Let me begin by saying this place is great and full of knowledgeable people from what I've been reading. I've been searching like crazy to try and find someone with the same problems I'm having but been coming up short.

So on with the problems:

I have a 2000 Blazer 4-door, 4WD. Took it in to the shop because I knew the cat was blown out and banging around inside the exhaust, was gonna have them put a new one on. When I went to drive it up there it wouldnt start, so I had the battery charged (it was dead) but it still refused to start, so I ended up having it towed in. They told me it needed a new fuel pump and cat. Well my inlaws wanted to get the timing chain done since it has 125k on it and they wanted a piece of mind that it wouldnt break on them. So the shop wanted $2k to do it all. Well my uncle is an ASE certified Master mechanic, so i called him up and he told me to get it towed to his place and we would do it for the cost of parts and pizza.

My inlaws OK it so off we go to his house awaiting the Blazer to arive. In the meantime my sister tells me that its also leaking oil, and asks can we look at it. In the end I purchased:

Intake Manifold gasket set; O2 sensor; Fuel pump; fuel filter; cap and rotor; plugs and wires; timing chain set; timing chain cover; water pump.

So anyways, everything come apart and goes together great, no hiccups cept for the fuel filter that was rusted on. So we go to start it up and it doesnt start. So we checked for fuel, fuel is good 60 psi constant from turn on to turn off. Then we check for spark, we only get 1 little spark out of the coil and off of a spark plug when grounded. Then the car starts throwing a Crank sensor code P0336. So I read up on here a little bit and go buy a ICM and a new crank sensor. I took the ICM to get tested and they said it was bad btw. So we put the new parts in and still only 1 little spark. So we get out the test light and start probing around on the connectors, when we get to the CPS plug we can get crazy constant spark if the test light is grounding it, when we connect it to the sensor, we get 1 little spark.

at this point were confused as hell and ruling it out as an electrical problem. Anyone have any idea whats going on?! or something we can test?

btw my uncle did find 3 grounds behind the intake manifold on the passenger side that the black coating has worn out... could this be the problem? ( patching it up tomorrow just asking)

Sorry for the long post just wanted to make sure the whole story was here.

 

Check the continuity of all of the wiring from the CKP sensor to the PCM.

A problem with the CKP sensor can prohibit starting.

P0336 - CKP (crankshaft position) Sensor Circuit A Range/Performance

 

Thanks swartlkk for the help, we found the plug to be bad on the CPS and replaced it with a nice new one from the dealer. So with that fixed, the CEL is gone, but the Blazer is still not starting up. All we get is one little spark or no spark at all. My uncle says that he is all out of ideas and is about to give up on the thing, that I cant let happen due to the fact that it is my mother inlaws car and she needs it back on the road heh. Any other advice would be greatly appreciated.

Thanks!

 

If the pickup coil in your distributer has gone bad it may cause your spark problems, as the pickup coil is responsible for sending the signal to the ignition control module to control the spark.

Since your ICM was bad there is a possibility that the bad ICM damaged the pickup or possibly a bad pickup damaged the ICM.

Either way you should test the pickup as well as the connections to it.

You can test it yourself with an OHM meter or take it in to be tested as some auto parts stores will test them for you.
I believe that a steady reading between 500 and 1500 ohms is the acceptable range for the 4.3 but you may wish to check your Chilton manual to be certain of the values.

 

I had trouble with the 5.7L in my 2000 step van not starting last year. I hooked up a timing light and only detected spark occasionally. Tried both the coil wire and plug wire and had the same result with the light.

I replaced the ICM and no change.

Next I removed the cap and cranked the engine to be sure the distributor was turning. At this point my coil wire was laying near metal and I accidentally found that I had a contentious spark out of the coil and summarized if I had spark all of the time from the coil to ground it had to be not making it through the cap and rotor. My cap and rotor were not new like yours are but new parts can be bad sometimes

I replaced the cap and rotor and it has started every time since.

Not sure if this helps, but Good luck.

Blazme

 

Ok, about to give up on this thing and tow it to the dealer. I bought a new distributor because the guy at the parts store said they didnt stock the pickup coil. Well that didnt do anything at all to the starting problem. So.....so far I've replaced:

Plug wires
Plugs
Cap
Rotor
Distributor
CPS
CPS Plug
ICM

Still only getting a single spark or NO spark at all. Also theres no codes popping up at all.

What frustrates me even more, is that the damn thing started before we took anything apart, albiet it didnt want to start sometimes, if you kept trying, it eventually did.

Anymore suggestions?! or should i just bite the bullet and take it in??

Also, please keep in mind, I'm only getting 1 or no spark OFF THE COIL, therefore only getting spark from plug #1.

 

You defiantly should have tested the pickup before spending a hundred bucks on a whole new distributer. All the ignition system parts aside from the computer itself can be easily tested with a simple volt and OHM meter. Testing parts first rather then just replacing them on a maybe will save you big $$$

Have you tested the coil itself at all?

 

try finding every ground point u can on the engine and body, and clean em good. also look for broken wires or corroded wires along the engine wire harness.
corrosion adds resistance to the circuit and drops voltage signals.

 

Dropped it off at the dealer 2 days ago, they called to tell me that I somehow got the wrong timing chain cover or it was machined wrong. Had them put a new one on, damn thing started right up.

 

That would do it... Why did the cover get replaced in the first place?