car started...then stopped...

[encasemyheart]

Yesterday I got my SR running, I bought it non-running in a 93 coupe on Friday.

After yesterday, I had changed the o2 sensor and timing, and as soon as timing was set up the car fired right up.

I drove it around the block and let it warm up and it seemed to idle fine and everything. Well about halfway around the block I started boosting, I hit about 6psi and I heard a pop. Getting back to the house I saw it had blown a hose off of the throttle body. So after attaching it, I drove it around the block again. This time it wouldn't really go above 2000 rpm or so. So I left it and decided to work on it today.

After a cold start this morning, it idles very badly and got worse and worse. The it stalled and won't re-start again after stalling a couple times. When it did start I revved it up to about 3100rpm and it backfired badly and there was alot of smoke, and now it won't run at all, just crank. While it was idling today, it was sitting at about 10in/hg vacuum, which seems low to me.

Can anyone tell me what the deal is?

The car has an open Greddy BOV, the stock SR mafs, greddy vspl intercooler, nismo step 2 cams, exhaust ect. Stock injectors.

[180fan]

Check your intercooler piping. One of the couplings may have popped off.

[encasemyheart]

I just did after you said that, nothing. Everything is fastened securely.

[encasemyheart]

Could it be a wiring problem that only manifested itself under acceleration and now needs to be fixed?

[mynismo]

make sure the maf connector is fully plugged in. those have a habit of popping off.

[encasemyheart]

make sure the maf connector is fully plugged in. those have a habit of popping off.

I did. The MAF is connected with a connector and then wired to the harness, I tried the first one, and then put on another MAF. I have three, the SR MAF, the SOHC MAF and the z32 maf. I figured I would get either the SR or SOHC maf to work and not worry about throwing extra stuff on until I'm running smoothly.

[Onizuka]

Go over all plugs, my CAS plug fell off when I stepped on it one time. Take off your valve cover check for broken rocker arms or anything out of the ordinary. Take out sparkplugs and check them.

Honestly has me stumpped, could be something really stupid (it has happened to me :P )

[GTS4-R]

ill second the MAFS....seems to be runnuing too rich so the metered air isnt getting read correct also the 3000rpm limit also hints me to that

[GTS4-R]

o n/m didnt read it all....listen to jspec tuner tho...try that and get back to us

[GTS4-R]

make sure the temp sensor to the ecu is plugged in and fuctional....this seems kinda familiar to the problem when mine was unplugged

[nab911]

Make a boost leak tester, if it cant idle but ran fine once... its probly a vacuum/boost leak.

[encasemyheart]

Wow guys...I just got back and saw all of the responses. I have owned many different cars, each with their own assorted problems, and this is the very first time i have had this much help. The SR community has helped me with everything I needed so far, much appreciated. I knew I bought another 240sx for some reason.

I'll go through and check all the suggestions tomorrow.

[encasemyheart]

Alright guys, car is up and running again, that hurdle is over. It turns out the plugs were fouled, when I first started the car I hadn't tightened down the valve cover all the way and oil leaked into the plug cylinders. I guess it fouled the plugs pretty badly.

In fact, here's a pic:

You can see the plug itself fouled and the top of it covered in oil. I just got new plugs and cleaned everything and everything was good.

Now...when I first started it I could rev all the way, I revved to 5krpm, no problems. I drove it around about half a block just like normal and now the revs won't really go over 2000rpm, if I throttle it good they will slowly slowly build up past 2500rpm. Boost doesn't seem to be coming on either, I hear the turbo spooling but nothing, the boost gauge will stay at zero and then jump to 5 and that's it. I'm thinking leak somewhere and that's why I can't give it throttle after driving it. What do you think?

Any ideas?

[encasemyheart]

Okay, well I keep driving it around the block now and it works fine, but it doesn't feel fast at all, even while boosting. It drives though.

And sometimes it will not accelerate very much at all, just slowly accelerate. The Greddy BOV flutters badly everytime I let off of the gas, is it too loose?

[DSMs_Suck]

intake leak is my guess... dont just "check the clamps".

Make a leak tester and check for leaks!

[encasemyheart]

intake leak is my guess... dont just "check the clamps".

Make a leak tester and check for leaks!

I'm going to do that right now.

Also, I am oging to mess with the dec. air settings on the AFC, maybe that has something to do with it? I can free rev it fine, and everytime I shut down and come back up it runs perfect for a minute, then back to the slow acceleration. Maybe it has to do with the BOV letting out metered air?

Also, any idea what the vacuum should read with the Nismo Step 2 cams?

[DSMs_Suck]

Dec air may help a little bit, but I would definately say check for leaks... many times, you would be amazed at how many are there.

Not sure on that exact cam, but in general I would say you should probably have 12-15 inHg of Vac at idle (around 700 rpm).

[GTS4-R]

something with the MAFS

[180fan]

Try this. Disconnect the AFC at the MAFS wire. Try it without the AFC and see what happens. If that still doesn't resolve your issue, pop the valve cover.

[encasemyheart]

Alright, I tweaked and tuned today, no leaks, unfortunately. I haven't popped the valve cover, but here's the weird thing:

My girlfriend decided to go around the block, so I floored it. It slowly accelerated as described, and I noticed it was hitting full boost about 3300rpm, but still slow acceleration until about 4400 rpm where the car lurches forward and throws you in the back of the seat, it's fast. I am hitting about 9-10psi on my t3/t04b turbo.

It's fast, and works great above 4400rpm, below that it is the slowest thing I have ever driven.

So since I'm holding boost I assume no boost leaks, but there is no low end, even at full boost or partial boost below 4400rpm, what could be causing this? The cams can't be *that* extreme to only allow top end power, can they? It's almost dangerously low power, like you can't do anything.

[encasemyheart]

Also, the idle is a bit 'off.'

I dunno if it's the cams or what, but the idle is strange, Sometimes it will sit at 900 rpm (this is only after adjustment with the SAFC dec air settings BTW) and sometimes it will hunt a bit higher, like 1600-1900rpm. It does feel lumpy though.

[GTS4-R]

its called turbo LAG!

[encasemyheart]

hmmm...

I don't think so.

I know what turbo lag is, and it generally occurs from the time you step on the gas to the time the turbo spools. My turbo hits full boost 1000rpm before anything happens.

[DSMs_Suck]

sounds like the timing is a little too retarded

[encasemyheart]

sounds like the timing is a little too retarded

Honestly I'm thinking that this is it, I'm gonna get it set exactly with a timing light tomorrow.

[GTS4-R]

make sure your cam timing is on as well as ignition timing

[encasemyheart]

make sure your cam timing is on as well as ignition timing

Cam timing is dead on exact, I checked that when the valve cover was originally off.

[soflajdm]

And sometimes it will not accelerate very much at all, just slowly accelerate. The Greddy BOV flutters badly everytime I let off of the gas, is it too loose?

yes

[encasemyheart]

yes

Will that affect anything?

[soflajdm]

not really sure... it's kind of annoying though when your bov goes off and youre not even boosting, right?