Bad gas I hope...

[Motorhead350]

Just got my car dyno tuned last night and over all it's making about 465 to the crank or so they say. My cats are clogged and I know some of you now hate me for never replacing them after my kerosene meeting last year. Now I know I need to change my cats or get rid of them all together... I know we need 2 for back pressure so I'll get rid of all of them and put in 2 new ones. The car is a lot better of the line, but in the top end it seems to rev and not shift for a second plus the car isn't shifting as fast anymore, but BigDogJim said my shifting was too hard anyway.

Now here lays the problem: When I start the car is idols to 2,000 and when put it into gear it'll go down to 1,100. Sometimes it'll even die when it goes down too low while in drive. In netural it'll idol to 2,200, go back and forth on the rpm and eventually drop dead in 30 seconds. All of this happened after I put additional gas in the car which was 92 not 93. I put in half a tank and will put in a full tank of 93 today along with octane boost just to be sure.

Could bad gas be the problem or did these people screw up my tune?

[fastblackmerc]

First how do they know you have 465hp to the crank? Did they take the engine out and dyno it on an engine dyno? If they left the engine in then the only valid hp number would be at the rear wheels. Anything else is a WAG (Wild A$$ Guess).

Second, the cats, although do provide back pressure the engine doesn't need them.... they are only for emissions control. Replace the four stock cats with 2 hi-flow cats. That will keep the computer and the enviromant happy.

Third, the octane in the gas has nothing to do with the way a car idles. You have a bad or dirty sensor or the tune is messed up.

[KillJoy]

Your tune is junk.

Did the Dyno person dyno tune the car?

If not...congrats on tossing your $$$ away.



KillJoy

[RF Overlord]

Dom, if the car didn't do this before yesterday, then check to be sure nothing got disconnected under the hood while the tuner was under there...like the MAF, or a vacuum line. Also, could be the IAC has gone south.

Your car won't notice the difference between 92 and 93 octane except under WOT. Don't bother using octane boost, either...it doesn't do jack.

[1of327]

Sound like either a bad tune or a sensor is not connected/ bad

[racorcey]

Just got my car dyno tuned last night and over all it's making about 465 to the crank or so they say.

What kind of corrected figures did they give you? Was the TC locked and were you in 3rd gear when they dynoed? How much alcohol was in your fuel (typically 5 to 8%)? If you can get me these items, it's not too dificult to determine your FWHP from your RWHP.

[CRUZTAKER]

I have an entire set of cats, near new, if you want to spend some more money.

[sabtaj1]

I agree on the IAC, do to mustang problems. Been there done that. But I would definately say somthing to do with the tune forsure. Sounds pretty weird. What happens when you are running the wrong computer code in the tune? Never done that but I know some of you guys here have. ????

[Blackened300a]

Dom, if the car didn't do this before yesterday, then check to be sure nothing got disconnected under the hood while the tuner was under there...like the MAF, or a vacuum line. Also, could be the IAC has gone south..

^^^I agree^^^
When my intake tube started slipping off, I was having problems like the ones you are talking about. My idle would surge and sometimes the car would even stall out and have a hard time starting up again.
If the car was fine right after you had the tune done then I would look for loose connections.
I had a 86 Monte carlo and the cat became clogged to the point that it would stall and the car struggled up to speed. I thought it was the transmission at first until I noticed there was hardly any smoke coming out the tailpipe in the cold morning.

[KillJoy]

OR.....

You could have toasted your Trans

KillJoy

[rayjay]

Dominick, you payed good money for a tune. Take it back and have them make it right. Put two new high flow cats on and she'll run even better.

[sicilianmarquis]

i agree with killjoy on the tune, you should get a new one thats kinda guy that you got a supercharger, and now instead of creating power, it stalls your car

[HwyCruiser]

Did all the issues start after the dyno tune? If so it sounds like the tuner used his own base tune instead of the custom FIT Diablo custom tune from what you're describing with the idle and shift pressures. Was this tuner a Diablo dealer? I think Mike had his car dyno'ed around there by a Diablo dealer with good results. I'd be hesitant to lay into it until you get the tune straightened back out.

[Motorhead350]

Now the car won't shift from 1st to 2nd when I hammer on it unless I take my foot off the gas. Sounds like my tranny is about to go so I drove my truck to Detroit this weekend. All of the issues started after the tune yes.

[FordNut]

So do you still have the original tune that came with the S/C kit or did you let the tuner screw it up? The shifting is also controlled by the tune. I'd try to get it back like it was and find a more skilled tuner.