Confused on the engine's performance

[DriftinNC]

I been having som trouble with the engine, and i thought i had everything straightened out. I had lower intercooler piping keep on blowing off, so i went to a desiel story and got soem heavy duty t-bolt clamps and turbo hose. While driving down the road, it will run good as new for a while and pull real hard, then it will start to bog and stutter. So i check the piping over again and everything is fine. It will do that often when im driving, im not sure what the problem is, because after it stutters and bogs for like 10 minutes it will run good again, does anyone have any suggestions onto what it is?

thanks for the help

[iliketocrash]

have you tried pulling ecu codes to see if it picked up on what's malfunctioning?

[f s t caz]

how much boost are you running

[DriftinNC]

nah, i havent tried getting any codes yet, i didnt even think about doing that, that might be a good idea. My boost gauge only reads 5psi.

Its weird cause when im riding down the road you can hear it change by the tone of the exhaust, it just does it randomly

[iliketocrash]

5psi doesn't sound right. mine goes up to somewhere around 10 usually, and that's just what the stock actuator is letting it boost to.

[float_6969]

Pull the ECU codes. It sounds like it's either detonating, or the detonation sensor isn't hooked up.

[DriftinNC]

well my check engine light stays on all the time even when i take the keys out of the ignition? Im about to take the bulb out, it getting on my nerves at night. Have you ever heard of it doing that?

[boost_boy]

well my check engine light stays on all the time even when i take the keys out of the ignition? Im about to take the bulb out, it getting on my nerves at night. Have you ever heard of it doing that?

Something is hooked-up that probably shouldn't be. Can't tell you what it is because I don't know the extent of y our wiring job, but you should not be seeing a check engine light and that's for sure. Your boost should be a pound or two higher than 5 psi, unless you are losing boost somewhere along the way.......

Dee

[float_6969]

the Check engine light shouldn't be on....

[DriftinNC]

i got everything checked out and im not seeing any codes, im pretty sure i did it the right way according to the instructions on a previous post. Im getting the 3 red and green light flashes but then when i wait nothing else happens.

Will i need a fpr iff i install walbor 255? My friends say it smokes whenever i give it gas and it smells like gas too resulting them in watery eyes and a headahce....hehe, maybe im overloading on fuel?

[DriftinNC]

also my vacuum only reads 5 most of the time, Iff that helps you out any. And iff im not using the stock boost controller should i have that sensor hookep up?

[DriftinNC]

im still having the same problem, but now it only runs good when the car is cold. Iff it sits more than 3 or 4 hours, and i go out to drive it, it will run good for about 15 minutes then after that it will start the bogging, almost like running on 3 cylinders. Im not sure what the problem is, sounds like when the engine gets warmed up something expands and causes it to do that....can any1 help?

thanks

[Robin@BPD]

Mike, did you replace the Sensor i told you to replace ?and did you beat the oil pan out ? Also if the Couplings on the Intercooler get hot they might start expanding it happen to customers car that he made his own piping and used rubber couplings from Home depot ..

[iliketocrash]

i dont' believe a reading of 5 for vacuum is good. Mine sits around 15 and sometimes near 20.

[r34 gtr]

i would check the cold start junk. aacv, coolant temp. sensor, etc.

a boost/vacuum reading of 5 isnt right. but if it is, those 450cc injectors you say youve got in your sig. are waaaay too much for the task at hand. you may want to try cranking the boost up to like, 12psi and then plant your foot into it down the street and see how it goes. 450cc injectors on 5psi would require a freaking huge turbo; im assuming yours is stock or similar.

- tim

[T88lexus]

well if you want to come up and pick up the intercooler on stuff. i will take a look at your car. I have a coulpe of extra stuff i can try out..

[DriftinNC]

well took it to 1 of my friends today, knows all about nissan/datsun cars. He showed me some old trick that you can do. He took a $1 bill and while at idle hold it over the muffler with 1 hand, iff the dollar sucks into the muffler then that means you have warped valves. It seems kinda odd at first, but i guess it seems right. He said thats why the smoke smells like fuel and why it cuases it to backfire pretty loud

Has any1 else ever heard of doing that?

