How to check if timing belt has slipped

[joebeets]

Hi,


My 88 Accord DX auto suddenly won't run right--no power, barely idles,
stalls, backfires--and I want to see whether my overdue-for-a-change
80,000 mi timing belt has slipped. I plan to check the cam pully marks against the flywheel mark indicating TDC compression on #1 cyl, unless there's a better way. Any pointers? Can I loosen the belt to restore it to its rightful place, to drive it one mile to the shop for replacement?

Thanks,
JB

[FyreDaug]

Well if you pull the timing cover off and you can tell if it has slipped, and get it to run right you might be able to get to the repair shop. I wouldnt trust it though, once it slips it could do it again any time. Atleast we are non-interference engines so it wont hurt anything but your chance to get it there.

However, do you know for a fact its the Timing belt?

[Blkblurr]

Remove your valve cover, rotate your crank pulley so that your cam pulley has the marks lined up with the valve cover surface. The "up" on your cam pulley should be up. Check your timing mark on your flywheel and see if it is on tdc. If so you did not slip a belt. You might want to take out your plugs to make it easier to rotate your engine to tdc.

[joebeets]

Thanks--right now it's just a guess.

[Bigg_Billy]

It would really have taken a jolt for the timing belt to slip a cog, my guess is it didn't. There are just oo many cogs that would have to all pop, in order to slip. Pull the coil wire off the distributor and hold it near an engine bolt and see if you get a nice blue spark to ground. If it's a weak orange spark, you may need a new coil. Hook up a timing light to any spark plug wire and pull the trigger. If you're getting an intermittent flash, not a nice steady one, you may have a problem distributor. In the olden days of loose chains and sprockets, jumping teeth was possible, now a days with tensioners and multiple cogs, breaking would be more a problem than jumping. Also, change the PCV valve.

[shepherd79]

if the timing belt didn't slip, i would check the cylinder compression. i bet you blew the gasket between the cylinders.

[joebeets]

Belt's OK. I checked compression cold and got 160-190-130-210. Not good but nothing that should cause sudden onset of symptoms. Will keep at it.

[Oldblueaccord]

Belt's OK. I checked compression cold and got 160-190-130-210. Not good but nothing that should cause sudden onset of symptoms. Will keep at it.

Pull the valve cover and check that the valves over that piston are moving and adjusted correctly. Backfire is fuel unburned.

wp

[joebeets]

Did find some corrosion in a distributor tower, and it runs fine again. Still perplexing, because I have run on 3 cyls in other cars and it wasn't this bad. Thanks for all the replies.

[joebeets]

Oops. Spoke too soon. Much better but still idles rough once warm. Fortunately I have a duplicate coil, igniter, and ecu. I suppose the EGR should be checked too, maybe PCV. Failing that, I'm inclined to take it to the dealer and let them figure it out. There's a vacuum test port and I have a pump/gauge. Can this be used to diagnose vacuum leaks?

[Oldblueaccord]

Well your missing the fact that you have a lazy cylinder. If your getting 130 psi then its not gonna make the same power as the others so its never gonna run smooth. You can throw all the tune up stuff you want on it its not going to rebuild itself.


wp

[joebeets]

Problem solved. One of the two plastic plugs inside the distributor, that cover up the screws holding the plate, broke and was fouling the stator blade, preventing any spark advance. I just removed it. Thanks for all the suggestions.

At least now I know my compression numbers, and I can think about putting on a rebuilt head and installing new rings.

[joebeets]

On second thought, it was the rotor: Had a carbon button underneath the arm that showed spark damage. $3 repair. Plastic plug is back in, runs fine. Added Vavlemedic for sticky rings too.

[FyreDaug]

Good job, good to know you went through the proper procedures to checking it out!

[joebeets]

Thanks. Distributor arcing was the first thing I checked, but didn't look *under* the rotor until I set out to swap the igniter and happened to notice the plastic plug. At that time the underside button--what is this for anyway?--on the rotor looked like well-worn contact points, so I dismissed it as the cause of my days-old problem. I replaced it anyway, along with removing the plastic plug, and only later, after reading more references to known Honda aftermarket distributor cap/rotor problems, realized a carbon button could wear much faster than a metal one, so it could be, after all, the problem. Funny how your mind works.