98 C70 2.3L Poor running MVSUCCESS bad MAF

epukerob · Post by **epukerob** » 23 Apr 2014, 10:08

Ran like a CHAMP, then all of a sudden. Codes P0300/0301/0303/0304 - multiple cyl misfire. Plugs/wires/cap/rotor all checked. All wires read 600~1100 ohms (IPD cool-blue set). These ignition parts are all 1~yr new. Coil is ~ 0.5-ohm on primary; 8700-ohm secondary (terminal to ground is OPEN, term to either primary terminal reads 8700-ohm). Crank pos sensor reads a consistent 280~ohm, fluctuating only a few ohms as I crank the engine (Is this proper? The Fluke digital can't really see quick fluctuations). Unplug cam sensor and engine won't start at all. I sometimes smell raw fuel - seems to confirm she ain't far'n right. When running, I listen to all injectors w/ the stethoscope and they all do the clicky-clacky loud-'n'-clear. Off now to get adapter to check fuel pressure - but if that is good ... ???

Post by **rmmagow** » 23 Apr 2014, 11:43

You can also check pressure with a pencil type air gauge, probably ruins it for air but it's only a buck. Got a spare 103 relay for the fuel pump? You are probably going in the right direction with the cam sensor though. Won't run without the cam sensor and cranking like that will give you a gas smell and rinse off the oil on the cylinder walls. Any sudden dampness, heavy rain, big puddle?

epukerob · Post by **epukerob** » 23 Apr 2014, 11:52

No rain or wetness - I am in So. Cal. paradise ... it has been dry as a bone. Finding adapter for that tire stem/Schrader valve is like chasing a rat hole; I have cheapo tire gage and will do that rat-now... I'll see about F/P relay...

epukerob · Post by **epukerob** » 23 Apr 2014, 12:27

F/P checks to 38 ~ 42 psig. Unplug MAF sensor and she starts/runs/revs and idles smoothly in the garage. Plug the MAF in and she dies instantly. Now reads P0243.

Post by **kahl** » 23 Apr 2014, 13:00

I think your MAF is bad and you have a loose inter cooler hose. Search code P0243 for more info

Post by **rmmagow** » 23 Apr 2014, 14:20

Check at the bottom on the intercooler, that's where mine came loose. Really give it a good yank, not just a look as it can look fine.

epukerob · Post by **epukerob** » 23 Apr 2014, 16:25

Yanked, pulled, got crap in my eyes ... it is all quite solid and tight.

Post by **abscate** » 23 Apr 2014, 16:44

MAF replacement next. New part, Bosch only. Lots of junk out there at 1/3 price that work well as bookends

epukerob · Post by **epukerob** » 23 Apr 2014, 20:33

Yes... I read only horror stories about the cheapo parts. I went through the MAF drill on my '85 Z28 Camaro years ago... but that's another story. So new Bosch @ $140 bucks... here we go.

epukerob · Post by **epukerob** » 26 Apr 2014, 18:28

Ok... BOSCH replacement - good, clean, used part. Exact duplicate. Rec'd in 2 days from Texas (to Callie) e-bay with 14-day money back gaur. Installed in 5 mins. - everything else already put back together; I am thinking "success oriented project". Fired right up and HAULS ASS! We are good to go... hopefully I can help others now w/ similar trouble. BTW - here is a fitting to attach to the fuel rail for pressure check: http://www.skygeek.com/ats-556.html