Spark Plug Gap For '93 4.3?

[peavey85]

Hi all! I gave my '93 Silvy a tune;new plugs,wires,cap,rotor,air filter,etc. all AC Delco! I used the correct plugs (CR43TS) and according to my Haynes manual,the gap should be .035;however the new plugs came set at .045 so I closed them down to .035. Now I don't have as much power! Have tripple checked all new componets I installed,so now I'm suspecting Haynes is wrong about plug gap,but would like to know what factory was before I go back in to open them up again! I'm also considering installing an MSD Blaster coil,and opening the gap to .065! Has anyone done this to their 4.3,and how did it run? Thanks in advance!

[txab]

From what I see, .035 is the correct gap for that plug in your engine. What plugs did you remove? Brand and Part #? What was the gap? If they are the same plug and gap, (they will be bit wider than how they were gapped during installation) then I'd look at other things you changed. Did you get the rotor installed correctly? Distributor cap on properly and well secured? All wires firmly attached and routed to the correct plug? Distributor didn't get bumped did it?

[peavey85]

Thanks for the response txab! I had NGK UR5's gaped @.035,cheap cap&rotor,cheap wires. I went all AC Delco because of all the recomendations on this and other forums! Engine runs smooth,just not as much 'git up & go'! I'll check my timing tomorrow,thats one thing I haven't checked. I'm still curious about the higher voltage coil and opening the plug gap some;how do you think it would respond?

[txab]

I ran a Jacobs Electronics system on my '80 350 Silverado. Gapped plugs at somewhere between .055 - .060. It ran fine, of course, since the Jacobs system put out enough juice to jump that gap. Stupid question..... you do know how to properly gap plugs?

 

Did you knock anything loose while you were working. Vacuum line? Some sensor wire?

[peavey85]

Yes,I know how to gap spark plugs,and I've already checked hoses,wires,etc. I have the 5sp in mine and it seems sluggish in 2nd below 1500rpm,like ive lost some torque! The 4.3's are supposed to be known for their torque aren't they? I guess after 100k miles it could be timing chain or compression! I checked timing,it's ok. Rebuild will have to wait till next year,so I suppose I should be thankfull it runs good!

[peavey85]

Well,I wiped the grease & grime off the catalyst sticker attached to my fan housing,and the plugs should be gapped at .045 ('93 4.3/5sp). so its back under the hood I go!

[txab]

Well,I wiped the grease & grime off the catalyst sticker attached to my fan housing,and the plugs should be gapped at .045 ('93 4.3/5sp). so its back under the hood I go!

 

I looked at 3 different references, all said .035, except for one specific plug type. That's one reason I asked what the old plugs were set to. I know all my older vehicles with carbs are .045

[peavey85]

Yeah,I know,I think the original HEI systems fom the 70's were .045-.060,so It suprised me that Haynes would say.035! I closed down the NGK's 2yrs ago because of Haynes! I guess I should have cleaned off the catalyst sticker then,but it was like 12* and just wanted it done! I'll let you know tomorrow if opening them back up to .045 solved the gutless blah!

[peavey85]

Sunday up-date; Happy Grandparents Day! While I'm awaiting the arrival of the kids & grandson I'll let yinz know that the truck ran MUCH better with the plug gap set at .040"! Before,when set at .035",it fet like it was running out of gas @ 4krpm,now it goes easily to 4.5k! Yinz have a great Granparents Day!

[97SierraGMC]

it should say in your owners manual

[peavey85]

Hi Riggs, I bought the truck used without a owners manual,so I didn't have a reference. Thats ok, I hope my experience is someone elses reference! I also opened them to .045" (my bad on the previous post)!