When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Sorry for this long story. Hopefully some intelligent person out there is also very patient, because I want to share as much info as I can. My son parked the car one day without issue, and the next day it would not start. Battery voltage is ok & terminals clean. I tried to jump start and it did not help. Starter cranks consistently, as I would expect it to, but car won't turn over. Can I assume starter is OK, just based on that sound? The answer to that may be key here, based on the other things I have now tried. But I assumed starter is good. Spark is ok so I moved to fuel.
I could NOT hear fuel pump engage when ignition turned to "ON". So I shorted the diag connector "B" and "FP" pins. When I do that, I CAN hear fuel pump run constantly when ignition is "ON". But even then, the car does not start.
CIRCUIT OPENING RELAY CHECK:
I had trouble probing "circuit opening relay" while it was installed, but I probed for expected voltages at it's connector after it was removed (when ignition turned "ON). With relay REMOVED, I also (1) verified relay continuity, and (2) Manually engaged the relay, by applying 12VDC. Those checked OK based on service manual info.
One issue I noted was seeing only 10VDC across "ST" and "E1" at circuit opening relay--when IGN turned "ON". I don't remember if that was with relay installed or probing the mating connector wires when relay removed. I will recheck this but I suspect it's related to my problem. I checked E1 and it has a good ground connection. So it seems something upstream of "ST" wire, towards starter or related starter relays would be suspect. (I did check starter relay by manually engaging it when removed from car. But I don't see the value since starter sounds like it's trying to crank the car.
FUEL PRESSURE:
I hoped I could temporarily drive the car with those 2 diag pins ("B" and "FP") shorted, while I tried to find the source of the problem. So I checked fuel pressure when I short the "B" and "FP" pins: When IGN set to "ON" (engine off), I have 0 psi at cold start injector. So i moved pressure gauge to fuel filter output and 0 psi there also.
[At this point I wondered if I was using fuel gauge & fittings properly since I had never used a fuel pressure gauge before. But I connected it to another car and it works fine. ]
Fuel filter has never been changed so I was going to change it anyway. I removed filter and put a hose over fuel line. I set ignition switch to ON and pumped a few ounces of fuel into a container. So pump is pushing fuel to a small degree (with "B" & "FP" diag pins shorted). I figured maybe fuel pump was just not strong enough to pump a pressurized system, so I replaced it, plus fuel filter and the small strainer/pad that is on the input side of fuel pump.
Do I need to bleed air out of the fuel system after fuel filter and pump replacement--and before trying to measure fuel pressure? The fuel gauge has a bleed off valve that I thought I could use for this. But I don't think there is any pressure there anyway. So nothing came out. Plus gauge shows 0 psi at output of new fuel filter.
I clearly am missing something. I thought power to fuel pump, and a good pump, was the ONLY requirement to establish fuel pressure at fuel filter--since that is upstream of basically all other fuel system components. I think nothing but fuel line is between fuel filter and fuel pump...and most or all of that line is metal.
Can somebody shed some light on this for me? Thanks very much in advance.
(As a sidenote, the ECM and volume air flow meter are not related to the starting problem. I checked by substituting an alternate ECM and also continuity tested the volume air flow meter)
Do you have a shop manual or other data to reference?
Does the engine turn over at normal speed?
Check battery voltage at battery. Battery having rested for 30 minutes. A reading of 12.6V is charged. Something below 12.1V is charge low.
If the engine has good spark the ign should be OK. Good spark is blue or white in color and the ability to gap 1 inch of air.
It is rare but has happened the timing belt "jumps" a tooth. The result is spark but at the wrong time.
Jumping the FP/B pins will bypass all relay and power the pump directly.
Normally the pump will only run when the engine is cranking over or running.
There is no fuel pressure? Did you tap into the fuel line coming from the pump?
The fuel system is return flow. The fuel pump sends the fuel to a pulse damper, then to the fuel rails. From here it goes to the fuel pressure regulator, then back to the tank.
The fuel system needs to be closed, then pressure tapped to get an accurate pressure reading.
The pressure should be 33-37 psi with pressure regulator vacuum hosed connected and 38-44 psi disconnected. The pressure regulator responds to engine vacuum.
You need to tap into the fuel line with a bango or other fitting. This is done at the cold start injector fuel fitting. The injector is pressured when fuel pump is running. A valve turns the injector on/off.
Since the fuel system is closed loop, it will push out any air to the fuel tank.
IF zero pressure, the fuel pressure regulator could have failed open (rare) or the fuel is bad (more common).
