Doc , Help for a friend of mine's son..

My friends son has a 96 cavalier Z24 with 2.4, 4 banger. It died at school on him yesterday and I went with him to check on it and read the codes. It threw several the first time we read them, mainly the one we thought was
the problem was the crank sensor circuit a malfunction. we replaced that and now it still only runs on 2 cyls it seems and has a strong gas smell and throws only a code of P0440 "EVAP system malfunction. but it still will not run very well.(at all).we had to drive it last night to his grandads barbershop and park it(2miles) and the cat was glowing red . it doesn't seem to have alot of restriction in the exhaust, but it may still be stopped up. But that wouldn't explain the running badly and loping and jumping.. Reving it up is slow and boggy,, as if plugwires are not on,, but no wires on this,, we did replace plugs with no avail. We're at a loss with this,, any ideas??? you can email me at snipped-for-privacy@hotmail.com if you like. i will chack back in in a little while. thanks in advance for any ideas or fixes philc
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Phil C,
She's running super rich. If the evap system is what's causing it (it's only supposed to open under certain driving conditions), it could be bogging the motor down with too much gas.
Find where the line from the vapor cannister hits the throttle body or intake manifold. Disconnect this line and plug the port on the intake or TB. Also plug the line from the vapor canister as you don't want to incinerate yourself if she is in fact purging all the time.
If this was the problem, the car will start and run better, but still crappy as the plugs will be fouled and the 02 sensors are likely shot from all the carbon in the exhaust stream.
You might get vapor lock after some time with the evap system blocked off, so you could just loosen the gas cap to allow the excess vapor pressure to seep out (nice and far away from hot parts!).
Doc

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We'll try that in the morning and see what happens. I'll post back and let you know what happens.( or to get more ideas) thanks again doc! Philc
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They're notorious for killing spark coils. Each coil fires two plugs...
Al
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We tried the evap lines and it didn't change anything,, We are changing the coil packs this morning and hopefully that will cure it's woes. if not,, someone told us that the cat may be stopped up and to take it off and drive a hole through it and replace it to see,,possibly even the resonator behind the cat also. It bothered us that the cat turned "Red hot" driving it 2 miles. any ideas on why that happened? I"ll post back later and let you know what happens. philc
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cause you dumped raw fuel thru it

once you have it running, ALWAYS carry a pair of coil packs, the plastic piece that they mount on, 4 of the spark plug tubes, and sufficient tools to change threm (along with a flashlight or clip-to-battery trouble light), especially if you drive in very hot locations
we did on Deb's dad's 91 GrandAm with the 2.3, I changed them out twice out in the middle of nowhere, once in southern UT, once along I-15 in Montana
The 2.3 was a running SOB, but hell on ignition parts
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Update,,, My friend just called,, and he replaced the coils,, NO CHANGE!! Still runs rough and misses.. He wants to cut the cat lose and fire it up to see if it will run better and smooth out,,, then go from there,, Anyway, I'll post back and check back to see if there are any other ideas posted. Thanks again philc
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did he change that plastic 'runner' piece that the coils mount to ?
if not, he should have.......it arcs over internally

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Final update!! Gary you were right, It was the plastic runner/plug boots. Changed it out this morning and all is well once again. He really did have his heart set on cutting the cat lose ,, but i told him that this would be much easier to try, and comes from automotive gurus, and he agreed and changed the coil pack runner and the plug runner/boots,, and it runs great again. Thanks again for your input and advice. Very many folks have had their questions aired and advice recieved by you and doc (and others) and if taken, Time and money(and anguish)are spared. Thanks again. Philc
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heheheh
I guess all the hours under the hood of Deb's dad's 91 Quad finally paid off.................

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it ain't the cat

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Quad 4 ?
bad coil pack; each coil fires two plugs

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