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New Q-jet Hard To Start -- Update From SMI

Is your fuel pressure taken at the carb?
You say the choke blade is at 90* and closed...this is right when cold, if you pump the throttle a couple times and it stays open that isnt right for a cold engine.
Sounds like the float is maybe stuck up and keeping the needle on its seat and not allowing fuel in the bowl
Try filling the bowl through the vent tube then pump the throttle a couple times
It should show fuel squirts in the primary throttle openings
 
So that tells me that the fuel pump doesn't have power during cranking. That doesn't explain the dry carb. But I would suspect that either the needle is stuck in the seat, or maybe the fuel line, possibly filter is plugged somehow. I wonder if the needle got jammed due to shipping?
 
When your cranking the engine it may draw down the battery enough to pull full power from the fuel pump therefore showing 0#

If your choke blade is slighly open at 88* that should be ok but I dont think it should be fully open until the engine temp is up to 150 or more.
That choke plate needs to be open 3/16 or so while engine is cranking to allow some air into the engine....if it is fully open and cold it may want to die or be sluggish and hesitant.
If you fully open the throttle the choke plate should open that slight amount by the linkage forcing it open.
 
My truck has no problem keeping the electric pump at full output, while cranking, at 10 degrees ambient. It has done that lots of times. I will bet that the power to the pump is dropping while cranking. A lot of Ignition hot circuits do that. I put a jumper from the starter solenoid engage wire to the fuel pump relay, to provide power while cranking. On EFI trucks, the ecm does that.
 
Typically it has fuel pressure while cranking. Tonight it seems to fall off in sync with the battery struggling.

How likely is it I could loosen the float if I tap on the carb (assuming it's stuck)?

As for the choke I just realized that I did jot have the key on when I stroked the throttle so there was no power going to it. That's probably why it didn't set right.

Just to clarify, it did run good and I have driven it with this carb but this was all immediately after installing, not having sat. I did notice high idle on start up so at that time it seemed to be working correctly.
 
The choke sets itself by mechanical means when you open the throttle before a cold start--not electrically...the 12V going to the choke heats up a heater element to "unwind" the tension spring,to open the choke,that's all..
 
Small update:

I looked at the regulator this afternoon thinking it might be the problem. I pinched the return line to try an force fuel into the carb to check to see if the reg was somehow bypassing the carb and returning fuel. You can hear a dramatic change in pump sound from the load but still no fuel in the carb.

I then removed the carb inlet fuel line and stuck it in a can, turned the key on and it pumped about a cup of fuel out in 3-4 seconds. At that point I removed the carb inlet fitting and the fuel filter cavity had gas in it (no trash seen in there).

Note: I am not running a filter in the carb inlet. I am still using the OE TBI filter on the frame rail.

I guess my next step will be to call SMI tomorrow.
 
I don't think there's fuel in it but I don't know how to tell without taking it apart. I did put a pick down the from vent tube and could feel it push something that rebounded like it was spring loaded. While doing this the pump was running but no signs of fuel.

I don't want to take anything apart because it's under warranty.
 
That was the float springing back, should of had fuel flooding the bowl if you have fuel pressure and the needle is off the seat when pushing the float down.

The filter didn't have a black check valve in it did it? If so take it out and or try without the filter to see if you get fuel.

You said you have 5 lbs of pressure, is the gauge between the pump and the carb and you closed off the return line?

I wouldn't take it apart until you talk to SMI.
 
I don't have a filter in the carb, I'm using the frame mounted, canister type from the original TBI set up.

The regulator is a Barry Grant bypass regulator that's mounted after the carb, it uses backpressure to feed the carb. The gauge is an Autometer mechanical type with an isolator that's fed from a dedicated port on regulator.

It's a blurry pic but I think you can see all the parts (this pic was taken when I initially installed the carb but had not wired up the choke) -

 
I have an SMI Q-jet on my Caprice that does the same thing when I haven't driven it in a few weeks. I have an electric fuel pump that is frame mounted to boost the high output mechanical pump. Once the fuel bowl is filled, she lights right off but it takes considerable cranking to get there if It hasn't been driven in a month or more. I chalk it up to fuel evaporation:dunno:
 
After the checks I posted last night it seems like mine either has a stuck needle & seat or some sort of actual blockage.
 
Welp, SMI says send it back so they can tear it apart. I'll probably ship it off Monday.
 
You oughta ask them if they will let you take the air horn off.

Wonder if the needle fell off the float arm, or was installed improperly. Doesn't hurt them a bit if you can fix it that easy.
 
Just for info my 74 after sitting for 7 days it took 6 seconds of cranking and pumping to start and actually only pumped the pedal the last 3 seconds. I do have the plug kit installed, not just epoxy.

That sucks you have to send it back and wait.
 
I don't know squat about q-jets so I'm chicken to start pulling the top off. SMI has offered to cover the freight and promised 24 hr turn around so I'm just going to hit the easy button and send it to them.

I have other things I can be doing on the blazer so the down time is no a big deal.
 
UPS tracking shows they got it today and James at SMI called me a few minutes ago. :thumb:

They diagnosed it as having a stuck needle and seat. They have replaced it are boxing it up to ship out tomorrow. He is also throwing in a new base plate gasket to boot.

FANTASTIC customer service! :bow:
 
that's great to hear...When I was quad shopping, I couldn't get a call or an email response from them.
Did they say anything about the carb bowl drying up while sitting?
 
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