Troubles with car after it has gotten to operational temp

[turbo98_240sx]

Ok this problem is driving me crazy and I've allready gotten a new Crank angle position sensor and its still happening, The motor seems to be misfireing, possible detonation I'm not quite sure, the idle is erratic at best too, I've set the idle and checked the timing several times and didn't seem to find anything out of the norm, this problem can't seem to be pinpointed to anything that happens as it happens if I've gone into boost or if I drive it lightly, the onlything that seems to be a constant is that the car is at operational temp, sometimes it takes a while to happen and sometimes it happens as soon as it gets up to opperational temp, The only code it has ever shot out from the ECU is the CAS code, and I'm guessing that it is only set off by the misfiring since I'm under the assumption that the CAS sensor isn't used for the actual opperation of the motor although it has thrown the code for the CAS before the problem started happening but I'm thinkin that might just be because I didn't here it misfire right away... I did check and change my sparkplugs and I'm lost as to what could cause this. So you know my setup is the greddy kit W/ Intercooler and the same program that came in the E-Manage from greddy, I'm waiting to get this problem under control untill I go any farther with the build of the motor, this set up ran fine for 2 years now well up untill this. Any help would be great or any Ideas on what to check.Thanks and Peace,Pat

[Structure240sx]

you are correct, the CAS is just there for the ecu to be happy, not for engine operation

i would definitly try a tune up with new spark plugs, wires, cap and rotor.

do you have a wideband on the car?

[turbo98_240sx]

No I don't have a wideband otherwise it wouldn't be sporting the greddy tune as I have the cable already, and I was kinda thinking of getting an EGT to help pin point this problem (if I end up droppin some cash soon on the car as my maxima needs a few thing to keep it going too), thinking it is detonation that would be a good indication as to how well the car ran because it does seem to be driven in hot temps, today actualy for an hour and a half before it started with the probelm and this was by far the hottest day out yet 85Deg F, so I think its more a misfire prob then detonaion, The wires are only a year old and the rotor and cap looked fine, plugs are new for today's test even tho the ones I took out wern't that old Figgured it couldn't hurt to do them just in case I missed something but I'll look into the cap and rotor thing

[TheOne]

have you replaced the coolant temp sensor or the likes? maybe cleaned the connector? sometimes when the engine warms up the coolant temp sensor makes the car run strange i believe.

[Structure240sx]

its still possible that the wires are a little too old and/or arcing. how old are the cap and rotor? for $15 its good to get new ones.

[S13FX]

Hey check this out I had the exact problem and I cant belive how simple it was to fix.

Clean the ECU Water Temperature plug, It is on the intake manifold, right next to the water temp sensor for the gauge on the cluster. What that does is it tells the operating temp to the ECU, and it changes the operation of your injectors. There is a post on here showing how the injectors work when the engine is cold and how they work when its warmed up. All u need to clean it is a little nail file, and some of that electrical cleaner stuff.

[turbo98_240sx]

OK I've have yet to get a Multimeter to check the coolant temp sensor but, I did clean the connectors. Once again the car was at operational temp for a while before the problem came back, this time I noticed a few things that might help in trouble shooting the problem and maybe give me things to look for once I get the Multimeter. The car stutters under any throttle besides ~5% or under, and once it should be seeing boost seems to stutter right away and never gets a chance to hit boost. The car is better and somewhat responsive from the ~2K to ~3K range assuming that you don't apply anything but a very small amount of throttle outside of that range I didn't really even want to test out the car as it was running so ruff. Also, when I would stop the idle becomes erratic and jumps from 1k to as low as 250 RPM and if you would let the car get down to 1.25K (rpm) it would also run ruff and lose power. The only code it has thrown so far was the CAPS. Anything you can think of to check out let me know as this is baffling me so far and I appreciate all the help I've gotten so far but it is confusing me to no end because it seems unrelated to being boosted (As I've given her some full 2nd and 3rd gear pulls) and the problem wouldn't happen till after that and I never saw the boost go over the ~6psi of the stock wastegate on the turbo and even though the stock tune from greddy is crappy I'm told I doubt it would make my car run this bad. Thanks tons and Peace,Pat

[DammitBobby]

I am wondering if your fuel pump is crapping out. I had a problem when I first installed my turbo. Car ran fine before turbo install but everytime I started to boost it would do that stuttering like it was missing. Come to find out my stock fuel pump was crapping on me. We found it on the dyno I had a fuel gauge and when it started to boost it would lean out and start that stuttering like it was miss firing. The fuel pressure started dropping off. Installed a walbro and it fixed my problems.

[turbo98_240sx]

What confuses me is that it runs for so long without any sign of a problem and then boom it starts up, wouldn't a fuel pump be acting up from the start and when I start it again it should be acting poorly too right? I do have a 255lph Pump but was waiting till I could get a FPR that is adjustable because I herd the 255 would bump up base fuel pressure so it would screw up the car and I would need to retune it and since I don't have a Wideband that makes it a lil hard. Oh and I'm still working on the multi meterPeace,Pat

[DammitBobby]

No I had no problems starting the car or driving under normal driving conditions. It would only happen under boost. Wideband right now would really help you figure out if you are running lean. I ran a 255 with stock fpr I think it did raise the pressure a little bit. If it were me I would install the new fuel pump and see if it fixes your problems.

