any chance the distributor was put in 180* out?

 

i would love to know what happened as I am working on a friends blazer and having the same issues. had it at the dealership to do a case relearn and the service manager showed me the tech 2 and its not even giving an option for the relearn drove it home and found out the distributor wasn't plugged in. once we plugged it in it would not even run. All of the timing set is new everything as far as disty and lining everything up has been checked and double checked. No idea what is causing this. this truck wont even start with the distributor pluged in but it will run without the connector plugged in the back for what that may tell you. any help would be greatly appreciated.

 

Well, reviving this thread. Finally got a chance to get out there and mess with it a little bit. Decided to start back at the beginning. lined up cyl 1 on TDC compression stroke and threw the dizzy back in. Got it to start and idle on its own. First time this has happened since I got the motor back in it.

Still a problem. The blazer will sit and idle, but idle is ~300 rpms and sounds like the timing is seriously retarded. Tried advancing the dizzy a bit in case I dropped it in wrong. 1 or 2 teeth advanced will begin to make it run as it did before last night, just totally erratic idle and stalling. 1 or 2 more teeth retarded and it runs similar and then the next tooth back it will no longer start.

Was able to test fuel pressure and it read a constant 62 psi. This is new since I couldnt get an accurate test before due to the erratic idle.

Also, with the dizzy in this way even if it is idleing, if i open the throttle blade at all the engine begins to die. I can just open it or pump it back and forth and it begins to stall out either way until I close it back up.

This spark any new ideas?

Thanks fellas

 

I apologize if this is a dumb question, but why are you adjusting your distributor by teeth? I would expect you could install the distributor, leave the clamp loose and then gently twist it to adjust your timing. Without a count of teeth on the distrib gear I can't break it down for you, but you could be adjusting your timing by several degrees at a time if you're pulling the distrib and re-installing it to move the timing. Assuming I'm not talking out my butt in the first place, doing so is imprecise, to say the least. When it comes to engine timing, a little adjustment can make a big difference in idle quality.

Even using just your ear, you should be able to hear a difference by slowly turning your cap while the engine is running. I strongly suggest you buy a timing light and a bottle of white-out to dial in your timing after re-installing your distributor. Typically, most engines are set to 10 degrees BTDC at idle (I have no idea what the factory spec is on our trucks).

 

The reason I went by teeth was that I was under the impression that these trucks would adjust the timing to counteract what you were doing while moving the distributor. I had initially moved the dizzy that way and was told that it was of no use because the PCM would see those changes and reverse them. I will go out and try this on my next night off. Same thing as far as using a timing light, I thought that was ineffective because of the way the PCM adjusts timing. If this thinking is incorrect, I will also try this method on the next night out there.

Any thoughts as far as the blazer idling and then stalling when the throttle blade is opened? As I said it sounds like the timing is retarded, but didnt know if this stalling was due to that, or maybe another peice of this big blue jigsaw.

Thanks

 

Did you check your coils Ive seen coils do some crazy stuff if they have a slight crack try to check with known good coils.

 

Yes, coil was replaced with one from a known running motor. Anyway the map sensor could cause this? I did not try this one, as I didnt want to break it by pulling it from the plenum. Would the blazer run with no MAP connected?

 

got to messing around with it more. still no real progress. Started it up, with the dizzy in the same spot as before, where it would idle itself, unless the throttle was opened at all in which case it tried to kill itself, and unplugged the MAP. idle jumped from ~200ish to probably ~400ish, just not sure what to make of that.

On a side not, picked up a fun little toy. Got this gem for 150 bucks. Motor runs strong (165k on it) tranny is supposed to be on its last leg, and he managed to grenade the g80 out back. all that I wanted was the motor and maybe a few spare parts. It looks like it may come down to having to swap this motor in. I hate it because of the couple hundred I have in mine, but I do not seem to be capable of solving this problem.

Side note, with the donor motor coming from a 96 there isnt going to be any wiring differences in there correct? I noticed there was a sensor in front of the T-stat housing where I have a block off, but no other major differences.

On with the pics



The day we picked it up. when they grenaded the rear end the clip that holds the pass side axle in was also broke. This means every few trips into the shed I get to stop and jack it up so I can kick the wheel back on.



First night working on it. Trying to make things simple for pulling the motor/tranny. my blazer was a PITA to get all the bellhousing bolts undone and lucky for me the body is already **** on this one