NEED HELP BAD-NO CODES, CEL-on, Rough Idle, Hard to Crank

I have a 97 Tacoma, 3.4v6 4x4. She sat for several years before I bought it from a friend. I got it, cleaned the fuel out, put new gas in and she ran perfect. I would drive it every afternoon and she ran great and idled great. One afternoon I get in and start driving, then it started acting like it was going to stall out. The CEL started flashing like limp home, so I limped home. After that I could barely get it to crank again, and if it did finally crank it would idle rough, low RPM's and the exhaust stinks. I tried jumping TE1 and E1 since the CEL was on-NOTHING, it would not blink. I bought a OBD2 scanner (Bluedriver) no codes found. I replaced the following:

-Fuel pump
-Fuel pump relay
-Fuel filter
-Spark Plugs
-Coil Packs

Same issue. I thought well could it be bad gas. I drained the gas, put good gas in, then disconnected the fuel line to the filter to make sure the pump was actually pumping, when I got back in the truck it started like a champ and ran perfect for 4-5 hours. I drove around all afternoon. But when on my way back home going 55MPH it cut off without warning and was hard to get cranked again, same problem, hard to start and rough idle with low RPM's, when it is doing this you can not drive it, when you press the throttle it will try to stall out, I can throttle the truck slowly and it will let me give it gas, but if I just hit the gas it wants to die.

Fast forward. A buddy told me you might have gotten a bad fuel pump from the store. Buy a new one along with the sending unit. I did. Put it in, got in and it cranked great, and idled and ran great for a few hours, I thought well that was it. The next day I go out to crank it and it started ok, but as it was idling I heard the RPM's drop down and now it is back to the normal rough idle, low idle, can't drive CEL on. Still no codes, and still can't get the TE1 E1 thing to work. Since then I have replaced the Fuel pressure regulator, and the upstream O2 sensor.

I plugged my scanner in and was watching the live data, and this is what I found. It's staying in open loop, the o2 upstream sensor is reading .97, which says it's rich, which would make sense. As i watch it when it's been idling it keeps going open loop, closed loop, open loop closed loop. When it briefly goes into closed loop the RPM's seem to get better and the CEL goes off, but then goes right back to open loop, CEL, bad idle. (I wish I could find a sequence of operation for what the ECM looks for in what order after the vehicle is turned over to make it go into closed loop)

I have just recently replaced the battery, I have also checked the MAF, the VSV, the IAC valve, the CTS Coolant temp sensor, both O2 sensors. All are within factory ranges.

Also checked all the grounds, all are tight.

The only thing I can think is maybe bad injectors leaking fuel. Both times it has ran decent I had disconnected the fuel lines for some reason. That's the only thing that has made any difference. I have not checked fuel pressure (no Shrader valve and SST for this is not available). I really have no clue. I just wished I could get a code...

 

I didn’t see where you changed the fuel filter. I had a diesel pickup that did just about the same thing you describe, and I changed the filter and no more problem.

 

I did change the fuel filter when I replaced the fuel pump.

 

what about fuel pressure regulator?

would make lil sense bc would run when you removed fuel lines

 

Thought the same thing. Just replaced that a week or so ago and no different.

 

dang^^

 

man, after reading searching i was 90% sure was leaking injectors for my 96 2RZ
but i had Hot No Start condition(no codes either)

your rich condition(reading) could point to leaky injectors as a possible cause

if you do want to RR injectors
i recommend MotorWest in CA
sent my OE injectors there and no issues after install
very fast turn-a-round/reasonable $100 for 4 (one of mine was so bad, was only charged $20 for a core)

 

Thought about injectors. I'll definitely go to MotorWest if so. I have attached a few screen shots of my OBD2 reader so everyone can see what its doing. I went ahead tonight and replaced the spark plug wires, and removed the spark plugs and checked gap (I was told they came pre gapped, they ranged from 25-35) I gapped them all to around 40-43ish. No change. I even disconnected the fuel filter again to see if I could duplicate, not so. This time the RPM's were pretty good, but you could still tell it was really rich, it's idling sluggish, and the exhaust still smells. Cranked the truck and let it run for 8 mins before the o2 sensor #1 even showed voltage, see pic. Also both sensors at the 14 min mark were showing voltage, #1 at .98v and #2 at .885, it was still in open loop with CEL on. Then I show one picture where the o2 sensors show to be modulating, and the truck went into closed loop, but then right back to open loop. I'm probably going to get a MAF sensor and an ECT Engine Cooling Temp sensor, the coolant temp was erratic.

One thing I did tonight was go around to all of the grounds and wiggled them and any wire bundle or harness that I came to. Nothing that seemed to be the issue with that. I love Toyotas, but sometimes I don't like them......