[turbo98_240sx]

Think the extra pressure would screw up my tune and also anyone got a writeup on the install? I found one for a s13 but no pics worked and ppl said the s14 was way harder, so an s14 writeup would rock, and I did search but came up empty, I have have started looking back through the pages to see if I can just find it like that, And then why would my Idle be crappy if the fuel pump was dieing... because it's not just in boost that the car seems to take a crap, in fact up untill it starts stuttering it runs great even under boost all the same as soon as I find instructions for an Install and get some free time I'm all over that as I should have A multi meter tonight rock onPeace,Pat

[dontbugme]

O.K., from the title of your post I'm assuming the engine runs absolutely perfect when cold, yes? After the problems start, when it reaches operating temperature, do the problems continue while it's idling so that you can do some trouble shooting?

The CAS code does indicate a misfire but OBDII would have thrown an immediate code for an ignition missfire, like no spark, which you didn't get, right?

This leads me to believe it's:

1) Some sort of fuel problem like others have mentioned.

2) A weird problem with one of your valves or clearances.

3) A crack somewhere in the intake that opens when hot - not likely.

Troubleshoot:

#1, Stick the blade of a long screw driver onto the edge of the injector, preferably on a metal part and stick the handle end in your ear (works best with a foam ear plug inserted) and listen and make sure it's opening and closing when idling. Do it to all four. You should hear it clicking away w/no skipped beats. This has to be done when the problem presents. If you had to do any rewiring to different injectors, make sure it's bullet proof as electronics, wires and resistance change with temperature.

#2, Is easy, do a compression test and check your valve clearances if something is suspect.eul

#3, You definitely don't want to be here!

Make sure you check out the temp sensoras others have mentioned. On, pre OBD, an much older cars these could actually cause stalling. It's one of the most important sensors on ecm equipped cars.

A '98 car of Nissan's quality should not be having fuel pump problems and fuel filter problems should only occur at high loads. 10 psi either way from normal's not going to do anything like what you're experiencing. A faulty FPR, yes.

Keep the faith - sometimes the most complexing problems are solved with the simplest solutions.

[turbo98_240sx]

Trouble shooting results from don't bug me:#1 All injectors were "clicking" normaly durring the Problemalso it runs fine cold and takes a while once warm to start having the problem so I'm confused.Compression check yet to come

I'm not going to install the fuel pump untill I get this solved because If I screw up that I don't want another problem added to the list

All sensors seemed to be with in spec, even durring the problem, I'm going to recheck them all again and this time keep a log of the voltage or resistance, mostlikly post results up

Also The compression check should be done soon I can't seem to find my gauge and tubes (the kit I got from sears) but when I checked it last year it was 140 +\- 5psi or so, I don't think that is the problem but would at least elimanate some possiblities

If I could I would just replace whatever sensors I thought it needed but I'm trying to ball on a budget so thats out of the question Thanks again

Peace,Pat

[DammitBobby]

When you are testing your sensors make sure you do it as soon as the car warms up and haves problems. I had a problem with a camry that would run for 15 minutes and quit on me it end up being the coil. The coil would read less then 1 ohm when cold but after it quit running it read around 38k ohm. Good luck with your trouble shooting.

[turbo98_240sx]

I try to do it as soon as its having a problem because some times It's been warm for an hour and nothing happens

[turbo98_240sx]

I notticed going over the car that I have heat range 6 plugs when range 7 is recomended could this cause the problem as all the sensors were within spec. even when the problem was there, I'm going to recheck them again when I get time and do a compression check as I finaly got my compression checker back. I'm slowly starting to lose my mind to this problem going over anything that it could be. As soon as I've done the compression check I'll post up results along with the ohm's and voltages of the sesnsors I'm checking just to see if even tho one is in spec it could still be on the verge of being the bad guy. and if anyone knows about the plugs let me know, and for the record I can varify that it is getting fuel and spark so ??? on those 2 being the issue. Also I do have a video I could post up of both the car runnin good and when the problem is there if anyone thinks it could help just let me know where I can post it for free or how to load it up to the board. Thank you for your help again.Peace,Pat

[turbo98_240sx]

OK I just had some Ideas real quick on things to check kinda, First off the car was in storage for 6 months without a battery, and yes the fuel that was in there was replaced with some fresh 93, But I was wondering if that could have started this by the e-manage losing it's tune from not having power for all that time of if it is the e-manage over compensating for timing or something that would deal with the e-manage since it seems to be a electrical thing that is wrong somewhere, I'm going over the car again this time with a fine tooth comb, Looking for a loose connector or an exposed wire and checking stuff with a log to compair it to at a later if need be, Is there a cheep tool that I could obtain that would tell me what all the sensors are doing and where the timing is set at or how much is being pulled or added? Would a wideband help with this problem? I kinda wanted to wait to get this figgured out b4 I started dropping more cash into the car since I don't know what is wrong I didn't want to drop some cash and be too broke to fix the orignial problem. If anyone can thing of any tools that might help me out I'd be forever in your debt as I'm really missing my baby. Peace,Pat