What is the outside air temperature. The engine has a cold start injector. This injects fuel into the intake manifold when engine is cold. If air temps are cold and engine cold, hard starting is possible.
The circuit opening relay and circuit is complicated. Not sure what voltage check points you are referencing.
The is only one "hot" wire (battery voltage) at the relay when the ign switch is on. This is for the actual relay switch then when closed powers the fuel pump relay power switch.
This wire should have battery voltage. This wire also powers the injectors and host of other circuits when ign switch on (color is supposed to be black/orange).
Thanks for the response, toyomoho. I do have a Haynes service manual.
Related to your other question/comment, the (Autozone loaner) fuel pressure gauge kit has several adapters--including a banjo fitting adapter so I am able to measure pressure "in-line" with full system pressurized--at either cold start injector or output of fuel filter. Already had the gauge connected at fuel filter output since yesterday. So with ignition switched to "ON" I rechecked.
Still saw 0 psi on gauge.
In frustration I planned to move the gauge to cold start injector location (yet again). But as I began to loosen that banjo bolt, a tiny squirt of gas shot about 5-7 feet. I almost got an unpleasant eye wash from that. So pressure was certainly there. I abandoned the gauge at that point and just tightened that bolt again.
When I look at the fuel gauge fittings I see the banjo adapter has a Schrader valve on the threaded end that the pressure gauge (with it's pre-connected hose) screws onto. But there's nothing in that hose to depress that Schrader valve. Surely something must push the valve in, on banjo adapter, to allow fuel to flow to pressurize the hose and gauge? It's a used "loaner" set from Autozone. Maybe somebody returned it broken and they didn't notice? Here's a picture of the 2 parts that get screwed into one another.
Left fitting fits banjo on bottom side and screws into fuel filter. Right fitting screws onto top of left one, and has pressure gauge at other end.
But your comment about the closed loop fuel system (return line to tank) was helpful. Based on that, I loosened gas cap and engaged fuel pump for about 20-30 seconds--to ensure fuel moved through full system and air was able to evacuate back through to tank. Then I tried to start and this time it did. So thanks a bunch!
I am thrilled to have it start. Unfortunately it seems to be running really rich--with a decent amount of white smoke from exhaust. I removed the shorting wire that connected "B" to "FP" and the car did not quit, so that's good. I had my son drive it about 1 mile around the neighborhood. it doesn't sound like engine is 'missing' but does sound slightly different than it used to.
If a clogged fuel filter was the cause of the 'no start' issue, could the ECM now be trying to adjust to a fuel pressure change, and maybe the rich running issue will be automatically resolved after a few miles--once ECM adjusts?
I removed the cold start injector, thinking maybe it was "stuck open" and causing the run rich condition. But it measures 3.3 ohms across the 2 pins-- where 2-4 ohms = good. I will clean it and reinstall, then check. It appears there are some related things I need to check:
- Cold start injector time switch
- Engine coolant temp sensor
- 2 "VSV" valves--near fuel rail. The one nearest fuel pressure regulator measures out of spec (43 ohms when it should measure 30-40 ohms). But without ability to use fuel gauge I can't follow the service manual procedure to check it's full functionality.
Any thoughts? Am I sounding ridiculous about the fuel pressure gauge or is it truly missing a part inside end of hose? It would be nice to have that working to further diagnose the "VSV" valve that's related to fuel pressure.
My mistake in not warning you about the system being pressurized.
If you can get the pressure gauge to work, this would aid in quicker diagnostics.
Would assume the Schrader valve should unscrew from the gauge body. It does with any other installation such as a tire stem.
There is a special very low cost "valve stem" removal tool available from stores that sell tires, tubes and repair products. Department stores, bike stores, and of course auto parts stores.
The valve is used in all kinds of tubeless valve stems and tubes for cars, bikes, wheelbarrows, trailers, etc.
Can also try needle nose pliers.
In a pinch have also inserted a small bolt, rivet, etc between the hose fitting that screws onto the valve and the needle of the Schrader valve. This inserted item then presses against the needle valve when the fitting is screwed on to open the valve.
The engine now starts which is good. Would expect white smoke at start up as excess fuel cleans out.
A plugged fuel filter tends to result in less engine power. This shows up when trying to accelerate, go up hills, sometimes if bad enough even up over curbs. Unless very plugged the engine typically starts and idles OK.
Toyota canned type filters seldom plug up much less to the point of the engine not starting. If the engine has good power the filter should be OK.
