need a shop to diag a problem (cbus)

[chevysoldier]

ziiing

[ducati guy]

DO NOT MESS WITH THAT CAM SENSOR! The EGR stuck open is the first thing that needs addressed! The Cam sensor will almost NEVER make it missfire, or even run bad on that thing. The cam sensor is there just so that the engine will know what cylinder is which for misfire detection, and sequential fuel injection. The ignition is all run off the crank sensor, ONLY. I think it does have 2 crank sensors though, one that goes to the ignition control module (does all the firing of the plugs, provides the rough crank location to the computer. Then it probably has a higher resolution crank sensor, usually a 24x signal that's used for misfire detection, that runs straight to the computer.

So the camshaft sensor does not relay timing information to the ecu? I do not see how one cam sensor will generate a misfire fault code in the ecu and tell you which cylinder is mifiring. I do not see how everything is ran off a crank sensor w/o the ecu knowing what position the camshaft is in

[ducati guy]

Yeah, these things are notorious for head gasket failures. I'd say about 80% of the time, the head is cracked. GM never should have put the 2.2 in the S-10.

Before you break your arm trying to pat yourself on the back, what did you call right? Unmetered air? Sort of, but not so much, because it's a speed density system, and it doesn't actually meter the air coming into the engine.

I said bad cam sensor, and he's got a fault for it, and if he had a head gasket issue, he'd have more running issues like eating coolant and over heating

[ducati guy]

Actually, there is only one crank sensor, and it's a "7x" signal.

From our repair info, which gets their info straight from the manufacturer, without reformatting it, here's what they say about the cam sensor:

Basically, without the cam sensor, misfire detection may not be able to determine which cylinder is misfiring, and it won't know which injector to fire out of each cylinder pair (1-4, and 2-3) so it will fire each for that cyl pair at the same time, which COULD decrease fuel mileage, and increase emissions, but most likely not enough that you'd notice much other than the light being on.

Thank you for answering my question:)

[chevysoldier]

[natedogg624]

so which is it... i got lost in the debate that just happened.

[natedogg624]

also looking around at egr symptoms it shows that rough idle is a symptom, which i do not have, idle on the truck sounds normal. the stutter only happens every once in a while off the line and whenever under a load (uphill, push gas pedal etc)

the stutter off the line doesn't happen everytime, i'd say around 80% of the time. also every once in a while i can get it to run as if nothing's wrong and then the next tap of the gas pedal to pass someone it won't accelerate.

[jporter12]

also looking around at egr symptoms it shows that rough idle is a symptom, which i do not have, idle on the truck sounds normal. the stutter only happens every once in a while off the line and whenever under a load (uphill, push gas pedal etc)

the stutter off the line doesn't happen everytime, i'd say around 80% of the time. also every once in a while i can get it to run as if nothing's wrong and then the next tap of the gas pedal to pass someone it won't accelerate.

That sounds more like an ignition secondary problem, only happening under a decent amount of load? The other codes must not be all current codes. There are several types of codes, current, pending, fail since clear. It does matter when trying to fix it.

[natedogg624]

fudge.

[jporter12]

I said bad cam sensor, and he's got a fault for it, and if he had a head gasket issue, he'd have more running issues like eating coolant and over heating

It's not always enough of a coolant problem to be noticed! I wen through this on a 97 S-10 with a 2.2 a couple months ago. No noticeable coolant loss, no oil contamination. The only way we found it was steam out the tail pipe, but only under certain conditions.

Thank you for answering my question:)

Reread:

The Camshaft Position Sensor (CMP) is used in order to correlate the crankshaft to the camshaft position so that the Powertrain Control Module (PCM) can determine which cylinder is ready to be fueled by the injector. The CMP sensor is also used in order to determine which cylinder is misfiring when misfire is present.

I can almost guarantee that the cam sensor will NOT CAUSE a misfire. It can cause a misfire to not be detected by the PCM, and can cause the PCM to go to "ASDF mode" for the injectors. I had some info at one time on what that mode did, but basically the PCM would "figure out" when it was firing the injectors right, and could keep it in sync from then on, or something like that.

