12a DHLA Hot Start
06-15-20, 05:51 PM
#1
12a DHLA Hot Start
Have an issue that has happened twice so far in the last ~ 2months of daily driving my FB this summer.
Setup:
-Relatively fresh rebuilt 12A Streetport (resurfaced and nitrided irons, all new OEM Mazda seals, good housings).
-RB DLHA48 Side Draft with Wrap around manifold. Good jetting, mixture, I believe.
-(Running header heat shield, intake manifold heat shield, and a heat shield between bottom of carb and engine)
-Stock ignition, except MSD Coils. Plugs in good shape, runs well.
-Aftermarket fuel pump, regulator, return line etc.
Any 'normal' hot start (ie after getting gas, shutdown the restart immediately), it will instantly fire up and idle smoothly. Often I wont even touch the gas pedal. Make me think compression #'s are fine.
On two occasions now, spread a month apart, after I drive the car (fully up to temp) and park it, and leave it for 10-20mins, it won't want to immediately start. Doesn't even seem to catch. Typically on a warm start I will give one small shot of the accel pump and it will start no issues.
Because I am used to the car starting easily and I'm super paranoid of flooding it, I try to start it for a bit (small accel pump shot, but limited throttle opening during cranking), then I immediately freak out, pull the plugs to see if they are fouled... but never even look wet... After I let it cool off a bit more, it fires right up.
My thinking is leading me to a heat soaked carb issue, and maybe my warm start technique makes it worse. All of my heat shielding is useless once the car is shutoff and parked. The carb and manifold that are usually cold to the touch heat soak to the engine temp.
I read a bit about a more flat footed approach if this happens? Maybe that will give you an accel pump shot but then also a lot of air. I think my pedal technique is maximizing accel pump and minimizing throttle plate opening.
I also have a Sterling Nikki sitting here ready to go... because I know some of the carb gurus will say to ditch the Dellorto!
Setup:
-Relatively fresh rebuilt 12A Streetport (resurfaced and nitrided irons, all new OEM Mazda seals, good housings).
-RB DLHA48 Side Draft with Wrap around manifold. Good jetting, mixture, I believe.
-(Running header heat shield, intake manifold heat shield, and a heat shield between bottom of carb and engine)
-Stock ignition, except MSD Coils. Plugs in good shape, runs well.
-Aftermarket fuel pump, regulator, return line etc.
Any 'normal' hot start (ie after getting gas, shutdown the restart immediately), it will instantly fire up and idle smoothly. Often I wont even touch the gas pedal. Make me think compression #'s are fine.
On two occasions now, spread a month apart, after I drive the car (fully up to temp) and park it, and leave it for 10-20mins, it won't want to immediately start. Doesn't even seem to catch. Typically on a warm start I will give one small shot of the accel pump and it will start no issues.
Because I am used to the car starting easily and I'm super paranoid of flooding it, I try to start it for a bit (small accel pump shot, but limited throttle opening during cranking), then I immediately freak out, pull the plugs to see if they are fouled... but never even look wet... After I let it cool off a bit more, it fires right up.
My thinking is leading me to a heat soaked carb issue, and maybe my warm start technique makes it worse. All of my heat shielding is useless once the car is shutoff and parked. The carb and manifold that are usually cold to the touch heat soak to the engine temp.
I read a bit about a more flat footed approach if this happens? Maybe that will give you an accel pump shot but then also a lot of air. I think my pedal technique is maximizing accel pump and minimizing throttle plate opening.
I also have a Sterling Nikki sitting here ready to go... because I know some of the carb gurus will say to ditch the Dellorto!
06-15-20, 07:17 PM
#2
Waffles - hmmm good
iTrader: (1)
Try waiting about 10 seconds with the fuel pump running before kicking off the starter (is that possble on an FB?). Otherwise give it a pump or two then crank it. I had a Dell and they will heat soak. Like t he time I was driving back from GA to NC in 100F+ weather. Barely got it going on the gas stop and babied it for most of the entrance ramp until cooler gas was flowing thru. My nikki does it too, I have gotten to the point of not turning off the car unless I know it will sit for at least 30-40 minutes. Which might just be old engine-itis in my case.
The following 2 users liked this post by t_g_farrell:
GSLSEforme (06-16-20),
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06-16-20, 04:12 PM
#5
ancient wizard...
