One clean plug

Hi everyone. 1985 LE manual w/ 240,000

I changed my spark plugs, rotor, cap, & wires about a year ago. I've slowly been losing power and now my exhaust is popping and it smells much more exhausty lately. It is not a rotten egg smell. Since losing power, I've changed my fuel filter. No change. I tested my ignition coil and it was out of spec, so I replace that. No change. I held my Cat up to the sun and could see light, but there is some white buildup on the catalyst. I'm thinking it is still good for a bit. I see or hear no vacuum leaks. My intake boot is fairly new.

I checked compression and it was 173, 179,175, 176. Looks good! While checking the compression, i noticed that cylinder 2's plug was much much cleaner than the others. I would consider the others "normal" and the clean one abnormally clean.

Any tips on what could cause a clean plug? Would the cause give me the symptoms described above? My van barely makes it up hills now and feels as if its choking.

I forgot to add that the fuel pressure is within spec too. I'm a little lost on what to do. Thanks all.

Sounds to me like no spark at that cylinder. No burn, no carbon.

I could be mistaken, but I think no spark would result in a wet plug from unburned fuel. Maybe no fuel? Of course the other possibility is the dreaded head gasket failure. If coolant gets in the cylinder it will steam clean everything. Are you losing any coolant? Is it misfiring or just running poorly? If you have a spare spark plug you could plug it into the number two wire and ground the plug. After that start the engine to see if it has spark and if it runs the same with the plug in the cylinder unhooked. Spark plugs can behave differently in the high pressure environments of the combustion chamber vs the open atmosphere but this can give you an idea of what the spark is doing. Also, since the problem appears to be number 2 and cylinder 1 and 2 connectors are accessible, check the injector wiring for damage.

I believe that yes, the plug would be wet but fuel evaporates quickly and may have dissapated by the time the spark plug has been removed.

I was worried about the head gasket, but I would think that could show up in a compression test. But no, I'm not losing any coolant. :)

I'm not sure if it is a misfire. It could be an exhaust blockage, but the cat had light passing through and the muffler is 1 year old.
-The flow from the tailpipe is inconsistent, with big bursts of air interrupting a normal exhaust flow.
-The engine vibrates/moves a lot more than it did, kind of like it is choking or unbalanced.
-It has very little power. It can barely make it up a hill unless your in 1st gear.
-It has a very strong exhaust smell

I think I'll try pulling the plug wire of cylinder #2 and see if it changes how it runs. I'll check connector 2 for damage too. I saw a Tim post where he was talking about removing all spark plug wires, cranking for 10 sec and then checking the plugs for fuel. That might help me see if the injector is passing equal amounts of fuel, compared to another injector.

Thanks!

If you pull the #2 spark plug wire with it running and the roughness and poor running doesn't change then the #2 plug probably isn't firing properly. The first thing I would look at after that is the distributor cap and rotor. Check the contacts. You could also do a resistance check of the spark plug. If it has infinite resistance then it is broken internally and will need to be replaced. That or try a different spark plug in that cylinder if you don't have an ohmmeter.

Quote:

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Originally Posted by Rufus

I believe that yes, the plug would be wet but fuel evaporates quickly and may have dissapated by the time the spark plug has been removed.

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I mentioned the wet plug because it's been my experience that gasoline leaves a oily residue after the lighter distillates evaporate making the plug appear wet. I would take Rufus' suggestion and pull the plug wire while it's running to help isolate the problem cylinder. You can do this on each cylinder to check for any change.

Thanks, you two. I do have a multimeter. I'll pull the wire and go from there. Looks like I'll have time on Saturday.

I referenced this thread first as I am having a similar problem.
I just replaced the distributor cap and button,spark plug wires,plugs and air filter.Cylinder #3 is loading up with fuel (Plug is soaked with fuel) and not firing even though I am getting fire to the plug.I am not a mechanic but have a mechanic friend and he is a bit stumped.Tested all plugs,wires,swapped plugs in cylinder #3 and still no go.Any help as to where I need to look for the problem would be very much appreciated.Thank you!

Eureka! I think I have found the answer thanks to this thread. http://www.toyotavantech.com/forum/s...it+manifold%3F
Damn Tim,that was awesome.Same van,same exact problem.The manifold looks a bit tricky.If you have any pointers/threads on how to do it properly while replacing anything else that may need to be replaced.Thanks in advance!

