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The camaro *UPDATE*

M

muddin4fun

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<font color=red>Update:Go to my last reply</font color=red>

For those who don't know, the camaro('87 TPI 350) has an off idle stumble. The best description I guess would be that it acts like her shoe laces are untied. After she stumbles, she runs like a bat outta hell!
Every sensor on that car has been replaced.....seriously.
What about this? Could possibly a bad valve spring be causing it? Cause if there is a bad valve spring, wouldn't it mess up the vacume to the fuel pressure regulator and cause trouble that way?
It's got a new fuel pump.

It's been lovely, but I have to scream now.

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<P ID="edit"><FONT class="small">Edited by muddin4fun on 10/24/01 11:39 AM.</FONT></P>
 
Re: The camaro

My old Ford 5.0 used to do that - after dumping close to the national debt into new sensors/etc, it turned out to be the cam timing was a little off, and the computer was overcompensating for it.

If the shoe fits, get another one just like it
<a target="_blank" href=http://pugsley.alloffroad.com>pugsley.alloffroad.com</a>
 
Re: The camaro

Ok Lara... sounds like you need to get down to basics. How does it idle? is it smooth? Hook up a vacuum guage and see where the vac is at idle and then watch the guage as you rev it. It should be stable at idle and not bounce. Take the engine up to like 1800 or 2000 rpm... is the vac still steady? next blip the throttle... The vacuum should jump as the throttle closes and return to normal. The last test would be to compression test each cylinder. basically this will tell you if you have a bad valve spring, a valve hanging open or what ever. If this all checks out I would say the engine mechanics are ok.
Next how are the plugs reading? Rich? Lean? Rich would have me looking at the wether the injectors are in spec and checking what kind of pulse width you have. Also a rich condition would have me looking at puting a KV (or you could scope it) on the plug wires to see if you have equal and good spark to each cylinder. Check the coil... It sounds like you seem to think it is going lean though? What lead you up to that?
Exactly what sensors have been replaced and what codes have been pulled? Have you replaced the MAP sensor? If the MAP is bad the ecm will usually substatute a set value to the tps (throttle position sensor) and commonly can cause a bog such as you describe.

-Mikey
1987 Chevy K5 Blazer- 350 TBI
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Re: The camaro

It doesn't idle real smooth. Not bad, but not smooth either. I'll have to check on the vacum thing. The car is in Dallas and has the mechanic (awsome mechanic there) baffled. I'll send this to him and see if he can try it.
The plugs read rich.
New injectors and the pulse width has been double checked. Plug wires (they are new too) are giving good spark...double checked also.
New coil.
No codes...and I really mean it...there are no other sensors that have not been replaced. They have all been replaced.

I was asking about the valve spring cause couldn't that make it flood at first?


It's been lovely, but I have to scream now.

<a target="_blank" href=http://www.geocities.com/muddin4fun79blazer/>http://www.geocities.com/muddin4fun79blazer/</a>
 
Re: The camaro

Is this a hot and cold problem?

yeah the vac guage is really a old school lazyman's trick for reading the motor and to try and find mismatched cylinders. I would strongly recommend the compression checkkk it will tell you exactly what is going on motor wise.

-Mikey
1987 Chevy K5 Blazer- 350 TBI
<a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
 
Re: The camaro

At first, it would only do this after it was warmed up....now it doesn't matter.

It's been lovely, but I have to scream now.

<a target="_blank" href=http://www.geocities.com/muddin4fun79blazer>My wonderful site</a>
 
Re: The camaro

How about rebuilding the distributor? Fuel filter? Fuel pressure?

Is the computer in the car even working? If you're running really rich all the time, you might want to check the computer.

What about EGR? I just replaced the EGR on my '95 Blazer... Thing was running REAL rich for some reason. Must have been the computer getting confused. Ran and idled rough as hell.

Dan Oglesby
1984 K10 Blazer Silverado: 6.2L diesel, 700R4, 3.42 gears, 31x10.5" tires
 
Re: The camaro

Have you checked the EGR valve? It will cause these symptoms on my 94 LT1.

My .02,
John

'83 GMC Jimmy 4x4 ZZ4 Crate Motor
'83 Chevy K20 Sand Drag Racer, 578 RWHP
'94 Impala SS
'01 Chevy 2500HD 4x4 w/8.1L & Allison Auto
 
Re: The camaro

Distributer-new
Fuel filter-new
Fuel pressure (regulator is new too)-checked by three mechanics and is good
Computer-new
EGR-new

It acts like it is flooding right when you step on the gas, then it stumbles, and when it's done stumbling, it's fine. Any time you give it more gas it does this. Idle is a little rough....don't know why that is.

