So I'm supposed to be testing the AP soon, but first my local shop had to lay down a baseline to report data back to cobb. The car has some hesitation above 7k, but I've never really felt it driving. The shop now wants to smooth out my stock dyno before putting on the upgrade.

Its got 54k on it, and just got out of the garage for the winter. I just changed the oil & filled up w/ V power on my way up there. It's bone stock except an agency power pulley.

It dyno'd at 170/130... and the hesitation looks scary. The shop said one of my spark plug wires was somewhat loose upon inspection after the dyno. They're replacing the plugs, then running again hopefully today.

Can anyone tell from the dyno what could be wrong? Is this really bad or normal?

 

Have you ever changed the coils? Where's the Graph?

 

attachment...

 

I've had the coils changed 2 times when the engine flooded. Once at ~10k, once at ~40k.

 

well its not normal and it seems to be up in the 3rd injector area ( if indeed you are a high power one!)

Bear in mind I have no real idea what im talking about, and that this is a pure guess, but it could be your 3rd injector is a bit clogged up or something?

What I can say with confidence is that its not normal....

 

I am assuming that you have the hi-power version.

It smells to a bad coil, spark plug, or spark plug wire to me. Under those conditions a "better" reflash will not improve results as much as possibly could in another car without the "hesitation" problem.

Let us know what the garage did to overcome the problem.

Cheers

jird20

 

It really looks like a spark issue of some sort. Check em, clean em, change em...

 

We're putting in Denso Iridiums or NGK today and hope that fixes the issue.

 

Just make sure that they are the stock replacement ones and not the rx7 ones.

 

You could always substitute my car, for the test, instead.

 

Yeah, but your engine might pop...J/K

 

sounds like sparks or fuel injectors to me. I got the same major hesitation you are describing around the same rpms about 15k back. After I dumped in some fuel injector cleaner(gum out) she ran as good as new

 

Its probably not injectors. Look at the AFR on the Graph. It stays in the 12-13 range after the P2s come online...

 

i guess. im not the car expert. that was just the case with mine..

 

I would buy mazsports spark plug wires. The factory wires suck

 

I changed the plugs w/ factory replacements & the car feels much butter.

Thanks guys!

I did, however, buy the Mazsport Ignition Kit after seeing how much of a weak point this can be. Put off my exhaust again...

 

Good choice on the coils--have you ever seen a spark test using the oem coils? the spark is yellow/orange with a little blue. Not good at all for a 9K engine.
Seen a lot of dynos with the same picture--99% of the time it's ignition. However like someone said run a tank of bk44 through her also. Then dyno again.
olddragger

 

yeah I got a similar dyno bumpiness uptop. Ordered the mazsport coils too, we'll see how it comes along.

 

This is the first baseline Dyno I did on my 05 MT and I am 90% sure that my 2nd rotor trailing coil was bad or going bad on this run. I dyno'ed the car about 15 days ago (on a dynapack which is usually within 1% of dynojet) and pulled 184 WHP. Only adds were a AP pulley, NGK plugs and the replacement coil.

I'd say it's ignition as well. The AFR's would be pretty lean if you had a plugged injector.