HALF FIXED - After new head gasket install, timing issue?

I've got a 1998 Toyota Tacoma Regular Cab 4x4 2.7L automatic.

While changing a harmonic balancer I found oil in the coolant. Tracked it down to head gasket. I've replaced the gasket and now upon reassembly am having what appears to be a timing issue.

After reassembly I had to jump it and give it gas to get it to run. The ODB dongle shows multiple misfires on all cylinders. With more gas and higher rpms it sounds fine, lower rpms the misfires are more pronounced, and at no gas kills the engine. The exhaust smells similar to a lawn mower. I removed spark cylinder by cylinder, and verified that there is not a single cylinder having issues, it is systemic.

During head removal I tied the timing chain to the cam sprocket, and had marked the cam shaft mesh point.

I suppose it is possible the cam shafts are a tooth off. Or perhaps the chain slipped on the timing down in the block.

Is there another issue that would cause the misfires besides timing?

If it is a timing issue what would be the most sensible way of fixing it? Removing valve cover and playing with cam shafts isn't too bad, but I want to avoid taking the motor back down to the block to fix it.

Right now my idea is that the timing chain is fine, and the exhaust cam shaft is a tooth off, causing misaligned exhaust venting and higher pressure to crank and start... And causing poor gas air mixtures and causing the misfires. But I'm by no means an engine guru in the slightest... Help?

 

Sorry to double post... After some more researching, I'm more confident that the timing chain is in position, because I believe it would be running way worse.

Any one have a direct guide with pictures for timing?

 

You could hook a timing light up and measure the timing at the crank pulley. See if it agrees with the timing on the OBD reader. Since the distributor is driven by the exhaust camshaft, it's unlikely that the timing would read correct if something was off between the crankshaft, intake camshaft, and exhaust camshaft.

Another possibiliity is you missed a vacuum line somewhere on the intake. Check all the hoses. I assume that all the electrical connections are correct, otherwise the check engine light would come on.

 

Thanks for the reply!

I was able to fix the timing issue, the camshafts were a tooth off. I was going by paint markings instead of the dual dot and single dot mesh point. At least now I'm aware of which marks are supposed to line up... Lesson learned!

After the new timing it still idled pretty rough, and was still getting a few misfires at low rpms (but waaay better than before). After running a while and trip around the block it started sounding pretty decent. Power was still kind of sluggish.

I drove it back to my house maybe 30 miles, and it started driving normal. About half way through my 4WD light came on, which I found strange.

Find out that part of the cabling harness was touching the EGR brass tube behind the head and singed some wires. The power steering was also groaning real loud, and I found the fluid to be foamy. I'm going to replace the fluid and see if perhaps air bubbles low fluid level is the cause, and insure no leakage.

Upon arriving home there was also a loud line hissing noise. I think I narrowed it down to the bottom EGR valve connection being insecure.

I'll replace the tube to the EGR valve, change the PS fluid, and double check those wires in the harness (might need to splice in side replacements).

This was my first time delving this deep into an engine. Plenty of lessons being learned... None of the wires in the harness are deinsulated, so I'm hopeful that it will not be too bad...

 

Replaced the bottom tube to the EGR valve, hissing went away and engine sounds great now. I removed the brass EGR tube to reroute the cabling loom, and now my stuck 4WD light is working properly, all all is looking good there.

My power steering is still groaning awful, I'll replace the fluid and bleed the lines. It probably got air I there from the pump being upside down for a few weeks while doing the head gasket when time permitted.

After that is done, all that's left is to change transmission fluid, do a coolant flush, and I should be good.