markheth

I have a 89 240sx, and I had to replace my timing chain.

Now that it is all put back together, I have a serious lifter tick after the car warms up... What do you think this could be?

The timing is 15 btdc, and a manual inspection of the timing mark at tdc, and a feeler gauge shows the valves have some clearance.

I thought I may be off by 1 notch in the chain, so the lifters would float a bit, but the feeler guage disproved that (i think).

Any ideas?

-HyJynX-

Moved to N/A

devnull

I'm fairly certain that a having the timing chain off-timing wouldn't cause excess valve lifter float/clearance. If you think that the timing chain isn't on correct timing, which is very likely, I recommend opening it up again and double-checking it.

markheth

I ripped it all apart again, and reset the timing chain to where the marks/silver links were. Threw it all back together, and lifters quieted right down... The only way I can describe this behaviour is that the power stroke was causing the partly open valves up against the rocker arms causing the intense tick.

It ran good for a couple days, now i have a bad idleing problem... I have found out (through process of ellimination), that cylander 3 is not producing power. (pulled spark wire off, and car ran same).

I changed wires, plugs, rotor and cap... still same problem. Verified I have spark, checked compression (it was ok), and have come to the conclusion it must be a stuck injector.

Man, talk about a run of bad luck all at once

I have no idea how to clean/check the injectors... but I know it has never been done (230,000kms later).

I think this may be a dealer thing unfortunatly.

devnull

The first thing to do is to check the open resistance on the injector. Unplug the injector, and using an ohmmeter, touch the test probes to the terminals on the injector. It should measure 10-12 ohms. Anything more than 1 or 2 ohms outside that range indicates a bad injector. Next thing to do is listen for injector pulse. Use a screwdriver as a stethoscope on each injector. They should make a ticking sort of noise.

If they're ok, ask your local dealer if they offer a fuel injector cleaning service. They use a high-pressure system with a special cleaning solvent. It should clean it right up.

markheth

The injector measures 15 ohms, and a by using an automotive stethoscope, I have found that it is operational... Wondering if I should get some new ones, or just clean em...

It is kind of odd that this would happen all of a sudden, could it be because my cam/crank timing was slightly off before? (Trying to compress the cylinder when the injector fires or something?)

I also disconnected the injector and ran the car, there is no difference with it unplugged or plugged in, so I am pretty sure there is a problem with that cylinder/injector.

I have found some redtop injectors from a 1990, do you think they will fit?

Project Cheap13

Did you check to make sure you are getting power to the injector plug?



Yes, The sohc injectors are the same for both years.

markheth

Yeah, injector was firing. I did a idle speed compression check, and the cylinder went to about 30psi total 93 psi when just cranking it.. Tried the cylinder next to it, and was 60psi running/110 psi cranking.

30 seems low to me, but i dont know what to expect when its running like that. Mechanic friend just mentioned it is something I should try.

Stuck lifter cause the valves to stay open longer than wanted? resulting in low compression?? I did notice doing a compression check, there was gas in the cylinder (at least i could smell it).

devnull

One good test, is to unbolt the fuel rail and turn it so you can observe the fuel spray.

On cranking, all four injectors should fire at the same time. They should all spray a fine mist in a conical pattern. If any of them dribble fuel or don't spray then you should probably get that injector clean service.

If any of them leak fuel with fuel pressure applied but not cranking, then you should replace the injector seals.

markheth

Ok... here is what I have done...

1. Took the fuel rail off, noticed all injectors looked good.
2. Switched injector 1 with Injector 3, still same problem with Cyl #3
3. Switched the lifters from Cyl 1 to Cyl 3... Still same problem with Cyl #3
4. Re-did compression check... Cyl 3 is showing random results, mostly bad... from 5 tests on this cylinder, it was (90, 93, 120, 85, 87)

Im wondering if a valve is bent slightly, and sometimes it feels like moving, other times it does not... hense the random results.

Also, yesterday it ran ok for 1 hour, then started acting up again.(with the compression thing)

So... now, im pulling the head... 230K kms... time for a valve grind anyhow... good excuse to get rid of that burning oil I have had for the last 100,000 kms. I'll probably switch the oil pump out as well, to get that little extra oil pressure to help those lifters out.

markheth

Seeing the insane price of head bolts these days... do you thinks its an absolute replacement part, or can i get away with reusing them...

devnull

I don't know about the head bolts. Some can be reused. Others you toss after they've been torqued once.

Another thing you can do before you pull the head is to do a wet compression test. Pour a tablespoon of oil into the bad cylinder. If the compression returns, then the piston rings probably need replacement.