Is it a compression issue?

1991 Acura Legend 6 cylinders

For about a week, my car was hard to start, and very sluggish upon accleration. By Friday, the car was not getting over 20 mph, chugging, and semi-backfiring. I took off the valve covers and found quite a bit of oil in the 2nd cylinder, along with a crude covered ignition coil. I replaced all 6 spark plugs (properly gapped) and bought a new coil for the #2 cylinder. I also replaced the valve cover gaskets, and all 6 rings to prevent more oil seepage.
After putting everything back together, making sure wires were correctly aligned, the car will not start. It cranks, but does not turn over. I put the old coil back on, and it did the same thing- crank but no start. Have I lost compression? How can I restore compression? The engine sounds so close to turning over, but not quite there. I’m stumped. Thanks for any advice.

First off would be a compression and spark test and check for any stored codes in the ECM. If the routine maintenance isn’t up to date as suggested in the owner’s manual, you’ll likely save yourself some $$$ by doing that first before bringing in a pro to figure out exactly what is going wrong.

My first guesses – given nothing else to go on – would be either something wrong w/the ignition system, the intake manifold vacuum, or a plugged exhaust system.

Sounds like you had an external oil leak which fouled ignition bits? Being down 1 or 2 cylinders on ignition will certainly affect performance. Does a misfiring motor cause a cat failure due to excess fuel being burned in cat? Maybe remove O2 sensor to relieve back pressure and see if it helps? Not sure of motors overall condition? You did have CEL light last week?

No “check engine light” ever came on. The motor is a fair shape, for a 22 yr old car. It was low on oil when I started tearing things apart. I’ll try the O2 fix, I’m not sure if I understand your catalytic converter question.Thanks for the tips.

Check for spark at the plug, Make sure you have one. Sounds like you don’t since starting fluid did not work. Those coil overs can be sensitive to abuse.

@ClaytonT misfires can destroy and plug up a catalytic in a VERY short period of time. I’ve personally seen it happen.

When did the OP say anything about starting fluid? Not that it’s a bad idea.

A car that can’t go about 20 mph is pretty sick. You continued to drive the car when it had obvious problems, which might have caused more damage.

A compression check makes sense at this point. It isn’t that hard to do, but if you aren’t experienced in doing compression checks you should have an experience mechanic check the compression. An inexperienced DIY’r will not get accurate readings and therefore you might be led astray in getting to a diagnosis.

For a motor to run you have to have fresh fuel and air mix pulling into the cylinder and the old fuel/air mix expelled out the tailpipe. If the exhaust is blocked, then you don’t get fresh fuel/air pulled in and the motor won’t run. So you could have fine compression but still not run.

If the compression is low, the 1st area to look at on a Honda/Acura is the values. Misadjusted valves could be the cause and relatively simple to fix. Your motor has variable valves and a problem in that system could get more complicated and expensive. Poor compression could be bad and worn piston rings, but in this case you should see a lot of smoke out the tailpipe and regularly need to add oil since bad rings will let the oil blow by them.

Turned out to be a bad fuel pump. Thanks for your suggestions.

@ClaytonT thanks for the update!

And congratulations!

I am amazed at how often finding and correcting one problem results in an engine that fails to run when the work is complete and an unrelated problem is finally discovered. That situation is a real pain for shops. It makes mechanics appear incompetent, crooked, or both. I am very glad that you brought your problem here and are keeping us filled in on your progress.

Good luck, @Clayton T.