backfire+no start?

[shmed]

ok the 4.1 is all back together    fired it up an shook   like it was having a seizure???  did run   terribly tho...
then it shut off ok  checked a few thing   fixed a few wires   that were wrong   start up right away   still shaking with this exhaust type leak sound then bang backfire and it shut down.   try to restart an nothing but the sound of the new starter struggling.
so far I checked  the wires there on correctly
all the sensors are plugged in except the two on the intake coolant ones (broken)
took off the cam sensor cap  its all tight an the reluctor is screwed tight??
any ideas>

[earlbrown]

Crank sensor got smacked by the reluctor ring?

[earlbrown]

That wouldn't make the starter struggle though.   Might not be a bad idea to pop the plugs out and verify the engine turns over smoothy (for two full loops)

[Forzfed]

Double check your cam sensor.  I put mine in at 3:30 in the morning and accidently put the cap on 360' out.  Car started fine when cold put really hesitated when warm, similar to what you described, pulled a lot of amps on the starter.

[motorhead]

Double check your cam sensor.  I put mine in at 3:30 in the morning and accidently put the cap on 360' out.  Car started fine when cold put really hesitated when warm, similar to what you described, pulled a lot of amps on the starter.

360 degrees out, you say? 

[Forzfed]

Double check your cam sensor.  I put mine in at 3:30 in the morning and accidently put the cap on 360' out.  Car started fine when cold put really hesitated when warm, similar to what you described, pulled a lot of amps on the starter.

360 degrees out, you say? 

Divided by 2!

[shmed]

ok  earl did as you suggested   pulled plugs  turned over no problem..  no funny noises nada
ok   took a look at teh crank sensor ane it appears to have been rubbing  on the inside on the ring hopefully this is the problem

[Just a Six?]

If it's not the crank sensor (which when mine was rubbing about a year ago it ran fine but had a ticking sound that drove me crazy finding it) the big Backfire could be Timing Chain related but I hope that's not your issue. I sheared about 3-4 teeth off my crank sprocket years back & my car ran like yours when you say Shuttered. I hope it's something simple for you since the car has very little run time.
Is it possible you have 2 spark plug wires mixed up? When I did it ran like Crap & was hard to start!

[shmed]

ok    it  now starts....BUT>........ it wont idle or keep running   starts an  dies   unless i keep on the throttle...
if i unplug the maf it  runs longer but still  stalls.
ideas?

[motorhead]

Did you disturb the IAC?

[Scoobum]

ok    it  now starts....BUT>........ it wont idle or keep running   starts an  dies   unless i keep on the throttle...
if i unplug the maf it  runs longer but still  stalls.
ideas?

Almost sounds like something I did a year ago. I had the MAF pipe off...for some reason. I somehow plugged the 3 to 5 pin connector in upside down on my Z06 MAF when reinstalling. Did the same thing your car is doing.

[shmed]

thanks bum  but I'm  running a stock maf still. i did swap it it out for a now one i had laying around  with no change.
i did the iac reset thing  no change,  but does the iac  number on the scan master continuously change or should it be a certain number an stay there?
this one was jumping 10 30 25 15 etc?
i did hold the throttle till the car was fully warm  160+ an it idled  on its own but i noticed my wide band would swing from 0 to maxed out an back again as well as the vac gauge  10 15 20 0  etc
I'm starting to think theres a vac leak but i don't hear any kind of air movement noise/>

[Just a Six?]

My IAC numbers are around 30-40 & some days they hang aver 60+ but the car always runs the same. Lately it's been more in the 30's but I don't find any difference & if I didn't see the numbers on SM I would have no idea if they were Normal or High?
Any of the plugs look like they are burning different than the rest?

More specific answer to your question is the Numbers start high (around 100) then slowly get lower as engine temp comes up & AC is Off & your in Park. They will change in Drive so they are not Locked On a value yours seem in the correct range. Steve has a link on his site but I don't think there is much else to IAC numbers?

[Scoobum]

thanks bum  but I'm  running a stock maf still. i did swap it it out for a now one i had laying around  with no change.
i did the iac reset thing  no change,  but does the iac  number on the scan master continuously change or should it be a certain number an stay there?
this one was jumping 10 30 25 15 etc?
i did hold the throttle till the car was fully warm  160+ an it idled  on its own but i noticed my wide band would swing from 0 to maxed out an back again as well as the vac gauge  10 15 20 0  etc
I'm starting to think theres a vac leak but i don't hear any kind of air movement noise/>

Any codes on the SM?

[shmed]

no mal codes bum
tonight i switched out the iac from my car into this one why ?  why not
an didn't change a thing...   fires up   shuts down instantly...
wtf 
the plugs all look the same,
ideas I'm  at a loss now