you may or may not have read my other posts on here so let me start from the beggining...

I purchased a '98 chevy blazer, 4*4, LT, vin W. the engine had a bad knock when I bought it, i planned to put an engine in it. I bought a used engine from a junkyard only to find out when I got it home it was from a '96 VIN X s10. when I pulled the engine from my blazer I noticed that the donor engine must also have been from a 2wd model, mine is 4*4. I was unaware of the differences in vin's/engines before this project so I called the junkyard to make sure everthing was going to work, they assured me it would. obviously I had to swap the oil pan, oil pickup, and remote lines from the old engine to the donor. I wasnt too happy about it but I didnt feel like waiting around for another engine so whatever, I did it. we also changed the crankshaft position sensor because the electrical connector was chipped on the donor engine.

I installed the donor engine in my blazer and began cranking it over but it wouldnt start. just *put *put *put out the exhaust like a very mild backfire, VERY mild! After investigting fuel, spark, air i began swapping parts. I swapped over the parts from my original engine because I knew it ran. I swapped the plugs, spark wires, coil, rotor, cap, camshaft sensor in distribitor?, i swapped the crankshaft sensor back to the one that came in the donor engine, I swapped the spyder injection assy, throttle body with both sensors in it. A few things that just pop in the valve covers (not sure what they are. and still with no luck! I have good spark, and when I pull the plugs there coated with fuel. I have 60 psi on the schrader and it doesnt leak down fast either. maybe 15 psi in ten mins. I can hear my fuel pump running too.

also, the distributor is in time, I set it a tooth behind and ahead to see if that made any difference. still no luck so I set it on with cyl 1.

I have fuel, I have spark, I have ignition timing. what else can I do? what sensor tells the ECM when to open the injectors? I thought it was the cam sensor in the distributor but I swapped that and the crank sensor. I have not swapped the knock sensor yet. or coolant sensor but my coolant read 5c. My scanner cant read all the sensors but I have a hard time believing its one of the sensors already discussed because they came out of a running engine. I also dont thing it should be anything on my vehicle because all the hardware on the chasis ran my other engine. what other sensors could it be, or what else could it be period?!?

I'm a newbie here, I have decent mechanical skills but I dont know all the jargon yet so clear explenations are apreciated!

 

Whenever your take out the distributor hold down clamp or even open the timing cover to get to the sensor in there, you need to do a re-learn to get everything back in proper timing. It's best if you take it somewhere that has a live-data scanner and can set it back. These vehicles are not like the old school chevy's, you can't just use a timing light on these engines.

 

I thought someone said you would need the VCM and complete wiring harness from the donor vehicle? I don't know either way myself. Still, with fuel on the plugs there should still be some explosion I would think.

Are you 100% sure that you installed the distributor at TDC on the INTAKE stroke? Common mistake to install 180 out on the EXHAUST stroke. Everything looks exactly the same on the outside. Not trying to insult your intelligence, but describe how you determined you were #1 TDC on the INTAKE stroke when installed the distributor? Maybe you are overlooking something because you are so close to it. When you the distro was installed, it is pointing at the little '6' on the base of the distro when it's seated...yes? Not starting on the '6' when you drop it in, but ending there when it is completely seated?

You have the spark plug wires plugged into the distributor (drivers side, from the front) 3-1-5...yes?

I've never tried it before, just now making it up, but maybe you could install a compression gauge on the #1 cylinder and hold the spark plug so it will create a spark off the engine. Have on eyeball on the compression gauge and one on the spark plug...in those first few stroke when you see the needle bouncing on it's way up, the plug should spark at the same time. Just now made that up so it is only a theory and maybe a real dumb one.

 

My father in law has worked quite a bit on blazers so he guided through the timing process.

I removed the cyl one plug and bumped the ignition over until I thought it was close, the put a long screw driver into the cylinder and began turning the engine over by hand with a ratchet on the crank pully. It was very slow doing all this myself, I would turn it just a little bit , get up and feel with the screw driver if it was up yet, then go turn a little more... I did this several times to get a feel for what I was doing and even played around with my old engine. When I could feel the piston coming up it caused my screw driver the see-saw down. I kept it just a tad low rather than a tad high and it was right on the little arrow with the six...

Here's the funny thing, my old engine, that was running , was a tooth behind! So, even though I knew it was on I set my donor engine a tooth behind then ahead, and it made no difference.


