I own an 87 TII with a racing beat exhaust system and a fuel cut defenser. Yesterday was the first time I was really trying to go fast and I could redline it through 1st and 2nd then when I shifted to third I let off the clutch and hit the gas to the floor, as the rpms passed thru the 5.5-6.5k rmp range the car "stutters" i guess you could say, or skips, hesitates, whatever. Anyone have any ideas?

Also how much hp do you think a stock TII with my mods has? The exhaust claims to add 60hp and im not sure about the fuel cut controller. Thanks

 

If thats all you have done (exhaust and FCD) it was probably detonating its *** off...

 

thats really strange, mine worked fine when I put it on. Check your connections make sure you have no leaks. Also you should have an aftermarket boost and Air/Fuel gauge so you can see if you're leaning out too much. My engine lasted 6,000mi with that setup because I did not modify my fuel system.

the hesitation sounds sort of like fuel cut, which is weird because you have the fuel cut defenser. Hopefully someone much more brilliant than I can answer you question.

 

i just bought it from an older man, and he was the one who put the mods on. I assume thats all he did though because thats all he told me when I bought it. Should I try disconnecting the FCD and see if it stutters then? What mods should I have to make the FCD and exhaust work well without detonating?

 

Nah, if you unhook the FCD it will hit fuel cut and buck a lot harder.

I'd recommend buying a boost gauge ASAP, and not ragging on the car. An 87-88 TII with your setup+ stock fuel+ stock wastegate will pop from overboost (and the resulting detonation) in a hurry if you aren't careful.

Do some searches for fuel pump rewire, that should make it safe to about 9 psi or so. Also search for wastegate porting. I've heard of people spiking to 15 psi

 

Do you also have an intake?
I doubt your hitting a fuel cut or detonation without one. But its possible. Ether way, yes make sure you have enough fuel, you don't want to blow the engine figuring it out. How new/old are the plugs & wires? It might be cutting out due to old ones? Good luck!

 

I am guessing you should reset the timing when I put that exhaust on my car it started doing what you described it was accompanied buy a horrible sound that I found out later is detonation. the timing wasn't far off but enough to cause some problems. You can get a cheap *** timing light at advanced auto for $30 it will do the job

 

Mine sort of did this when I first got my TII. It was an intake leak. Check all the hoses and the TID especially. Oh and I never hit fuel cut but from what I've heard you know when you hit it. Kinda like hitting a wall, not a hesitation.

 

Oh and if its not an intake leak I say new plugs and wires will fix it.

 

Well I'm pretty sure I've hit the fuel cut a few time, its like a big hesitation, every time you hit the gas it bogs down more, am I correct........

 

i've never hit fuel cut in my 89. i hit fuel cut in my 87 when i drove it around with no exhaust and full exhaust without the FCD

 

I found that when you hit fuel cut, you'll lift your foot off the pedal so fast it'll make your head swim. Its like the engine has gone down the toilet. Like someone turned the key off. Violent.

Maybe you are pinging *detonation* and the knock sensor is retarding the timing, causing the hesitation.

When this hesitation happens, is it similar to the key being turned off, or is it something milder. Might give us a idea of what it is.

Did you look at your factory boost gauge to see what its doing. If its pegging at the top of the gauge, and I mean pegging the top, your within a heart beat of fuel cut.

 

i have an 87 t2 and had the same problem just a little higher in the rpms than you one my first trip to the dyno it was even notice able in the graph and it was really pissing me off so i just started trying things to get it to stop it and what it finaly ended up being was that in the upper RPMs and with a lot of boost your motor is actually starting to chock i discovered this buy completely taking out my air filter and just puting the lid on teh box (stock) and took a run and to my amazment the graph actually continued to climb

so in conclusion get your self an intake

 

Ya mine also improved when I put my intake on, the boost would stay up longer.

 

My fuel cut isn't that bad, it just bucks a bit... I've had worse bucking before from unrelated things. I watch my fuel pressure jump and the A/F ratio change, then it comes back on again pretty quick, then off, then on. I tried an FCD and it was nice and smooth 3rd gear... 4th, oh no, 100 mph!

 

The hesitation I experienced was more of a mild shaking forward and back when I put the pedal to the floor, in third gear only. The man I bought it from sent me an email when I bought it that says "if you feel it skipping change the plugs" so that could be it. The boost gauge doesnt work because of the FCD so Im not sure what it was doing while the stuttering happened.

I will change the plugs and wires as soon as possible, as for intake, what do you guys recommend for a TII? I saw a pretty cool setup where someone took out the filter, and put a cone filter inside the "mazda box" then ran a flexible tube with like 3-4" diameter from the box down to the front of the car where a front mount intercooler would go.