98 Frontier XE, KA24 mystery problem

[240_Frontier]

Here is some general info. My car is at 80k mi now, I have replaced, the distribitor cap and rotor, sparkplugs and wires, my distribitor coil, cleaned my MAF, and had a fuel pressure test, which read 64psi on the pump, and 3 psi off on the fuel pressure reg. Now the problem is I have a cold starting problem, My engine goes to about 1.3 rpms, then slow decreased to about 0.9, then just hits a little about 0 rpms, then stalls. There is no check engine light. Any ideas? Help ASAP

[NISTECH]

64psi is extreamly to high. I think possibly you gauge was reading wrong. Your problem sounds like something is up with your Iacv [idle control] Try adjusting the idle air valve out. its a large flat head screw inside a port on the drivers side front of the throttle body. see if screwing that out a bit allows it to idle once its warmed up.

[240_Frontier]

during warmer weather it seems to run just fine, i don't think its the idle control, because it would screw up my idle all the time not just cold starts, i was thinking something in the ignitions systems or egr valve

[NISTECH]

all you need to do is turn a screw to prove or disprove it. I really dont think its your egr. Does it miss when it dies out or does it simply drop in idle smoothly till it dies?

[240_Frontier]

my engine does not miss, and it doesn't smoothly idle till it stalls. when the engine first turns over during cold weather, it will go up to about 1.3 rpms, then idles slowly to to about 1 rpm. then it shoots down somewhere close to 0 rpms, stays there for a few secs, then stalls.

[NISTECH]

it so sounds like its starving for air. If it was ignition it would foul out on start up. Does it smell flooded? or can you smell raw fuel?

[240_Frontier]

well its hard to distinquish between new pacesetter headers, and that but, i think i did smell fuel, after i tried to get started a few times

[NISTECH]

how many other mods are done to this thing?

[240_Frontier]

i have pacesetter headers, Magnaflow hi-flo cat, Custom made magnaflow cat-back exhaust (2.5 inch diameter) and a apex'i s-afc 2

[NISTECH]

take you afc out of the equasion and see if it will stay running.

[240_Frontier]

I had my afc installed about a year ago, and there where no problems then. So I don't know why it would cause problems now? I'm wondering if my mass airflow sensor is getting bad? I heard Nissans are notorious for having maf problems. You said if it was an ignition problem it would foul up during start up, does that have the same meaning to a faulty ignition module?

[NISTECH]

no but the 98 frontier does not typically have problems with either the ignition module or the airflow meter. Nissan being notorious for airflow meters only applies to certain model vehicles the frontier/xterra is not one of those vehicles, Again disconnect your AFC and see if it is causing your problem.

[240_Frontier]

i removed my afc and my problem still occured, this time it the afternoon. I also checked my MAF, and it showed two things, either the maf is bad, or something is causing the maf to read bad w/ the afc disconnected. I honestly think its the maf itself.

[NISTECH]

It may very well be but your had to get anything that can alter its reading out of the loop before you can truly test it. With your AFC still off , back probe the MAF with a volt meter and see what kind of readings your getting off it.

[240_Frontier]

when I did the first check i disconnected the AFC, i even rechecked it, to make sure i didn't see wrong, same readings, it says fault. whether its the maf's or something thats effecting the maf. I also went ahead and got a loner maf from a friend. see if it still fouls up.

[240_Frontier]

new MAF same problem, Now I bypassed the wire that reads the maf on the afc. I have a out of the ball park question. If a engine runs to rich in fuel could that cause a symptom close to starving for air or if it runs rich it gives you bad fuel eco? (and sorry for the delay)

[NISTECH]

yes to both.

[240_Frontier]

so far i was able to get the truck to a drivable status with out problems so far, still haven't investigated the running rich yet, plan on doing that in a week or two