Hello everyone, just finished putting a new head gasket on a 95 blazer, cpi, vertical sparkplug tower. Is there any special relearn process I need to go through? This truck does not have a crank sensor but it does have a cam sensor in the distributor - I put the dizzy in so the *** was pointing at #1 on compression stroke.

I have checked

fuel - about 58-60 psi and can smell gas
spark - will start briefly so it's getting some kind of spark
valves - I tightened the valves about one full turn past lash (I did not do a compression test yet and of course I should have when engine was out but everything looked pretty good (engine has low miles)

 

Sounds like your pretty close here.
I have only seen this motor timed one way, with the front balancer lined up to the two marks then the dizzy dropped in pointing to #6. So with that you have a 50/50 shot.
I don't know if that applies on yours as mine is setup with the horizontal.
Do a little search in the google box on the BF hompage for that.

Your FP seems low and on a CPI that's really low. First and easiest is were I would go, with a FP leak down test. Gage hooked up key on engine off, FPR should open at 61 then drop to 60 immediately and hold above 55 for at least ten minuets.

Welcome, by the way!

 

58-60 at keyon is good. What is it after ten min of sitting holding pressure

 

I had the same problem one time after an engine replacement and it turned out to be the maf sensor. I guess I must of damaged it sometime during the removal/install. It did just like yours ran briefly than stalled.

It could almost be anything but as you know they need fuel, air and spark. You verified 2 of three............

 

How can you get TDC on #6? I'm pretty sure with the crankshaft match-marks lined up I'm on TDC for #1? I think you are thinking for 96+ that have horizontal plugs

Anyway, I have a Haynes manual that is just about useless and does not explain how to set the timing

 

Get rid of the Haynes manual, they're worthless.

If it has vertical plug wires on the distributor cap, it has High Energy Ignition system, (HEI) and it does NOT have a camshaft position sensor, crankshaft position sensor, or MAF sensor and there is no "6" on the distributor housing. No relearn is necessary or possible with that system. It has OBDI engine controls, not enhanced, (OBD1.5).


The crankshaft makes two revolutions for each one revolution of the distributor shaft. Are you sure #1 piston is at TDC of the compression stroke? If it's at TDC of the exhaust stroke, it will not start, just a bunch of induction, (backfire through throttle body) while cranking. If that's the case, the distributor is 180 degrees out of phase. Bring the rotor to #1 plug wire. Then manually rotate the crankshaft with a socket & ratchet, one revolution clockwise and stop when the timing marks are aligned. Remove the distributor and reinstall it so the rotor segment points at #1 plug wire in the cap when it is fully seated.

 

Just did a compression test and I had several dead cylinders - apparently 1 full turn past lash is too much for my engine? On some valves if I go past 1/3 turn I get low compression results.

I'm almost done with the adjustments and all my cylinders are reading 115-125 psi so its looking good. But it doesn't seem right to leave the valve nuts so loosely tightened.

But yeah the Haynes manual has been pretty useless as far as timing my 4.3 I just bought a Chiltons manual on Amazon hopefully it will be more useful but not doing a compression test when the engine was out with easy access was REALLY dumb of me........

thanks everyone

 

Valve lash is not adjustable on your 4.3L. Torque the rocker arm nuts to 20 foot pounds. Chilton & Haynes are basically the same. Half of the information is incorrect, the other half is missing. They're OK if you need to learn how to change oil, but beyond that, forget it. Alldata subscription is better, but the GM factory shop manual is the way to go if you want ALL of the right answers. Over 3000 pages covering one model year. Ebay usually has them at reasonable prices.

 

My bad not a maf but a map. They do basically the same thing.

 

I can't get even close to 20ft lbs on the rocker nuts. The best I could do was remove "lash" (when the push rods stops rotating between my fingers and then a 1/4 turn, anything more and it appears I'm opening the valve (what does that mean? Bad valve springs?? The engine only has 78k on it but I guess the valve springs can go bad too.

Anyhow, after putting everything back together she fired right up and sounded pretty darn good. Since I dont have the muffler on I don't want to wake my neighbors so I will have to wait till tomorrow to check timing (with tan wire removed ect).

Thanks everyone