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-   -   I Think I Killed my 84 SFI, No Spark. (http://gnttype.org/forums/showthread.php?t=12791)

Rusty 06-06-2009 09:46 PM

I Think I Killed my 84 SFI, No Spark.
 
ok, to make it short as possible.
The car was running but had a bad Crank. the #1 Piston rod bearing was shot. the cam it rides on was toast. so I poped a .030 bearing in and fired it back up. well the clank was still there but the new Manifolds sounded good(I had cracks in the old ones). any how. I ordered a crank and waited weeks. finaly it arived and I Managed to drop the old crank out and install the new one,(Factory Specs with new .010 bearings)and I only had to unbolt and slide back the trany an inch or so. I only made one Boo Boo, I Crunched the Crank sensor, another $118 dollar error. I installed the new Crank sensor and tested all. NO Spark at all. this has been going on for 3 weeks now since I finished the crank and as of yet can not for the life of me get a spark. I have striped the casing and inspected the whole wireing harness and even cleaned, soldered and rewraped the whole ting. lookes great but did crap to improve the issue. Heres where the fun starts. I own a 1984 turbo 3.8 SFI Grand national, and it is like all info for my particular Year and set up is as rare to find as the parts. so far I have kept everything Factory spec, but what those specs are is the trick. my point is. it Ran before, so what did I miss or toast that has led me to this insanity... this is my daily car, and I need to get past this and start getting to work on time(LOL). any help or info would be most Apreciated. thanks

kenmosher 06-07-2009 09:17 AM

Re: I Think I Killed my 84 SFI, No Spark.
 
My bet is you installed the crank sensor with the reluctor in the wrong slot on the sensor.

Keller 06-07-2009 11:08 AM

Re: I Think I Killed my 84 SFI, No Spark.
 
Agreed. Its easy to do, and there is nothing that screams out at you that it is in the wrong position.

Thankfully, it is also easy to change. :lite: Been there, done that...

Rusty 06-07-2009 03:20 PM

Re: I Think I Killed my 84 SFI, No Spark.
 
first off, thanks for the fast reply.
but. believe it of not I have two sensor at moment. one of which was/is brand new, and I did manage to mount the new one. and then ripped it out and resorted back to the old one as I tried both groves. yes, another silly move. am still getting nowhere. I bought the guage tool that is avalible and have , each time set the distance as directed. and when I read though some of the articls they become confusing, such as" install in the grove clossest to the plug and goes on to also state next to Engin. which to me is two opposits.

any who...
second question, the ECM from what I have read, is located inside the car in the Passenger side. would this be inside the side wall behind Molding?
lastly, where would I take my C31 modual to be tested and can I?. off to hunt for the ECM...I think...

still twiddling with Crank sensor as well.
oh and 1 more...lol
will the engine produce spark if Cam sensor is disconnected. I think I read some where that it can run with out sensor.

(3 years with out a problem and now all this becouse I changed the crank)
makes the saying "if it ain't Broke, don't fix it" sound like a good rule of thumb

Peace out and again thanks for the input.

Rusty 06-07-2009 05:05 PM

Re: I Think I Killed my 84 SFI, No Spark.
 
As I was sitting here watching Nascar. I remebered something...
I see from endless harness work that one of the connectors for my sensors can in fact reach the 3 wire connector that comes of the top of my manifold. could I have not realised that in hooking up my harness the first time
(so many weeks ago),that I may have plugged one of my sensor wires into this cluster that goes to the waist gate, I think. dunno, total veg at moment, due to can't stop thinking about where I went wrong....lol

Rusty 06-07-2009 05:47 PM

Re: I Think I Killed my 84 SFI, No Spark.
 
ok, first, thanks to whom ever mentioned finding there ECM while changing Upolstry. yes, I'm that thick, but have found the ECM and inspected it for any sign of water Damage. due to many statments of they suposedly all leak in the right side dash area. but to my suprise, all dry as a bone and looks in great shape. though by the writing in pen on it stating it's a "84 GM Good" I take it this is not the origanal...
(had night mares all night about finding a rusted out box).
welp, 14 laps left. gotta go...

kenmosher 06-07-2009 06:25 PM

Re: I Think I Killed my 84 SFI, No Spark.
 
Quote:

Originally Posted by Rusty (Post 52224)
will the engine produce spark if Cam sensor is disconnected. I think I read some where that it can run with out sensor.

It will not start without the cam sensor, but if it's disconnected with the engine running, it will continue to run.

Spark is tied very closely to the crank sensor ... 8 out of 10 times if you don't have spark either the crank sensor is bad or the ignition module is dead. Since the engine was running when you tore it down, it points pretty strongly to the crank sensor and less so to the cam sensor.

Rusty 06-07-2009 07:02 PM

Re: I Think I Killed my 84 SFI, No Spark.
 
ok...
back to the Crank sensor I go...went.
I have closed the gap of outer grove as much as I dare..
tried a spark test again...
no spark...BUT....it turns over like it's tring to fire....
si I test spark indicator light thingy I got from Napa glows bright orange on girl friends Dodge stratus. so the test light should work on mine, right?
so why does it sound on the verge of firing???

(have resorted to babbling incoherently in the corner).

Rusty 06-07-2009 07:26 PM

Re: I Think I Killed my 84 SFI, No Spark.
 
ok...lets try and establish a base line...lets say for srgument that my cam sensor is in fact now working but the cam may be wrong. does this equil spark at wrong timeing or no spark at all?
also. to remove some of my confusion. when setting the cam am I suposed to turn the crank an aditional 25 degree;s beyond the 0 mark or back counter clock wise. I ask cuz my harmonic indicator reads counter clock wise from the 0 mark and goes to 20 degrees. get confused at this point. have tried both which ezplains some of my nightmare.

and I have a concern about no oil yet in motor, you would think that with all this test rotation that the oil would at least begin to draw into pump. yes I did pack it with Vasaline twice now, just to be safe. should this kick in once Engine is running and begin pumping oil then?
guess question is should I again repack the iol pump to keep it from Air locking or cross that road when I get to it. hate to fire it up just to toast it due to additional stupidity.

hell if nothing Else I gave you some interesting reading....NOT

we hell tomorrows another day I guess..
peace and thanks

Keller 06-07-2009 07:29 PM

Re: I Think I Killed my 84 SFI, No Spark.
 
It is extremely important that everything be in sync. That include the cam/crank timing, the cam sensor aligning with the #1 cylinder TDC, the crank sensor interrupter ring alignment with the crank, and the proper crank sensor slot with the interrupter ring with adequate gap.

Given that this is a waste-spark system, the ignition only fires three pulses NOT six. However, that means that it fires them twice as often, and one cylinder gets a spark on a non combustion (i.e. waste) stroke each time. This keeps the ignition simpler, but it is very important that everything be properly timed. Otherwise, you may find the ignition trying to fire at the wrong time, injectors trying to fire at the wrong time, etc. The proper synchronization of the cam and crank pulses is what keeps this all in check. In addition, the cam/crank relationship has to be right. Otherwise, the game is lost from the get-go.

I suggest you read the article http://www.gnttype.org/techarea/ecms...ensor_FAQ.html While it doesn't speak about the crank sensor, specifically, it does give some insight about how things all work together and how important all these things are and how much little adjustments mean. Other articles in the tech area of our web pages may help your insight as well.

I still question whether the crank sensor is aligned on the correct slot. And whether you have the cam set correctly with the crank. You might double check firing order, too.


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