Intermittent Random Missfire

[GOBR]

Its a Comp XE274. Now I got the timing all set good and carb tuned its not as lopey just real choppy. Its got SOME lope but its a faster choppy type idle. Comp said that cam with my heads and intake this was the best off the shelf pick. Was about to go with a XE262 which would of had more tq but I went with this one and sacrificed a lil for a more choppy idle.

I mean the miss isnt bad, its just there. You cant feel it and it doesnt affect performance at all. If I had stock mufflers I doubt I could hear it.

 

[Jims86]

Its a Comp XE274. Now I got the timing all set good and carb tuned its not as lopey just real choppy. Its got SOME lope but its a faster choppy type idle. Comp said that cam with my heads and intake this was the best off the shelf pick. Was about to go with a XE262 which would of had more tq but I went with this one and sacrificed a lil for a more choppy idle.

I mean the miss isnt bad, its just there. You cant feel it and it doesnt affect performance at all. If I had stock mufflers I doubt I could hear it.

Maybe its time to de carbon the top end of your engine. You said the only questionable plug is #3?

 

[89Suburban]

Got the oil problem fixed. Added a qt and its fine now. Guess Ill start usin 6 qts instead of 5. Still workin on the missfire. Broke till tomorrow and in between startin jobs soooooo. Heres a vid of the oil pressure and the temp it runs at. Nevermind the talkin some guy stopped next to me and wanted to know who does my body work.

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I thought the average was 5 1/2 to six quarts. Is there something wrong with the dipstick? Are you not getting an accurate reading?

Ok, I just looked in the Haynes manual, it says 5 for small block. Hmm. Plus 1/2 - 1 qt for filter? Mine takes 5 1/2 to hit the full mark with a full standard size filter.

 

[GOBR]

I thought the average was 5 1/2 to six quarts. Is there something wrong with the dipstick? Are you not getting an accurate reading?

Ok, I just looked in the Haynes manual, it says 5 for small block. Hmm. Plus 1/2 - 1 qt for filter? Mine takes 5 1/2 to hit the full mark with a full standard size filter.

My dipstick doesnt read. I ordered the wrong one. Pickin up a new one tomorrow. I didnt check the pickup/oil pan clearance so that could be an issue also.

Maybe its time to de carbon the top end of your engine. You said the only questionable plug is #3?

The heads were just cleaned and I installed new valves. The motor was just rebuilt. The engines only been runnin for the last week. I think #3 was #5 on the old engine and #5 was burnin ALOT of oil. I forgot to clean it before installin it in this motor and I think it dried it up. I cleaned it yesterday and checked today and its a brownish white color now so its ok.

 

[79K10]

im not sure if your miss was diagnosed but if the oil pressure flicks during the miss then it has to be electrical right? maybe the coil wires crossing with the oil pressure wire... grounding the coil out once in a while, making the oil dip and causing a miss

 

[89Suburban]

im not sure if your miss was diagnosed but if the oil pressure flicks during the miss then it has to be electrical right? maybe the coil wires crossing with the oil pressure wire... grounding the coil out once in a while, making the oil dip and causing a miss

He has mechanical gauge, it was low on oil at high rpms.

 

[GOBR]

Wonderin could a sloppy timin chain do this...... I need a reason to put the gear drive in there......

 

[Guardian]

I would look at the distributor cap and coil. Had a similar problem and found the cap was breaking down.

 

[Jims86]

Wonderin could a sloppy timin chain do this...... I need a reason to put the gear drive in there......

Put a timing light on it, unplug the vac advance, and check it in drive.
Sloppy chain affects EFI more than carb.

 

[GOBR]

Somethin electrical aint right. I put a ground strap on it yesterday and when I cranked it over the starter kept hesitating and the temp gauge went crazy. its a mechanical gauge but it has the metal line on it and its touchin the body. Gotta be a short somewhere. Guess Ill start cuttin out wires I dont need.

 

[89Suburban]

Somethin electrical aint right. I put a ground strap on it yesterday and when I cranked it over the starter kept hesitating and the temp gauge went crazy. its a mechanical gauge but it has the metal line on it and its touchin the body. Gotta be a short somewhere. Guess Ill start cuttin out wires I dont need.

Check there isn't a hot wire laying on that sending unit line, I have been through that many times when I used to run aftermarket gauges. A rubber grommet where it goes through the firewall would be smart too.

 

[Jims86]

Somethin electrical aint right. I put a ground strap on it yesterday and when I cranked it over the starter kept hesitating and the temp gauge went crazy. its a mechanical gauge but it has the metal line on it and its touchin the body. Gotta be a short somewhere. Guess Ill start cuttin out wires I dont need.

If your talking about the efi harness you can send it to me!

 

[GOBR]

I took the ground strap back off. I remember I took it off last time cause it was gettin smokin hot while cranking it over. It didnt make a difference in anything on or off so Ill just leave it off... Still got a missfire. Maybe some of the wires are bad. I really dont have the money to work on anything right now. On top of this I beleive my starter is goin out. Guess Ill go have it checked in the mornin. Wonder if I could rebuild it with this other starter I got in here. Its smaller and different teeth than this one but I know everything is good. Mainly the solenoid would be all I need right?

 

[GOBR]

If your talking about the efi harness you can send it to me!

The harness is junk anyway. The guy before me hacked into a bunch of stuff. The PCM is still in there tho...... Im sure its non Cali emission stuff tho. Would it matter?