1996 Z26 lost power

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MWM42V
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1996 Z26 lost power

Postby MWM42V » Mon Nov 05, 2012 10:03 am

1996 Z26 160,000 miles. First time out with this it ran good for 30 miles, then started losing power. Has a mis, changed fuel filter and pump. Same. New plugs. old ones looked like it was rich. Same. Checked injectors with Ohm meter. all 13. Fuel pressure reg. gets wet when running. Ordered a new one. If this isn't the problem, is it possible one or two injectors are stuck open? Can they be cleaned and if so how? Any other ideas. Forgot to mention, it seems to have gas in the oil. Thanks for any help



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Re: 1996 Z26 lost power

Postby Money pit Beretta » Mon Nov 05, 2012 12:20 pm

A bad O2 can make it run rich.


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Re: 1996 Z26 lost power

Postby MWM42V » Mon Nov 05, 2012 12:42 pm

Hooked up to scanner. Shows random misfires. No other codes. Went to data stream. 6 is the worst. 1 is so so oithers are good.



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Re: 1996 Z26 lost power

Postby 3X00-Modified » Mon Nov 05, 2012 2:42 pm

I'd try coil swapping to see if the missfire follows that coil. Or even easier swap plug wires for 3 and 6 and see if the misfires go to cylinder 3.

Being waste spark system you can swap the wire position on each coil... So 6 and 3 can swap, 1 and 4 can swap and so can 5 and 2.

The misfires on 1 could be false reading from 6.

Also if a regulator is bad it sucks fuel from the vac part of it making the engine run very rich.



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Re: 1996 Z26 lost power

Postby MWM42V » Wed Nov 07, 2012 11:22 am

Ok, thanks. I'll try this this weekend. Had to order regulator. Noone in town had one.



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Re: 1996 Z26 lost power

Postby MWM42V » Wed Nov 14, 2012 11:34 am

Finally got regulator. replaced it and plug wires. Still has mis. scanner shows cyl 6 misfiring. Switched 3 and 6 like you suggested. Still shows 6 misfire. Any ideas what to try next. Thanks



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Re: 1996 Z26 lost power

Postby 3X00-Modified » Thu Nov 15, 2012 11:51 am

MWM42V wrote:Finally got regulator. replaced it and plug wires. Still has mis. scanner shows cyl 6 misfiring. Switched 3 and 6 like you suggested. Still shows 6 misfire. Any ideas what to try next. Thanks


Check the plug and after that it's possibly the injector if #6 is still misfiring... So if you wanted to test before investing... swap the #6 injector for another one and once again see if the miss follows it.



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Re: 1996 Z26 lost power

Postby Rettax3 » Thu Nov 15, 2012 7:12 pm

Have you tried swapping the coils, like Jon suggested? Swapping the 3/6 coil-wires tests the wires, but you need to swap coils around to test them. I'm not sure why #3 wouldn't show as bad as #6 if it is the coil, unless #3 maybe has a little lower compression, making it easier for a failing coil to still bounce a spark through it. If that doesn't help, then yeah, investigate the fuel side.


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Re: 1996 Z26 lost power

Postby 3X00-Modified » Fri Nov 16, 2012 3:39 pm

There are two posts on each coil if only one cylinder is missing badly you can swap wires for those two cylinders on the coil, in this instance 3 and 6 to see if the post on the coil is bad and only affecting one cylinder(this changes where the plug is getting its spark from)... In this case it is not... if it were the whole coil you would have equal misses on 3 as you do 6.

I'm leaning toward a bad injector and seeing how this is SFI the engine will still run... With a MPFI setup when an injector goes bad or shorts, it kills a whole bank.

He could try swapping the coil position but I doubt that will do anything.



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Re: 1996 Z26 lost power

Postby beretta » Fri Nov 16, 2012 8:02 pm

You said the oil seems to have gas in it.... This is bad to run a engine with gas in the oil it will ruin the internals.. but further more it will keep the engine flooding because of the gas fumes inside the engine. After you have changed the fp regulator that was most likely the main cause for the excessive fuel in the oil, change the oil and filter.



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Re: 1996 Z26 lost power

Postby MWM42V » Mon Nov 26, 2012 11:17 am

Sorry this takes so long. I don't get much time to work on this. I fp regulator and changed oil and ran. still has mis. I ran some injector cleaner in tank for awhile. didn't change anything. I took the plenum off to get to the injectors and switch 6 with another one. The plenum and down the ports (mainly 1 and 2) had a milky oily substance in them. Not sure if it was water or gas and oil. I stopped right there. Any ideas what would cause this. Thanks



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Re: 1996 Z26 lost power

Postby 3X00-Modified » Tue Nov 27, 2012 1:15 pm

lower intake gasket is leaking badly... Pull the lower and replace those gaskets.



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Re: 1996 Z26 lost power

Postby daguse5853z » Tue Nov 27, 2012 3:32 pm

has your car been having overheating problems also?



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Re: 1996 Z26 lost power

Postby MWM42V » Wed Nov 28, 2012 11:29 am

Is it hard to replace the lower intake gaskets? Any tricks? What's the best kind of gasket set? Thanks, I'll dig into this this weekend.



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Re: 1996 Z26 lost power

Postby MWM42V » Wed Nov 28, 2012 11:32 am

I just got this car from my niece. The electric fan hasn't been working, but she said she never let it get hot. I only drove it maybe 100 miles before it started losing power and developed the mis. I didn't warm up much at all for me. On the fan, I jumped the fan. it works. replaced sensor by thermostat. replaced breaker. nothing yet.




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