The fuel pressure regulator is solely mechanical. It has a valve controlled by a diaphragm that reacts to engine manifold pressure.
There is a computer controlled on/off valve (VSV) for the vacuum line that goes to the manifold. There is no computer control of the valve beyond this valve being on/off.
Would assume the VSV is off when engine cold? This to increase fuel pressure which should enrich the fuel mixture. The computer uses the coolant temperature sensor (ETC) to know when to turn the VSV off/on.
The service manuals functional test method for the cold start injector it to remove it from the engine. Then connect it to the can fuel filter via a special hose.
The fuel pump wiring is then jumped and the injector electrical plug powered by 12V. The test is for flow with valve on and leakage with valve off.
It may be possible to unbolt the valve from the engine but leave the fuel line attached for easier test. Then route the fuel into a can.
Jump the pump then turn on ign key. Power the injector to check for fuel flow then depower and check for leakage.
Suggest here you try to remotely power the injector to avoid any possibility of arcing at the injector electrical terminals as you power the valve with gas in the area.
The injector has a combination coolant temp sensor/timer. This item turns the injector on when coolant is cold and keeps the injector on for a prescribed time period.
Yes, the resistance between injector electrical terminals is supposed to be 2-4 ohms.
The VSV can also be functionally tested by applying 12v and checking for valve on/off and leakage.
The timer can be tested via a volt meter to replace the injector. The timer should only operate for a short period of time.
Based on past experience. Speculate the issue may be the cold start injector system. Perhaps a bad timer.
Get the gauge to work. Then run the pressure checks with pressure regulator working and not per shop manual.
Check for leak down with engine off. The system should hold pressure for a prescribed amount of time once the pump is off.
If the engine starts and runs but sounds different. Try unplugging the electrical power to the cold start injector to determine if it runs better.
No. I should have realized the system was under pressure, because I was intentionally relieving pressure each time I would loosen gas gap in past days--out of paranoia between starting attempts. The 0 psi reading on fuel gauge somehow had me thinking differently.
Anyway, your comments about clogged fuel filter and loss of power are interesting. I noticed a few months back back it seemed to lack the acceleration it used to have--what I remember from when I drove it as a daily car. In fact I did a simple wipedown of deposits in throttle intake 3 months ago, thinking maybe the (butterfly?) valve was sticking and causing sluggish behavior when trying to accelerate. It wasn't that dirty and the effort did not help. Now I am wondering if a slow buildup of sediment in fuel filter was the cause. It has also stalled about once every few weeks, always at a stoplight. But it starts right up again so with all my other issues I tended to forget about it. When I removed fuel filter, I shook it up and then dumped black, sooty-looking fuel out of the input side of it. So maybe that was indeed the cause of the issue.
Either way, I need to resovle the running rich issue (and white smoke from exhaust). I will try to remove the Schrader valve in brass fitting (or force it in) as you suggest and get some accurate pressure readings.
I was not able to do much today, due to work and darkness (garage not available). I did clean the cold start injector and remove both VSV valves. I checked valves on bench and they both function ok when forcing air while electrically switching on/off. The fuel pressure VSV measures 43.2 ohms across pins when disconnected. Haynes manual says it should be 30-40 ohms, but an online service manual for 3VZ-FE engine shows 30-50, so I am ok with that.
if I have a problem getting fuel pressure readings, I may fall back to simpler option and dump some fuel injector cleaner into gas tank just to see if maybe those are fouled and causing the issue. Plus I haven't done a true test of cold start injector as you say. But I am paranoid to test it in car considering the fuel mess I have already made under the hood and on driveway. Maybe I will re-install it just see if it behaves differently--with and without connector installed.
More to come when I know more. And thanks again, Joey.
The throttle action is mechanical via a cable. It does route through the cruise control box. Have someone press on the gas pedal as you watch the action at the throttle plate pulley.
For idle/stall issues try cleaning IAC valve in the throttle body. Look at bottom the throttle body intake barrel for rectangle slots.
One slot is located before the throttle plate and the other after. The valve regulates bypass air flow around the plate post plate ports to adjust idle.
The internet has lots of posts on cleaning an IAC valve. Use a cleaner safe for plastics of which the valve is made (not brake cleaner). Spray barrel and use a tooth brush to scrub it.
Might try changing the can filter. Caution the steel fuel line can be VERY tight. Best to use a tube wrench to help prevent rounding of the tube fitting flats.
