Car backfired big time, blew mufflers apart,put new ones on,now won't start. Cranks good, wants to start,but won't. put new coil on, checked compression. #8 plug looks good, #1 fouled, fuel flow was 9 oz. in 7 seconds( holley double pumper). book say flow should be 1 pint in 30 seconds.
Found oil in gas, think diaphragm has a hole in it.. Plugged gas line, put gas in carb,still won't start checked optics in dist. says it's good.
Anyone got any ideas why it won't start, any help would be welcomed
Thanks in advance gurus,
Rich

 

When I had a no start problem back when I was putting back my 74 someone said to me the three basic words.
Air, Fuel and spark.
Check and make sure you are getting all 3. Since I'm not familliar with "optics in dist" I cant help with that but if you have points, make sure they are gapped properly, make sure you are getting spark to the plugs.
Sounds to me like you have no spark.

 

,,is the timing chain good ??

 

I checked spark at plugs and there is spark there and at coil,not big spark, but spark. Had a guy tell me it jumped time. but dot it to TDC and rotor was at #1, getting plenty of fuel, maybe to much,air well that's not a problem.
Going to put new fuel pump in today, the oil in the gas from the fuel pump, does mean a hole in the diapraghmn and there was quite a bit.
But, your right that's the first thing i thought of was no spark, I checked coil and thought it was bad so I got a new msd.
Worked on this thing now for three days, it's starting to drive me buggy.
Thanks for your input, I appreciate it.
Rich

 

It maybe that your plug wires are off by one plug. That would cause the backfire & not starting. Double check. If you don't have a shop manual move all the wires over one try to start. if fails move them back and then back one in the other direction. I wouldn't start or run the engine w/gas mixed in the oil chg it first. GL Jim

 

Jim
There is oil in the gas from the fuel pump so there is probably gas in the oil, for sure when I replace the fuel pump today I will definitely change the oil, Had planned to anyway soon. Will try what you reccomend with the wires, just put a new cap on it and might have got them wrong, but it was doing that before I changed the cap, so I don't think that's it. All this trying to start it is killing my new battery.
Thanks for the help
Rich

 

Sounds like a timing issue. Can you get your hands on a static timing light?

 

DON'T HAVE A STATIC LIGHT, just the old type you hook on a wire, thought the same thing, but when I get it to TDC everything lines up.This is driven me nuts .
But i'm a stubborn old cuss, I'll figure it out if it kills me
thanks
Rich

 

What have you touched on the engine? Sounds like you've made lots of changes. Are you doing a rebuild? Or are you just upgrading some parts? Did you touch the cam? Try a compression test. See if there is a valve open when it shouldn't be? I agree with prior posts, sounds like timing or something dumb like wires on wrong.

 

I'm thinking you have a carb issue. It doesn't sound like you jumped time IMHO. I bet you're dumping too much gas in which would account for the backfire in the first place. Are the plugs wet after you crank it for a bit? Drain the carb and see if you can get it going with starting fluid. If so, then you know where the problem is.

 

Rich,

Have you removed the distributor? Maybe 180 out.

 

Rich, was the motor running before you changed the cap? If so you have your wire crossed over one. I've done this many times myself on different sports cars. Motor running then minor tune-up and it will not start & loud backfires, it the wires this is the order they go in clockwise
1-8-4-3-6-5-7-2 The only other time my vette had the same problem start the distributor module went bad. However that is not commom so charge the battery and try the wires.
JIm

 

Jim,
Yes the motor was running good until i changed the mufflers, but it was backfiring bad before that, that's what blew the mufflers apart, I hadn't run it for about a week or so and I thought I would start it to go for a ride and it just started backfiring real bad. I then checked the dist. cap and found the center caron contact was broken off and the cap was melted at the hi tension lead from the coil so I took an old one I had and put it on and then,no start I ck'd the coil(mallory 92440) and it seemed to be bad so I bought a new one the guy said I didn't need one like that and sold me a MSD Blaster 2 coil and I put it on, checked the module and it did what it was supposed to according to Mallory.
It's been like thissince it started the backfiring and I put the new mufflers on. seemed to me like it wants to start but i thought it was flooded, took the gas line off the carb to see the flow, got 9 oz. in about 7 seconds. book says should be 1 pint in 30 seconds, about 1 pint in 1/2 the time. thats when I noticed the oil in the gas and that indicates a hole in the fuel pump diaphragm, accorrding to the chiltons book I got. The haynes says nothing about that.
sorry to be so long winded, but I thought I'd bring you toaolly up to speed on this.
The wires are just as you say on the cap. the auto parts guy said to disconnect the gas line and put some good gas in the carb and seeif it will start, did that, nothing, just cracks , but it seems like it wants to fire but won't.

So i'm replacing the fuel pump and changing the oil and the will start all over again from square one.hope I didn't screw something up in the engine when it backfired.
Thanks for the help, will let you know if i get it running.
Rich

 

Ahh, ok didn't realize you swapped the dizzy. You seem quite mechanically competent, so I don't want to insult you. But are you sure you're not 180 out? Can you pop a valve cover off and just verify that for us real quick?

 

WC,
What the h--- is a dizzy. once i put the new fuel pump on and it doesn't start, thats my next move. I never removed the dist. so I don't think that's it, but that's my next move.
been working on my own cars since I was 16, that's 50 yrs. now and I never came accross a problem like this before in my lifeand I'm about right now you could be right, but if it is180 out Then i'll have to kill my neighbor cause it must have been hin that snuck over here one night and changed the dist.
Thanks a million, i appreciate any input i can get right now.
let you know what happens on tues,
Rich but I love these vettes so I don't mind the hassle at all

 

dizzy = distributor

Sorry, I should read more carefully. I guess you didn't restab after all.

So back to my original theory, have you checked to see that you're not flooding like mad? After you crank for a bit, what do the plugs look like?

 

So , did you ever get it to start?

 

I've also had this problem - IGNITION MODULE. Car would crank fine but would not fire/start. Bad ignition module. Part cost me $13. Advance Auto Parts tested it for me and let me know it was bad. Started up nicely with a new one. If you get the GM one, it will cost a little more.

 

Holley Carb + Backfire ... often = Blown Power Valve in Carb.

Unilite LED/Module = history of leaving folks in the lurch.

-edit- someone else mentioned timing chain ... I second that ... because: OE timing set used plastic-jacketed cam gear ... Backfire + Plastic Gear ... often = Shucked Cam Gear Teeth & Loss of Timing.

 

even if you blow a power valve in the holley it will still start, blew mine in my nova. never could tune it after it blew.

i would really look at the ignition module. had problems with the one in my z-71. tested fine but wouldnt start. got tired for fighting it and took it to the chevy dealer, they changed the module and havent had a problem in almost a year now.