Idle problems: surging, poping through exhaust, and poor gas milage
 

Alright, i have spent all day working on my brothers t2 and didn't have much succes. First of all, the car is in really rough shape. He bought it about a month ago so i really dont know what exactly has been tinckerd with When he got the car, somehow it was running despite all the wired being switched up and the timing being out.
The car has many problems:
1)It has been getting about 150 miles to the tank. 2)Idles very poorly- pops through the exhaust and surges at idle. Entire car shakes badly- might have some bad motor mounts, but i still think it shakes to much.
What i did today:
First thing i did was check for the proper voltage on all of the wires going in to the ecu. Tps was low so i adjusted it to 1v. Everything else checked out fine at the ecu.
I then got to thinking about the popping through the exhaust. I had read about this many times on this foroum and the majority of ya'll seemed to think the timing has something to do with it. So i made sure the pulley on the E-shaft was correct. Turns out that it was off by aproximently 15-20 deg. Also noticed while i had the plugs out that they were terribly fouled out. Replaced the plugs and tried to set the timing. It ran a little better, but i never could get the idle to come down or stay the same. So I removed the cruise control cable, loosend the throttle cable, screwd out the BAC, and lossend the little screw with the bolt around it under the intercooler. Still no luck!!! I also checked the TPS, AFM, and CAS. They all checked fine.
Also tried adjusting the variable resister following the fsm. It says to turn the screw untill u get the highest rpm. Well, i got the highest rpm all the way rich wich can't be right. Must be starving fo r fuel. But what do i check?
Did a compression check couple of weeks ago and got 90 psi on both rotors, so i know the compression is good. The guy said that it only had about 12k miles on a motor that was put in by a guy that worked at the mazda dealer. Thats probably one of the problems lol
This problem is absolutely driving me mad so if any body has any suggestion to any of these problems, please let me know. I'll try anything right now. Thanks and sorry about the long post.

Steve

bump

TTT

last month my na s4 did the same thing, i posted here and nobody had anything to say. well heres what i did... it might sound simple but i figured from the idle increasing with increasing the fuel that i was lacking fuel. i put a bottle of injector cleaner with about 4 gallons of gas and gradually the car starting running better. now it runs fine. my mistake was being in a rush and buying gas at wal-mart. i let the gas get to almost E (not a good thing with a fuel pump in the tank) and my car started running like that. i thing i jy st sucked something up to clog the fuel system. i kept driving the car even though i had to put it in nuetral at stop lights and rev the engine so it wouldnt cut off. but after 4 or 5 days it was fine.

You're being pretty thorough.. it'll pay off eventually. Two things often overlooked are fuel filter and 02 sensor.

I'm thinking about running a new o2 sensor wire. The wire looks really bad. One think i can't figure out is why does it like the variable resister all the way rich? Seems to mean that it would be running lean, but theres no way it could be running lean with that much fuel consumption. Tonight i'm gonna check and make sure that the injectors are correct. I believe it was running 15-20 degrees advanced (new mark is on the right side of the old mark), so there's know way it could have not been detinating. Unless somebody did some modifications to the fuel system to keep it from detinating, wich would explain the fuel consumption issue. Thats my theory. I'm also gonna look for vaccum leaks. I'm thinking thats what is causing the surging.Thanks for the help guys.

Steve