Best to get a pressure reading to eliminate fuel pump issues.
The ohm reading on the VSV is not exact. It's just an electric solenoid valve, either on or off. The valve can also fail in the open or closed position.
More good info...this has become my browser "home page". I am taking notes and they are starting to stack up now
I bought some fuel injector cleaner and am going to put it in the tank in about 30 miles when tank is almost empty. Between the fact that the fuel in tank has been there a month (as I work on car), plus whatever may have crept through system as I had fuel filter off between changeout, I am hoping that may help some. Was thinking about the quality of fuel and realized for a handful of days in past 2 wks I have left the fuel line open/disconnected at some location or another--namely banjo fitting on cold start injector or input to fuel filter. One of those days an estimated quart of gas dripped out at fuel filter location due about a 25-30 degree rise in outside air temperature on a warm day. It must have increased air pressure in tank and gas seeped out of line while I was at work. (I caught half of it in a container but never guessed so much could have flowed out).
Likewise when nights were getting cold again, I am sure some condensation must have gotten into the system. So I added a bottle of fuel line water remover to talk.
I started the car to take a test drive and see no white exhaust smoke nor signs of it running overly rich. So I think cleaning the cold start injector must have helped.
I was about to close the hood & take a test drive, but heard popping sounds.
The main wire from coil to distributor cap was arcing badly--in 2 diff places. I rotated it 180 degrees at distributor cap side, to guide it away from most of the other components it was arcing to. No more arcs right now, but I obviously need to replace it. I had an overhaul done (water pump, timing belt, gaskets, plugs, plug wires, ...) about 6 years ago. By the look of them, I'd bet the normal plug wires were changed at that time. But unsure with this one as there's some spiral plastic wrap around it. it's more beat up than the others--and pinched by a little clip that it slides into, off the air intake, to secure it. Anyway, I placed an online order for plug wires tonight.
It seemed ok so I drove it a few miles and it ran ok...not a lot of acceleration as we have discussed. But same as in past several months.
Knowing main plug wire had issues, I checked spark at 1 plug and it's orange, not blue like you said it should be. Hopefully new plug wires will help that. (note: I had already installed a new distributor cap and rotor in the past several months). Could the poor plug wire insulation be the reason there's not much pep/acceleration, and or the reason this car has run rich (inefficient) in the past several months?
Based on all this I think the fuel problem may be licked. But I will try to check with pressure measurements while I wait for plugs to arrive in mail. I will also have time to look at IAC you mentioned.
This IAC reminds me of another adjustment activity on this car that I tried but knew nothing about. About 2 years ago, I was dorking around with something related to a throttle stop screw. I have no memory of why. Maybe it was for a lack of acceleration or abnormal idle. But I remember trying to follow service manual and starting to adjust the gap and realizing manual said to "...apply vacuum.." Well i didn't have a tool to do that with. So I just tried to guess where it used to be and put it back. I probably moved it incorrectly. Maybe I will review that again and buy a vacuum tool, in case I have created a minor issue there.
Sorry for my rambling. A lot of seemingly unrelated things going on, which is weird.
I will try to start on the list of items you mentioned. Probably won't be able to work on it tomorrow. So will likely be weekend before I can repost with any updates.
Joey and others....I greatly apologize for the long delay in responding. Between work & personal travel, + other home and car problems I have not done anything on this. After changing only the main plug wire from coil to center of distributor cap, the car runs reliably. I know should install the others but the ones on the back side of engine block look like a real hassle. I think I'll cause more problems than I fix until I have time to do it correctly. And since they appear to be in decent shape I'm waiting on that for awhile.
I am still due to check idle air control, as you have suggested. I need to get on that one, based on symptoms that are left. Possibly directly related to that is 1 main issue outstanding--surging at idle, whether engine is hot or cold. At idle, RPMs surge between ~ 900-1000 RPMs in a very consistent manner, every second or so. Unsure if forum allows this, but here's a short video clip showing tachometer: https://photos.app.goo.gl/TPUeTx8FkGbwbT883
Normally when I turn on the AC the surging stops, and idle goes to about a steady 950 or almost 1000 RPM. However I saw in one instance starting the AC stopped the surging idle only momentarily, and then it began again.
So I will recheck your past suggestions that may be related to this idle issue and hope to look at this in a week or so. If something else jumps out at you please feel free to share. Thanks again.
03-25-2018, 09:24 PM
92 Camry V6 (3VZ-FE) - Won't Start - No Fuel Pressure