 

I suspect that your engine coolant temp sensor (ECT) is bad. The -40.0 should have been your first clue... ALL of the readings you are looking at are calculated values from the PCM because of open loop status and are not actual LIVE sensor data. Replace your ECT and she should go into closed loop.

 

I'm not taking offense to that one bit. I'll be the first to tell someone I'm only a youtube mechanic... I thought that was really weird but figured it hadn't had time to read correctly. It seemed like it being erratic as well. I will replace that and come back to update. should I stick with OEM or O'Reilly's? Thank you very much for taking the time to help me, it is very much appreciated.

 

I looked and the factory part cost is so close to the aftermarket I would get the Toyota one, NTK is the brand that I would get if I was to go to O'reillys.

 

alright. I just replaced the Engine coolant temp sensor with a new one from Toyota. I had to disconnect the fuel crossover line to get to it but got it connected. Started the truck and it ran great for a couple minutes, idled a little high, but when I looked at the scanner in live mode the o2 sensors were reading and going up and down, the short term fuel trim was going up and down slightly it was acting like it was trying to relearn where it needed to be, i felt good about it. I revved the engine up to around 2000 RPM and it settled back down pretty good, but right after that it acted like it was starting to run rich again, the CEL started trying to come on (it would come on then go right back off, then on and right back off-it's not limp home). now my truck is doing the same thing again. It's idling rough, RPM's are in a decent range, but the scanner now is reading .98 on the upstream o2 sensor, now everything on the live stream on the scanner is flatline. The o2 sensor, the short term fuel trim is 0 Engine coolant temp flatlined at 129 but showed a range of 129-304 F. also the MAF sensor is flatlined. I'm still waiting on the MAF sensor, should be in tomorrow, I have no idea what is going on with this truck......

 

I understand the frustration. First off this is a system everything relates to everything else. It sounds like you have multple things that arent right. Get the MAF replaced and monitor the following...

For the readings to mean anything it has to be in closed loop, find that and verify that she is indeed running in closed loop.

Monitor the intake air temp, it should show the temp of the outside air. If it is off drastically, there is an issue.
Monitor all trims.
Monitor you mass air flow rate, that is what your tool calls it. Change your tool settings to display metric. The "standard" is 1 gram per second per liter of engine displacemnt so your 3.4 should show 3.4 ish g/sec at idle.

In re-reading your inital post, do a voltage drop test on all of your grounds. Volt meter set to DC volts, 3 volt scale if you have it. Start the truck and put one lead on the negative battery post and the other on the negative clamp... should show 0.0 volts. Do this on the battery to inner fender ground and on the common ground post by the DIAGNOSE box on the intake. I am mentioning this because of the 129-304 ECT reading, that 304 is not right.

 

Ill update about the MAF tomorrow mid day. I went ahead and checked the voltage like you suggested. using my voltmeter set to 2 volt DC I was reading 0.0 on the negative terminal and the negative clamp. I went to the negative on the body right beside the battery and was reading .001, I went over to the ground on the side of the intake manifold by the Diagnostic box and was reading .007-.008. the scanner i have is a blue driver so I'm also contacting them to see if something needs to be updated (if its a problem with the scanner itself) Thank you very much for all of your input and help on this, it is more than frustrating..

 

EGR functioning correctly? Engine starts fine when cold, hard when hot?

 

BlueDriver is my "inital" scan tool and I have not had a vehicle that it did not connect to.

 

I just went through this on my truck. Check the connector in the cts. I changed my sensor 3 times before figuring out that it was the connector and not the sensor. Look inside the connector to be sure if the white part of the insulator is cracked.

 

alright, changed the MAF sensor, no change to how the truck runs, still not going into closed loop. Says MAF rate was 4.13 g/s, but ranged from 3.99-178.25 g/s (seems like crazy variance), engine coolant temp is 88'C, 02 bank 1 sensor 1 at .975 flatline, 0.0 short term fuel trim. The fuel system status is saying open loop-due to detected system fault (bank 1 or both).

F.I. Letsgofishing, I'll go out and check that out. Thanks for that.

 

Unplugged the connector and all looked good on both ends.

its trying to go into closed loop, when it does the scanner will change to closed loop and the check engine light will go off, but then it goes right back to open loop and CEL. sometimes it goes in and out a good bit as in just a second ago when I had it idling, and other times it will barely try to go into closed loop. It's random.

 

Have you tried pulling the battery for a few days to completely clear the ECU? You may have an error lock and it can take a couple days or longer to drain the stored power. I was told of a faster way but my truck is older so I won’t go there. Also mine is a 2.7 4 cylinder but the systems are very similar.
Also, when you start you scanner, does it show all the completed units? Mine was instantly giving 0 DTC and not showing the finished check areas or would give failure.