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Series I Engine Tuning Forum EMS (Flash Tuning, Interceptor, Piggy Back, Stand Alone)

kmr/b2a streetport tuning, fresh rebuild.

Old 12-25-2016, 06:27 AM
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GA kmr/b2a streetport tuning, fresh rebuild.

I have Mazda edit.
And I have finally got my fresh motor put back in.
Rebuild has
***The built2apex Bridgeport, without the bridge.
So I'd say it's a big streetport. Exhaust is maxed out, literally.
*** Atkins solid corner seals,
**Atkins apex,
**new bearings.
**new eshaft.
*header,catless mid,catback, aem intake
*air pump blocked off.
*corvette coils
Motor ran when pulled out. Before the rebuild

Car cranks an will idle 1500 rpms . But once the car drops to the 800 range it stalls. No vacuum leak, But. I don't have my intake valves hooked up yet. Which these aren't used at idle so that shouldn't be the issue. I'm getting random missfire and idle insufficient codes car runs and revs smooth unless rpms go below 1000

I'm guessing the porting needs a higher idle. Do I just need to start off by raising the idle on my mazdaedit, or should I start with maf scaling,

If anyone has some streetport Maps that I could compare to mine would be perfect.
Is 1200 a good starting point for setting the idle ?


I've also heard of hard starts/ idle problems on fresh rebuilds, taking time to seat the Apex seals to unrefinished housings. Is this true ?
Old 12-25-2016, 09:29 AM
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Bridgeport without the bridge? Atkins cryo seals? Why solid corner seals? What does "corvette coils" mean? What tune are you running?

When you say "I don't have my intake valves hooked up yet", does that mean you have the vacuum solenoids blocked off?

Hard starts on rebuilds is due to poor quality rebuilds. It sounds like you should have done some more research before starting down this path.

Last edited by 9krpmrx8; 12-25-2016 at 09:32 AM.
Old 12-26-2016, 03:57 AM
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Vacuum solenoids blocked off. Corvette ignition coils... running a tune with increased ignition dwell, cels turned off. Added some timing up top. Ran perfect on this tune.

It's their Bridgeport template, I just ported all the other ports to match the template without cutting the bridge.

Atkins cryo? No the standard Atkins Atkins apex seals for a rx8.

Only time I have hers starts is when the car dies out.
Old 12-26-2016, 04:19 AM
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Originally Posted by nlsolja123
Corvette ignition coils... running a tune with increased ignition dwell
I'm willing to bet you're hitting the auto discharge threshold. Possibly an expensive mistake.
Old 12-26-2016, 09:43 AM
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TX

Originally Posted by nlsolja123
Vacuum solenoids blocked off. Corvette ignition coils... running a tune with increased ignition dwell, cels turned off. Added some timing up top. Ran perfect on this tune.

It's their Bridgeport template, I just ported all the other ports to match the template without cutting the bridge.

Atkins cryo? No the standard Atkins Atkins apex seals for a rx8.

Only time I have hers starts is when the car dies out.
Yeah well different engine means a different tune due to the change in VE. And 1985 Corvette Coils or LS coils? Or do you mean GM truck coils?

I only ask about the Atkins seals because my buddy received his like this from Atkins. he didn't spec them before he built the engine because they were new and when it would not start, he pulled it back apart and spec'd everything and found this.


Old 12-27-2016, 10:05 AM
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That makes me sick. I hope to god that's not the issue. The car is running the sme tune as before the rebuild. The coils are set for the dwell they need the coil style is the same as bhr with the heatsink. I think d85 or something. I can'tremmeber exactly. It's been a year since they was installed

The car cranks almost every time. I can hold the rpms at 1500 and it seems to stay idled there. (With my foot on it) under that range it does misfire. But it isn't throwing any codes now. Just stalling.

Maybe bad gas ? I already went through 3 gallons of 93*.

Some engine rebuilders say to hold revs at 2k rpms to break in the seals . Is this common? Rotary redirection and addicted performance both recommend this.
Old 12-27-2016, 10:23 AM
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Oh okay so not Corvette coils, the D585's never came on the LS engine. And yeah my buddy was pissed and Atkins didn't handle the issue well either. Stalling on home build is not uncommon, sometimes it can just need to run a while to compression due to using sub par parts in the rebuild. But if you have been running it a while and it still won't hold and idle then it is either a tuning issue, a vacuum leak, or low compression. Assuming you are not getting any weird codes, but I would assume things like fuel pressure and ignition are fine since it will run with some throttle.

If I were you I would go drive it and put some miles on it. But maybe take a buddy in case you stall it.
Old 12-27-2016, 10:25 AM
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But since you did more than a street port, then it could definitely just be the tune.
Old 12-27-2016, 06:38 PM
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i managed to get it to hold a solid idle at 1200, felt sluggish like it was misfiring


I saw Alot of people talking about injector wires getting mixed up, so I pulled the upper, wired by the schematics. Now it revs up, freely. No sluggish. Seems like and improvement. But now I have an intake leak somewhere. It does try to idle and it's erratic but it has a leak. It's very loud
Old 12-29-2016, 10:57 AM
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Everything is good now. Kinda.

Motor runs good, drove it around the block and back 2 times. Cranks right up when cold BUT. I have hot start issues. I'm guessing the seals just need more time to seat. I know fresh rebuilds take a little time to build optimum compression. Motor feels great, pulls well under half throttle and under 4k. Revs nicely.

I have now about 1 mile driven lol . About 3 hours of idling smooth at 1100. I'm guessing it's to early to make tune changes so I'm kinda stuck.

Do I just need to keep cranking it daily and letting it run and idle to let the seals break in ? Maybe a few more trips around the block ? It isn't registered so I can't drive far.
Old 12-29-2016, 11:35 AM
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I wouldn't call that good but it's better I guess. It's not uncommon for home builds using sub par parts to take a while to build compression. But there are also many that don't ever build compression and need another rebuild.
Old 05-26-2020, 03:36 PM
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I know it's been a while. But I figured I'd update. So after the car gets to running temp car stalls. My compression is at 30ish psi.

I do have the motor partially ready for removal. I also have a spare motor. I have all the parts to do a rebuild .

Really thinking of just having someone do it ... Anyone located in GA with some time on their hands that wants to make some money?
Old 05-26-2020, 04:42 PM
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Mazmart is my recommendation.
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