BajaRunner

OK this might be my last post, and if I can't figure out whats going on, I gotta bring it to a frigging mechanic.

Basically, I've had a misfire since I bought the truck about 7 weeks ago. I've pretty much gone through everything 2-3 times.

Everything being:
Replaced TPS, AFM, O2 sensor, intake gaskets, all vacuum hoses, all ignition components (plugs, cap, rotor, wires) and cat ($), remanned injectors
Tested: ECT, all VSV's, timing (x 10) (mechanical and electrical), compression (160 across board), valve clearance, fuel pressure
Somewhat new (within last 4k miles): Head, valves, camshaft, fuel filter, raditor, water pump, alternator, etc...
Cleaned entire EGR system, blocked it off, etc.

I've ran seafoam 2 times through intake, through the gas tank, used 3 other types of fuel cleaner.

I've checked all vacuum hoses with an unlit propane torch, water, carb cleaner, you name it.

I feel that the engine is being starved for fuel. Either through unmetered air or lack of fuel delivery. Open loop startup/warmup power is much better (I feel the increased richness of ECU helps that). O2 sensor being connected helps as well. I feel that fuel pressure is good, but I haven't found anyone able to measure it for me. I know this is something I will be doing ASAP.

I've driven other 22re engines and they have much better torque and power. Any ideas/tests weird things you've encountered that caused a misfire would be greatly appreciated. I am sorry for all the posts, but I'm starting to freak out. Thanks

Update as of 9/20/2010
I've tested fuel pressure and I have also sent my injectors out. Both of which have not fixed my issue.

whokrz

Coil
Little box that sits on top of the col (forgot the name)
Is the distributor installed correctly? If it is a tooth off it can run like crap.
Is the timing chain a tooth off?
After that in the FSM there are flow charts for the MFI, make sure it is getting the correct information.
Here is the beginning of it http://ncttora.com/fsm/1990-1995_4Rn...e/troubles.pdf
Here is the FSM for the 95 http://ncttora.com/fsm/1990-1995_4Rn...es/repair.html

After that I would try a larger hammer.

BajaRunner

AAAAAhhahahahahahah! I love the hammer part!

Well, for all that I know, the distributor looks like its installed correctly. I am at 5* (when jumpered) and the distributor is right at the halfway mark of adjustment.

And wow, I guess I could go to town with a multimeter ... damn thats some troubleshooting crazyness. If it has to come down to that, I guess I can start...wow.

whokrz

Testing the MFI should eliminate components and wires. Its a pain but worth a try.

I had a misfire with my girlfriends 4runner that would start 2500rpm+ It turned out to be the new napa plug wires and what ever plug they gave me. I replaced them with the NGK wires and plugs which fixed the problem.

On my truck I had a tear in the hose that runs from the air flow meter and the throttle body. This unmetered air caused a misfire because of the, a 400-500rpm idle and a huge loss of power. It was misfiring due to a lean condition.

LifterCatcher

Have you checked the fuel pressure?

You can buy or even rent a fuel pressure tester that connects to the valve on your fuel rail. It also sounds to me you are having fuel issues.

Here is what the tester looks like they are about $30.00



Chris

myyota

Have you had the injectors cleaned ?, that would cause the problems your having if there plugged.

BajaRunner

You guys are correct, the only thing left is the fuel system. I keep getting denied trying to do anything though with it. Why? Cause my buddy who is a 20 year mechanic keeps telling me its NOT the fuel system.

So rather than trying to find someone to do the fuel pressure for me I guess I'll have to try and track down a banjo fitting for the CSI. I know its been posted on the forum before by Sr5Walker. Its made by Acron or something.

Also I know the fuel filter was recently replaced with an OEM filter. I remember reading somewhere that people run into problems installing them. Is this true? This was replaced by the PO so I might just go ahead and change to get it out of my mind.

Looks like next week I'll go ahead and pull the injectors and send them out. I was thinking that if the system was being starved for fuel, wouldn't the CEL come on saying its running lean? I am still unsure on how to read the output voltage from the O2 sensor. I know stoichiometric is read at .45V. Do I read this off of VF1 @ 2500 RPM? I know the voltages oscillate but my multimeter is digital and the resolution might not be able to read it correctly.

myyota

I just thought of something that you might try. There is a vacuum line on the fuel presure regulator and the vacuum line runs to a vsv and then to the intake manifold, take the vacuum line off of the intake manifold and run the vacuum line from the fuel presure regulator to the intake were the vsv was connected, and see if that makes a difference. I have the the fuel presure regulator on my 4Runner hooked up this way.

