please help! weird problem

[brocsbar]

Ok I'll try to keep this short. 95 blaz vin W 4.3 with 5000 miles on it. Had a vacuum leak and code 305 so i did the intake and it fixed it, put it back together and i got code 1345 off a tooth so i backed it one tooth and ran great no more 1345. Ran good for two days with no codes and then ran like crap yesterday Fuel pump ok new fuel filter. getting code 300. cap wires plugs good. seems like it is starving and i even got a small backfire or two when it was surging. can i guarantee it is timed without removing timing cover? isn't there a cylinder i can get to TDC and the rotor should point to the 6 marked on the DIS?
Another thing i checked is the spider assembly. It seemed wet in there so i turned on the key and pressurized the system and checked for obvious leaks and found none. Is it supposed to be totally dry under the plennum? It wasn't soaked but damp. Also the Battery was disconnected but i could still hear like a buzzing or something coming from around the spider so i got out my trusty rubber hose and put it to my ear and it sounded the strongest when i stuck it down the #1 hole. It doesn't always give me code 300, and this 300 problem seems to only appeared after i did the intake. There is no turning the distributor so is it possible i could be off a tooth or two without code 1345? the only code i get now is 300. It did it cold yesterday morning and that's when i did the fuel filter and the wife said it ran great all day yesterday and today it ran good for most of the test drive but then started acting up??? Please help!!

[old_master]

Wow, lots of questions, I'll do my best..

P0300 is usually due to a problem with secondary ignition, (spark plugs, plug wires, distributor cap, rotor and ignition coil), or low fuel pressure.

Starving...for fuel??? Ignition in RUN position, engine cold and off, fuel pump running; fuel pressure must be 58psi to 64psi. It must remain above 53psi for 3 to 5 minutes after the fuel pump shuts off. (This will tell you if there are fuel leaks) The 4.3L CMFI engine MUST HAVE correct fuel pressure for the poppet nozzles to squirt fuel properly.

#1 cylinder at TDC: Manually rotate the crankshaft until the rotor points to the #6 on the distributor housing. Make sure both lines on the damper are lined up with the tabs on the timing cover.

If the distributor is off a tooth, P1345 WILL be set. If no P1345, you're ok.

Hope this helps.

[brocsbar]

i will check tonight about the fuel pressure but im sure it will be fine new pump last year. so if the balancer marks line up and im not on the 6 mark then i will pull DIS and get it right. I think that i am not timed properly but was wondering why no 1345 code like as if the computer was compensating or if i was 2 teeth off and crossfiring but not throwing a 1345 when i checked with my timing light the mark didn't line up with the notch, but i couldn't find tan striped wire by distributor as it said in the chiltons

[old_master]

First off, throw your Chiltons book away. Your vehicle does not have the EST wire, that's why you couldn't find it, Chiltons doesn't have a clue.

Like I mentioned earlier, if the SES light is not on, (no P1345), the distributor is installed correctly. The timing light will tell you nothing, the ECM controls timing. If you really want to know what the timing is, connect a scan tool and you can check it right on the scan tool.

Just because the fuel pump is new, is no guarantee that it's good. I've seen bad ones right out of the box, especially Airtex pumps! Check fuel pressure and leakdown then post the results.

[brocsbar]

ok i checked timing and dead on. new bosh lifetime warranty pump and i will go do the fuel tests and readings and post in an hour.

[brocsbar]

cold motor fuel pres 59 1/2
after 1 minute 59
2 minutes 58.5
3 58
6 min 57.5
8 57
20 min 42
like i said it is a lifetime pump ( thought it should be 62-65 so i will probably fight for a new one anyway but with these results i think i can say my spider is good ( did the presure test with plennum off so i could look for obvious leaks) little wet but can't see or smell obvious fuel. Looked at the wires and they still have numbers on wire so not new. Changing them tomorrow and will post. got new autolite platinums and will change them with AC delco reg plugs unless i need platinums

[old_master]

Fuel pressure is low, should be 60psi to 66psi. Your leakdown rate is fine.

The 4.3L engines are very fussy when it comes to spark plugs. Save your money on the Autolite plugs and invest in AC Delco CR43TS, you'll be glad you did.

Autolite professional series plug wires have the best specs though, and that would be a good choice.