Fuel / Ignition Gremlins (3RZ-FE)

[selfish]

Okay, I will try to summarize as much as possible.

I have had P0171 FOREEEEEEEVER, been trying to fix it. Here is what I have done so far:

• Cleaned the MAF / Throttlebody
• Sort of checked for vacuum leaks
• Replaced both O2 sensors
• Replaced all 4 injectors with brand new ones

After I replaced the injectors I started having trouble starting, when it was warm in the morning it would take 8-10 cranks, if it was cold outside it would take 2-3. Combined with really poor pickup from a stop I thought it was the fuel pump. I spent about 3 months mentally preparing for replacing the fuel pump. :scared:

Last week it died merging onto the highway. First I lost power to the wheels, as I was coasting I could rev the engine to 3500, then 3000, then 2000, then it died completely and I coasted to the side. I towed it back to the garage, only symptoms are not starting. It cranks, but nothing happens. So now I have done this:

• Replace fuel pump
• Replace fuel pump relay (circuit opening)
• Put in more gas / and tried starting with starter fluid

We tested for spark and saw really good spark prior to relay swap, but now nothing. When I stop cranking, for half a second I can hear the buzz that I assume is the fuel pump. That was NOT there before replacing the fuel pump. Adding the starter fluid did not change the cranking behavior one bit, I thought it should have done SOMETHING. I tested the EFI relay by swapping it with the tail light relay and it looks like it's okay.

This is my daily driver, 250k miles. At 200k I had the whole top end rebuilt after a blown head gasket, including valves, timing chain, everything I could pull off of the block was replaced.

Where do I go next?

Thanks for looking.

 

[Red October]

To me i sounds like you have already gone thru the fuel system and now youre getting fuel.

If the starting fluid doesn't change the way it cranks and you say you don't have spark now, that would be where i would start. Is your 3rz coils or dizzy?
How did you test spark?

 

[selfish]

I have two coil packs, and I tested spark on one cable connected to each of them to make a guess if one of the coils was bad.

My buddy has a little tester that looks like a spark plug, but has a U-shaped piece of metal that curls back around to get close enough to spark.

First, we put it on, and saw nothing. We bent the U to be closer to the sparker and then saw good spark while cranking. Now after replacing the relay, there is no spark on two different cables.

 

[Wikano]

Have you considered an electric short to your fuel pump?

While doing my elocker retrofit using stock wiring, I had some similar problems. First my engine would crank just fine but there was no ignition. When I did get it to work by removing the added wiring the engine would sputter like it was starving for gas every once in a while. When I plugged all the wiring together again (one of the individual wires seemed to be loose) and put some more gas in the tank it seemed to work fine.

Later, when I added the rear differential ecu to test the locker, everything was still running fine but removing the elocker and the rear diff ecu for storage seemed to cause no gas to get the engine while starting the ignition. When I wired everything back up, it seemed to work fine again!

The lesson of the story was that messing around with wiring can jack up my fuel pump and ignition.

Check to see if all your plugs are snapped in correctly along the drivers side and be sure to also check the that the smaller wires going into the plugs are snug as well. HOPEFULLY this helps but I am no master mechanic. Good luck!

 

[gamefreakgc]

Still have your old relay? Something went wrong between taking out the old one and putting in the new.

By the way, if the MAF sensor is failing/has failed, then you will never have fuel when cranking it over since it's a safety cutoff if it gives a bad signal/no signal. But you should still have spark.

If you have a multimeter and access to the service manual, there's one resistance value you can check. It's dependent on temperature so you need the service manual specs. If you can't find it I can dig it up for ya.

Fuel pumps don't go bad very much... I know a lot of people end up replacing them but it's rarely the issue.

 

[selfish]

When I dropped the tank, it was spotless, like brand new. That made me think maybe the pump was okay, but since I already had it out no point in not doing it.

I have not considered a short, but I am taking the multimeter over there today, as well as an OBD2 tester.

 

[iowajosh]

Not that this is your problem but if the ground under the diagnostic connector is not hooked up on the intake manifold, it won't run. Crank sensor, same thing. Good luck

 

[selfish]

So I pulled the codes today and it was showing "camshaft position sensor" so I ran to Autozone and picked on up. No change in cranking, so I removed the existing spark plugs to look for spark and they are sparking strong.

After changing the CPS, I unhooked the battery for about 2 minutes, and cleared the codes hoping that maybe the ECU needed to be reset. No help.

We loosened the fuel pressure regulator hose, and fuel came out, so wouldn't that mean gas is getting at least to the fuel rail?

I tested the EFI relay with my multimeter and it was sitting at about 90 ohms.

