I have a serious problem!!!

[95Vert]

My car drives and idles fine. It even runs strong right to about 5300 rpm. After that, it feels like I hit a wall, kind of like a rev limiter. It'll run strong to that rpm, then it'll just die. As if the car had just turned off, the rpms will keep dropping right around to 2k rpm and the car will accept my acceleration again. It doesn't matter if I have it floored or not, the rpms will drop to 2k before the car will respond again. I have no idea what it is. I already checked my engine grounds, plugs and wires, and I even increased the fuel pressure but nothing helped. What could it be? Keep in mind that it cruises fine and idles very smooth with my cam. Any ideas?
Thanks

 

[Pokageek]

That is exactly what would happen if you were using tweecer and set too big of a gap for the rev limiter. I forget the setting but it should be only like rev limit = 6300, then kick back on at 6200. Sounds like there is way to big a gap there however it is programmed. Should be an easy fix. Sorry I forgot the coding.

 

[95Vert]

Pok, I'm not running the tweecer anymore. I sold it. I did the a9l swap about a month ago. Everything was working fine, til last Wednesday.

 

[HISSIN50]

Any codes?

How old is your ignition coil?

That's gonna be tough to diagnose till more crap goes wrong..............

Good luck.

 

[95Vert]

Haven't checked for codes. My coil isn't more than 2 years old, it's the screamin demon coil. Besides that, any ideas.

 

[Pokageek]

Could you possibly take it to a dyno shop and have them look at it? It sounds like the rev limiter setting has been somehow corrupted.

 

[95Vert]

It may seem like it Pok, but the a9l doesn't have one, at least I don't think so.

 

[final5-0]

You do have an aftermarket ignition?

Grady

 

[HISSIN50]

Rev limiter on an A9L is 6250 RPM.

Grady opened the can of worms that I was afraid to (but a very wise thing to ask about). I honestly have no idea what ignition retrofits need to be made for a converted car (you need an aftermarket box I think, but I don't know fine points of the wiring).

Post up about that (including if you kept your TFI or how that works. I'm kinda conversant with the differences in the two fox TFI's and ours).

Good luck.

 

[95Vert]

Yep, I have the 6al box. TFI, enlighten me.

 

[final5-0]

Sorry my friend

Just like JT, I know the stock setup won't work correctly

I know you need an upgrade but the details I don't have

You won't have a prob finding some info however

Search On!

Grady

 

[95Vert]

Grady, what other upgrades could I possibly need? I mean, I have an aftermarket coil, msd ignition system, fms wires, walbro 190lph fuel pump, kirban afpr, fuel gauge, dyno module. What else could my fuel system need? I've got the 19lbers in there but it shouldn't cause this problem. Well, at least I haven't heard of it ever happening before.

I was thinking that maybe my 6al is going south. I'm in Houston right now so I can't check it til Friday, but I wanted to gather ideas so I can get it ready for this weekend. Several Houston mustang buddies are visiting me this weekend and I wanted to be able to compete. I hope I can find something quick.

 

[95Vert]

I don't want to pretend that I know what TFI is, so can you explain what you mean? Thanks

 

[SVTCobra306]

TFI is the Thick Film Ignition module, the module under your airbox ( on the side of the dizzy on '93 and older cars and all 5.0/5.8 F-series trucks)

It controls everything that happens with the ignition, and can cause a lot of strange things to happen when it goes bad. It works hand in hand with the PIP (ignition pickup) in your dizzy. Make sure both are good.

 

[95Vert]

OK well the TFI is the Dyno Module I bought from performancedistributors. I'll trade it out for the stocker this weekend as well.

 

[final5-0]

Grady, what other upgrades could I possibly need? I mean, I have an aftermarket coil, msd ignition system, fms wires, walbro 190lph fuel pump, kirban afpr, fuel gauge, dyno module. What else could my fuel system need? I've got the 19lbers in there but it shouldn't cause this problem. Well, at least I haven't heard of it ever happening before.

I was thinking that maybe my 6al is going south. I'm in Houston right now so I can't check it til Friday, but I wanted to gather ideas so I can get it ready for this weekend. Several Houston mustang buddies are visiting me this weekend and I wanted to be able to compete. I hope I can find something quick.

JT and I were just trying to let you know you needed an aftermarket ignition to make the retro fit pcm work like it should.

That fact and that much info alone is the extent of our knowledge to help here but we did want to give you a heads up.

Has it done this stuff ever since you did the A9L?

Grady

 

[HISSIN50]

I'm with the other guys. See if one of your buddy's will swap his box and TFI with you for a test run. I'm not a fan of ignition boxes (though it's necessary for ya now). I have a dead box hanging on my wall - I don't think it liked the desert heat.

I always recommend disconnecting the box for diagnostics first thing. But for you, swapping on a known good box (and TFI while at it) seem kinda logical (if you can do it - free testing).

Oh, Grady hit the nail on the head for me - I don't know much about PIH swaps at all. I've helped a few folks with little stuff but I needed them to tell me exactly where they were at and what they needed to accomplish (I was like a ant who didn't know the overall plan, but helped in the role I was assigned).

Good luck with it bud.

 

[BlackVert]

i'm sorry man, but i have a hard time seeing not running real strong above 5300 rpm as a "serious problem".

i call burning a quart of oil every 200 miles a serious problem.

sorry, just venting.

might that just be the limit of your heads and intake?

 

[95Vert]

Chris, well it's serious to me cause I can't run my car to it's full potential. Plus it got some attention from the top dogs like JT and Grady.


JT and Grady, thanks for your help. I hope you didn't take my comment in the wrong way, not my intention. But I have possibly most, if not all, the ugrades needed for good spark. I was thinking that it could be my box, I've got the stock TFI and coil at home so I'm going to swap them out and take for a test drive. I bought the harness adapter for the msd box, so disconnecting it should be a breeze. I'm also thinking of running yet another ground cable to the block/frame as a JIC.

 

[69clark]

So no matter what, the rpms will fall to 2k before the car will respond to your throttle?