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2.8L Auto Ignition/Fuel/Air Issue?

Old 03-16-2019, 07:48 PM
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2.8L Auto Ignition/Fuel/Air Issue?

First time posting on a forum, and I'm not that well-versed in auto mechanics so bear with me, explain it to me like I'm 12.

I bought an 87 Camaro LT a few months ago and in just the last 3 weeks its gradually begun running like an 80 year old man.

It accelerates incredibly slow no matter how much gas I give it, it feels like a 20 tonne rig and I'm starting to hate just driving it around town. I dread going uphill even more considering I cant go much faster than 30km/h. I seem to have remedied this part of the issue, but when I tried turning the wheel sharply in super low speed situations, like in a parking lot, it would stall. And now, as of yesterday, it started making an erratic thumping/knocking sound which I believe to be misfiring.

The spark plugs and ignition cables were replaced in the summer of 2016 by the previous owner and in the last 2 months I have replaced the distributor cap and rotor (but not the distributor itself), ignition coil, oxygen sensor, air charge temperature sensor, MAF sensor, fuel filter, air filters, added fuel injector cleaner to my gas, and the PCV valve. Only AFTER I had replaced the PCV valve did the engine begin to misfire.

Other than the new issue of misfiring I haven't noticed any other odd noises. The only other things I can think of to replace are the TPS and camshaft position sensor. The only fault codes Ive been able to pull from it were for the oxygen sensor which went away after I replaced it, and for the TPS when I forgot to plug it back in after checking it out. The TPS code went away after it was plugged in.

Any wisdom would be appreciated, and keep in mind I prefer to do all my own work since I'm on a low budget. Thanks in advance.
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Old 03-16-2019, 08:11 PM
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Re: 2.8L Auto Ignition/Fuel/Air Issue?

Sounds like it could be a plugged cat or fuel delivery issue like a weak fuel pump.
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Old 03-17-2019, 08:41 AM
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Re: 2.8L Auto Ignition/Fuel/Air Issue?

A new (to you) car is an unknown quantity . You know nothing of the condition of it's engine through various tests as yet unperformed . So far , it sounds as though you've got a laundry list of new parts into it with no success in rectifying the low power issue ,so it's time to back up a bit , hold off on any new parts just yet , and dive into a couple of tests . First & foremost , do a search here and read up on how to do a proper "Cylinder compression test" and do that . The second test will be a "Fuel pressure test" , and don't forget the "Fuel rail pressure leakdown" part of the test . The instruments for performing both of those can be borrowed from your local Autozone and when you've done both come back and report the results of each test .

PS , don't bother looking for a "Camshaft position sensor" on your engine , it doesn't have one . Nor a "Crankshaft position sensor" either . HUH ??? Well then how does the fuel injection know where the piston is in it's cycle to spray the fuel ???? Believe it or not , the computer (ECM) is totally clueless as to the position of either the Cam or Crank , and operates in a so called "Batch Fire" configuration . As the distributor turns the ECM counts the pulses and every specific number of pulses fires the injectors all at once . Yes indeed more modern true "Sequential" fuel injection sprays each injector individually , but ours operates in function closer to a TBI setup (but with an injector for each cyl) than the true "SEFI" (Sequential Electronic Fuel Injection) it physically resembles .
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Old 03-18-2019, 05:54 AM
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Re: 2.8L Auto Ignition/Fuel/Air Issue?

To add to that, you'll want to check timing too. I agree with it sounding like a plugged converter as well, but think you should do some testing to rule out other issues first. Taking a parts cannon to it will just cost you money and make you more frustrated each time you replace a part and it doesn't fix it.
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Old 03-20-2019, 02:33 PM
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Re: 2.8L Auto Ignition/Fuel/Air Issue?

Subscribed ! I was driving my car today and suddenly I have no power I'm going to make sure my timing is working tmrw. I am wondering what sensors the computer uses to decide on timing adjustments too ???
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Old 03-21-2019, 07:56 AM
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Re: 2.8L Auto Ignition/Fuel/Air Issue?

Also, i would inspect the plugs and check the gaps yourelf. I had a "mechanic" do a tune up for me several years ago, and he broke the porceline on the plug. I refused to believe that i had a bad plug after just changing them. Cost me a lot of heartache and money before changing something so simple.

I would guess that your old tank is full of rust and the sock is clogged. This would also explain your lean backfires. This lean condition causing detonation is very bad for your engine. You need to quit driving it until you get this solved, or you'll be looking at new pistons or worse in my opinion.

Last edited by Sierra6; 03-21-2019 at 08:00 AM.
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Old 04-02-2019, 08:31 AM
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Re: 2.8L Auto Ignition/Fuel/Air Issue?

Hi, did you get anywhere with this ? I had a leaky ignition , actually cut out eventually and i found water all over the coil. All sorted now and running sweet untill next time , good luck !
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Old 04-02-2019, 05:31 PM
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Re: 2.8L Auto Ignition/Fuel/Air Issue?

A quick and easy check for a dead cat is one of the inexpensive laser-pointer infra-red temperature gauges.

The outlet side of the cat should be considerably hotter than the inlet side. The cat on my V6 is 100 degrees hotter on the outlet side.
If you google, you may read that In a good catalytic converter, the rear of the converter will be 20+ degrees hotter than the front.

Other more-involved tests described at https://axleaddict.com/auto-repair/H...ytic-Converter
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Old 04-03-2019, 08:27 AM
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Re: 2.8L Auto Ignition/Fuel/Air Issue?

I would have thought a clogged cat would also be hotter on the back end
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