Raylo

You're fast! What do you mean you "put it back in timing"? Are you talking about at the distributor? Also, do the timing gears have marks that get lined up? On my car you put the crank gear mark at 12:00 and the cam gear mark at 6:00 so they match up.

Raylo

Here is a diagram for a LT-1 V8 that shows the timing marks. They have to be lined up to establish the proper relationship between the crank and cam. If they are not lined up it means the chain has slipped. Again, not sure that a 3.1 is the same but since it is GM it might be similar.

http://shbox.com/ci/sprockets.jpg

VincentBanuelos

RAYLO, they did have marks, and they were lined up just as you stated.
and about being fast, i have power tools haha

anyways, yeah, i turned the balancer to 0, made sure # 1 and # 4 were on compression stroke and they were, the distributor was pointing towards the # 1 cyclinder, have spark everywhere. but it just rumbles for about 4-5 turns, then does nothing at all. it did backfire EXTREMLY LOUD, then i figured out i had the #1 wire on the # 2 plug (its been a long day).

any suggestions?

Raylo

I dunno, dude. Perhaps it's the car's computer? If you could find another one to swap in that would be an easy way to test that theory. Again, I'm not sure exactly what kind the 1991 3.1 has but used ones seem to be readily available for LT-1s so perhaps you can find one.

Another thing I had happen once was the air intake boot gapped a bit where it attaches to the throttle body after some routine maintenance. Since air was bypassing the MAF the computer saw no or little air and cut off the fuel. Also, the rubber was fluttering. So the car ran rough and had no power. So check the intake path (and manifold) for any leaks. Wouldn't hurt tolook at all the vacuum hoses and connections, too.

Raylo

One other possibility. My 1994 S10 4.3 V6 had the EGR valve stick open a couple of times. The truck would hardly run, especially at idle, which is when the EGR should be fully closed. Lots of vibration, bucking, etc. But it did run. New EGR fixed it right up. You might consider pulling the EGR and having a look.

bruiser

Go over here: www.camaroz28.com/forums/ and sign up. There is a V6 forum there. Post what's going on, and what you've checked. Ask about the fuel pressure.

VincentBanuelos

alright, i appreciate it. I'm prolly going to end up taking it to my mechanic. he's ganna charge me 69$ an hour, but atleast it will run.

thanks again, i will let you know if it is resolved.

cardoc

Ok lets ck some basics.Does have good spark from coil/let coil arc to wire should jump about a half inch.Do same at dist cap.Wet plugs usually means no/weak spark,spark out of time,no compression,no exhaust flow,way too much fuel.Fuel presure should hold near run spec while cranking,ECM may be getting faulty info and dumping fuel.I'll bet the oil smells gassey.For giggles try disconnecting the Mass Air Flow sensor after the plugs dry.The ECM will put in it's own value and may start is sensor is fubar.We're not done yet,keep us posted.A no start is usually just basic trouble shooting to figure out.
Good luck,Cardoc

mack1

Hi Vince,
I'm kindly like cardoc in that I think you should be able to fix the problem, though he didn't say it that way. Here's my thought patterns when I read your first post. It started backfiring after a car wash. "Probably mosture in the distributer cap", but just under that, you said that you had replaced the distributor (and other ignition parts). Since it backfired and the distributor was OK, must have been something else that caused it to fire at the wrong time. (fuel is OK, or it wouldn't have been able to backfire) "It must be timing", so the timing chain between the crank shaft and the camshaft must be off (chain slipped or stripped plastic gears). Now, I hear that the chain and timing marks between the chain and gears are in alignment according to the marks on the chain and gears mesh up. (I was going to apologize for not telling you about the marks on the chain and gears, but you seem to have known)'"good show".
That being the case, I then get to wondering if when you installed the new distributor, did you make sure that the gears between the distributor and the camshaft matched such that it was in time. Don't know about your vehicle, but they normally have to be meshed in such that when the rotation caused by the angled gears(distributor and camshaft) end up with the rotory button pointing to the right position when the distributor is bottoms out. Your posts suggest that you are on top of that situation, again "good show".

