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[Brook24v]

Isn't the SHO dead in it's tracks with a bad crank sensor though? It's never had a problem starting and there is a tach signal with key-on power, BUT when watching the tach while it's running rough it just seems like the car is revving at a higher RPM than what is actually showing on the tach. When the engine is running smooth it's dead on with the secondaries opening up. Or maybe it's just in my head.

I did question the cam sensor. Does this engine have just one cam sensor?

So far I've replaced

Plugs
Wires
MAF
Coil

It does have a CEL. I do not have an OBD1 scanner at the moment.

 

[kevinspann]

OBD 1 Scanner = paperclip

Just one cam sensor...

Does it only start to run like crap when it's hot? DIS could be overheating...is the DIS or it's plugs cracked at all?

 

[Brook24v]

Actually it's really odd. It will run fine sometimes when it's cold and hot. Doesn't really mater either way. Totally random, although I've yet to have it run smooth no matter what today.

I'm heading over to the parts store shortly to grab a cam sensor.

 

[Brook24v]

Okay, just got done with a KOEO code test (I think I read them right). Some of this might be from when I was unplugging plug wires and stuff lastnight.

157 (R,M) Mass Air Flow signal is/was low or grounded - MAF
176 (M) Oxygen sensor not switching - system is or was lean Left or Front HO22SSS - Fuel control
217 (M) Primary circuit failure - ignition coil 3 - Ignition Systems
542 (O,M) Fuel pump open, bad ground or always on - - Power / Fuel Pump Circuits

I'm going to unhook the battery and see what still comes up.

 

[zblackbeast]

542 will come up if the car stalls fyi..

When my cam sensor failed it would run great until it warmed up.. sometimes it wouldn't even do it at all, and sometimes it'd run like crap all the time.. Didn't have any issues with tac signal until the day I changed it. Tach wouldn't work for one or two minutes after sarting the car.

Replaced the cam sensor and I haven't had a problem since.

In reply to Jason, it very well coupld be the crank sensor, but like Brook said, only cases I've seen of a failed crank sensor left the car dead completely..

 

[Brook24v]

Good info. Thank you.

Well I was planning on getting a cam sensor, but I got the urge to start up the car one more time and see how it ran. I gave it one good rev (fairly high RPM) and the damn alternator exploded. I'm talking a broken casing and grinding, aluminum chunks splattered everywhere. Just my luck.

:laugh_ti:

 

[yamahaSHO]

It could very well be the cam seonsor. I went with the crank sensor as he hasn't mentioned completely losing the tach signal. The issues with the crank sensors in the past is that they would get warm, start having issues, and after cooling down, the car would fire back up and run fine for awhile.

 

[Brook24v]

Haha. There is a bunch of bound up metal shining in there right where the fins are missing on that casing.



I also scored a used cam sensor from a buddy that is doing an SHO-powered Ranger swap so I can see if the cam sensor is in fact the problem. I'll do that this coming Wednesday when my new alternator comes in. Hopefully it works so I can continue on with my voyage to 300,000 miles on an OEM timing belt OEM rod bearing Yamaha 3.0L.

 

[zblackbeast]

Lol. Good luck dude... you must be religious with oil changes for the bearings to be good still... hah

 

[Brook24v]

Time to swap cam sensors.


At least the sensor is easy to get to! !!! (my hand says otherwise)


Yep, looks like shit. It's got to be bad.


Got the sensor swapped, started it up and VRRRRRRRRMMMMM. Runs great. I get excited as sparks shoot out from the alternator as if it's throwing a celebration party for me. Pull the car out on the street to park it and........ it starts running like shit again. WHY?!?!?!

Oh, and here is a random chunk flying around in the alternator.


So this pretty much sums up my night:
http://nooooooooooooooo.com/

 

[typhoon5000]

I would say the resistance on the cerp. belt from the alternator can't be helping the situation. It's probably bogging down the engine, wouldn't you think? I wouldn't run it again until you put the new alt on there.

Did you also happen to do the cam seal when you did the cam sensor? If the seal is bad, the oil stuck in the sensor housing can cause the sensor to read improperly, no matter how good the sensor is.

 

[frosho]

Have you checked to see what voltage the alternator is putting out in its damaged state? You could harm something else if it's overcharging.

 

[Brook24v]

Did you also happen to do the cam seal when you did the cam sensor? If the seal is bad, the oil stuck in the sensor housing can cause the sensor to read improperly, no matter how good the sensor is.

I did not, but I suppose I could do it all again. I did not take off the aluminum housing. Just the two 5.5mm bolts that hold the actual sensor onto the housing.

Have you checked to see what voltage the alternator is putting out in its damaged state? You could harm something else if it's overcharging.

It won't charge at all unless you give it a rev, shooting sparks everywhere. Hopefully my alternator shows up soon.



Would a bad DIS cause random misfires across all cylinders?

 

[frosho]

Would a bad DIS cause random misfires across all cylinders?

Certainly could.

 

[Brook24v]

Well that's next on the list then. After that - lighter fluid.

 

[SHOtimer]

You need to pull the timing covers and check the crank sensor, you probably have a coolant leak on it causing the problems.

Sometimes they fail completely, other times it can be sporadic. It's an electronic part, it can fail in a multitude of ways.

Doug

 

[frosho]

I've experienced a couple DIS failures, and both resulted in a seemingly random misfire. It's a lot easier to swap than the crank sensor, so might as well start there.

 

[Brook24v]

How bad is the crank sensor? From looking down there I'd guess it really sucks. Luckily I've never had to replace one in any of my SHOs.

 

[frosho]

Look through the lower 60k guide on shophoenixproject.com. That'll give you an idea.

 

[Brook24v]

Thanks.