Hello all!!
I have an issue with my Daughters 92 4X4...
let me start off with this the truck runs pretty good about 18MPG not too bad for the 3.0.

So today I take it down to have the emmissions test done...Failed big time on HC min requirements are 220 this truck came in at a whopping 2234. CO = .06132 and CO2 11.9 all at idle.

Well this tells me a few things, timing, vacuum leak, bad plugs/wires/cap/rotor...any or all could be whats wrong..so first thing I do is jump the pins, and grab the timing light...well the mark is about an inch or more below the lowest mark on the timing chain cover, just to get the mark up to around 5-8 the distrubtor is bottomed out I can't even get to 10 degrees...

do you think this could be a major part of the high HC's..oh yea the truck has about 190k miles.

thoughts would be appreciated

Ken

 

That would be at least part of it.

I am trying to decipher what you mean by "inch below the lowest mark" . Assuming you are meaning all the way to the right is the lowest section, it means your timing is retarded (higher the mark the further advanced it is) which means you have a TON of unburnt fuel coming out of there.

You say you can barely get it to 5-8, but you can't get it to 10? its supposed to be set at 5 degrees BTDC with the check connector shorted at idle (and at op temp)

 

Yes you are correct fully retarded, the mark was about an inch below 0. the check connector was shorted and at op temp. the sticker in the truck say 10 degrees, but after a quick drive it was pinging so it needs to be retarded just a tad.

thanks for the quick reply.

 

Those are about the same numbers my truck (my brother's at the time) had last summer. It had 6 burned exhaust valves with the #6 being really burned. Compression was down on all cylinders, but #6 was about 25psi. The others were around 110psi. Amazingly enough, the head gaskets were fine and the engine wasn't using oil. It actually ran pretty smoothly, enough that when my brother went to buy it he believed the scum who sold it to him that everything was fine. After he failed emissions, I took a look at it and realized that at the minimum it needed a top end rebuild. Fortunately, that was all it needed as the cylinder bores were in great shape with no sign of rod or piston noise after about 211,000 miles. I decided to buy it from him and pull the heads and have them rebuilt. I also replaced the timing belt and associated parts and put it all back together. The emissions retest had numbers that could have been from a new engine and it's running great now.

To make a long story short, even if you find a bad plug or wire do a compression test and be prepared for the worst. With HC's that high you probably have at least one or more cylinders not firing, which hopefully is just from a bad plug or wire.

Good luck and there are a couple of good head gasket replacement threads here on the forum if it comes to that.

Bugs

 

DC: timing on the 3VZE is 10 degrees; it's 5 for the 22re. C'mon, man; you KNOW that~

 

If you can't get to 10 BTDC for timing, considering you've got 190K miles on it and it pings anywhere near 10, it may be time for a rebuild. Before running around blind, do a compression test (at least) or a leak down test. Either should tell you the condition of the rings but the leak down can help diagnose valve or head gasket issues out as well.

Also, severely retarded timing will rise HC emissions due to the spark occuring too late. If the piston is already on its way down when the plug fires, there's not enough time to combust all the fuel in the chamber.

 

Inablility to get your timing right can also be caused by the timing belt being off a few teeth...

 

Ok, so just a thought...if the timing belt jumped a tooth, then the setting of 5-8 degrees of timing may be more like 10-15.

I'll do a compression test, what do you think a 190k engine should have at a min 180?

Ken

 

No: if the timing belt jumped a tooth, 5-8 degrees at the distributor is 5-8 degrees since you're measuring when the spark occurs in relation to the crankshaft position. That would explain why you can't get the timing advanced properly though.

 

[QUOTE=kenf729;51173560]Yes you are correct fully retardedQUOTE]

They prefer to be called "mentally challenged".

 

[quote=DupermanDave;51174024]
HaHa...got me on that one...so being politically correct I should have said...my timing was mentally challenged beyond expectations...

Ken

 

And now you know that I don't own any 3.slows

 

I just wanted to give an update to my failed emissions test...after setting the timing and running around for about a week (wanted to clean out the cat) the truck passed with flying colors today, was going to change oil and check compression, but my daughter was in a hurry...
thanks for quick replys

 

So how did you set the timing? How many degrees BTDC?

also, how did you plan on cleaning out the cat? Is this even possible?

 

Well, I jumped the two pins in the diagnostic box, when I applied the timing light I was reading approx 10 degrees retard, so I turned turned the distrubutor to advance it, I could turn the dizy all the way and only hit around 8 - 9 degrees, took it for a test drive and it was pining, so I retarded it back to about 5...

As far as the cat...if it had been running rich I wanted to try and burn off the excess unburnt fuel before we re-tested...it seemed to work..

Ken