As far as the wiring harness I kind of ruled that and the PCM out. I think the gentleman was on different page describing the newer x engines and not the old x's and w's. Although when I make it over that way again I want to ask the junkyard for one just to make sure.

 

You don't have to remove the timing cover for any of the sensors but I did talk to a GM dealer about the crankshaft re-learn and they confirmed my theory, the car should still start, in fact you have to bring it to operating temperature do the re-learn . So if a CPS re-learn is what you mean then I don't think that is the issue.

Can they do final time on the scanner? There is no way to adjust it mechanically on the blazer!

 

The one key thing you don't mention in your description is the presence of pressure/vacuum at the #1 cylinder. You may have the distributor placed 180 degrees out.

Here two key things to note: 1) there are two timing marks and they both need to be aligned with the protrusions on the timing cover; 2) the crank makes two revolutions for every one revolution of the distro rotor.

Take #1 spark plug out (actually it's easier to turn the crank buy hand if you take them all out). Have someone put their their thumb on the #1 spark plug hole (if you're able to turn the crank and use your own finger, even better). When you are are approaching TDC on the COMPRESSION stroke (or INTAKE) there will be a significant amount of pressure blowing out of the #1 spark plug hole (assuming the piston rings are good). This happens because both valves are closed as the piston rises. NOTE: There is some pressure blowing on the exhaust stroke also because the piston is rising for that stroke, but it very noticeably less then the COMPRESSION stroke. You might want to try this out on your old engine first since it sounds like it is much more accessible. That way you can feel what to look for on your donor engine. Once again, you will feel the air blow by on both the COMPRESSION and EXHAUST stroke, but it is a ton more noticeable on the COMPRESSION stroke. There are about a half a dozen different methods to do this. Some people use a strip of tissue paper and watch when blows. Some plug the hole with wadded up paper and watch for it to pop out. Probably the best way is to use a vacuum gauge. But barring a vacuum gauge, I like using my finger so I can feel what's going on (plus I just don't like sticking things in the spark plug hole).

When you feel that large amount of pressure and are approaching the timing marks, finish lining up the marks. You will be at TDC on the COMPRESSION stroke. At that point, look at your rotor and see where it is pointing. It should be pointing at the tiny '6'. If you have installed the distributor wrong, it will be pointing 180 out. Remove the distributor and re-install so that it seats pointing at the '6'. I've never seen the "arrow" before. I'll hunt around and try to find a couple pics for you.

If you find the rotor is pointing correctly at TDC on the COMPRESSION stroke, it has been known for the piece on the dampner with the timing marks to slip on occasion. It rides on a piece of hard rubber and I have heard of it slipping which throws your timing marks off. But I'm betting you have the distributor installed 180 out.

However, if the dampner has slipped, you can find TDC on the COMPRESSION stroke by using a vacuum gauge (that shows pressure and vacuum). As you approach TDC on the COMPRESSION stroke the pressure will rise, rise, rise....go very slowly. At the EXACT point where the gauge starts to switch to vacuum, that is TDC on the COMPRESSION stroke.


EDIT: I've attached two pics on what you should see. I'll look for a video that explains what I've described above.

EDT 2: This is an ok link...shows the overall idea, but two things to note...first, he is speaking about find TDC on any cylinder, obviously you are only concerned about #1....second, he states that once the gauge switches to vacuum to then back up...DON'T BACK UP!. There is a small amount of slack in your timing chain. If you go past TDC, you need to rotate the crank TWO complete revolutions (remember, crank rotates twice for every one rotation of rotor) and come back up on TDC for #1 on the COMPRESSION stroke.

 

Just to make sure I understand, the piston travels up, then down, up then down, for every complete single rotation of the rotor? And one of those strokes allowed fuel in and compresses it while the other pushes the burners gas ( exhaust) out of the cylinder?

 

Correct. You want your timing marks aligned at TDC on the COMPRESSION stroke and your rotor pointing at the '6'.

 

Your a godsend! That did the trick! After fighting with this thing for three weeks you have no idea how awesome I'm feeling right now! Thanks a million!

 

Good deal. Now your next step is to get it either to the dealership or a shop you are confident has the capable tool and the knowledge to adjust the Cam Position Sensor (CMP) and do a Crank Variation Relearn (CKP).