2002 4.3L Replaced intake manifold, all wires disconnected. Installed Dist and started but rough, code 300 (misfire random). Replaced all wires,plugs, still running same. Removed dist, rotor at 12 oclock, verified need 180 out to reseat on shaft. When installed, rotor at 1 oclock, now won't start. Oil pump key???. Does PCM have to be reprogrammed???? Help

 

I don't believe the PCM needs reprogrammed. I've had a 2000 Safari with a 4.3 for about 11 years, and replaced the distributor at least three times. Finally bought a good NAPA one after two junk Autozone ones. Found out that the bearing in the OEM distributors for a certain run were short lived and caused the P300 randome misfire/ run rough. Changing the dist cap and rotor was only a temp help. After about 5 of those I went for the Dist. It's tedious, but make sure you have the alignment marks on the bell housing and the engine block exactly right, making sure not to turn it past, or you gotta go all the way around again. Then make sure the dist key aligns correctly with the oil pump key. use a LONG screw drive and turn it if you have to.

 

When the bearing goes bad the dist wabbles in the housing causing the spinning rotor to sometimes be closer to the wrong point in the cap, sometimes the spark actually jumps to the wrong point. The cap points will look pitted and burnt.

 

Thanks, some of this matches to what I am fighting. Question, Plug wires in cap(from 12 going clockwise) 5-1-3-2-4-6-coil. sounds wrong but haynes and chilton both say so. Then when finding where to set dist, I am trying to set with #1DTC comp stroke, should I still make sure rotor pointing approx 8 oclock, tht is where #1 cap pick up looks to be??? From your comment, (marks on block and bell housing), housing of dist??? Because dist placement is set, No slop back and forth,,,,and how would I know if ket for pump is wrong. Really appreciate you help

 

Let me get the instructions on how I did it and I'll put them on here in a bit. I don't have any pics, I used drawings from Justanswer.com, another web site, and pics in the haynes manual. I'll describe it the best I can.

 

The engine front cover has two alignment tabs, one at about the 1 oclock position above the crankshaft balancer. The crankshaft balancer has 2 alignment marks (spaced 90 degrees apart) which are used for positoning #1 piston ( Left hand forward piston) at TDC. With the piston on the compression stroke and at TDC, the crankshaft balancer marks must align with the two alignment marks on the front engine cover located 90 degrees apart. On my Blazer, the bottom tab is what looks like a "tab" at the 4 oclock position.

Rotate the crankshaft balancer clockwise until the alignment marks on the crankshaft balancer are aligned with the tabs on the engine front cover, and the #1 piston is at TDC of the compression stroke. Use a socket and ratchet or breaker bar on the nut in the middle of the balancer. If you go past, don't back up, go all the way around again to the same spot.
Ater putting on a new gasket on the distributor, align the hole on the drive gear of the distributor with the paint mark on the distributor housing.

Ensure that the the distributor rotor segment, or contact point, points to the cap hold area (the #6) on the distributor housing. (There may be a 6 cast into the distributor housing pointer indicating that the distributor is to used on a 6 cylinder engine or an 8, indicating that the distributor is to be used on an 8 cylinder engine).

Align the sloted tang in the oil pump driveshaft with the distributor driveshaft. Rotate the oil pump driveshaft with a LONG sloted screwdriver if necessary, don't rotate the distributor to match the oil pump shaft.

Align the flat part of the distributor housing toward the front of the engine and install the distributor and distributor clamp.Once the distributor is fully seated, check the alignment of the distributor rotor segment with the #6 pointer that is cast into the distributor housing base. If the distributor rotor segment doesn't come within a few degrees of the #6 pointer, the gear mesh between the distributor and the crankshaft may be off a tooth or two. repeat procedure in order to achieve proper alignment.

Install the distributor clamp bolt and tighten to 18 ft/lbs.

Install a new cap and rotor and wires. Wala!

 

Thanks alot, good info, and I will take a look. I believe that I am on the right timing mark. If I go one tooth in any direction, engine says no way. I believe I have a bad dist or programming issue, manuals keep referencing an EPROM, not exactly sure if my engine applies. Any test to verify Dist,????? that sounds like a probable suspect. Just trying to verify before buying a good one, know whar ya mean about Auotjunk, warranty is good, but you wiil use it. I did get it running after playing with it ,,,,after reading your post, the key for the oil pump doesn't feel like it wants to turn much, but it did move 1 tooth and ,,,wala,,, running but rough. Friend says to drive for 20 miles and see if it cleans up. kinda worried about murphys law and all that, Thanks for the help.

 

After replacing my intake gasket in a 2000 blazer I have a crank sensor code and the car does not want to start. I didn't line up the oil pump key like y'all are saying to do but it looked very close on the timing marks. Could the oil pump key be why mine is acting up? Will that cause you to be off a tooth and create that code?

 

If you dont line it up, the dizzy will bounce around and it'll run really rough. It also means no oil is getting to your engine.

 

That makes sense. I'm gonna do it again and see what happens. Thanks for your help