Problem im having s i pulled my car outa storage and she started having driving concerns. under wide open throttle everyonce in a while the car will start bucking and misfiring kindof. The car bucks back n forth and backfires. my AFR is at 11:1 while at 8psi of boost. I have a full 3" turbo back, upgraded intercooler and walbro 255 fuel pump.Stock ct26 Running greddy electronic boost controller. I havent changed anything in my setup yet it randonly decided to do this. Previously i was running at 10psi no problem. Ignition timing is set plugs are gapped correctly, no check engine lights. I know it is running too rich but would that caouse it to buck underboost? Also my car backfires alot under decel. any suggestions?
7mgte Bucking and jerking under boost.
- Thread starter Boostedmkiii91
- Start date
Okay so you're running a walbro 255, did you delete the jtube? I had similar problems til I installed the DM AFPR kit, set the base pressure to 36 psi and now she runs strong to redline everytime.
Yes i replaced the jtube with a shorter stainless braided line. Ill order up a afpr and see how that goes. does that kit go in place of the stock unit and do i need to get custom fittings made bc i know they have some weird sizes on the 7m rails.
gsxr141;1865968 said:what was it? i can't boost past 5 without throwing a boost leak code. time to make a boost leak tester.
I thought my car wasn't going to boost past 8 psi til I left it floored in 4th.. Then my stock boost gauge maxed out and started bending the needle.
i have an autometer gauge in the car in addition to the stock one. when it hits 5psi, the car hesitates and kicks a boost leak code. the car was doing it before with a cheapo boost controller so i took it out. it wqas fine for a few days, but now it does it at 5psi every time. i'm going to try and make a boost leak check setup today. i'm sure there's a leak somewhere in the 22 year old piping. i hope i find a leak, so i can buy the new dm kit.
So i tested out the tps and it was all kinds of messed up so i recalibrated it only to find oput it goes open at 1/2-3/4 throttle so im going to start there. If i ease into 1/2 throttle it boosts 10psi noo problem so im asuming at this point its my tps. Although recalibrating it did fix my idle issues. Also the CEL keeps coing on so ill have to check into that too. Ill let you know what i find.
When you recalibrate the TPS, retime it as well.
You'll have to put a timing light on and move the CPS with T1/TE1 jumped and set it to 10 degrees.
You'll have to put a timing light on and move the CPS with T1/TE1 jumped and set it to 10 degrees.
i'm looking for some of the same answers.... my car suddenly won't go past 5lbs without cutting out. i tried to do a leak test, but i'm not sure i did it right. now my car has a high and erratic idle, and seems to have a miss too. is there any way a bad sensor can cause the car to see an "overboost" condition? i previously had a code for a boost leak and one pertaining to the tps sensor.
thanks.....
thanks.....
Sucsess Finnaly! i reset the timing fixed on small boost leak and it goes like a raped ape now! And to gsxr141 i had similar problems with my idle for the longest time and after recalibrating the tps and playing with the throttle stops it is perfect now. And as far as boost leak testing just make sure the tester is a tight fit and plug the other end of the ic piping.. ex if the tester is plumped in were it would go to the tb make sure to block the other end before the turbo anfter the IC. i usualy use soapy water on the connections to find the leaks, dont forget to look at vacuum fitting too. But give the tps recalibrate a shot and see how that works out then reset your timing after wards.
Forgot to mention about the "bad sensor" if your tps isnt properly calibrated since it works with the maf you could be getting mixxed air flow reading for your designated throttle position before you start claiming bad parts do all the basics you will be surprised, as i said in the posting below.
Boostedmkiii91;1866657 said:
Glad to know that retiming it helped you, it seems most people forget to retime it when they play with the tps.
ok guys. where do i find a 2 3/4 coupler to use as a boost leak tester? i want to make a cap to mount on the turbo so i can pressurize the system. none of the hardware stores have anything in that size. i need top find the problem so i can move on to the next issue. lol
please help...............
please help...............
also, i swapped out the maf and air filter for another one i had. now the car idles right at 700, but it still hits a wall at 5-6 psi. i spotted a bit of oil on the lower right corner of the intercooler. i'm sure if i could pressurize it, that's where the leak might be.
gsxr141;1866884 said:
The coupler on the TB is 2 3/4. Cap off the piping at the turbo and pressurize it from the TB.
good news guys. i pressurized just the intercooler, and it definitely leaks. it's leaking right where i've been seeing the oil. luckily i have a spare to use until i order the dm kit. i'm sure there are other issues with the car, but am i correct in thinking that the leak will cause the code 34 and the jerking/hesitstion? either way, i'm swapping it out tomorrow.
thanks for the help.......
thanks for the help.......