67 twin turbo dart

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turbodart68 said:
One of two things is happening. Either the motor makes no power and adding boost results in no power or the boost reference is wrong and its not really seeing 15psi at the intake valve. Or timing. Whether the computer is pulling timing for some reason or the timing was set wrong to begin with and the reference is off. I hate to say it but this is where these mix and match fuel injections can be a total nightmare and not worth the headache.
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Boost reference is right off the spacer plate if you will on the tb elbow. I'll check to see what they have timing set at and if it is low up it. Thanks my friend its turning into a nightmare.

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Matts440 said:
Boost reference is right off the spacer plate if you will on the tb elbow. I'll check to see what they have timing set at and if it is low up it. Thanks my friend its turning into a nightmare.

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Thats a perfect spot for it. Some efi systems also have a timing retard for certain conditions. You or they would need to go through and make sure one of these safeties is not turned on.
 
I'm going with a timing problem as well. Have you or the shop verified timing with a light? Doesn't matter what number is in the timing cell if you're off of TDC. Also, I'd look at the timing dwell. If that's too low, the spark will be like that of a Briggs and Stratton 2.5HP. I run the dwell at 3.5ms on the LS D585 coils.
 
racerjoe said:
I'm going with a timing problem as well. Have you or the shop verified timing with a light? Doesn't matter what number is in the timing cell if you're off of TDC. Also, I'd look at the timing dwell. If that's too low, the spark will be like that of a Briggs and Stratton 2.5HP. I run the dwell at 3.5ms on the LS D585 coils.
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I did set it all up at TDC when I set in everything, tooth wheel and cam sensor. Will have them check the dwell too. Thanks my friend.
 
Regarding timing, there should be no mystery around it. In MS you can lock the timing at a sane number where it will idle or run at low RPM and then put a light on it to confirm. A small variation between what you programmed and where it is actually at is common in my experience but shouldn’t be huge.
 
Did you degree the cam? Laboring up to rpm and no power sounds like cam timing to me. I suggest tuning this thing without boost until you get it figured out. Like subcom said, lock the timing at something like 26 degrees and verify it with a light, it will idle and rev at 26 with no curve.
 
What’s the air gap on your crank sensor? In the pic you posted it looks huge.
 
Matts440 said:
Where you engine liked the timing the 60-70 degrees. Sorry might be a MS3 thing where I can either use fixed timing or a table.
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With my car I had the base timing off. So when I set the timing at 20 BTDC it was really 50 degrees BTDC. We didn’t notice any performance change at the time because boosted cars are a handful as is. But upon disassembly i found the headgasket had leaked at some point. Subcom is right, there should be a way to command the ecu to lock the timing at a value you choose. I do mine at 25 degrees so that the motor stays running while I am doing it alone. The value you see with your timing light should be 25 degrees. Any variation of that will affect your timing when the computer is managing it. As far as coil dwell time goes, it will misfire not be lazy. Also pick up air gap will not make it lazy, it will be fine or not start pretty black and white. TT5.9mag also has a great point. In the past on another turbo build we had too big of a cam (which would act like a retarded cam) in the motor, and it wouldnt even build boost on the dyno. This goes back to my original point. Do we know the engine is running properly to begin with, N/A.
 
Also Matt as a side note. I had trouble with my 36-2 wheel. It would misfire over 6500 (i was running the motor to 8800) and it was the trigger wheel. I use the holley sensor you originally mentioned. I had to turn down my holley wheel and make an adapter to make it work, what a pain in the ***. So while I was at the dyno we had problems and the tuner I hired (Brian Macy) mentioned the wheel had too many teeth and the signal gets noisy. We tried all kinds of tricks like closing the gap on the plugs and increasing dwell time on the coils and it didn’t help. I talked to Holley and they recommended the MSD flying magnet wheel. So I bought the entire crank trigger set up for chrysler. It bolted on the motor no problem and has worked perfectly ever since. I used the holley sensor on the MSD wheel and MSD bracketry. Your crank trigger is held by one bolt and that will vibrate and cause signal changes. I don’t think that’s your current problem but its something you may run into in the future.
 
With harmonics on the crank, and a big gap at the sensor, rpm can cause wired signaling issues at specific points in the rpm range. That’s exactly why I asked what the gap is.
 
TT5.9mag said:
With harmonics on the crank, and a big gap at the sensor, rpm can cause wired signaling issues at specific points in the rpm range. That’s exactly why I asked what the gap is.
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Your totally right but it would not have a signal at that gap. So it wouldn’t even start in my opinion. My Holley sensor is so sensitive a few thou will make it a no start.
 
TT5.9mag said:
Did you degree the cam? Laboring up to rpm and no power sounds like cam timing to me. I suggest tuning this thing without boost until you get it figured out. Like subcom said, lock the timing at something like 26 degrees and verify it with a light, it will idle and rev at 26 with no curve.
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TT5.9mag said:
What’s the air gap on your crank sensor? In the pic you posted it looks huge.
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I did degree the cam in per spec from Crower. That pic was before I set the gap, plug that has been moved to where there is no signal drop front the .040 that I originally had it set too. The place said they changed timing on the ecu and still no change.
 
Matts440 said:
I did degree the cam in per spec from Crower. That pic was before I set the gap, plug that has been moved to where there is no signal drop front the .040 that I originally had it set too. The place said they changed timing on the ecu and still no change.
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In that case what’s the O2 look like? If the afr is down in the 8s-9s on gas it will seem lazy and hesitant to rpm also.
 
Matts440 said:
I did degree the cam in per spec from Crower. That pic was before I set the gap, plug that has been moved to where there is no signal drop front the .040 that I originally had it set too. The place said they changed timing on the ecu and still no change.
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I know we just talked but you should also look at torque converter slip and see what mph its turning on the dyno.
 
I think I gave my comments elsewhere in this thread. I originally purchased one of those narrow wheels and the sensors easily “lose it” and the signal drops. I ran into this on my DS sensor. My AR Engineering wheel has a tooth width equal to the sensor face.
 
Hemirunner said:
I think I gave my comments elsewhere in this thread. I originally purchased one of those narrow wheels and the sensors easily “lose it” and the signal drops. I ran into this on my DS sensor. My AR Engineering wheel has a tooth width equal to the sensor face.
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Signal drop has been taken care of, they just moved the sensor a little more closer. Once I get it back will swap sensors to the holley one I have.
 
Update: called the shop yesterday, they pulled the trans pan, found the bands were loose, a bolt missing from the servo, and a nut off I forget something was in the pan. They test drove and said the trans felt a lot better then before when it felt like the brakes were on. They hope to get it back on the dyno soon and see.
 
Matts440 said:
Update: called the shop yesterday, they pulled the trans pan, found the bands were loose, a bolt missing from the servo, and a nut off I forget something was in the pan. They test drove and said the trans felt a lot better then before when it felt like the brakes were on. They hope to get it back on the dyno soon and see.
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Glad to hear some promising news!
 
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