Won't start, backfires - The 1947 - Present Chevrolet & GMC Truck Message Board Network

JET4x4 · 10-28-2010, 12:51 PM

So I replaced the valve cover gaskets in my 69 yesterday. I steam cleaned the engine afterward and it was running great. Drove it home and parked it. Went out to start it this morning and no start. It cranks over but backfires out of the exhaust. I don't see anything loose under the hood as far as wiring or anything like that. I grounded a plug wire and it seems to have spark, still has the original points distributor. The dist isn't loose so I'm assuming it's not a timing issue. I guess my question is if the points/condenser crapped out, would that cause the engine to back fire? I'm going to do away with the points setup no matter what, just looking for some input on where else to look for a problem.

JRBECK64 · 10-28-2010, 01:00 PM

Were you getting on it hard yesterday? You may have jumped a tooth on your timing gear. Or it may just be wet inside of your distributor cap. I would check the inside of the distributor to see if its wet first.

JRBECK64

JET4x4 · 10-28-2010, 01:25 PM

Nah wasn't beating on it. I was thinking moisture in the cap but I figured it would have dried out by now. I reckon I'll have to take the cap off and have a look see.

RustyParts · 10-28-2010, 01:43 PM

If you used a steam cleaner you probably have condensate in the distributor cap.

ChevLoRay · 10-28-2010, 01:44 PM

To dry the cap, you can use some WD-40, which will displace the moisture. The other thing you can do is grab some toilet paper. It will soak up any moisture that is in the cap.

By the same token, you might want to take a good look at the cap and be sure it doesn't have any cracks that will allow moisture to enter, aside from the "window" that opens to adjust the points. If you have an HEI, then disregard the window comment.

**DANTIP** · 10-28-2010, 02:29 PM

I agree with the moisture under the cap. They won't typically dry by themselves.

JET4x4 · 10-31-2010, 08:17 PM

Thanks for the replies. The problem was indeed moisture under the cap. My hei came in the mail yesterday so I put that in this morning, no more points and it runs like scalded cat.

10-28-2010, 12:51 PM	#1
JET4x4 Registered User Join Date: Jun 2009 Location: Birdsboro, Pa Posts: 135	Won't start, backfires So I replaced the valve cover gaskets in my 69 yesterday. I steam cleaned the engine afterward and it was running great. Drove it home and parked it. Went out to start it this morning and no start. It cranks over but backfires out of the exhaust. I don't see anything loose under the hood as far as wiring or anything like that. I grounded a plug wire and it seems to have spark, still has the original points distributor. The dist isn't loose so I'm assuming it's not a timing issue. I guess my question is if the points/condenser crapped out, would that cause the engine to back fire? I'm going to do away with the points setup no matter what, just looking for some input on where else to look for a problem. __________________ 67 Chevy K20 LWB Fleetside project 85 GMC K10 High Sierra LWB, 37's, 8 lug rears, 4.10's project 86 m1009 blazer, 6 in lift, 35's, driver 69 c10, 307, long bed, 3 speed, driver 07 Dodge 2500, cc, lb, cummins turbo diesel 00 z28 camaro, ls1, 6 speed, rarely leaves the garage

10-28-2010, 01:00 PM	#2
JRBECK64 Registered User Join Date: Sep 2008 Location: Cornelius Oregon Posts: 1,073	Re: Won't start, backfires Were you getting on it hard yesterday? You may have jumped a tooth on your timing gear. Or it may just be wet inside of your distributor cap. I would check the inside of the distributor to see if its wet first. JRBECK64

10-28-2010, 01:25 PM	#3
JET4x4 Registered User Join Date: Jun 2009 Location: Birdsboro, Pa Posts: 135	Re: Won't start, backfires Nah wasn't beating on it. I was thinking moisture in the cap but I figured it would have dried out by now. I reckon I'll have to take the cap off and have a look see. __________________ 67 Chevy K20 LWB Fleetside project 85 GMC K10 High Sierra LWB, 37's, 8 lug rears, 4.10's project 86 m1009 blazer, 6 in lift, 35's, driver 69 c10, 307, long bed, 3 speed, driver 07 Dodge 2500, cc, lb, cummins turbo diesel 00 z28 camaro, ls1, 6 speed, rarely leaves the garage

10-28-2010, 01:43 PM	#4
RustyParts Registered User Join Date: May 2006 Location: Wyman, Kentucky Posts: 403	Re: Won't start, backfires If you used a steam cleaner you probably have condensate in the distributor cap. __________________ 1972 GMC Jimmy, 4WD, 454 CI, 350 Turbo, 4" lift, 35" tires The math teacher said my son "Bubba" could be a mathmatical genius. cause he's got 13 fingers!

10-28-2010, 01:44 PM	#5
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Re: Won't start, backfires To dry the cap, you can use some WD-40, which will displace the moisture. The other thing you can do is grab some toilet paper. It will soak up any moisture that is in the cap. By the same token, you might want to take a good look at the cap and be sure it doesn't have any cracks that will allow moisture to enter, aside from the "window" that opens to adjust the points. If you have an HEI, then disregard the window comment. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.

10-28-2010, 02:29 PM	#6
DANTIP Registered User Join Date: Sep 2001 Location: Fort Wayne, Indiana, USA Posts: 1,888	Re: Won't start, backfires I agree with the moisture under the cap. They won't typically dry by themselves.

10-31-2010, 08:17 PM	#7
JET4x4 Registered User Join Date: Jun 2009 Location: Birdsboro, Pa Posts: 135	Re: Won't start, backfires Thanks for the replies. The problem was indeed moisture under the cap. My hei came in the mail yesterday so I put that in this morning, no more points and it runs like scalded cat. __________________ 67 Chevy K20 LWB Fleetside project 85 GMC K10 High Sierra LWB, 37's, 8 lug rears, 4.10's project 86 m1009 blazer, 6 in lift, 35's, driver 69 c10, 307, long bed, 3 speed, driver 07 Dodge 2500, cc, lb, cummins turbo diesel 00 z28 camaro, ls1, 6 speed, rarely leaves the garage



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