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Author Topic: Diagnose This Problem Please  (Read 1972 times)

Offline blitz

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Diagnose This Problem Please
« on: 10:30:54 PM / 23-Oct-07 »
OK, when I 1st start the car, it didn't go to the warm up mode at all. then the vacuum on the boost gauge is not at the very left but at the left edge or middle of the 1st bar on the vacuum side. I have autometer boost gauge, and before I got this new turbo and exhaust it always goes to the warm up mode and vacuum reads at below 20 (20-22) in-Hg on the boost gauge. now it's between 15-12 in-Hg when the engine is cold. when the engine is warm it's fine. Today was a cold and rainy day, so it should go to the warm up mode.

then there is the drive/cruise problem. it feels like the car getting too much fuel randomly. It'll buck/miss now and then . it feels like when you just learn manual transmission and you buck the car. not that drastic; it is very subtle but you can feel it (another benefit of blown shocks). it happens at random around 2.5k-3.5k rpm at partial throttle (1/8th maybe) or when speeding up very slowly and the turbo is just start spooling. to me it's feels like the car is getting too much fuel.

what can be the problems and what are the solutions?

what does the vacuum pump do? when is it working?

This is what I did yesterday:

I tighten up the clamps on the charge pipe. I wanted to change that stock charge to TB hose w/ silicone, but it's 2.25 instead of 2.5. so I just tighten the stock one to the max. I haven't got a chance to look at the engine today as it rains all day, and I don't have covered parking space.
« Last Edit: 10:59:49 PM / 23-Oct-07 by blitz »

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Car status:
- Ractive tornado air intake. stock ram air CAI  
- MSD Blaster SS dual coil, 7 mm high temp bosch leads
- unknown rota rims w/ michelin hydroedge. stock turbo rims w/ michelin x-ice during       winter
- Titanium weighted shift knob
- 280zx Short throw shifter
- Boost gauge, narrow band A/F gauge w/ sunfire O2 sensor
- custom made 3 inch turbo back with kakimoto muffler, JASMA certified
- JDM T25 turbo
- XS Turbo MBC
- Recirculating 1G DSM BOV.
- Old and tired stock everything suspension...

SOLD to OSAD!!
http://www.cardomain.com/ride/2510178

Offline 200sxkitcar

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Diagnose This Problem Please
« Reply #1 on: 08:00:01 PM / 24-Oct-07 »
Check to make sure your pop-up valve has not released (stuck open) and is dumping air out of the system.  What do your spark plugs look like?  Are they black at all (rich)?  How about vacuum leaks, do you hear hissing from anywhere (move the lines around a bit to see if there is a change).  Is it running at the correct RPM when it is cold?
Sterling Picton
 

Offline blitz

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Diagnose This Problem Please
« Reply #2 on: 09:28:29 PM / 24-Oct-07 »
Quote from: 200sxkitcar
Check to make sure your pop-up valve has not released (stuck open) and is dumping air out of the system.  What do your spark plugs look like?  Are they black at all (rich)?  How about vacuum leaks, do you hear hissing from anywhere (move the lines around a bit to see if there is a change).  Is it running at the correct RPM when it is cold?

- umm pop up valve is questionable. the lid is not touching the valve body. has been like this since I bought the car.

- as for spark plug, I just found out today I don't have long enough extension to clear the head and dizzy (OK, I don't have the proper tools, I have that tiny mastercraft home owner socket set) gonna buy one long extension tomorrow.

- I can't hear any hissing.

- it's some kind of vacuum leaks for sure because when the engine is cold vacuum reads at 14-16 in-Hg. Based on info on internet it should be around 21-22 in-Hg for 4 cyl engine. if I let go of the gas while driving I get 23 in-Hg. it doesn't idle properly when it's cold, it sits at 600 rpm and act like it has a lumpy cam. if I give it a gas quick, it sounds like it's gonna die -> it stumble then rev up (maybe it just a turbo car? it was like that with the old turbo).

I'm gonna get an injector cleaner and just dump it in the tank, see if it helps. Also, gonna get help from friend to diagnose this. Gonna get an oil change, as on this one website it's a possibility that make this, dirty oil (oil is black).

Engine hasn't been started in maybe almost 3 months until last saturday night. it fires OK and run fine, so we thought there is no problem. It was a warm day and we have no problem with the car at all.

Can dirty MAF causes this? how do you clean them properly?

Thanks a lot!
Car status:
- Ractive tornado air intake. stock ram air CAI  
- MSD Blaster SS dual coil, 7 mm high temp bosch leads
- unknown rota rims w/ michelin hydroedge. stock turbo rims w/ michelin x-ice during       winter
- Titanium weighted shift knob
- 280zx Short throw shifter
- Boost gauge, narrow band A/F gauge w/ sunfire O2 sensor
- custom made 3 inch turbo back with kakimoto muffler, JASMA certified
- JDM T25 turbo
- XS Turbo MBC
- Recirculating 1G DSM BOV.
- Old and tired stock everything suspension...

SOLD to OSAD!!
http://www.cardomain.com/ride/2510178

Offline 200sxkitcar

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Diagnose This Problem Please
« Reply #3 on: 07:40:40 PM / 25-Oct-07 »
You can remove the pop-up valve and replace it with a 1" NPT threaded plug found at any hardware/home improvement store (should be like $.50) to see if this is the problem, if it is not, I would put it back in.

This isn't the safest thing in the world, but you can redneck check vacuum leaks by spraying something flammable in nature (propane, or engine starting fluid) lightly over the motor as it runs, and if there is a jump in RPM's somewhere, then your leak is located there.  This is how I found out the intake mani gaskets on my CA were blown.  It may be hard to hear vacuum leaks with the fan humming all of the time, its kinda a noisy thing with these cars.  I'm looking forward to installing an electric unit in mine.  

A dirty MAF can cause all sorts of problems, usually it will cause a car to run rich.  I actually found MAF cleaner spray for cleaning the heating elements in them at the local Murrays auto parts store, but check with your local parts joint, if I remember right it was made by CRC (a big autochemical mfgr).

I have heard for many years that the pipe that goes between the turbo and intake manifold is a problem, as in it comes off and leaks, but if yours is nice and tight just keep looking around for other problems.  Good luck!
Sterling Picton
 

Offline blitz

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Diagnose This Problem Please
« Reply #4 on: 12:24:33 AM / 26-Oct-07 »
I RTV the ish out of that charge pipe. I'll look for MAF cleaner.
Car status:
- Ractive tornado air intake. stock ram air CAI  
- MSD Blaster SS dual coil, 7 mm high temp bosch leads
- unknown rota rims w/ michelin hydroedge. stock turbo rims w/ michelin x-ice during       winter
- Titanium weighted shift knob
- 280zx Short throw shifter
- Boost gauge, narrow band A/F gauge w/ sunfire O2 sensor
- custom made 3 inch turbo back with kakimoto muffler, JASMA certified
- JDM T25 turbo
- XS Turbo MBC
- Recirculating 1G DSM BOV.
- Old and tired stock everything suspension...

SOLD to OSAD!!
http://www.cardomain.com/ride/2510178

Offline silverarrow27

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  • Location: Banning, CA 92220
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Diagnose This Problem Please
« Reply #5 on: 12:46:50 AM / 26-Oct-07 »
Future reference blitz, don't rtv the charge pipe. Gonna be messy and a pain for you in the future. Just get better couplers and clamps.
2013 Veloster Turbo Base
2007 Versa SL
1989 240sx XE