larrys93pickup

Guys,

After reviewing lots of posts on the internet, I'm still stuck on trying to find the source of a misfire on my 92 22RE. A little about the truck, I'm the original owner and have taken relatively good care of it. It would get regular oil changes at either the dealership or me. In about 2006 or 2007 I was using it as my daily driver, and it ended up overheating on me. I immediately pulled over and let the truck cool off, I ended up taking the head off the truck and having it checked for warp-age. The head was fine, not warped, but I did have the machine shop do a head clean, valve-job. I used a head gasket from the dealership and made sure that everything was torqued down, etc. That was in 2007. I used the truck without any problems from 2007 to about 2013, when 1) the truck became my weekend parts hauler, and 2) basically parked due to not being able to pass smog. I leave here in California, so there are some strict smog laws. I then did the following: replaced cap, rotor, wires, plugs, verified the TPS, replaced the VAFM with a re-manufactured one. Also, I had a small pin hole leak in my Y-pipe (from header to cat) and had a muffler shop weld it back. Lastly I did have my injectors professionally cleaned by a shop here in California. The guy at the injector shop stated that he thought that one of my injectors was gone, but his dad suggested to continue with the cleaning (which he did) and the injector tested fine, no drop outs and had a normal spray pattern just like the other ones. I think the print out that the guy gave me showed all of the injectors with-in about 2% or so of each other. Also I did replace the catalytic converter with a bolt on one from I think magnaflow. I checked the pipe temperatures before at and after the catalytic converter and from what I can tell my Catalytic converter is not the problem. Also due to the fact that this truck basically sits, I don't think I have over 2,000 actual miles since I put on the cat. Also I did replace my 02 sensors with Denso sensors.

Present: I talked to a mechanic that works on foreign cars only, MGB, VW, BMW, Honda and Toyota's. I informed him about my misfire, and he suggested that I take some throttle cleaner and spray near all hoses, etc to make sure I have no air intake leaks. I wasted one can of the stuff, but just can't seem to find any air leaks.

What I'm noticing is that when I rev the engine up to about 2,000 the engine responds very well, but still has a very noticeable misfire. But when I take my foot off the gas, this is where the misfire is most noticeable. Realize that I'm testing this in my driveway and in park, but the "deceleration" of the engine is where the misfire is most noticeable. I unplugged the TPS and checked for the misfire again. The misfire is there, but just not as strong as when the TPS is plugged in.

The truck as 206,000 miles, except for cap, rotor, wires, professionally cleaned injectors, and a re-manufactured VAFM, all parts are original, including the EGR and the TPS.

Oh and the reason for not passing smog is due to high HCs. and it looks like I have a lean misfire.

Please anyone, help me get this truck back on the road.

AKHeathen

measure the pickup gap in the distributor on all 4 points by barring it over by hand. check for excessive play in the distributor bushings. ohm the plug wires. test the coil..... next step after that, do a load ballance by pulling the plug wires one at a time and feeling for a power drop. be careful as you can be shocked and it does not feel good... but not really harmful...... but thinking of it, first thing is to pull the plugs and see if they tell you something.

larrys93pickup

AKHeathen,

thanks for the reply, I checked the distributor and it is tight, no excessive play, the air gap checks fine. I checked the wires for resistance (at 60degrees F, COLD) and found the following:
Spark Wire #1 : 4.44 on 20K scale
Spark Wire #2 : 7.57 on 20K scale
Spark Wire #3 : 6.97 on 20K scale
Spark Wire #4 : 9.78 on 20K scale
Coil Wire : 7.21 on 20K scale
These are well with in specs.

I checked the Primary Coil Resistance : .7 ohms (measured with Actron) and .6 ohms (measured with a Fluke meter) all at 60 degrees F or COLD. lastly I checked the secondary Coil Resistance and it measured 12.24 on 20K scale.

According to the 93 FSM, the only questionable measurement is the primary Coil Resistance, it should read between .36 ohms and .55 ohms, which in both cases measured above .55 ohms with the .7 and .6 ohm measurements.

any thoughts, on this, the coil is not really that far off, and could that little extra resistance cause such misfire?

and lastly I measured the pickup coil resistance in the distributor and it measured 224.9 ohms, well with in tolerance, and checks out fine.

again, any thoughts?

thanks, Larrys93pickup

grumpin

I had a coil on my son's Bronco that wasn't out by much, like yours and it was very hard to start when cold. I know a different symptom, but if it's not within specs I would change it.

AKHeathen

what does the meter zero out to? even flukes can zero to .2. also, isn't #1 &#2 plug wire length the same? coil wire resistance is measured on length, so #2 might be bad, or might not.

larrys93pickup

The fluke zero's out to zero because it is a digital meter. as for the length, they are toyota oem wires and each one is a little longer then the first one. but I can actually measure them to be sure. The FSM states to replace them if they are more then 25K ohms per cord. When I have some time I will check the spark plugs for any abnormal signs, etc. Also I bought these spark plugs at the dealership and they are also toyota oem. This is getting fustrating..

Terrys87

iTrader: (1)

As I understand it, an aftermarket catalytic converter wont pass a smog check in California and I can believe that. Look at the quality and size of an aftermarket compared to the factory. There is a big price difference but there is also a big quality difference. I do not know if a magnaflow is poor quality or not.

With your ohms being 36-55 I would feel better if it was around 42ish. It could be in your meter but I would be tempted to change the coil. Usually if the readings are much further off instead of just on the very limits in my experience.

93s have a better injector connector then the earlier models but I have seen them fail. With a long pair of needle nose pliers, try lifting and pushing down on the injector connector and see if it cuts out. I have seen that before.

There are some sites to replace the connectors if they need replacing. I get mine from connectorfast.com and hear Rockauto sells them as well.

Denso wires can be bought off of ebay for about $30 and that is including shipping. Denso wires are the best out there in my opinion. Get a factory cap from the dealer as they are reasonably priced.