It's been lovely, but I have to scream now.

<a target="_blank" href=http://www.geocities.com/muddin4fun79blazer>My wonderful site</a>
 
Re: The camaro

<font color=blue>Do you have good vacuum going to the EGR? I worked on a TPI camaro the other day and the EGR was stuck partialy open at idle and it turned out it wasnt getting vacuum. It had the same symptons your describing</font color=blue>
 
Re: The camaro

Could you have a timing problem?

Have you tried setting the timing with the TPS disconnected? I have a '92 camaro (305 TBI), so I'm not up to par on the TPI, but I remember reading somewhere that the timing needs to be set with the TPS disconnected?

I know, not much help .......... hope you get it resolved soon

Thomas.

-- '84 K5 Blazer --
<a target="_blank" href=http://stoopalini.off-road.ws/blazer>My Blazer Site</a>
 
Re: The camaro

Here's my shot in the dark-

FALSE AIR.

The '87 TPI computer uses a Mass Air Flow sensor to make the air/fuel calculations. (Shoot me down if I'm wrong here...) ANY air that enters the intake plumbing upstream of the MAF hasn't been measured for purposes of air/fuel ratio calculation, so it causes the motor to run lean. This is called "false air". Kinda like a leaking TBI gasket for us with injected K5's. This false air could be leaning the motor out just enough to cause your off-idle stumble.
So you could try the carb cleaner trick on the intake plumbing joints, or you could throw a light bead of silicone around the joints. Also, look over all the intake plumbing for any cracks, etc.

There's my 2 cents... Hope it helps.

It's a happy day in Marine Aircraft Group 49... 405 is ALIVE!!
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<font color=green>Semper Maintenance!<font color=black>
 
Re: The camaro

Jarhead might have something there. That makes sence. If the car uses a MAF sensor instead of a MAP sensor then a leak down stream of the MAF sensor could cause some strange driveability problems.

Make a visual check of the integrity of the air ducting leading to the throttle blades, most likely between the blades and the MAF sensor. Allthow, a leak somewhere in the manifold -might- also cause somekind of drivability problems, I would think if there was a leak down stream of the blades, then idle quality would be efected aswell.

I hope you get this thing figured out SOON!

Sometimes life just makes you want to say,
"F*bleeeeeeeeeep*K !"

<font color=blue>Twiztid</font color=blue>
 
Re: The camaro

Yup the fellas put up a good point. I am assuming all the basics and compression test checked out. If none of this is the case you need to find a good diagnostic place or maybe suck it up and take it to the dealer. I know at one time you said you were getting a code or check engine lite...what code was it flashing?

-Mikey
1987 Chevy K5 Blazer- 350 TBI
<a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
 
Re: The camaro

I still have my money on the Flux Capacitor!
laugh.gif


But they do make a good point with the "false Air"....

Mike

<font color=green>"My K5 is purdyr than your sister!"</font color=green>

<a target="_blank" href=http://www.geocities.com/emmettology101>www.geocities.com/emmettology101</a>
 
Re: The camaro

repalce your air filter ! or chevk it .and your fuel filters they are cheap .

WHATS WRONG WITH A 305 ?
 
Re: The camaro

Any luck with the Camaro yet??


September 11, 2001--"A date which will live in infamy"
 
Re: The camaro

we parked it for a while. tired of looking at it...
mad.gif


Just taking a break from it right now and it still hasn't been long enough..LOL!

If you see my truck on a trailer, call 911 cause it's <font color=red>STOLEN!!!</font color=red>
Website link is in my profile
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Re: The camaro

I have an 85' 305 TPI. The "stumble on mine came from a leak in the gasket on the plethem (sp??) and the runners. Replaced the gaskets worked. Then after awhile it came back. The runners didn't line up very well, could be like headers that always seem to leak after time.
 
Re: The camaro

That's been replaced and checked.

Nick discovered something this weekend. He took an ohm thing and hooked it to his battery and his alt. It read fine, and the guage inside read low. He did this several times to different places and the guage inside would read different each time...always on the low side. So, he hooked it up and grounded it to the body and it started to stumble real bad and the guage dropped way off. Seems to be electrical. Also, the fuel pump got changed. the little bag it sucks fuel thru was sorta clogged and had a hole in it. So, that might help too. Any ideas on where to start? It's got wires running everywhere!

Peace and stuff
tongue.gif
,

Muddin

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