bad coil pack

[wishful_laser]

to make a long story short, i was driving on the highway at about 60mph when my car felt like it was starting to stumble and then it backfired really loud and then my car died. when i poped my hood i found my timing belt was shreded.(just the end of it though maybe about 3-4mm at the most. in fact the rest of the belt was still there and didnt even lose tension. when i took it home and started my timing belt install i noticed that my coil pack had some corrosion on two of the coils and the end of my spark plug wires were missing a little bit of the metal. now my car wont start and cant figure out the problem. i had the coil pack tested and it was reading volts but the manual says they are suppose to be the same resistence between the coils and the harness terminals were suppose to be a .77-.95 and mine read a 1.15. do you think my coil pack and wires are causing my no start problem. oh and i did check for bent valves too. there were none. let me know what you guys think.
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[GTM]

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it was starting to stumble and then it backfired really loud and then my car died. when i poped my hood i found my timing belt was shreded.(just the end of it though maybe about 3-4mm at the most. in fact the rest of the belt was still there and didnt even lose tension. when i took it home and started my timing belt install i noticed that my coil pack had some corrosion on two of the coils and the end of my spark plug wires were missing a little bit of the metal. now my car wont start and cant figure out the problem. i had the coil pack tested and it was reading volts but the manual says they are suppose to be the same resistence between the coils and the harness terminals were suppose to be a .77-.95 and mine read a 1.15. do you think my coil pack and wires are causing my no start problem. oh and i did check for bent valves too. there were none. let me know what you guys think.
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Without a manual I can't help with your continuity test of the circuit.

I would suggest that you do a compression check if you have not gotten too far into the timing belt replacement that you can't safely crank it over. I have seen frayed belts occur when they jump time and bang valves. If you have gotten into it to the point you cannot rotate the engine and you are concerned enough you could pull the cams and make sure the spring heights are all the same within reason. Alternately setting the crank so all 4 pistons are level (not 2 up and 2 down) (this would be at an imagenary mark of 90 degrees to the crank rotation. Then you could safely remove _ALL_ the cam followers without the worry of banging valves. Using a suitable adapter you can then pressurize the cylinders and see if you have a leak either through the intake valves or the exhaust valves.
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You don't usually get crossfiring spark plugs with multi coil systems and no distributor, but this would be one of the more common causes for backfiring. If the ECU, CAS, or coil packs have decided to go south this could be a good case for what you experienced. Sparkplugs can also cause this problem but none of this explains the Timing Belt issue.

There should be a test to determine if the coils are in fact working, one of the more simple involves using a test light but again without a manual I'm not in a position to tell you which connection to probe.

Let us know what you find.

Cheers,
GTM

 

[wishful_laser]

as for my timing belt, i know why it frayed. i tryed to do a compression test but the manual says your car MUST be at operating temperature. i cant do that cause my car wont even start. i try though, i pulled the mpi fuse, the plug to the power transistor to keep it for sparking, and had the throttle wide open. still nothing. i have already took off the cams and the head to see if maybe my pistons were screwed but everything seemed to check out. no bent valves, piston rings are still good.i even tried new plugs cause i thought maybe i might have fouled mine out. still the same result and that is why i am turnig to my coil pack cause i never heard of corrosion on a coil pack.my wires were horrible looking to me. the ends of them were literally looked like they had gotten to hot and deteriated away or something. only on two of them though. i know i was running really rich cause my pockerlogger said my fuel trims were maxed low(81%)on all three levels. my plugs actually have gas on the end of them you can wipe away with your finger. not neccesarrily soaked but wet from gas.my mods are in my profile. let me know what you think. n e advice is greatly appreciated as this car is my daily driver

 

[GTM]

as for my timing belt, i know why it frayed. i tryed to do a compression test but the manual says your car MUST be at operating temperature. i cant do that cause my car wont even start. i try though, i pulled the mpi fuse, the plug to the power transistor to keep it for sparking, and had the throttle wide open. still nothing.
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i have already took off the cams and the head to see if maybe my pistons were screwed but everything seemed to check out. no bent valves, piston rings are still good.i even tried new plugs cause i thought maybe i might have fouled mine out. still the same result and that is why i am turnig to my coil pack cause i never heard of corrosion on a coil pack.my wires were horrible looking to me. the ends of them were literally looked like they had gotten to hot and deteriated away or something. only on two of them though. i know i was running really rich cause my pockerlogger said my fuel trims were maxed low(81%)on all three levels. my plugs actually have gas on the end of them you can wipe away with your finger. not neccesarrily soaked but wet from gas.my mods are in my profile. let me know what you think. n e advice is greatly appreciated as this car is my daily driver