I knowTim,just poking the bear,lol
Been repairing cars of all types for 45+ years and it’s nice to get in my SE and turn the key and it starts and runs no matter temperature or weather conditions.
I like 1st gens,old school,real sports car and SE has just enough of that character and bridges the gap to a more modern car.
Didn’t like 2nd gens styling,didn’t like working on them,lot more technical than 1st gens. A LOT of electrical issues.
3rd gens disliked most,of all 3 gens I did more warranty work on 3rd gen cars than all 3 gens put together.
When I would pull a ticket for a 1st gen after weeks of 3rd gen warranty work it was like seeing an old simple friend.
Owned a 3rd gen for a little over a year and while it was a competent car,entire time I owned it,in back of my mind was what it was going to need next.Like a high maintenance woman,no sooner than serviced,something else would crop up needing attention and$$$.
IMO,highly technical,very complex,highly refined-but they weren’t good cars,couldn’t refer to them as reliable.
That’s what1st gens are,reliable and fun to drive. I’ve had my current SE for 28 years now and while I’ve broken things on it being heavy handed,it has been reliable like a good old girlfriend. I know how to treat it and it rewards me with smiles each timeI get behind the wheel.
It’s not the fastest car I ever owned but it’s quicker than it was when new and always runs,stops and steers the same way and i’ll never sell it as there are times I take it out for a drive cause I like the way it works thru the backroads near my house or just hold pedal down in 5th and let it eat on interstate for several miles. It’s always happy to do what I want,always.
Been repairing cars of all types for 45+ years and it’s nice to get in my SE and turn the key and it starts and runs no matter temperature or weather conditions.
I like 1st gens,old school,real sports car and SE has just enough of that character and bridges the gap to a more modern car.
Didn’t like 2nd gens styling,didn’t like working on them,lot more technical than 1st gens. A LOT of electrical issues.
3rd gens disliked most,of all 3 gens I did more warranty work on 3rd gen cars than all 3 gens put together.
When I would pull a ticket for a 1st gen after weeks of 3rd gen warranty work it was like seeing an old simple friend.
Owned a 3rd gen for a little over a year and while it was a competent car,entire time I owned it,in back of my mind was what it was going to need next.Like a high maintenance woman,no sooner than serviced,something else would crop up needing attention and$$$.
IMO,highly technical,very complex,highly refined-but they weren’t good cars,couldn’t refer to them as reliable.
That’s what1st gens are,reliable and fun to drive. I’ve had my current SE for 28 years now and while I’ve broken things on it being heavy handed,it has been reliable like a good old girlfriend. I know how to treat it and it rewards me with smiles each timeI get behind the wheel.
It’s not the fastest car I ever owned but it’s quicker than it was when new and always runs,stops and steers the same way and i’ll never sell it as there are times I take it out for a drive cause I like the way it works thru the backroads near my house or just hold pedal down in 5th and let it eat on interstate for several miles. It’s always happy to do what I want,always.
The following 2 users liked this post by GSLSEforme:
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06-16-20, 04:26 PM
#6
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Join Date: Mar 2001
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Been repairing cars of all types for 45+ years and it’s nice to get in my SE and turn the key and it starts and runs no matter temperature or weather conditions.
I like 1st gens,old school,real sports car and SE has just enough of that character and bridges the gap to a more modern car.
Didn’t like 2nd gens styling,didn’t like working on them,lot more technical than 1st gens. A LOT of electrical issues.
3rd gens disliked most,of all 3 gens I did more warranty work on 3rd gen cars than all 3 gens put together..
I like 1st gens,old school,real sports car and SE has just enough of that character and bridges the gap to a more modern car.
Didn’t like 2nd gens styling,didn’t like working on them,lot more technical than 1st gens. A LOT of electrical issues.
3rd gens disliked most,of all 3 gens I did more warranty work on 3rd gen cars than all 3 gens put together..
06-16-20, 04:27 PM
#7
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Location: https://www2.mazda.com/en/100th/
Posts: 30,832
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06-16-20, 04:52 PM
#8
Rotary Fan
your new title
Mike,
I just noted your new title. Hope you're well.
Clyde
I just noted your new title. Hope you're well.
