When I installed my Pettit Unlimited Ecu the cars boost pattern went all screwed up!! with the stock ecu i was getting the 10-8-10 pattern now I am getting like 8-5-4-4 something like that, what could be the problem? the car ****** rips with the computer but I am not getting proper boost? any ideas? did i install the pettit unlimited ecu right? or did i pop a vacuum hose? oh my the way i have the main cat put back in, and the cat is kind of cracked and its diffinintly heading south.

 

Best way to see if the ecu is causing this problem is to swap your stock ecu back in.

 

anyone else?

 

I don't see how you could have knocked a vacuum hose off installing the ECU...

If you ALSO re-installed your main cat, I would imagine that it's your problem.

Just basic troubleshooting, whatever you changed on the car to break it, undo those changes until you are back to where you were.... start with the cat...

 

What mods do you have?
The ecu should actually improve your boost pattern. Mine went from 10-8-10 to 13-11-12. I would start with the cat though. If it is clogged it will really screw up your boost pattern.

 

exactly

 

well my main cat was in with the stock ecu and the boost pattern was fine, but as soon as i put the Pettit unlimited ecu in the boost pattern went fudged! but i think maybe the cat is clogged up, but how can you tell if the main cat is clogged?

 

Put back your stock ecu and midpipe, get a baseline boost pattern, then change ONE thing at at time and test again. No one here can figure out what is wrong with your car, or what you may have screwed up putting in the stock cat & Pettit ECU. Simple process of elimination.

 

DO NOT DO THIS!!!!

Stock ecu + midpipe = blown motor

just keep the main cat on, and stick the stock ecu back in. If boost pattern is still bad, then is not the ecu. check the vaccum hoses before anything. goodluck~!

 

I have a full open off-road racing exhaust with a stock ECU... 3.75" ID Midpipe and cat back w/ OE down pipe.

..running boost at 7 for now until I have an WB02 handy. Pulls rich all the way with 7 psi.

 

13-11-12 WOW! Isn't that a little high to be safe?

 

What probably happened is the Pettit ecu runs higher boost and you prob blew off a hose the first time you romped on it.

First check all your IC pipes, especially the connection from the ypipe to the crossover pipe. Sometimes you actually have to take it apart and put it back together to double check it.

There is a little black vacume box in front of the uim, pull it off and shine a light up under the uim and see if you can see any hoses that are not hooked up. You will prob see some open nipples because there are supposed to be some open ones, just look for a hose thats poped off.

Also you can pull the big intake hose that goes by the lim and check all the hoses there.

Good luck,
STEPHEN

 

it must be a vacume leak, because i had the same problem with the ECU after using it for 2 days and after doing a vacume job, the problem was fixed. i'm not sure which hose popped off but the problem is fixed. my problem was also worse than yours, i get 13 psi on primary and 2 on secondary in 1st and 2nd gears but 13 on the secondary in 3rd.

 

What do you mean "a little high to be safe?" I have done a lot of things to ensure I don't blow my motor so yes, its safe

 

"What probably happened is the Pettit ecu runs higher boost and you prob blew off a hose the first time you romped on it. "

Just want to clarify that boost is totally independent of the computer, the computer will not alter boost.

As for the original problem, leave the computer in, put the midpipe back on, and everything will be back to normal.

Andrew Wojteczko
93 RX7 R1
voytechco.com

 

bump

 

 

Actually thats not entirely true. The boost can be controlled via computer by working the solenoids diferently. As a example, the Power FC controlls boost nicely via solenoid control. Now, I might be wrong about the Pettit ecu, it might be just like the stock setup but I thought it raised the boost some by controling the wastegate differently.

If it was totally mechanical you wouldnt be able to control boost with the Power FC, also I believe the pmc purple controls boost.

STEPHEN

 

No, stock ECU + midpipe does not automatically equal a blown motor. Look at the next post after yours. That guy's got no problems and he's actually measuring his A/F ratios. It sounds like you're just repeating back something you've heard-- kind of like "Don't swim within 15 minutes of eating or you will get stomach cramps and drown!".

We don't know the other mods he's got, but he basically said that the car ran fine, then he changed two things and now it doesn't. By process of elimination, he can figure out what went wrong. And the most likely candidates to check are the two things he just changed, THEN the other usual suspects, like vacuum hoses, etc.

 

guys its the computer, i got a fake!!!!! well be getting refund and another computer.

 

sorry im afriad i wasnt being specific enough. He didnt mention he had any type of boost control, so i assumed he was about to run a full exhaust on a stock ecu. If it turns out that he didnt have any vaccum problems, then there was a good possibility that he would get a boost spike and blow his motor, In which i would hate to see happen to a fellow member.


anyway, you are correct. I am only repeating what i have heard from many other people who have had bad experiences with midpipes. I was fortunate enough to have no problems with mines.

 

Actually thats not entirely true. The boost can be controlled via computer by working the solenoids diferently. As a example, the Power FC controlls boost nicely via solenoid control. Now, I might be wrong about the Pettit ecu, it might be just like the stock setup but I thought it raised the boost some by controling the wastegate differently.

If it was totally mechanical you wouldnt be able to control boost with the Power FC, also I believe the pmc purple controls boost.

STEPHEN

Hi,

As far as the pettit is concerned, it does not control boost.

Andrew Wojteczko

 

Then what is in charge of the solenoids?

 

I am not sure where you are getting this information, but I have talked to Cam myself and they DO change the duty cycle of the wastegate solenoid to control the higher boost levels that will be introduced with more fuel and air. I am not saying that this adjustment to the duty cycle will always limit the boost to what you want it at, but it is lower than the stock setting. Theoretically, it is supposed to limit your boost to 14 psi with stock pills, but variations in each car can change this.

Jeff