Progress Thread Car runs poorly over 4500rpm

Windsor_mustang · Apr 14, 2020

hey all! New to the forum here so please forgive me of any wrong doing!

Here's the deal. 94 mustang gt, was originally purchased as a 347 naturally aspirated car. I bought it about a year ago and this winter I put a microsquirt ecu, dw 340 lph pump/60lb injectors, msd distributor and coil, pro comp intake/elbow(super Victor efi knock off), and vortech super charger. Took the car to get it dyno tuned and about an hour or 2 in to it my car won't rev past 4500 due to it breaking up so badly. I take it home and change the things and car seems to improve but still not running great at higher rpm. While running one day the embrace got hot and started smoking and it also started to melt the distributor connector. I went back to stock dizzy and added another 2 ground wires. I'm sort of new to performance builds so I need help to be able to get back to the dyno!

revhead347 · Apr 15, 2020

Does it work better with the stock distributor? MSD = Makes sparks dissapear. Those distributors are a known problem.

Kurt

a91what · Apr 15, 2020

I can sanity check the tune for you if you like, I am very familiar with it.

Something most shops overlook quite often is checking the spark hardware latency, they assume they are getting what is commanded but often they are not. improper ignition settings can cause a meltdown of the ing system components.

Windsor_mustang · Apr 16, 2020

revhead347 said:
Does it work better with the stock distributor? MSD = Makes sparks dissapear. Those distributors are a known problem.

Kurt

It does run somewhat better however now it seems once the car climbs to 5000 ram it jumps to 5500 and has a slight miss, any ideas?

revhead347 · Apr 16, 2020

Windsor_mustang said:
It does run somewhat better however now it seems once the car climbs to 5000 ram it jumps to 5500 and has a slight miss, any ideas?

What ignition coil do you have? What kind of plugs, and what are they gapped to? Sounds like it just blowing out the spark a little bit up high. This might be a simple fix.

Kurt

a91what · Apr 16, 2020

Or the timing is retarding at higher rpm. This will make the car nose over or break up like its hitting a wall.
If you lock the timing in the software and rev the engine and hold at 5k does the timing wander or retard at all? If it does your settings are incorrect.

96pushrod · Apr 18, 2020

What cam and valve springs are you running? We’ve chased tails with ignition before just to have valve float occurring under boost.

Windsor_mustang · Apr 18, 2020

96pushrod said:
What cam and valve springs are you running? We’ve chased tails with ignition before just to have valve float occurring under boost.

Trickflow track max cam and tfs springs, how can I tell if thats whats happening? How would I resolve it?

96pushrod · Apr 18, 2020

One thing you can do is pull a rocker and look at the weat pattern on the stem. If it looks like a star pattern and looking beat up it’s float. If it’s a nice and uniform sweep then you’re good.

How much boost is the engine actually making? Usually the float issue doesn’t happen under 10lbs unless your springs are barely adequate anyways.

Windsor_mustang · Apr 18, 2020

a91what said:
I can sanity check the tune for you if you like, I am very familiar with it.

Something most shops overlook quite often is checking the spark hardware latency, they assume they are getting what is commanded but often they are not. improper ignition settings can cause a meltdown of the ing system components.

How would you do that, I'm not sure if I have the capability but if I do I'm interested and willing to pay for help

Windsor_mustang · Apr 18, 2020

96pushrod said:
One thing you can do is pull a rocker and look at the weat pattern on the stem. If it looks like a star pattern and looking beat up it’s float. If it’s a nice and uniform sweep then you’re good.

How much boost is the engine actually making? Usually the float issue doesn’t happen under 10lbs unless your springs are barely adequate anyways.

General karthief · Apr 18, 2020

Is that a crack I see ?

a91what · Apr 18, 2020

all you would need to do is download tunerstudio onto your laptop and get it connected to the ECU, then fetch the tune and post it here for me to look at.
If you feel like you may make a mistake doing this, I can remote in to your pc via anydesk ect and walk you through it or just look it over from your end if you have internet near the car.

Windsor_mustang · Apr 19, 2020

a91what said:
I can sanity check the tune for you if you like, I am very familiar with it.

Something most shops overlook quite often is checking the spark hardware latency, they assume they are getting what is commanded but often they are not. improper ignition settings can cause a meltdown of the ing system components.

Just saw this comment, I will say that after my partial dyno session my msd distributor plug was sort of melted. I'm due to go back on the 28th for them to "finish" the tune.

Progress Thread Car runs poorly over 4500rpm

Windsor_mustang

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revhead347

Apparently my ex-husband made that mistake.

a91what

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Windsor_mustang

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revhead347

Apparently my ex-husband made that mistake.

a91what

SendMeUrDataLog

96pushrod

I think they're a little easier to get off

Windsor_mustang

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96pushrod

I think they're a little easier to get off

Windsor_mustang

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Windsor_mustang

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General karthief

wonder how much it would cost to ship you a pair

a91what

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Windsor_mustang

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Progress Thread Car runs poorly over 4500rpm

New Member

Apparently my ex-husband made that mistake.

SendMeUrDataLog

New Member

Apparently my ex-husband made that mistake.

SendMeUrDataLog

I think they're a little easier to get off

New Member

I think they're a little easier to get off

New Member

New Member

Attachments

wonder how much it would cost to ship you a pair

SendMeUrDataLog

New Member

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