Clyde
I knowTim,just poking the bear,lol
Been repairing cars of all types for 45+ years and it’s nice to get in my SE and turn the key and it starts and runs no matter temperature or weather conditions.
I like 1st gens,old school,real sports car and SE has just enough of that character and bridges the gap to a more modern car.
Didn’t like 2nd gens styling,didn’t like working on them,lot more technical than 1st gens. A LOT of electrical issues.
3rd gens disliked most,of all 3 gens I did more warranty work on 3rd gen cars than all 3 gens put together.
When I would pull a ticket for a 1st gen after weeks of 3rd gen warranty work it was like seeing an old simple friend.
Owned a 3rd gen for a little over a year and while it was a competent car,entire time I owned it,in back of my mind was what it was going to need next.Like a high maintenance woman,no sooner than serviced,something else would crop up needing attention and$$$.
IMO,highly technical,very complex,highly refined-but they weren’t good cars,couldn’t refer to them as reliable.
That’s what1st gens are,reliable and fun to drive. I’ve had my current SE for 28 years now and while I’ve broken things on it being heavy handed,it has been reliable like a good old girlfriend. I know how to treat it and it rewards me with smiles each timeI get behind the wheel.
It’s not the fastest car I ever owned but it’s quicker than it was when new and always runs,stops and steers the same way and i’ll never sell it as there are times I take it out for a drive cause I like the way it works thru the backroads near my house or just hold pedal down in 5th and let it eat on interstate for several miles. It’s always happy to do what I want,always.
Been repairing cars of all types for 45+ years and it’s nice to get in my SE and turn the key and it starts and runs no matter temperature or weather conditions.
I like 1st gens,old school,real sports car and SE has just enough of that character and bridges the gap to a more modern car.
Didn’t like 2nd gens styling,didn’t like working on them,lot more technical than 1st gens. A LOT of electrical issues.
3rd gens disliked most,of all 3 gens I did more warranty work on 3rd gen cars than all 3 gens put together.
When I would pull a ticket for a 1st gen after weeks of 3rd gen warranty work it was like seeing an old simple friend.
Owned a 3rd gen for a little over a year and while it was a competent car,entire time I owned it,in back of my mind was what it was going to need next.Like a high maintenance woman,no sooner than serviced,something else would crop up needing attention and$$$.
IMO,highly technical,very complex,highly refined-but they weren’t good cars,couldn’t refer to them as reliable.
That’s what1st gens are,reliable and fun to drive. I’ve had my current SE for 28 years now and while I’ve broken things on it being heavy handed,it has been reliable like a good old girlfriend. I know how to treat it and it rewards me with smiles each timeI get behind the wheel.
It’s not the fastest car I ever owned but it’s quicker than it was when new and always runs,stops and steers the same way and i’ll never sell it as there are times I take it out for a drive cause I like the way it works thru the backroads near my house or just hold pedal down in 5th and let it eat on interstate for several miles. It’s always happy to do what I want,always.
06-17-20, 04:26 PM
#11
Ok guys some good advice. On the Fuel Injection topic, yes a longer term plan for the car is a more extreme setup with some sort of ported 13B running ITB.
As j9 says, yes my 82 can have pump running whenever. My aftermarket relay is triggered by OEM power line, so pump runs whenever key is in ACC or IGN. Typically I do practice that, let pump run for a bit before starting.
And I like your idea of the FB GSLSEforme.
Next time I park it for a 'heat soak' duration, I will try a technique of two accel pumps then start with throttle at idle. In all other scenarios, even hot traffic, no issues with the Dell.
As j9 says, yes my 82 can have pump running whenever. My aftermarket relay is triggered by OEM power line, so pump runs whenever key is in ACC or IGN. Typically I do practice that, let pump run for a bit before starting.
And I like your idea of the FB GSLSEforme.
Next time I park it for a 'heat soak' duration, I will try a technique of two accel pumps then start with throttle at idle. In all other scenarios, even hot traffic, no issues with the Dell.
06-18-20, 08:42 AM
#12
seattle seven
Don't forget, they like to ice up on colder days too! just the nature of the beast. I call it character... don't get that with F/I.
Last edited by lwrobins; 06-18-20 at 09:17 AM. Reason: add pic
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t_g_farrell (06-18-20)
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