P0171 P0300 P0301 P0302

So I originally had a P0420 code a while back that I fixed with changing the cat. A few weeks later the P0171 came around and I haven't been able to trouble shoot(not that I was too worried about it). Last night I just started driving after driving about 60 miles about an hour earlier. As soon as I got out of reverse and started going forward I heard two thuds and CEL started flashing. Scanned it and received the addition three codes. I took it easy and went to the gym then limped the truck home. I don't have any oil in my coolant but the oil is a little low. It has been about 6k miles since my last oil changed and when I checked it about 2 weeks ago it looked normal.

I want to say after I changed my spark plugs I noticed an occasional loss of power at ~2.5k rpms, but it has always gone away and been random. I don't fully remember when this issue started after I changed the spark plugs though.

So this morning started working on it. Pulled plugs I replaced in the middle of May(~7k miles ago) and found cylinder #2 was pretty black.



The other 3 plugs look similar to the #1 and #3 plugs.

I have rented a compression tester. I don't know if I fully did it write but I got some low readings. I disconnected all of the coil packs and took out the EFI fuse from under the hood. These are the results(cylinder, 1st pulse, final pulse)

#1, 60, 120
#2, 15, 30
#3, 30, 60
#4, 15, 30
#5, 60, 120
#6, 30, 60


I'm not the most knowledgeable when it comes to this truck. I only know what I read on here and I haven't been able to find anything with a situation like mine. Any help is greatly appreciated. If anyone has any recommendations on what else to do as far as tests to get a better idea, I'll try it.

I'd like to try and fix it, but if it costs to much I'm just going to buy a new/lower mileage motor.

If the engine is toast... Where can I buy a reman'd one? I'm going to start searching craigslist and local junk yards for a donor.

 

How are you counting cylinder numbers? Odds in 1 bank and Evens on the 2nd bank (correct) or 1,2,3 on bank 1 and 4,5,6 on bank 2 (incorrect, but need to be on the same page)

Was cranking speed even through the testing and normal/quick?

Continue to a wet compression test?...http://www.freeasestudyguides.com/compression-test-wet.html

What part of the valley is the truck currently? What's the setup underhood (intake, filter, mods, etc)? More details on the thuds (area, volume, etc)?

 

Uhh.. Not sure on banks really. From front of engine passenger side is 1, driver side is 2, middle passenger is 3 and so forth across like that.

5 6
3 4
1 2
Front of engine. That's how I saw it online.

Crank speed seemed even throughout testing, but I wasn't paying the most attention to that. I didn't notice anything out of the ordinary though. Seemed like less than a second in between cranks.

I'll do the wet test in the morning.

It is currently stuck at my house now on the west side in Peoria.

Another note: When I did the compression test, the engine was cold. Not sure if that makes a difference but I saw on the link it said to warm up the engine.

 

Ok, your correct on cylinder numbering/banks.

Hot vs Cold will have a slight affect, but should be consistent. The oil of the wet test will help the piston rings seal if they are bad. Pick one of the low compression numbers and do a dry and wet test back to back. If it is a big improvement, ring issues.

I'll be available after 2:30 tomorrow, got my number?

 

Ok, I'll test them again tomorrow. Should I do all of them or any?

I'm not fully sure if I'm going to school tomorrow or not yet. I have your number in my messages here. Text cool?

 

I'd want at least 1 from each side for sure as an indication; if 1 is a real pain or your short on time.

Yeah, text is good.

 

I have a few hours in the morning I can work on it. Anything else that would help?

I'll send you one now.

 

For help with the catalytic and fuel trim codes, please read my post:

https://www.tacomaworld.com/threads/addressing-some-common-misnomers-of-the-p0420-code.396763/

This should shed some light on things.

 

That's a good read. I'll refer back to that post once I figure out what to do with my truck. Thanks!

