Why DSM’s Break Your Heart

[secongendsm]

A years worth of long hours in the shop and money I should have been putting into retirement brings me to my heart break of today. How does my new 1995 Eagle Talon run? She runs like a champ . . . until 5500-6000 rpm. Then that smile brought on by my hard work turns to a frown. Why? Because at 6k if feels like I just ran into a freakin brick wall!

‘95 Talon
6 bolt swap w/1g head (2g pistons, 1g rods)
DSMLink V2
RS65 – 30psi (now turned down to 20-25psi)
Dual in tank 255 Walbros (swapped out to one single Walbro)
Evo Maf – settings from DSMLink Wiki (swapped out to a 2g maf)
FP2 Cams
1000cc FIC injectors
Mallory FPR
New BP7ES’s gapped to .024 (now gapped to .018)
3in exhaust, etc, etc

Car feels great to up to 6k, then hits a brick wall (throws you forward in the seat as if everything just stopped, which in the logs, it does). I can move the “wall” down to about 5500 when I lean the car out. I can get the rpms up to 7k+ with little or no boost. The “wall” comes when it’s under load/boost. Above are the mods and what is currently on the car (swapped out for testing purposes)

Here’s what we’ve tried:
Turned off NLTS, also turned it on and upped the rpm to 9k
Boost tested to 30psi, also watched fp gauge raise too (don’t have a fp gauge in the car)
‘91 CAS / 2 different black top CAS’s
Coils
Tried another Evo maf and 2g maf
Tried with and without the MBC hooked up
Another ECU that had DSMLink
Dropped boost from 30psi down to around 20-25psi
Double checked timing
New alternator
Pulled off valve cover to make sure rockers were still on
Tried another set of spark plug wires
Gapped 2nd set of br7es plugs down to .018
Compression is 125 across all cylinders
FP set at 43
Went through and made sure everything is grounded
Checked cas wiring (1gina2g)
Checked if the injector wires were swapped at the ecu (for the 1gina2g without DSMLink)
Tried using fake maf at 2200hz with the evo maf (2400hz is where the wall hits)
Tried another FPR
Complete new fp assembling with one walbro (had duals in there before)
Tried other Injectors (FIC 1150’s)
Injector driver box (firewall)
Igniter
Double checked timing marks
Logged the clutch switch to make sure it’s working
Logged voltage, looks good

 

[->PrOjEcTGS<-]

I know you said you tried changing your NLTS setting. But what about the launch control. In a 1g the launch control is based off of the speed sensor. Therefore if the car is not moving the launch control is engaged and once the car starts moving the RPM limit is raised to the set rev limit. If the speed sensor is not working properly you'll get the launch conrol revlimit everytime whether or not the car is rolling.

What is your launch control set at? Try raising that one.

I've had that problem multiple times in various 1g's. If your speedometer is acting up I'd look into it for your 2g.

 

[TURANO-]

Have you done a boost leak test? Sounds like fuel cut, I would check your tune out.

 

[blackrosenova40]

How many miles are on your valve springs?

 

[BoostFrenzy]

What does your A/F ratio gauge say when this happens? With your plugs gaped that small, it sounds like you were having trouble with the spark blowing out. Maybe you are getting that now because you are not getting a strong enough power to them??

 

[secongendsm]

I've turned on NLTS and upped the RPM with no luck.

Done a boost leak test up to 30psi

No clue on mileage for the valve springs, but valve float is an option

I gapped the plug down that far to test, I've had them all the way up to .028 previously. I'm running around 11:1

 

[TURANO-]

Man that has to be frusturating, however, I would take it to a local DSM shop or experienced (not saying you aren't) tuner just to get a second opinion that may be better than ours. But honestly I had the same EXACT symptom, at around 5500 RPM my car felt like a brick wall hit it, it is caused by the ecu seeing too much air going into the engine so it pulls timing (I am sure you already know that), you may need more fuel to go along with the increased airflow Check your logs and see where your A-F ratio may be too lean.

 

[secongendsm]

Fixed