of 22 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top