Flash319

I have had coils crack. Run it at night and see if you are getting arcs anywhere. I have also had bad grounding of the wires that ground to the intake manifold (1st to second section). They are 3 red wires that are crimped together to a ring connector. If they come loose you get a mis-fire condition.

sb5walker

Here are the posts on the fuel pressure tester you referred to: https://www.yotatech.com/forums/f116.../#post51210586
http://www.toyotanation.com/forum/sh...76#post3022876

Fuel is not the only thing left. There are other possibilities. For starters, I don't see a mention of codes. Maybe you posted about them in another thread, but have you checked?

Even if you have good fuel pressure, there are several areas where trouble could cause the ecu to not fire the injectors, or to fire them intermittently.

• I'd check resistance and air gap of the signal coil in the distrib. http://personal.utulsa.edu/~nathan-b.../4onvehicl.pdf
• Also try wiggling distrib's rotor shaft side-to-side. There should be no slop.
• Clean up the igniter ground (mounting bolts).
• Check the coil, as mentioned. Best to do it when hot, using the hot specs: http://personal.utulsa.edu/~nathan-b.../4onvehicl.pdf
• Check the ecu's grounds, especially engine & sensor grounds. Look for close to zero ohms resistance between ecu terminal E1 and a good chassis ground. Between E01&E02 and the engine block & head. Between chassis & neg batt post, and between engine block & head and neg batt post. E2, the sensor ground, is best checked by looking for continuity between ecu terminal E2 and the E2 terminals on a few sensors. The E2 wires are brown with black stripe. You could tap into E2 terminals on the harness side of the connectors to the tps, air meter, engine coolant temp sensor. You can use jumper cables if you don't have a long test lead.
• If the EFI Main Relay were failing, it could cause ecu power to be intermittent and cause stumbling. To eliminate that as a possibility, jump from positive batt post to +B in the check connector (running through a 15 A fuse would be safest - you could tap into the relay side of the EFI fuse in the fuse/relay block instead of tapping the positive batt post)
• Check that the high tension wire from coil to distrib is not shorting on something
• If ignition switch were failing, it could cause interruptions in power to coil & igniter, or to the injectors, either one of which could cause the symptoms mentioned. You could try jumping power direct to positive terminal of coil, which will feed igniter and injectors too.
• If IGF had a bad connection between igniter & ecu, that would cut off the injectors, but you'd get a code 14 if that was happening
• If you still don't find anything & fuel pressure is good, I would start backprobing ecu terminals when ignition was on. Target volts are in the efi troubleshooting section: http://personal.utulsa.edu/~nathan-b...27troubles.pdf
• Could be a bad igniter, but unlikely

There must be other possible trouble areas, but those come to mind at the moment. Hang in there & keep checking, you'll find it eventually. There are a finite number of things that could be wrong.

BajaRunner

Hmm well I thought this was a little strange. I pulled the vacuum line off the top of the throttle body that goes to the VSV that goes to the F.P.R. I put it to the top of the fuel pressure regulator. However, there was absolutely no vacuum coming from the line. I checked with my gauge. I revved the engine, and no vacuum. Whats up with that? I thought the 4 ports on the top would have vacuum. :/

I have a strong vacuum coming from the back of the intake plenum, I think its the pressure regulator. (3 ports, 1 is plugged).

Another interesting vacuum related issue is that when I pull the hose off from the PCV valve, the engine dies. I don't remember that happening before on other vehicles.

BajaRunner

I will try that tonight. I've heard of this before. The igniter is definetly suspect because all the wires coming from it look pretty old.

BajaRunner

So anyone feel that its a little weird when I pull my PCV hose off the valve the truck dies? This can't be normal. I know its supposed to run like crap, but I've never had a car die instantly.

myyota

Its not really weird that the truck dies, with the hose off your creating a large vacuum leak, so the truck is either going to run real ruff or its going to die.

tim a.

My truck dies when I pull the pcv hose.I think I asked if you checked the fuel pressure regulator a couple of weeks ago in your first few posts on your high nox failure.....

BajaRunner

So the front port on top of the throttle body....Does that only open on WOT? That is the one that eventually leads to the fuel pressure regulator, correct?