[KaZ (VaBch)]

Most vehicles w/ a US boost gauge (i.e. not metric measurements) should be around 20 in/Hg at vacuum... my '84 200SX w/ a CA18ET reads 20in/Hg at idle...

My Sunpro Boost gauge sits like that, touch under 0 when off... and reads 19/20 at idle, and 20+ during in gear deceleration... I've seen boost as high as 12psi before (cold weather spikes). You definitely have a bad vacuum leak SOMEWHERE. Might want to try and pressure test it... You can fab a plug w/ a air compressor line nipple on it, and if you know someone with an air compressor, buy an air regulator and set it for 10psi, then let the air into the system... you'll hear it hissssss.... =)

[RMiller]

So the dollar did get sucked back? I backfire alot too, but that's because I vent my bov. But I still get just a hair under 500 mmHg vaccuum, or about 19 inHg. Does your car smoke when it's running poorly?

To pull codes, turn the thing on the ecu to the right, after both lights flash 3 times turn it back. Then it will give you your codes.

[DriftinNC]

yeah, it smokes alot when running bad, at idle and while driving it. i dont have the 450's in anymore, because it made it worse...so i took them out trying to get the motor running good 1st before i start upgrading more sutff.

Do some ecu's come without a code thing?

[gervs]

i have the same troubles as you mentioned above, about the car going hard when cold, but after its driven abit it stumbles under boost, i've been trying to figure that one out for a while now, if you get it fixed let me know how you did it

[Loofee95SE]

My boost gauge, never went under 0 psi !! on idle. read boost fine...but the arm never went under the 0 psi mark....can this be because of the vacume source?? but sound also like u may need to check ur IC u may have a small leak in it.. it happen on my FC before...just like ur situation... C

[DriftinNC]

well, i got the boost gauge situation straightened out, had a few vacuum lines messed up. At idle it reads 18 vacuum, then while boosting it goes up to 7psi. It didnt help the performance any, but atleast thats working right now

[RMiller]

Turn your engine on and then check codes. You don't need an aftermarket fpr for the walbro 255, either. Check the cold start parts. Obviously something is changing when the car warms up, probably caused by the parts listed by r34 gtr. Check your vaccuum lines. Maybe your plugs are too cold? What type of plugs are you using?

[DriftinNC]

im running the ngk PFR6A11 spark plugs

How do i check the aacv and the coolent temp. sensor to see iff they are working right?

[RMiller]

Check the ecu for codes, but you're not getting anything. Try checking for codes again. Make sure you have the car on while you do it. If you still get nothing, maybe that ecu doesn't do it and you can go to a smog station and see if they'll be nice and let you diagnose your car. Or you can always pay them. This will identify any problems with sensors and such. If you get a 55, then at least the diagnostics is working. Either way, you can look in the FSM to find out how to check to see if stuff is working right.

[biosehnsucht]

RTFSM, starting at EF&EC-25, for checking the sensors / gizmos. It has a complete flowchart of how to check things.

[NeedCAforS13]

My boost gauge, never went under 0 psi !! on idle. read boost fine...but the arm never went under the 0 psi mark....can this be because of the vacume source??

you have your boost gauge hooked into somewhere that doesn't see vaccum... you have to have it plumbed into the intake manifold somewhere for it to read a vaccum reading. if its on your intercooler piping it will read boost only

Sean

[T88lexus]

if you want to come by next weekend. for the intercooler and others. I have a few extra sensors and parts that i can try if it is come out to be a bad sensor..

I have checked every single sensor on my car so if you want me to check on stuff .. maybe I can help..

if you want to check your stuff by yourself.. I would check the water temp sensor.. as well as your o2 sensor. you can also email me

[DriftinNC]

Well i finally got around to checking the codes, lucky #34...good ole knock sensor.

T88lexus- i probably come visit this weekend depending on my work schedule, i let you know sometime soon