Now, there is a couple of things that are true that might not have been addressed as yet. Can't say about your car, but on a little later models, the computer tells the distributor when to fire each cylinder. It gets it engine position signal from a sensor located at the front of the engine that looks at a gear mounted on the camshaft. It senses when #1 cylinder reaches near top dead center and initiates a fire #1 plug signal based on that signal. Other signals follow until all is fired, then it looks for #1 again. (wider gap or something tells it that it is #1) Could this senosr signal be faulty because of loose or dirty connection or muck on the gear?????? (something is causing the backfire). Then, on your post #23, it sounds like timing is no longer a problem, except it might be a little off.(not backfiring after you got #1 and #2 wires straightened out).

So, if that gets us down to fuel and minor timing adjustments, here is a couple of things to know about fuel supply. When you turn the key from off to on(not start), the fuel pump runs for about 2 seconds. (you can hear this) You will measure the normal pressure with your fuel pressure gauge. May be up to 66 lbs., more or less, depending on your pressure regulator(I don't have a book on your vehicle). With no leaks, that pressure will slowly decrease. (several seconds to reach zero) Now, when you move the key from on to start, the fuel pump is susposed to come on again. (you can't hear this because of the noise of the starter) Put someone under the car to listen for this. If it don't come back on during the time the starter is engaged, it will not start. You might have the the observer to watch the pressure gage instead. Same idea applies.(when starting, the pump should come back on). You mentioned a leaking schrader valve where the pressure gauge attaches. That being the case, I would expect the initial pressure to blead off in just a few seconds, but it should go back up during a start attempt.(remember, the pump comes back on during starting)

If all criterian is met,(compression, ignition, fuel mixture) it should start and sound good when you start the car.

If you want to pay $69 per hour (plus parts) to fix it, go for it. I think you already know enough to fix it. Self confidence is a great thing to have. Ability comes with a little help from friends.

Have a nice day,
Mack1

__________________
"If you like yourself others will like you also" me
"Don't drink downstream from the herd" Will Rogers

Submit New Articles Here

Raylo

Something Mack said got me looking. The 3.1 has a crank position sensor. These can fail and cause similar symptoms to what you are getting by hosing timing. It also could have possibly got wet during the car wash, especially if that included any heavy duty spraying underhood. Definitely worth a look. Also a relatively cheap and easy repair.

cardoc

Hi everyone
If the car has a distributor it won't have a crankshaft position sensor.

cardoc

Fuel pressure should not drop.It has to go somewhere-still thinking .while cranking fuel pump should keep up.When stopped pressure should hold over an hour.Has any one checked ECM fuses(more then one).Have you got access to a scan tool?
Are you sure you have the dist.timed right,you could be off one tooth and it would cause a lot of your problems but not the fuel pressure drop.If the pressure drops out while cranking it,s either dumping fuel faster then the pump can supply (not likely) our the pump is not running while cranking(maybe fuse/Check them all with a test light if possible).This assumes the gauge it's self isn't leaking.Still thinking...

Raylo

Hey Doc,

I was wondering about the CPS so I searched and found this. Not sure what its function would be if there is indeed a regular distributor. Maybe just to provide input for OBDII misfire detection? If that's all it does it I guess it couldn't be Vince's problem anyway, even if it were defective.



http://cgi.ebay.com/ebaymotors/91-92...spagenameZWD1V

bruiser

A '91 wouldn't be OBDII. Some '95 V6 f-bodies were OBDII. That would be the earliest in the f-body. In '96 all were OBDII.

Raylo

D'oh!!! Sorry for the brain fart. I knew that. Still not sure what that sensor is for.

cardoc

Hi Raylo
I'am a little leary of that listing as it would be a redundit part.But it wounldn't be the first time with GM.I can ck into it better at work Monday.

Raylo

Yeah, we don't want to start using eBay as the definitive tehnical resource!

I think I was flashing back to a once upon a time discussion of LT1s. LT1s, of course, use an opitcal distributor, the good old Optispark. But when they went to OBDII they got a crankshaft position sensor and I sort of recall the discussion that it was just there for misfire detection (by comparing minute differences in crank position to some other timing reference) and to throw a code for OBDII. The reluctor wheel is supposedly mounted behind the harmonic balancer. So in this case the sensor wouldn't be purely redundant. I'm not 100% on this but that is my recollection. I remember being curious because my 1994 OBDI LT1 does not have a crank position sensor and there was no reluctor wheel when I pulled the balancer to do my cam job.

And all this has no relevance to the problem at hand.

bruiser

Your '94 doesn't have that sensor because it's OBDI. '96 and up got the crankshaft position sensor. Yep, it's just for misfire detection.

Raylo