zlathim

My friend just purchased a 98 Taco with the 2.7.

He is going to bring it over for me to look at tomorrow, so I thought I would get a headstart by posting the current codes here:

P0300 Random/Multiple Cylinder Misfire
P0301 cyl #1 misfire
P0302 cyl #2 misfire
P1300 Igniter Circuit Malfunction No. 1
P1310 Igniter Circuit Malfunction No. 2

The engine runs very rough. He said that he thought that there were two plug wires switched (based on a haynes manual he was browsing at Vatozone), and he said he switched them around. It had no effect on how the engine runs. Sounds unlikely to me unless both of those cylinders are dead ( I am assuming #1 & #2 based on the codes, but I forgot to ask which plug wires he switched).

Can anyone point me in the right direction? I haven't seen the vehicle yet, so like I said, I'm just trying to get the right train of thought going here.

toytech76

Check plugs and compression. Those engines also have problems with tight valves and heads cracking

zlathim

Thanks for the input. I will run the compression check first thing.

zlathim

Does anyone else have any ideas?

zlathim

I worked on the pickup last night for a little while as I got a late start. The NGK plugs looked fine, i.e. light tan insulator and electrode area. #1 was a little darker, but definately not fouled.
Here's the compression test results:

Cyl# 1= 50 psi
Cyl#2= 145 psi
Cyl#3= 150 psi
Cyl#4= 157 psi
A quick and dirt cylinder leakdown test showed no bubbles in the coolant or hissing from the dipstick tube on the engine. I did hear some noise at the intake and exhaust pipe, but I'm really not sure that I was using the right TDC mark... It was getting late and I was tired. I am going to pull the VC today when I get home from work and make sure both sets of valves are closed.
Can anyone give me an idea of what I'm looking at if I end up adjusting the valve lash? Is this one of those motors with replaceable shims for setting valve lash?

Any help would be appreciated, However please don't respond by saying that I should replace all plugs, wires, etc, etc. I can and will test everything in part, but I am not interested in throwing a bunch of money at this thing only to find out it still has a miss.

97ltd4x4

Igniter circuit codes sounds like a coil...does the truck have coil packs or distributer?....by chance if it does have coils are clyinder 1 and 2 sharing the same coil?...If so I bet that's your problem...

If not and you are sure wires and plugs,cap and rotor are good,along with good compression.Possibly fuel problem,Injectors are likely bad.

zlathim

Cylinders #1 & #4 share a common coil.

Injectors won't explain the low compression reading. I'm thinking valvetrain.

97ltd4x4

I didn't see the low compression at #1.Did you do a leakdown test? There will be no guessing after that.I must add If the leakdown is good,still consider an injector...If it stays open..It will wash down the cylinder walls giving low compression reading...If you can hear air from exaust (most likely if a valve does burn)...time to pull the head....

zlathim

It was getting late when I started messing around with the leakdown test. I did hear a hissing in both the intake and exhaust, however I'm not entirely sure I had #1 on TDC. I had a mark on the crank pulley lined up with the indicator, but I wonder if I had the right mark.

I intend to pull the Valve Cover (looks easy enough) and affirm that both sets of valves are indeed closed on cylinder #1. I will have the cover off anyway so I wanted to check valve lash. I don't have a FSM and I've never worked on this engine, so I was hoping to get some insight. I would greatly appreciate any help, especially a link to a manual.

zlathim

zlathim

Update- (as if anyone cares!)

I believe that the codes (especially the ramdom misfire) were all a result of the switched plug wires. I'm not certain, but that's what I'm thinking.

Cylinder #1 is definately leaking out of the exhaust valves, so I may be tearing the head off this thing over the weekend.

Judging by the plethora of responses so far I am not expecting to see much, but for the LOVE OF GOD someone come be my friend and help me with this funky 2.7!!!!!!

C'mon guys!! Ive seen posts from guys who fouled up the firing order when replacing plug wires with more replies. Help a brother out...

toytech76

dont worry about the fring order right now. The head needs to come off and be inspected. Have a good machine shop pressure test it first. Pending those results, HAve them grind the intake valves and REPLACE the exhaust valves with toyota valves. You dont want to grind the exhaust valves as this will only make this problem happen again and more quickly. Also have them surface the head if it is ok. Remember which cam goes where, and also remember one cam is a 'loaded' cam. There is a threaded hole through the gear of the loaded cam in which you can thread a 6x1.25 bolt through it to keep it from unloading BEFORE you remove the cam. If ya lived in norcal, I would just do the job for ya

zlathim

Thanks for the advice.

I am going to be tackling this thing over the weekend. My buddy has decided to have me do a minimal fix on this thing so he can sell it (doh, he just bought it) and get a pickup w/ a V6.

As such, I am going to replace the exhaust valves on cylinder #1 only. Just enough to make it run well enough to sell. Since he got this thing for a steal he wants to flip it and get into what he really wanted, which is a V6.

I might start another thread detailing this project, as "Random cylinder misfire" isn't really accurate of what's going on here. Thanks for the help.

New thread can be found here:

https://www.yotatech.com/forums/f2/1...valves-140030/