 

Just finished up the wet compression test. The order of the cylinders was 1, 2, 4, 6, 3, 5. It wasn't until #5 I realized I wasn't holding the throttle. So the original 1, 2, 3, 4 and 6 were without throttle open. I retested #2 after, and then added more oil on a second test. I did a dry test then the wet test right after. Results:

(Cylinder #: dry, wet)
1: 130 135
2: 38, 40 (83, 92[This was done at the end of all the cylinders with throttle open])
3: 88, 100
4: 50, 65
5: 110, 130 (With throttle open)
6: 78, 85

 

So the second set of numbers were all with 1oz of oil in the cylinders, and throttle open? Looks like a leakdown test is in your future.

 

Throttle was only open on #2 and #5. Otherwise correct.

 

You know, you can pull the breather hose from the manifold instead of holding the throttle open, it achieves the same thing. The soot on the spark plug is from either a rich condition or incomplete combustion.

Whatever the cause, just drive it until it wont drive anymore, as youre going to have to pull the heads to fix whatever is the problem. Proper head job if doing it yourself with all the tools, set aside $1000 minimum.

 

I don't have too much knowledge on engines, so I didn't know that.

Thanks for the help.

 

I grabbed a few of my things from the home shop and stopped by to give a hand this afternoon. Discussed/explained some engine/emissions/catalyst theory in person.

Started with popping the upper timing belt cover loose to take a peak. 223k on the motor and unknown on the belt (Gates sticker present, but any writing is way past gone). Some cracking of the rubber and somewhat thin looking over the cam gear. So it's got some age/use, probably about due, but not falling apart and fraying either.

Since everything was still apart, we ran a compression test again with my barely used Matco gauge versus the autoparts rental. We didn't directly record anything, but better than expected. #2 topped out at 125 psi, the others were 150-165. Cranking speed was ok, throttle and big vacuum hose off.

Put the plugs back in, swapped 1 and 5 as well as 2 and 6. Didn't think it all the way through, but thought about moving the coils and wires. Damn firing order . Once wires were back in place, idled smoothly, could rev smoothly/slowly ok, but snap throttles were real boggy. Broke a couple DRY vacuum hoses trying to hook up the vacuum gauge.

Fuel trims looked good. Short term was slowly fluctuating above and below 0 with Long term at +4%


It would still throw a P302. I'm not overly concerned with internal/mechanical issues. It's just a tired engine with #2 worse than the others, so any issue presents itself with #2 first.

Left him with the thoughts to get the biggest vacuum hose issues replaced. Look into checking fuel pressure and/or replacing fuel filter. Swap out plugs and wires (#2 for sure). Maybe move coils around to verify it doesn't follow a coil. Try and check the TPS and MAF with somewhat better meter and/or scan tool. Then once the quick throttle stumble gets better, just drive it.

 

Thanks for all the help bud! I'll update this thread once I get more info.

 

So replaced the main vacuum hose that was broken as well as the one that I found was cracked. I also got into the spark plug wires and replaced those with OEM.

Unfortunately I wasn't able to get into the fuel pressure. The kit I picked up from autozone didn't have the right fittings needed to make it work. I need 90* fitting right after the injector rail. The kit had a straight fitting that would connect into the 90*, but I ran out of space with the back piece of the timing belt cover. Any one know where I can get the correct fitting?

 

Today I cleaned TB, checked the IAC and TPS, re-checked coil packs and wires, replaced the fuel filter and put the truck back together. Everything has checked out fine besides the fuel filter it seems. I have it leaking on one side and not the other. I have run out of time for today, but I'm going to replace the oil filter and see if it still leaks.

Good side


Leaky side

 

So the truck is up and running and doing a lot better. I swapped out my old filter and started it up. No leaking from the filter. I finished filling up my radiator and rechecked everything. After sitting about 10 minutes and driving about 25 miles, everything seems to be running well. No CEL codes have shown up either.

Seems the issues was the plug wires, dirty throttle body and the vacuum hoses.

Thanks for the help guys!

 

You can screw an 1/8" NPT 90 deg fitting into the end of one of these.
http://www.autozone.com/fittings-an...110-and-641120/773861/?CJPID=2206300&cmpid=cj