semvhu

Is there a way to check the timing without pulling the timing belt cover? I'm thinking a timing light could potentially do it, but I'm having no luck with Google or this site as to determine how to use it, if it's possible. Sorry if this is should be a question I could answer myself, but I just haven't been able to find an answer yet.

ezone

On some engines it can be a very valid test, on other engine designs it is of no beneficial use.
Works best on a SOHC engine with camshaft driven distributor.

You posted in 7th gen, they don't have a distributor.

In order to check cam timing with a timing light, you'd first need to be able to actually check ignition timing with the timing light.
This engine with individual coils for each spark plug does not easily allow one to check this.

And you have to assume the ignition timing was actually correct before the timing belt (possibly) jumped time--- because there is no no way to verify that it ever was.

But in general,
a) You need a spec, (hood sticker)

b) you need a way to trigger the timing light, (spare plug wire made into an extension cord between #1 coil and its spark plug?)

c) you need to stabilize the computer controlled timing advance, (SCS function)

d) and you need to know how far off timing would appear if the belt were to jump (rule of thumb is "a lot", maybe 20 degrees change for one tooth and varies with design and tooth counts).

Labscope can show timing if you have a known good pattern to go by.
Pulling the top cover might be faster than going to all this trouble.
Know that beginning with the 7th gen 1.7 engines, most of these will quit running if the timing is more than a tooth out.

semvhu

Thanks for the response. I've had this car jump timing twice now with the timing belt slipping a tooth or two. The symptoms before were that it would start fine but then sputter and die every time but there were no engine codes. This time it's different. It has a tendency to briefly lose power, just quick quarter second drops in power, usually at higher RPM. It doesn't do it all the time; sometimes I can make my hour trip to work and take it to high revs and it doesn't do it. This time it has some engine codes. It has complained with P0420, catalytic converter, for some time now. Twice it has thrown codes for every cylinder misfiring (P0301 - P0304) and random misfires (P0300). Most recently it has thrown a code for P0339, crankshaft position sensor "A" circuit intermittent. It did that yesterday when I took it to 4k RPM and it stumbled a couple of times, but then suddenly it felt like it went into limp mode being limited to about 3500 RPM. I stopped, turned the car off, cranked it again, and it ran fine.

All that is to say that last night I was wondering if it might just be the timing belt again, but given how differently it is acting and the codes it has thrown plus your comments, I don't think so now.

It has complained about the cat for a long time now, but it has driven just fine and I've ignored it like a lazy bastard. A couple of months ago it started with the occasional stumble, then it threw codes for misfires a couple of times in the last two weeks. Then yesterday it threw the code for the crankshaft position sensor and went temporarily into limp mode (at least that's what it seemed to do). Any advice before I finally give in and take it to a mechanic is appreciated. I'll at least try to check out the crankshaft sensor in the meantime, but I'm unsure if that would be related to the other problems it has been having.

ezone

Manual trans car, I assume?
This can happen when you park on a hill with the shifter in gear but not setting the handbrake.
As the car tries to roll against the engine, the crank turns backwards if you leave it in the wrong gear, thus the timing jump.
So if you are parked facing UPhill, put shifter in reverse so the engine will spin the correct (normal) direction if the car rolls, and set the handbrake HARD enough to completely stop the car from rolling.
If you park facing DOWNhill, put it in first gear and yank the handbrake as above.


Yep. If out of time, the computer can shut it down at 2 seconds run time (sort of like a self-preservation move). Usually no codes, but I don't want to say always.


Cat code, ignore for now until all other running issues are fixed.

P0339, I'd pull the connector off of the crank position sensor, get a good flashlight and mirror, and look in the connector (both the wire side and sensor side) for evidence of corrosion on any of the terminals. (Water can destroy the terminals if it gets inside that connector.)
If no evidence, and the female terminals have a snug grip (have not lost tension), and no wiring issues (mice?) then I'd probably slap a sensor on it. (dealer part)

Misfire detection relies entirely upon that crank sensor, so fix that issue first.....unless you can tell the engine really is misfiring.

A timing belt jump will not jump in and out of time (cannot move back and forth between right and wrong), it jumps a tooth and stays there or gets worse. Running condition, lack of power is what is usually noticed first.

semvhu

Thanks! I'm about to head downstairs and see what I can do with the crank sensor. Probably not much but maybe if something stands out I'll see it.

It is a manual. I rarely leave it in gear when parked. On an incline I will put it in gear just in case the parking brake fails but always set the parking brake hard. I don't know why it jumped time the first time I had problems, but the second time it was because the timing belt tensioner was weak.

semvhu

I just crawled under the car. The connector for the crank sensor has been replaced before, not very well IMHO. Butt splice connectors were used but only covered in electrical tape. The tape has come off some. The electrical sockets in the connector have corroded some as well. The connector should be redone probably. In the meantime I'm going to try to clean the corrosion out of the connector and retape it.

When I first took my car to the mechanic and it turned out to be the timing belt, he also said that the connector for the crank sensor had been redone at some point and there was some corrosion. He cleaned it up and said it probably would need to be fixed at some point in the future. I suppose the future is now. I would assume to replace the harness it is on would be pretty expensive; I don't know if there are multiple portions of the harness or if the whole thing is one unit, so that's probably a costly way to go.

I don't know that this is THE problem at the moment, but it is certainly a problem.

ezone

If it is questionable, it is a problem. IMO
It might not be THE problem, but it is a problem nonetheless.

semvhu

I cleaned the contacts in the crankshaft position sensor the best I could then put dielectric grease in the sockets. I wiped it down and dried everything off, of course. I plugged it back in, hooked the battery back up, and took it for a spin. It ran like a scalded dog up to redline and the CEL is off. I am tentatively and hesitantly pleased.

The connector needs to be fixed, though. I don't know if I'll try to get a new connector and splice it in properly or see about replacing the harness or what. It's obviously giving some problems and has given problems before, so it needs to be fixed.

Oh, and it has an oil leak in the area. :-/ Something else I get to deal with, woot.