2G Car bogs at 2k rpms

[xxShaneOmac]

When I start my 99gsx and its cold the car drives like total crap. And I pretty much cannot drive it untill it meets operating temp cause it will bog so much.

Once it starts to warm up it acts better but not well enough.

Around 2k rpm the car bogs and chokes itself. The rpms go up and drop and up and drop while on the gas, soon as I let off its fine.

I need to get through that area and the car drives fine. While looking at the 2k bog on the AFR it seems that my ratio dips into the 16.5 - 17.0 or even dosnt read with a ---

This really makes it hard to daily my car.

I replaced the spark plugs and it fixed it for just under a day, now its back again.

Im thinking its time to replace my NGK wires, or check the fuel pressure but im not sure.

880PTE injectors Walbro 255hp and 420 deadtime at 45% global.

Any help out there? This is daily driving not under WOT, I wont even get the car near WOT Im too scared.

 

[Cspaintballer]

try new wires, have you tried a boost leak test?

My talon used to bogg down when i hit about 3k rpm, switched to 5w-30 and runs smooth as butter

 

[xxShaneOmac]

I wouldnt think a boost leak would be the issue, the car isnt under WOT or any boost at all this is daily driving when this happens.

I could be at 5% throttle and 5mph and it will happen.

Have people had many problems with the Coil packs on these cars?

 

[zfanatics]

It could be anything at this point. I would at the basic stuff first. How old is the fuel filter?Is your fuel pressure ok?

 

[xxShaneOmac]

Fuel filter could be replaced its at least 15k old and 4 years. Alot of sitting on this car.

I just checked and readjusted the fuel pressure, it should be 43.5 with the vac hose off right?

I added some plumers tape on the screw and made sure its 43.5 w/o the vac hose.

I need to do spart plug wires but Im looking for something other then the normal NGK.
This will be the 3rd set of wires I have replaced on the car in 15k (last 2 sets were NGK)

I bought a set of taylor super wires but one broke on installation, do you know if I can buy these wires 1 at a time?

 

[target12]

How did the plugs look when you pulled them out? Were they wet with fuel. If so, I would check into wires, coil, etc. If they weren't wet or fuel fouled, check for fuel delivery issues. Also, just because your problem isn't under wide open throttle, doesn't mean it couldn.t be related to a boost leak of some sort.

 

[kchaazz]

Im with the above post. Definitely check for intake tract leaks. Is the car difficult to start when its cold as well? If so, Id hook up your logger or scan tool and check to see if its got a code for a bad coolant temp sensor. If the CT sensor is bad, the ECU doesnt know what temp the engine is at and it dramatically effects fuel delivery. Im NOT talking about the sensor for the radiator fans or the temp gauge; this sensor is on the T stat housing and is wired directly to the ecu. Also, it seems to me you are going through plug wires like crazy. Try starting the car in the dark and look at the wires when the car is running, and if the wires are messed up, you WILL literally be able to see electricity passing over the wires' insulation covering. Do you have an oil leak on the upper valve cover, from the oil cap gasket, or in the wells? If the wires are getting oily, they will fail in short order.

 

[target12]

^^^^^ This car is a 2g, would coolant temp sensor affect driveability? I know it will kill an OBD I car, but I didn't think it would affect an OBD II car?

 

[Dsm4lyfe12]

I didnt think a boost leak could do it either,but mine was so bad that i couldnt make it up a hill.... Turns out i had a hole in my intercooler. What kind of blow off valve are you running? Intercooler piping? I'd boost leak test and then you'll find out where your problem lies.

 

[kchaazz]

One more thing I failed to mention. You are running dangerously lean. Did this start AFTER you installed the injectors? Heres the deal, you need to be sure you ADDED deadtime to the stock figure, rather than subtract. There are only two reasons I can think of at the moment that you could be that lean. Either what I mentioned above, or perhaps your fuel pressure gauge on the FPR is messed up and your base pressure is way too low. Ive seen lots of fp gauges fail, especially the dry ones, vs the liquid filled gauges. One way to check this is to shut the car off and relieve the fuel pressure in the rail. If the needle on the gauge doesnt drop to zero, theres your problem. Definitely dont drive the car until you check this stuff.

And, in response to post#8, the coolant temp sensor is extemely important, as it basically tells the ecu how much fuel to add, timing advance, open vs closed loop fueling operation, etc. Ever notice when you fire up a cold fuel injected car, the idle will be noticeably higher? This is because the ecu is adding additional fuel and using a higher idle map because the temp sensor says the car is cold and the ecu is running the motor at higher rpms in order to expedite engine warm up. This is because best fuel ecomomy and engine efficiency is achieved at "operating" temperature. Hell, sometimes, a bad CTS can prevent a cold engine from even starting!! Also, the ecu utilizes info from this sensor throughout the entire range of engine operation. For example, the hotter an engine is, the more suseptable to detonation the engine becomes, therefore, the ecu will pull a degree or two of timing in an attempt to avoid knock before it even occurs at a certain coolant temp.

 

[Below Ambient]

whats your base timing?

 

[xxShaneOmac]

1. Injectors have been installed a while ago and there was no issue till recently, I wouldnt suspect them. Is there a way to test them?

2. Aermomtive AFPR with a liquid gauge, and it reads 43.5 w/o vac hose, I will check to see if it goes to 0 when the car is off.

3. I will do a boost leak, I have the 1g BOV w/ an ETS Street race core and 2.5" Piping.

4. I do not know the base timing, I have never done that, It should be something I look into.

The car runs HORRID while cold, and pretty good when its fully warmed up, Ill hook up the DSM Link and log the car warming up to see if it has any tells.


Most of the time the car's AFR's are normal and it is around 14 +/- 1 but at random times it dips down into the 16/17+ marker for just under a second and the car idles low, or stutters.