99huggerorangeZ

iTrader: (2)

my bad lol yes the cam sensor is located at the rear of the intake manifold on the left side of the oil pressure sensor

LS6427

iTrader: (2)

You have to take the intake off...right?

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99huggerorangeZ

iTrader: (2)

yup

LS6427

iTrader: (2)

****..........alright, thanks for the help. Gonna do it tomorrow. Gotta be the cam sensor.

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LS6427

iTrader: (2)

A new "coolant temp sensor" didn't work, tried one today.

Tomorrow my new "camshaft position sensor" comes in and I'll try that. Gotta take the damn intake off, GAY!!!!!

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kmracer

iTrader: (1)

LOL! dont waste your time dude. seriously, test the coils the right way. its not hard. you're gonna spend 3 hours fighting the intake for nothing.

LS6427

iTrader: (2)

What do you mean? All of the coils are firing.....but they are all wacked out and firing in a crazy random out of sequence order. Isn't that a bad camshaft sensor, since the camshaft sensor is what controls the coils?

It seems like a pretty good indication of a camshaft sensor issue.

How do you check them properly, with the ohm-meter? I don't have one but I could get one. Exactly where do I put the meter, car running, what readings, etc....

Its impossible that all of the coils went bad at the same exact time and are all acting the same, so I figured look to what controls them instead

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t/a98

iTrader: (6)

my crankshaft pos sensor fell on my headers and melted then grounded to it. the car would run super rough, the sound like it cut off, backfire three times then roar back to life, repeat, repea...
that said, if your loosing the whole driver side it sounds like camshaft position sensor, hey are prone to killing one side or the other.

LS6427

iTrader: (2)

I have both sides firing all wacky and out of sequence.

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joecar

You need to use a spark tester (see image attached, about $25 from parts store) on the end of each plug wire (and connect the ground clip of the tester to a suitable ground like the engine block)...

[ you might also want to disable the injector for this cylinder by disconnecting it's connector, this prevents unburnt fuel being dumped on the catalytic ]

at idle, say 600 rpm, each cylinder fires 5 times per second... you should see a fairly strong snappy arc jumping the electrodes of the tester... also give the engine a quick rev (quickly snap the throttle wide open and back again quickly) while observing the spark... if it ever gets weaker or less frequent, then you have a problem on that cylinder (start with wire and work back to coil and to harness and to PCM)... repeat for all cylinders.

[ when done with a cylinder, reconnect the plug wire to the plug and remember to reconnect that injector ]

Also, the PCM uses the crank sensor signal to time the firing of the coils and injectors.

LS6427

iTrader: (2)

Hmmm, I wish I knew this before I removed my intake and bought a new camshaft sensor. But I'll get it back together tomorrow or saturday with the new camshaft sensor, if that doesn't fix it I'll get one of those and then have to track the problem down from there.

BUT....by removing the plug wires from the coil, and seeing the sparking the way I describe, all wacky and out of sequence, isn't that a clear indication that the firing order is way out of wack???

So, this wacky firing can also be from a bad crankshaft sensor? I thought the camshaft sensor was responsible for proper firing sequence.

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joecar

The spark tester has a "calibrated" distance for the arc to jump (notice the tester says "HEI" on it... this has a larger distance)...

When you pulled the plug wire, which end did you pull, and where was it arcing to...?


The PCM looks at the crank sensor signal to know the position of the crank...
it looks at the cam sensor signal to know which of the two TDC's a cylinder is on (TDC compression stroke or TDC exhaust stroke).

Sometimes, if the cam signal is lost, the PCM may batch fire instead of sequential fire...

if either sensor is bad you may possibly the get symptoms you see...

if the cranks sensor signal is bad, the RPM will be wrong.


Think back, this problem started happening after what event...?

LS6427

iTrader: (2)

I just saw the blue spark right at the coil port. I pulled the spark plug wire off the coil to see it.


Absolutely nothing. The only repairs my engine/car has had in the past 12 months were an 02 sensor like 12 monmths ago and I fixed a leak in my radiator like 3 months ago.

I walked out of my friends house, started my car and pulled away. About 2 minutes into the drive it just lost all its power and stumbled, backfired and missed all the way home. I could only get it going to about 35 mph, thats all it would do without hurting anything.

So it just happened out of the blue.

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joecar

You shouldn't really do that, you may damage the coil... where did the arc jump to...?

LS6427

iTrader: (2)

It looked like it was just arcing right at the end of the ports on each coil I did that to. Once I saw it jump to the bolt that holds the coil to the valve cover.

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joecar

The arc seeks the easiest path to ground... that's why you have to provide a definite path... if you just see it arcing in on itself that may be bad...

** Connect a spark tester on the end of the plug wire (where the spark plug goes) and check the arc quality there...

if the arc is not good, then inspect the wire for cracks/holes/burns, ohm it (while bending/unbending it), swap with a known good wire and test again (see **).

if the arc is still not good, remove the coil, inspect it for cracks/holes/burns, swap with a known good coil and test again (see **).

if the arc is still bad, then check the following:
- wire harness,
- ground connections (block, LHS head, chassis),
- PCM.

Also, do you see the correct RPM...?

LS6427

iTrader: (2)

I was just getting ready to put everything back together, along with the new camshaft position sensor, and I broke my damn Oil Pressure Sending Unit

Now I need to get a new one before I can do anything. If I get it back together with the new camshaft sensor and its still misfiring and going nuts I'll then put a new crankshaft sensor in. If its still misfiring on all wires......I'll have to look at the PCM I guess, maybe its toast. Spark plugs are new, wires are good. I can't see 6 wires going bad all at once....or 6 coils going bad at one time.

When I get it back together if the new sensor(s) don't help, I'll have to weed other things out one by one.

The rpm guage is working fine.

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98pontiac

coolant temp sensor? are you serious... take your car to a mechanic. although yes it is possible that it could be a cam position sensor. I would not recommend taking the intake off, although ls1s have a dry intake, witch makes it nice and easy (for someone who knows what there doing)

LS6427

iTrader: (2)

Bad coolant temp sensors on 1998 PCM's make the engine run like ***. When I had my heads off to get rebuilt years ago we snapped the coolant temp sensor off while tightening it back on. I figured, no big deal, I'll leave the broken piece in there till the new comes in in a couple days and I'll drive around without a temp guage. WRONG.....the engine would NOT run without a temp sensor. It was like it was running on half the cylinders.

So I tapped a sharp philips head screwdriver into the brass piece that was stuck in the head and spun it out, and waited till my new sensor was in.

I got the intake off in less than an hour, first time. It was easy. I needed to change my OPSU anyway. And the intake was nasty dirty with burnt on oil so I got it cleaned out.

Its got to be the cam sensor thats causing the problems. Everything else to do with misfiring has been checked. Possibly the crank shaft sensor. No need to give it to a mechanic when I can do all this stuff myself. They would charge $400 to remove and reinstall an intake.

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LS6427

iTrader: (2)

First of all...................

SUMBITCH BAG OF MONKEY NUTS

Listen to this ****.....

I put everything back together with a new "camshaft position sensor" and its the same ****....missing like crazy.

BUT.....after it ran for about 2 minutes I shut it off and went over and felt each long tube. The passengers side, all 4 were frying hot......the drivers side, all 4 were cool, maybe a tad bit warm to the touch like they never fired or maybe fired a few times only, if at all. Could have been the warm coolant making it across to them, thats how little warmth I felt.

So what the hell would make just the passengers side 4 cylinders NOT fire, and the passengers side fires fine?

Going out to get shitfaced after this crapola......

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