So...After reading a bit about pulling spark plug wires while the engine is running, I chose to not go that route due to safety concerns. I did pull all the wires and cranked the engine for 10 seconds. I check plug 1 vs plug 2. Plug 2 was very dry, compared. There doesn't seem to be much (if any) fuel going into that cylinder.

I decided to start pulling vacuum hoses and the intake off to reach the fuel injectors. While I was working, I kept smelling hints of fuel down there. When I got a good look at the #2 fuel injector, I could see that it is leaking a bit of fuel onto the crud caked into the area. :dizzy:Looks like I'll be getting at those injectors to have them tested, cleaned, and whatever else they need before they go back on. Oh well. Such is the way it goes.



:redvan:

Looks like I'll be attacking the same problem. I'm confused with your post, though. It sounds like you are getting fuel to cylinder #3, so it wouldn't be the rust clogged injector screen. The injector could be stuck open???

I'm not getting fuel (or much anyway) to Cylinder #2. This will be a fun one...so I try to tell myself. Ha ha

Yes,I think the injector is stuck open or it's a wiring issue.I'll definitely report back to let y'all know what our findings are.One thing I do know is that all the hoses could stand being replaced for sure.
(Also,yeah man,I'm no mechanic but I can do all the basics and not scared to get dirty! Thank goodness I have a couple mechanic friends to help but they both tell me it's a strange motor.(Neither one has ever seen the 4y) I'll love it even more when it's running smoothly!

At the very least, access to this motor is strange. Yesterday, I pulled off the driver side hatch completely. It gives you quite a bit more room. I'm definitely replacing most of the hoses, while I do this. One vacuum line was cracked really bad, but I think I did it while removing it.

http://www.toyotavantech.com/forum/s...=engine+access

You do know about this, right?
See post #2

Yes,I've done all of the maintenance so I do have a relationship with this van.Still learning.

I was actually mentioning that for Rudy's benefit since he commented about access being weird. I recently picked up another van and was talking with the previous owners mechanic who's shop the van was parked at. He was showing me the scrapes on his knuckles from doing a tuneup on the van and complaining how hard it was to get to everything from underneath and over the valve cover. When I mentioned removing the floor he gave me a bewildered look and then stammered and said ya, we did that. I think sometimes it's knowledge those of us in the know take for granted.

originalkwyjibo, Oh yeah. Ha ha. I definitely know about removing the passenger seat and that floor. There would be no other way to get back there I would think. I was talking about removing the driver side seat and that hatch. I had no idea you could do that, until I saw a picture. It's sooo great! Now I don't bump my head on that itchy insulation stuff or worry about the strap giving out and putting me in a wheel chair for life.:thmbup:

It definitely is nice when more extensive repairs are being done. I completely removed the driver side cover when I did the head gasket and then my 10 year old daughter and I were able to work on it from inside while the Washington rain poured down.

Teaching her right I see!! I'm in Tacoma too. Very Cool.

East coaster here but plan to hit west coast next year before heading north into Alberta.Found all the necessary threads to get this job done now it's just time and getting the parts!

One of the Carolina's, I see. Are you going to drive the van to the west coast and Alberta?

Today I was able to get the fuel injectors out. It took about 6 hours total for me to gain access. The injectors came out with the fuel rail with no removal problems. Unfortunately, number 2 cylinder's injector was not clogged like I thought. I'm going to have them cleaned and fitted with new gaskets, while they are out. I don't know if the PO had done any work to the fuel system, so I might as well do it while they are out.

I did do find some plastic filter chunks in the entry to the fuel rail at the fitting, so I'm glad I got those out. The plastic fuel injector connectors broke on 3 & 4, so I'm in for some soldering. All of my vacuum lines need replacing and one cracked during the process. Old van...but I going to get this thing jamming again. It was doing so well until 3 month ago.:spider:

North! It depends on what kind of condition the van is in by then.We'll see. Nice job getting to the injectors! Sounds like you're getting it done. I'm waiting on my mechanic friend to get some time...

I just got my fuel injectors back from Dr. Injector and I'm pretty excited with the results. One of the fuel injectors (injector for cylinder 2) failed the spray pattern test, failed the mL/second test, and had a flow rate of 10mL. The other had a flow rate of about 40mL!!! After cleaning them, I had a 360% increase in flow rate in the one injector. That was the issue. Very little fuel to cylinder 2. :dance2:I attached the results to this post, in case anyone wants to see.

Attachment 3749

Now...to get this thing back together.