View Full Version : KA-T Guys! I'm done but need help! Doesn't run right

11-08-2002, 11:50 AM
Well, we got it all together but now for some odd reason it is cutting out real bad at any rpm or gear (higher gears are worse). I'll be accelerating fine then it will just totally stop accelerating for no reason, then with the pedal still in the same position it will cut back in, then out, etc.. What could be the problem? We think it might be a vaccum problem with the emissions stuff that I lost. Any ideas?? I have a new walbro fuel pump so that shouldn't be it. I also have a new 300zx fuel filter to put on tonight, might be it. Also, we left the large metal tube that runs behind the motor and connects to the exhause (exhaust recirculating valve) open to the atmosphere, should we plug it up? Also, the four vacuum tubes just below the throttle body, should they be left open, plugged up or plumbed back into the system befor the turbo?
Any help is greatly appreciated.

11-08-2002, 12:17 PM
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, we left the large metal tube that runs behind the motor and connects to the exhause (exhaust recirculating valve) open to the atmosphere


Plug it up. that is some hot gas and it could melt things in the engine bay.

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Also, the four vacuum tubes just below the throttle body, should they be left open, plugged up or plumbed back into the system befor the turbo?


You should have one running to the waststegate, one to the FPR, and if you have more left they should be plugged up. I will assume that you took out your charcol canister, and are no longer using it.

check your timing and gap on your spark plugs.


11-08-2002, 12:26 PM
I dont think there will be any hot gas flowing from the EGR Pipe since its just conected to the intake. It should be pluged though. does the car run fine once its warmed up? I was thinking it could be a fuel filter problem. so see if that helps. Im not sure witch vacum lines you are talking about but I know of one vacum line under the throttle body thats left to the open in my set up. check the plug wires. ummm

11-08-2002, 05:11 PM
What are you using for fuel management other than fuel pump and filter? (injectors, ECU, FMU, etc..?)

11-08-2002, 10:18 PM
I've got the Walbro high flow/pressure, stock injs., and a Cartech adjustable FMU, the fmu is set to the highest rate of gain (7:1), I just replaced the filter and that didn't help a thing. I'm beginning to question the fuel pump. On my air/fuel guage it shows me running very lean almost constantly when I drive. We disconected the fmu and the problem was still there, we also regapped the plugs and double checked the timing, it idles fine for a while then tries to die then eventually does die. Doesn't this sound like a fuel problem? Spark could do it also but it would have to be a total lack of spark like the coil was cutting out but then the car would die instead of just cutting out when I drive right? http://forums.freshalloy.com/ubbthreads/images/icons/frown.gif
thanks for the help

11-08-2002, 11:32 PM
If you left the EGR open, it will open under part throttle cruising (and certaim other conditions) and cause a GIANT vacuum leak...

Sounds like that's you problem, if not just one part of it. And it's controlled by the BPT valve, which is vacuum actuated...

Good luck - Brian

11-08-2002, 11:39 PM
*Assuming you properly removed and shut the EGR system*

Sounds like fuel problem to me. I don't know if the FMU is doing its job right. Maybe it's not sensing manifold pressure to raise the fuel pressure (bad vacuum signal connection), maybe it is but not doing anything about it (bad FMU). I would start off by hooking up a fuel pressure gauge, and have someone drive your car while you as a passenger read the gauge. Then, report results here (specially what the gauge reads when your engine cuts off).

I don't like the idea that you're running stock injectors (260CC)... (bad feeling)

How much boost are you running?
At what amount of boost does the problem present itself?
Which Walbro pump did you get (pump flow rate, high/regular pressure, etc...)?

11-08-2002, 11:51 PM
Could also be that the rising rate is too high on the FMU, and actually drowning the engine with too much fuel. But that's unlikely, since the air/fuel gauge reads always lean... What kind of air/fuel gauge do you have, and how did you hook it up?

11-08-2002, 11:58 PM
"it idles fine for a while then tries to die then eventually does die"

I already mentioned previously, but what's your fuel pressure at idle? Measure that and notice its behaviour when the car is starting to die at idle.

Did you remove the charcoal canister? What did you do with the fuel tank vapor hose? Do not plug that up. Do plug the vacuum and purge hoses up, else you'll have a vacuum leak

11-09-2002, 03:25 AM
it could be the clutch slipping.

the smallest hose should go to the intake pipe after the AFM.

the hose that is right below the throttle body goes to the cool intercooler pipe.

the hose at the valve cover goes to the intake pipe after the AFM.

wastegate,boost gauge,bov could use the FPR vacuum port. you can also run a hose from the wastegate to the hot intercooler pipe or the turbo compressor.

if you do remove the egr; don't forget to plug up the vaccum hose ..

11-09-2002, 03:46 AM
Make sure your MAF is clean

11-09-2002, 08:46 PM
Check your spark plug gap. If the gap is too large, it may misfire. If this is occuring, it typically feels like you hit a rev limiter. It should only occur during hard acceleration and boost.

11-09-2002, 11:49 PM
EGR valve unplumbed, will cause very similar problems to what you describe.


11-10-2002, 01:40 AM
On the EGR,
simply remove the tube. Cut it so you can take off the nut that screws into the EGR valve. Get you a nickle and in nut and acrew it back on the EGR. Also use some RTV sealent when putting that nickle in that nut. Now that is sealed.

Next possible proble. Never just leave vaccumm lines loose. Do you have a boost gauge? You need one of these first so you can see how much vaccum you really have.

11-11-2002, 11:59 AM
Well, I got a fuel pressure guage and I'm gonna install it soon, that should tell me a lot. I'm also gonna reinstall my stock fuel pump for some no boost runs and see if the problems persists. Remember, this problem isn't happening on boost just during regular driving. I'm also gonna recheck the whole egr system and check my computer codes.