351W ignition "blip" or miss at 3500rpm or so

ggradtech · Sep 26, 2019

My 93 has a 351W swap. Car runs very smooth for the most part. I have a studder/miss that happens at a specific RPM. Seems to be around 3500 or so. It smoothes out after that studder/miss zone. The tuner thinks its an ignition issue, but he couldnt nail it down. Any thoughts on what it might be? Maybe distributor or coil retlated?

a91what · Sep 26, 2019

what does the ignition system consist of? do you have a dyno graph showing the AFR?

ggradtech · Sep 26, 2019

I'll post it up once I get the car back. I guess the tuning shop needs a new chip. He's using Moates and the chip he had in stock wasn't working properly. He needs to order one.

General karthief · Sep 26, 2019

Put a meter on your tps, slowly run it up to the rpm you have the 'studder' to see if there is a bad spot, do this key on, engine off. At least you will know if it ok or not, then move on to other things.

ggradtech · Sep 26, 2019

Ill try the TPS measurement. What is bugging me though is the tuning shop’s response..... they basically said “yeah, we noticed that miss/blip”. That was all they really said though. I asked if they could nail down the issue and they didnt seem to be very responsive. When I dropped off the car, I mentioned the miss. The car runs great otherwise. I figured maybe the tune would straighten it out.They basically said it was “tuned”, but the chip needs to be written. The miss issue is not resolved though. I think they use Moates Quarterhorse. Not sure what t do now. Im fairly certain that theyve already finished the dyno work and a tune I'm just waiting now for a new “chip” so the tune can be installed into my car, and not on their Moates tuning equipment.

General karthief · Sep 26, 2019

I'd be done with that shop.

a91what · Sep 26, 2019

A car with a miss is not a completed project...

vristang · Sep 27, 2019

Can they provide any data from the tuning runs? It may show something that points you in a direction.

Generally, it is best to fix little issues like this before tuning... Doesn't help you now, lol, but maybe the next guy reading this will...

ggradtech · Sep 27, 2019

So I just basically just rescued my car and gave up on that shop. It's a loooong story. Im not sure what the shop owners' problem is...... When I dropped off my car, I fully explained the situation. I wanted a dyno tune and for them to see what the "miss" or hesitation was at 3500 RPMs or so. He didn't even care or want to figure out that issue. I explained that I assumed they would corrddct the miss or at least let me know what path to go down. Nope. All he did was talk shift about how old and crappy Foxes are and that I should buy a Holley standalone system. I'm sure that the Holley is awesome. It's also big money. I'm sure that there are plenty of folks still using a Ford ECM. Old, sure. I think they still work though. I don't even have a FI car. Just a mild 351 swap. Rant over I guess.

a91what · Sep 27, 2019

A Miss under load is typically the TFI. The TFI is what actually fires the coil when they start to go badd or become weak they don't Saturate the coil enough and this causes spark loss or a miss under load

vristang · Sep 30, 2019

TFI is worth trying, especially if there are no codes...
Truthfully, as long as the cam is fairly mild, a 351w shouldn't 'need' a tune on a stock fox ecu. Mine did fairly well anyway...

351W ignition "blip" or miss at 3500rpm or so

ggradtech

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a91what

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ggradtech

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General karthief

wonder how much it would cost to ship you a pair

ggradtech

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General karthief

wonder how much it would cost to ship you a pair

a91what

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vristang

ggradtech

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a91what

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351W ignition "blip" or miss at 3500rpm or so

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wonder how much it would cost to ship you a pair

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wonder how much it would cost to ship you a pair

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