[jporter12]

fudge.

Honestly, I don't think a cam sensor will cause the problems you are having. If it is, it's because it is coming in and out, working part of the time. Unplug it, and run the truck to see if anything changes. If it's a constant failure (such as being unplugged) it should act the same all the time.

[Wicked1]

replace EGR (cheap)

Take a look at your cap/rotor- it could be a source/contributer of your issue (also cheap)

Then do your plugs

KISS

Keep it simple stupid

[jporter12]

One thing MANY people (even professional technicians) get caught up in is that if theres a code and it's running bad, whatever the code is for is what is causing the problem. I have seen many times that another problem, tuneup, engine mechanical, other electrical, etc... will cause a problem that the computer will pick up as something else. As an example, it looks like the EGR position and Cam sensors get their reference voltages from the same circuit inside the PCM. A problem with one could cause the other to set a code.

Trouble codes DO NOT mean run out and replace that part!

[natedogg624]

when was a 175 dollar egr valve cheap?

[jporter12]

It has coil packs' date=' dude. No distributor.[/quote']

The coils sometimes fail, too. Most of the time they completely quit though, then you have a 2 cylinder. They run surprisingly smooth when a coil fails!

[jporter12]

replace EGR (cheap)

Have you priced an EGR valve for that thing? They're usually around $100. Not exactly cheap to a poor college kid!

[natedogg624]

i can't even find them that cheap. autozone so far is the cheapest at 165ish. i might try and clean it to see if that'll do anything. also how bad would it be to drive it like this?

[jporter12]

Sure' date=' but diagnosing a failed coil pack is easy. The coils fail quite often. Did I mention Chevy sucks?[/quote']

WOW! I had no idea how much they were getting for those EGR valves!

Those coils don't fail nearly as much these days. late 80's to early to mid 90's, yeah. I'd say 96 and newer they don't fail as much.

Did I mention? Subaru sux.

[jporter12]

You fix that VF' date=' yet? [/quote']

A couple times! Old Hon-duh's suck, too! (At least the old VF's!) I love the way it runs, but parts are so tough to get, other than old worn out stuff. Any upgraded parts are out of the range of reasonable for the worth of the bike. At this point, I'ma jus ride it til the wheels fall off!

[natedogg624]

i think i'm gonna get a egr gasket and just attempt to clean it first before dropping that money on a new egr valve.

the code literally said the valve is stuck open, this could be from carbon build up i'd imagine. so i'll just start with the cheapest option and go from there. hopefully i'll get this done tomorrow and report back the results.

[natedogg624]

also what about the fuel pump going bad? i've been reading where a bad fuel pump is producing similar symptoms. like porter said a while back, something else could be causing these codes to come up.

i guess fuel pumps on s10's can go bad if under 1/4 a tank, and i've been sitting below that for a while (don't drive it that much or that far to need a fill up everytime i dip below that mark). opinions?

[jporter12]

i think i'm gonna get a egr gasket and just attempt to clean it first before dropping that money on a new egr valve.

the code literally said the valve is stuck open, this could be from carbon build up i'd imagine. so i'll just start with the cheapest option and go from there. hopefully i'll get this done tomorrow and report back the results.

I have removed EGR valves many times and replaced them with the same gasket. It is only a couple $ at most though, and sure enough, if I was to tell you it will be ok without a new gasket, it will be fubar, and you'd hate me for it. The hate I can live with, though, I just want you to get your truck running right again.

also what about the fuel pump going bad? i've been reading where a bad fuel pump is producing similar symptoms. like porter said a while back, something else could be causing these codes to come up.

i guess fuel pumps on s10's can go bad if under 1/4 a tank, and i've been sitting below that for a while (don't drive it that much or that far to need a fill up everytime i dip below that mark). opinions?

GM fuel pumps are known to fail. That's something that would have to be tested though.

[ross]

Ever priced an s10 fuel pump? If you thought the egr was pricey, wait 'til you see how big the bricks that you're about to shit will be.

[chevysoldier]

Did I mention Chevy sucks?

[natedogg624]

loose ignition wire. the codes were over 10000 miles old. runs like a champ now