NOPI 2007 or BUST.......Bust, what happened??

[pirate87]

Shortly after putting the 1000th mile on my RB25-S14 swap, without a major issue, I decided I'd like to try to make it down to NOPI from my home in Durham, NC....about a 7 hour drive.

For a few weeks prior to the event, I monitored the car very closely and performed all routine mantinence. Everything was fine, as far as I could tell, so I set off with my buddy in his IS300 following. We'd been driving for about 2.5 hours and were just outside of charlotte when my PowerFC flashed the check engine light and the car bucked as if the fuel had been cut. Over the next 10 seconds this happened 4 or 5 times so I shot over to an exit ramp and parked it.

We threw the hood open and began to inspect the engine finding nothing out of the ordinary. I cranked the car and with a bit of coaxing (kicking the throttle) she started up and idled for about 5 minutes before cutting off again. We did this two more times and then decided to take it back out on the highway. After about 3 minutes of driving the bucking returned. Not being near an exit, I tried to drive through it, and eventually the car gave out while I was rolling ~50 mph. It was like the MAF had come unplugged while I was driving ( I have had this happen so I know the exact feeling), however the MAF plug was secure when we opened the hood. This time, there was no recranking the car. We waited and tried this every few minutes for about 1/2 an hour before deciding to call AAA.

To shorten an already long story, the car was towed back to durham and I continued on to NOPI with my buddy. Nopi was a great time, and returning home I plugged the car up to my FC datalogit (which I regretably did not pack, thus not data) and let it idle for a good 20 minutes. No problems. I had to drive to Raleigh (45 min drive) to return to school, so I decided to try the car......still not a problem.

When the problem happened, we were on the side of I85, and without the datalogit or a multimeter, the best we could determine was a MAF issue or something with the CAS....

my personal theory was that the maf collected too much moisture, as it had been raining the entire trip, and eventually just took a dump. Everything is fine now, but I still need to know what went wrong as to prevent it next time. Thanks for the input

[300Plus]

I had a few issues pop up on me during a long drive one turned out to be the grounds on the intake mani (just above the water-neck) came loose causing the car to jump and skip and another was after a hard launch at the track I stretched the MAF wires breaking a soldiered point most of the way through caused bucking and maxing out at like 4k rpms.

Check you MAF wires and it may have even been your CAS getting too hot... Ive heard that causing ppl issues. Hope you get it figured out, keep us posted.

[gawdzilla]

my own car had this exact problem, as did my buddy's sr20. common problem: the MAF itself.

they just go bad over time, bottom line. I've messed with all the possible variables: cleaning it, cleaning the connectors, re-shielding the wiring, making it as short as possible.. etc. all to no avail. my friend's car would die while moving and idling. mine would buck while moving then die at idle. let them rest for about 30 seconds, jiggle the plug, flash the ign on/off, and its cured. only to come back 20 minutes down the road.

to be sure its your MAF, since you have pfc... try to catch the problem in action by staying in the sensor/sw menu where it shows the MAF voltage. when the problem is occurring, the MAF voltage will jump erratically. if your car dies, the MAF voltage might be blacked out. thats how you know its the MAF.

moral of the story: get a replacement MAF and keep a spare handy...

[Abdo]

Sorry to thread-jack! But where can I find a good Z32 MAF?

[pirate87]

Nissan dealership....

but, thanks guys for the helpful responses. Could the CAS overheat at normal coolant temperatures? I still really feel that it was just the MAF, however I did check all the wiring and the plug so it was not a connection problem.

[Carl H]

are you running a blowthru setup?if so ive found that during heavy rain the intercooler condenses enough water vapor to max out the maf.

[pirate87]

are you running a blowthru setup?if so ive found that during heavy rain the intercooler condenses enough water vapor to max out the maf.

no, just your standard before the turbo. However the maf is bolted to the intake, with maybe a foot of pipe until the turbo....don't know if that would cause any turbulence issues?

[cdorhout]

My car runs the same way in the rain. Yes, the MAF gets wet and runs like crap. It takes a long time for it to dry out too. Mine got wet on the way to the dragstrip and I couldn't get it to run right that whole night.

You may have to build a box or something to keep your intake dry.

I haven't, I just don't drive it in the rain anymore

[240z4u]

Odd, never had that problem yet with rain. Maybe thats something I should plan ahead for.

I am running blow - thru and my filter is about 4" off the road. I drove in heavy rain without any major problems.

Knowing my luck, it will crap out at the worst time possible.

Are you sure its not the water getting into the electrical box of the maf? Mine is sealed with strip caulking.

Evan

[digzsublime]

My RB does the same in heavy rain or when I take it to the car wash. In my case it's because I thought it would be a good idea to place the filter as close to the headlight bucket as possible. My friend was nice enough to make me a custom intake pipe wich wedged the intake filter directly behind the drivers headlight. Exactly what I wanted. Only problem is that when the car sits in the rain or when I take it to the car wash, water comes through the gap between the headlight cover and the hood. Thus getting the filter wet and causing the MAF to go wacky. My cure? I'll be redesigning intake piping when I pull the motor to replace the headgasket next week.

[wawazat8402]

Ive had water cause a problem as well, however I now just towel dry the engine bay before I leave the car wash. I havent driven the car in heavy downpours so Im not sure if it would happen then as well.

[FAST-DATSUN]

do you have the cover over the coils??? Heat causes them to break down,,,,,,common problem even in Japan...