I guess it would be proper to say you did the right thing by trusting the _book_; however: sometimes it's necessary to exercise wisdom and do what you know will not harm the car. In this case you really needed some answers thus any compression check would be better than none even if the engine was cold and the oil thick and a half dead battery. It's unfortunate that you have pulled the head but as long as you have it off and upside down you can fill the combustion chambers with kerosene or non flamible solvent. Let it sit for an hour or so to see if any valves are leaking, if something is showing then drain the fluid, using a rubber or plastic mallet give that valve hat a couple good smacks. This will usually dislodge any dirt that may have contaminated the seat and you can test with fluid again.
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It may be possible to hook the coils and CAS back up with the head off and the key turned on, using a sharpened wooden dowel (or a plastic knife) to look like a straight blade screwdriver you can spin the CAS blade drive and if everything is properly attached and grounded I think you should have spark. Do watch for fuel leaks, plug any open hoses etc.
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I'm not sure which wires you are talking about being "corroded", if it's the spark plug wires they can back their way out of the hole some distance and yet continue to fire. They will get burned and crumble at the very end if this has been happening for some time. If it's corrosion at the low voltage wires then water must have gotten in there and may have ruined the coils so they would have to be replaced. You could try spraying with WD-40 and try to clean any connections but without a manual I can't tell you where to probe for electricity. Essentially one side will be hot and the other grounded through the ECU except when it's ready to fire. At that moment the least positive side will be opened and the field collapses to make the spark. It is not uncommon for makers to turn the power off when the engine is not running to reduce battery drain so it will get it's power from the start circuit and then the charging Alt and/or the oil pressure switch.

Wish I could be more specific on some of this but you are just going to have to sort some of this out with a manual and the schematics. I don't recall there being any electrical connection on my son's TSI so I can't help with that. There may be others who have been into the coil connections and the specifics of testing with them off the car or it not running. There is the possibility that the ECU has gone south, did you check any codes before you started work?

Cheers,
GTM

PS: I'm working on my own project namely a 400 amp battery charger so back and forth for coffee and reading posts.

 

[wishful_laser]

i think i found the problem. my mechanic found some bent exhaust valves that i had apparently missed. that is why im getting no compression, as for the codes from the ecu, i didnt have any at all. im going to swap heads with my other parts car and see if that fixes. im pretty sure that it will. thanx for all the help. should have it together tonight maybe tomorrow since today is valentines day and im going out with my girl tonight.

 

[GTM]

i think i found the problem. my mechanic found some bent exhaust valves that i had apparently missed. that is why im getting no compression, as for the codes from the ecu, i didnt have any at all. im going to swap heads with my other parts car and see if that fixes. im pretty sure that it will. thanx for all the help. should have it together tonight maybe tomorrow since today is valentines day and im going out with my girl tonight.

Ah, just what I feared. The problem with trying to exactly hit the nail on the head from day one comes from being dependent on the owner's ability to communicate all of the details. In this case it would have been helpful to have mentioned that the engine cranked over at a faster rate because of the compression loss. The backfire and misfire sequence was my clue that it had jumped time and then damaged the timing belt when it hit valves which finished the job.

As it turned out you did not waste time pulling the head or chasing after ghosts though it would be wise to repair any bad wires before you put this back together.

Well there go the dozen roses, the boxes of candy, etc for Valentines day. Just goes to show that you don't have to be driving fast for one of these to self destruct.

Cheers,
GTM

 

[1fast97gsx]

damn dsms ... good luck fixing it man.

 

[wishful_laser]

aww it that bad. everything happens for a reason right? bull@#$%. haha. on a more serious note, i do have a parts car( thank god ) that has a good head on it so im not out any money besides the new plug wires, and coil pack. about 150.00 compared to the 4-500.00 bucks. i will probablly go ahead and get the arp head studs and the metal h.g. just to safe. it is actually a lot of weight off my shoulders cause i have been stressing so bad this past week cause i didnt know what the problem was. thanx for your help guys. ill let you how it runs later on this week. one more question, can i safely run 750cc injectors with just a gm maf setup to tune? my safc 2 is coming but not so soon n e more thanx to the damn timing crap