Backfire thru intake effects

[Hot Air Beast]

Was driving south on I75 after hours of driving and had to get out of my lane fast. Major backfire thru intake. Code set - I think 24 vehicle speed sensor fault. Engine kinda rough afterwards. Next day code 22 tps low set upon start-up. Checked engine compartment. Air flow pipe between MAF and TB had blown off. I reattached and tightened the hose clamp. Car bogs slightly from time to time.

Any ideas as to what damage i should check?

Phil
stock 84 GN

 

[696]

Does the turbo work? I destroyed a new TE44 by a backfire, but didn't hurt anything else.

 

[Hot Air Beast]

Yup, boost builds fine. Only occasionally does the engine bog on acceleration.

 

[1984 t-type]

Mines would do a loud pop under load wound up being a bad coil pack.

 

[ScottHeidinger]

What are tps and iac at idle?


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[Turbo6inKY]

Yup, boost builds fine. Only occasionally does the engine bog on acceleration.

Likely have a vacuum leak. Backfire could have popped a hose or the plenum gasket.

 

[michael evans]

Check all your hoses and your MAP sensor. I had one that came apart that made the engine run lean.

In my case it popped a head gasket because I didn't know better then.

 

[Hot Air Beast]

One more thing - looks like mpg is way worse. - averaged 21 mpg hwy on 1600 mile drive from Canada. Got to fill up and check on last 60 miles (city) but my guess (based upon gas guage only) is 13 or 14 mpg.

 

[mikestertwo]

Sounds like a bad MAF

 

[Hot Air Beast]

You saying the backfire could have blown the MAF? It is used but was just put in recently and solved a lean issue I had back then.

 

[ScottHeidinger]

Hard to find a working 30 plus year old MAF for these cars. I would look into a modern maf sensor (LS1) or LT1 and a translator for it. A bad MAF could have caused the backfire to begin with.


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[Hot Air Beast]

And your sure that would work with an 84 GN - I've heard MAFs nowadays can be bad out of the box.

 

[ScottHeidinger]

Sorry I’m not sure about a 84. I know some guys swap the 86/87 ECM this might be why. I do know that the MAF on the 86/87 is damn near impossible to find a good working one that isn’t way more expensive than its worth.


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[Turbo6inKY]

And your sure that would work with an 84 GN - I've heard MAFs nowadays can be bad out of the box.

They're all useless.
Convert to a newer MAF and a translator.

 

[Hot Air Beast]

No problem Scott. I am well used to having trouble getting parts for an 84. I sourced the one I have from a user in Georgia. New ones simply don't exist.

 

[ScottHeidinger]

http://www.gnttype.org/techarea/ecmsensors/8487ecm.html

I think I would upgrade to the 86/87 ECM and go with the translator and LT1 or LS1 maf


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[ScottHeidinger]

Now you see why they are called grand nationals. Every time something happens there goes another grand...

Doesn’t look too difficult. Couple of wires, probably find a used ECM (parts for sale or parts wanted post) ~ $60. LT1 or LS1 maf for about $50-$75 used and the biggest cost will be the translator. They might pop up soon as more people go GN-ECU that’s mafless

HTH


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[ScottHeidinger]

Eric can probably make you a chip so you can run without the IAT sensor or at least make it not throw a SES light until you get one installed. They normally read 71 degrees unplugged on 86/87.


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[Gary Durden]

Have you checked in the 84-85 hot air section on this forum for parts.

 

[GNRick]

You headed to Fla.? Enjoy the warmth!