I forgot to test the MAF while I was there, so I guess that's next. I'm pretty stumped on this. Is there anything else that can shut off fuel?

 

[gamefreakgc]

I recommend getting a PDF copy of the factory service manual and looking up the codes you are getting. Sometimes it's not just a bad sensor, but rather the circuit (wires). Like iowajosh said, the camshaft position sensor will keep the engine from running if the ECU is not getting a signal.

You can try the links at the top in this thread: http://www.toyota-4runner.org/3rd-gen-t4rs/69744-3rd-gen-faq-tutorials-documentation-reference.html.

I recommend not just throwing parts at it anymore and use the CEL light codes as a diagnosis. You know you've got a P0171 and a Camshaft sensor code, so start there.

 

[Red October]

The engine WILL run with no signal from the Cam sensor. (After my recent 3RZ rebuild I completely forgot to plug the Cam sensor in, and I started it and drove it to the alignment shop, and then home from there before I read the codes and found the plug dangling. Crank sensor signal is completely different, the engine will not run without signal from the Crank), still fix it, but it will run without Cam sensor input.

Right now you need to trouble shoot your no spark issue. If you have fuel at the rail you should have fuel to the injectors.

I would still check fuel pressure, if its within spec that will rule out the pump, regulator and other fuel bits (not injectors tho). You can get a node light to check injector pulse.

Using your spark tester check for spark from both coil packs, make sure you are grounding the tester correctly.

If no spark from either coil pack, then you need to check to see if there is a signal to the coil packs. To do this you will need the FSM for the correct precedure.

 

[Red October]

Here is a link to a Diagnostic flow chart for spark on a 3rz-fe, this is for a Prado but the flow chart should still lead you in the right direction.

http://www.moranbahweather.com/toyota/lc_trj12/rm/rm990e/m_18_0001.pdf

 

[kingin]

Are new parts OEM or pep boys stuff???

 

[gamefreakgc]

My bad meant to say crank sensor, not camshaft sensor. I was thinking about my own issues withe the camshaft and got them mixed up.

 

[Red October]

Did you get her running man?

My bad meant to say crank sensor, not camshaft sensor. I was thinking about my own issues withe the camshaft and got them mixed up.

No worries friend, I didn't mean to be rude, just tryin to give good, helpful info.

 

[selfish]

I towed it back to my house last night, working on it once a week was killing me. This weekend I am pulling the MAF out to see if its dirty and testing the crank sensor and grounds, etc.

 

[selfish]

There is most definitely spark, and I pulled and examined all 4 plugs. They were a little moist, but when I put them back and pulled out again they were still dry so I am assuming it was fuel from cranking.

I pulled the MAF off, and it looks different from every one I have seen online, but it is shiny and clean.

 

[selfish]

So I decided to clean the MAF even though it looked good. But, apparently I was looking in the wrong place because as soon as I shot the cleaner in there it cleaned the tiny little wire and now it is definitely shiny.

I next went to test it with my multimeter, and I need some help.

The attached image is my MAF sensor connector, three copper connections and two silver. I can't get an Ohm reading on any of them, all I get is OL. I thought the two silver were supposed to be between 2.2k and 2.9k based on this thread:

http://www.toyota-4runner.org/3rd-gen-t4rs/32558-how-do-you-test-if-maf-ok.html#post274993

I know the meter works, I just replaced the battery and I get the beep and .001 when I touch the leads together.

So, before I run out and buy a $150 MAF sensor, am I testing this thing correctly?

Thanks

david

 

[selfish]

Okay, I got help and I am sure the MAF sensor is testing good for resistance, but I didn't test voltage.

So it still won't start, even with a healthy shot of starter fluid. It just cranks and cranks. I know the plugs are sparking and I know there is fuel to the rail, but I haven't tested injector pulse. (But all 4 are brand new.)

What else is there?

 

[selfish]

I know the plugs are sparking

I don't know anything anymore.

 

[2000 sportrunner]

I am a mechanic and all cars are different, the same symptom can have 5 different potential causes, but my moneys on crank sensor, that it is intermittent, it is difficult to test without an oscilloscope but It can be done with a fluke meter or a multimeter that spits out a/c voltage, the crank signal is a 5v square wave pattern that tells the computer when to fire the injectors and the rpm of the engine, without it nothing will work, ive seen cars where the fuel pump will prime for 5 secs or so when the key is switched on but its up to the crank sensor to tell it to continue to run based off the signal it puts out, that is possibly why you have fuel but it wont fire. no guarantees because internet diagnosing is extremely difficult , have you checked all fuses and relays related to the engine? engine block grounds are good? compression and cam movement( ie chain is turning the cam)