Not sure what the cause is? Please help

I drive my girlfriends' 2002 Alero 4 cyl and at 101K miles the timing chain snapped. I took the motor apart and replaced all the bent valves, as well as the chain, guides, sprockets and every other part associated with it which came in a kit. At 106K miles the car would not start and the mechanic i had the care towed to is saying its the timing guide. He said "a lot of people dont replace it when they do this job." Well, i did replace it along with everything else including gaskets. Any idea what would cause this to happen after only 5K miles from being fully replaced. I dont really want to replace it again for it to only go another 5K. Please help. Thanks

Ok won't start, got spark, fuel pressure at the rail, injector pulse?

just heard from the mechanic and he's telling me that the guide is the problem. everything else as far as fuel, spark etc is fine. I'm just wondering if i got a defective part when i went to replace the old guide.

How in the world would a guide prevent a car from starting?,,,,,,was the engine making a slapping noise in the timing chain cover?

I assume this is an Ecotec engine? Kits I see are new cam sprockets, new crank sprocket, new chain, new tensioner, and new oil orifice....never saw a kit with guides.....they were only replaced individually if they were worn....

You have spark on all 4 cylinders? Fuel pressure is OK? Did he check compression?

If all ok, then injector pulse is next.....

Is it possible that this is a PassLock problem? Vehicle is not getting a fuel enable signal to the PCM?

http://www.autopartsnetwork.com/shop/-make_Oldsmobile-model_Alero-part_Engine_Timing_Chain_Kit-brand_Cloyes-position_N-fs-A-sku_9-ds-0390S.html?utm_source=google&utm_medium=gps&utm_term=Oldsmobile+Alero+Engine+Timing+Chain+Kit+ Cloyes+9-0390S+N%2FA&utm_campaign=google_base&fpi=OEF2EbT5N9CALQWXq9Y1qJBoz3nnhaW0f-pl-k6Ynh2lck=&gclid=CKuomq7AmrMCFREx4AodeHAAhQ

The mechanic said he would change the oil (which needed to be done anyways) and the guide which made the chain slip causing issues for $75. i'm going to pick it up today. Not sure how the guide was making it not start but they sent a pic of the broken guide i installed. looks like i got a defective part

i just got the car back. It was the tensioner that went. Took them a week to determine that. This is why i always do my own work when i'm at home and have tools