Hey everyone I just finished my engine i've been screwing around with for about 3 years now and i can't get it to start. I believe my problem is with the carb settings or possibly even with the carb being clogged and in need of a cleaning/rebuild. I did a TBI to carb conversion on my 92 RS and I have a mallory regulator hooked up to the stock in tank pump and run to an Edelbrock 750 electric choke carb. I have a fuel pressure guage on the carb side of the regulator and i have a steady 5 lbs through it while cranking the engine. The problem is i do not see any fuel at all getting through the carb into the engine. I know this isnt an ignition problem because if i pour a little bit of gas into the carb and try to start it, it fires right up, but if i give it gas it either dies or has even backfired through the carb once. Is there anything i can pull apart, or any way to test that the carb isnt clogged without pulling it off the engine. It's not really a big deal to pull it off, i've just had this thing together and back apart so many times i'm about to go crazy. Also for anyone who has run these carbs how did you set them up to start the engine the first time. Thanks.

 

Do you see fuel squirt from the accelerator pump nozzles when you open the throttle?

 

I don't see any gas getting through the carb while trying to crank the engine.

 

You're not supposed to, forget that for now.

Do you see fuel squirt from the accelerator pump when you open the throttle?

 

Yes when I open the throttle gas does come out of the accelerator pump.

 

Is the choke open or closed when you try to start?

 

tried open and closed, doesn't seem to make any difference.

 

How do you have the idle mixture screws set right now?

How are you trying to start it? Just turning the key and letting it crank? pumping the pedal?

 

Idle mixture screws are both 3 turns out. Tried just turning it over and pumping the gas and neither was enough to get it started, which is odd since the accelator pump is getting gas into the engine.

 

If fuel is going into the intake but it STILL doesn't start, then the problem isn't fuel.

Quit working on the carb, because you can't fix a no-start by messing with it, if it shoots fuel into the motor.

I'm guessing some other parts might have got changed at the same time.... at least, I hope so.... like the distributor. What dist did you put in it? How did you line it up? When the engine is at #1 firing (one of the 2 instances of #1 TDC during a complete engine cycle), as determined by compression coming out the #1 spark plug hole, which plug wire is the rotor pointing to?

 

The reason im hung up on the carb is because if i actually pour a small amount of gas into the intake it fires right up and idles fine until the gas runs out, but if you open the carb up while its running it dies or backfires. I'm guessing the timing is off some because of the backfiring but from what i've seen so far if the carb was getting the right amount of fuel into the engine it should at least start or continue running when you hit the gas.

 

MadOTC, did you ever get this problem fixed? I'm having the exact same problem but with a new/reman carb.

 

I'm actually still screwing around with this. I made some adjustments to the distributor but haven't found out if they work yet because my fuel pump quit on me. Ordered the new one earlier this week, so hopefully I can get something done on it again in the next few days. When I figure it out i'll let you know what I find.

 

Quick update. I took off the remanned non-cc qjet and put on the cc-qjet and everything started up fine and stayed running (despite having disconnected the ECM and having the vac adv distributor).

ive troubleshot everything else too. timing is good and have good spark. have good fuel pressure. accelerator pump even spits fuel. float isnt stuck up or down. i cant help but narrow it down to the idle circuit on the carb.

while looking at the primaries of the remanned carb, i could see the idle mixture screws sticking through a ways, certainly a lot more than the other carbs i have. and yeah, they were backed out 1.5 to 3 turns still. i read that some carb remanufacturers use "one size fits all" screws for these? the long pointy ones? that may be the source of my problem.

your problem sounds too similar to me. but i dont think edelbrock would make the mistake of putting in the wrong idle mixture screws. maybe its worth looking into the primaries just to see though? or maybe check to see of the float is stuck up?

 

Well i still cant get this dam car to start. Since the last time I posted i've replaced the in tank pump with a new hi flo walbro model, gone through the carb completely cleaning everything insde and out, blocked off all the vacuum ports on the carb to eliminate that as a possibility, and checked the timing again. Still have the same symptoms, still backfiring through the carb after running for a few seconds. Will not even fire unless I pump the gas while turning it over. Once it does fire it runs for a few seconds and then dies or backfires if i hit the gas. I've about had it with this thing, and i'm very afraid i've killed my cam at this point after cranking it for so long without a start. Anyone have any other suggestions?

 

Sounds like too much air, now; another word for a GIANT vacuum leak.

Check the PCV port (front of the carb, LARGE nipple); check the power brake port (rear of the carb IIRC, center of the throttle plate, LARGE pipe thread or some such fitting). Once you're CERTAIN that you've found both of those and either hooked them up or plugged them....

Back all the rockers off one full turn.

Start it up. When it starts, keep it running by whatever means necessary (short of physically pouring fuel in while it's running, since a backfire could light it off and spray burning fuel everywhere); adjust all 16 of them to zero lash with the engine running, as quick as you can; shut the engine off; then go back and add ½ turn of lifter preload.

Let us know if that makes any difference at all. No guarantees, but it's worth a try.

It's probably not the carb itself.

 

got the problem squared away. turned out that one of the brass insert idle tubes was clogged. cleaned the tubes and drilled them to .039"...idled much better.

 

Hello, i know this post is old, but I was wondering if you had a picture of what you are talking about. I am having the same issue.