1987 2.3L Fails smog after tunup - Fine before

BOBinCA

New Member
Jul 9, 2007
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Hi all,

Thanks in advance for your help. I just sold a car because I needed the money, had to spend some of the proceeds, and am now faced with resolving this issue art my expense or giving a refund. Either way is a problem.

The problem is regarding smog test failure on a 1987 Mustang Convertible - 2.3L FI 4cyl, w/4sp automatic and 109K miles. I've had this thing for 15 years during which time I have only put 20K miles on it. It is completely stock and always ran like new and has always passed smog in w/flying colors.

Afew years back I had loaned it to a friend long-term. He put it in his name, put a new ragtop on it and took it to - what my experience allows me to judge as - a hack (not heck - hack) of a mechanic. From the orange RTV silicone to unsuccessfully seal the leaking headlight lenses to the missing screws o n the now- cracked center console after my friend had an ignition cut-off switch installed in this console, to what he charged. A vote of no confidence.

A month after having it smogged (with impressive resulting specs), my friend decided to have the hack shop do plugs, wires, cap and rotor -- for no other reason than to instill confidence in it since his teenage daughter would also be driving it. They know nothing about cars.

Immediately after having this work done he first reported a rough idle. I'm not sure where it went from there. I'm going by the paperwork.

When I got it back after about 3000 miles, I notice that it doesn't drop to normal idle as quickly as it should with temperature...I would find myself checking to see if the floor mat was pushing the accelerator before realizing that the operating characteristics of this great-runner had changed.

It generally idles properly at 800RPM when warm. It runs great without detonation on cheap gas. It might stall upon returning to idle after pulling off the freeway, for example.

Take it in to have it CA smogged and it fails miserably. The test-only station says the timing is off. Makes sense but no reason for anyone to have touched the distributor much when putting a new cap and rotor on it. (I always mentally return to the distributor-is-off-by-a-tooth scenario from my (pre-computer). Mustangs. I have no idea what was actually done here.

Buyer takes it to a shop that sets the timing to factory spec. Now it runs better he says (i.e really nicely) but still fails smog miserably. In his interpretation of the mechanics words, the computer is not responding at all.

First thing I'll check when he returns it to me is what spark plugs ended up in it.

I'll have to assume that it has two problems now - whatever is causing the computer to not respond and the timing to be off and 2.) That the timing has been reset to compensate for that problem.

Beyond that, what might can cause this scenario in the course of replacing plugs, wires, cap and rotor. Seems pretty simple.

More info: The stock single exhaust was new from the catalytic converter on back a couple of thousand miles before all this. Also new is that symptom that the oil pressure guage varies rapidly (like a flicker) and fairly widely normal pressure (i.e. not representative of oil pressure fluctuations) until it gets to a certain rpm where it locks in to the middle of the range where it belongs. I've been assuming that this is a faulty sender.

HELP! (please) - I don't know enough about what the computer does on this car.

Thanks!!!

Bob in San Diego
 
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Ok so that I understand whats going on here...

You sold the car to a...friend or starnger?

If it's a friend, is it the same friend who you loaned the car to in the first place?

The buyer either way is asking for some form of warrante on a used car they bought of the side of the road or a complete refund?