Does the fuel pressure regulator have highest pressure at 0 vacuum or full vacuum?

I ran the truck last night looking for arcs. It was pretty much black outside, and I stuck my face in there and didn't see any. I'm still wondering about the igniter. Its sort of suspect. I cleaned off the grounds (mounting bolts).

84foyota

Ok, I will do my best to help diagnos your issue but I could use a better description of the "miss fire". Does it happen at idle or under load? At what RPM does the truck mis fire? If you can answer these two simple questions we a group might have better luck narrowing the search.

If it's missing at idle then we need to suspect things like injectors or valve that not seating properly.

If it's missing under load when your accelerating then it's most likely ignition related.

Fuel pressure is controlled by "Ported" vacoume which will only be present under heavy load or high speed. The vacoume line for the pressure regulator should come from the throttle body.

Keep your head up....it's most likely somthing simple. From experience you can often introduce somthing like this by simply replacing parts with new parts. I've often found a mis in vehicles after replacing spark plugs with brand new ones. Just because it's new does not meen it works as it supposed to. Defects are very prevelent in some brands. Take out the plugs and check the colour and condition. This will help you narrow the search to a single cylinder if the miss is bad enough and related to a single failure of secondary systems.

BajaRunner

Thanks 84foyota.

Sorry I have had so many threads I have forgot to put in some information.

The miss is heard under only at idle. However, I can feel the miss/lack of power under load. The miss increases with RPM.

I have also noticed a "hard start". As in, the starter is working great, but it takes a few times for the engine to turn over. Once it does, it sounds sorta rough, then it smooths out. Possibly a leaking injector?

I just went out to try and look for a banjo bolt to work with a fuel pressure gauge without any luck. The only Toyota mechanic in the area told me something about "getting the fuel pressure is a pia on these trucks"...whatever, I wont be going back there. Has anyone bought the M8x1.0 Banjo fitting to work in the CSI to pull the fuel pressure!?

Also I forgot to mention that the truck runs better (not perfect) when I disconnect the o2 sensor wiring harness. I feel that its just richening the mixture and making it run better.

Here's a video I took you can hear from the exhaust.


Here's the photos of the spark plugs I just removed out last night to check. They are NGK, maybe I need to replace them just in case?

sb5walker

Those plugs look good, it looks like mixture is good in all of them, except POSSIBLY the last one is running a bit lean (clogged injector?) but that's not certain. You could tell after running the plug for more miles. Also it looks like you're getting a bit of oil into that last one. Probably a leaking valve stem seal, possibly rings but if your compression is even it's probably not the rings.

Vacuum to the fuel pressure regulator should only be applied at idle, and only when hot, I believe. The effect of the vacuum is to lower fuel pressure by 5-7 psi. It's controlled by the fuel pressure vsv which is controlled by the computer. So just make sure there is no vacuum on that hose when motor is hot and above 1500 rpm or so. If there IS vacuum at higher rpm, probably the vacuum hoses are misrouted. I think I read somewhere that 4Crawler just disconnected and plugged that vac hose so the fuel pressure is not reduced at idle, and he said it worked fine.

When I mentioned checking ecu grounds, I was referring to the terminals on the ecu, not in the check connector (although I think the E1 ground is in the check connector - but the others are not). Pull the cover off the passenger kick, and probe the ecu terminals themselves. If you don't have backprobe adapters for your multimeter test leads, you can push steel needles into the backs of the connectors and hold the test leads against them.

I would try a new coil long before suspecting the igniter.

Did you check for codes? Check the signal coil resistance & air gap?

BajaRunner

The oily residue is from me using anti seize on the plugs. :/ The stuff leaked down onto them a little bit. At least I'm pretty sure thats what its from.

Ok, the port on the top of the TB had no vacuum at idle nor at higher RPM. This is taking me just sticking my vac gauge right to the steel tube on the TB. Didn't seem clogged, I could blow into it through a hose w/o problems.

OK the ECU grounds ... I'll try that.

I'm going to go rent a fuel pressure gauge right now, the guy said it comes with Banjo fittings but we'll see.

I double checked for codes, and the light just blinks every second...So no stored codes. Air gap "looked" good. Didn't use a feeler gauge. I tested resistance a few weeks ago and remember it was in spec. I will try again.

Thank you for your support.