91 Civic LX diagnosis

[kivnul]

My son picked up a cheap ($800) 91 Civic LX (with D15B2 16V SOHC, Manual) that had been sitting for a year and had not been driven much before that. Needing some help diagnosing what is going on.

Below symptoms are per the kid:
Randomly won't start or dies and won't start:

• Cranks fine but seems to crank "quicker than normal"
• He fiddles with/unplugs sparkplug wires/ distributor wire
• It eventually cranks normal and starts fine
• 5 full tanks of gas used to date
• Fuel efficiency is "bad, 250 miles per tank"
• Dying
  • Seems to happen at low rpms, like during a launch from stop condition
  • Revving higher during launch seems to help prevent
  • Not related to fullness of gas tank (does when 100% & 20% full)

My guess is a fuel issue and the fiddling of the wires is a placebo. I have recommended replacing the fuel filter at minimum. (I figure bad/old gas & h2o accumulation would be gone by now.) And I would probably replace the sparkplug wires/distro wires as a mater of course since they could be worn out by this point. Also recommended checking the grounding wires. The rapid crank over does not make much sense to me: that could mean no cylinder pressure so an open valve? Stuck valve? But wouldn't that just be for a single piston and just run rough? Plugged Cat (it does burn a little bit of oil I was told by previous owner)?

Ideas?

 

[Jabbit]

Compression test is easy. Plugs/wires/distributor are cheap/easy things to rule out and should be done anyways. 90s Hondas crank "quick" in my experience but it's all relative. Might be a gummy throttle body?

 

[TyphoonFiST]

Is it a Vtec engine?

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[RubenZZZ]

Change out the fuel filter.

Run a can of Seafoam through the engine (1/2 in gas tank to clean injectors, other 1/2 through vacuum line into cylinders).

Change out spark plugs and wires.

Oil change.


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[kivnul]

Is it a Vtec engine?

As far as I can tell, No.

I will recommend the SeaFoam treatment to him. Already having him run some IsoHeat in case there is still water left in the tank. He has a fuel filter in hand now, hopefully he installs it soon. I highly recommended new ignition wires to him but he hasn't purchased any yet.

 

[TyphoonFiST]

Every cars gas has water in it* FYI

 

[kivnul]

Every cars gas has water in it* FYI

Agreed. But after 5 tanks, would hope the water accumulation due to sitting a year would have worked itself out of the system, leaving a more normal water %