Elusive Starting Problem

Frustrating problem - which with required details and background - is 1,196 words. Not really a very long read. However - I have not been allowed to post the problem. It keeps refusing to show up. (probably because of number of required words.) I need help. Would you please go to: http://skybreeze.com/camry/elusive_starting.pdf and read the short description of what is going on; and then post some help here? Thank you.

1988 Toyota Camry Station Wagon; 3SFE 4 cylinder engine; manual transmission

The post is IMHO excellent.

Honestly, at this point Iā€™d go with the fuel pump. I know the symptoms might not be perfect for it, but itā€™s the only thing left.

+1 to everything @thesamemountainbike said. And you already have a replacement fuel pumpā€¦

Thanks to you both.

I do probably need to replace the pump - ā€œeven though the symptoms might not be perfectā€; because this would eliminate that possibility; and might fix it. Also, the reason I purchased the pump is because of the vehicle mileage; and my on-call job requires reliable transportation. No vehicle excuses allowed. I do wonder about the wiring since I have removed the engine 4 times since I owned the car - (various stuff) and seems easier to replace the timing belt - but the wiring gets moved around a bit when you do thatā€¦

Replacing the pump would remove doubt about it. And I do have it. Again, thanks to you both. If anyone else has some good ideas - please feel free.

Well I have to wonder if the real problem isnā€™t with the fuel pump relay. Even though it seems to work (energize) with your testing procedures you didnā€™t indicate if the fuel pump was really turning on. You can usually hear the pump run for a brief time when you turn to key to the ON position and not try to start the engine. See if you can hear the pump run while it is cold and if you can then try the test when the problem is happening. You could also just replace the relay since it is a pretty simple thing to do and see what happens.

I also have an '88 Toyota daily driver. One problem I had with slow start was fixed after someone gave me a tip. When you go to start it, turn the key to ignition for a few seconds, but donā€™t start it. Thos lets the pump re-pressurize the fuel system. Turn it off for a few seconds, then start it up. If that works, you have a bad check valve in the fuel pump assembly that lets the pressure bleed off. With a 25 yo pump, it may be worn to the point it cannot re-pressurize the system as the injectors open and close. The fuel pump replacement, along with the sock and filter, may fix you right up.

Thanks for those ideas. I hate to say what it is NOT - since obviously I donā€™t know what it IS.

The EFI relay has been replaced; plus the pump system function test (ignition on/short out B+ & FP) diagnostics connection - requires a working EFI relay. And if that were bad - I donā€™t think it would start on compression - and the vehicle would not remain running after starting using ether.

The pump check valveā€¦ I am trained in Hydraulics; but I do not have a fuel system and valves layout for the vehicle. If you would please elaborate a bit more on this - I would appreciate it. I have considered that the check valve is not the problem; because the vehicle will start right up after sitting for hours or days; and will also start up after sitting for 45 minutes after running to the store, etc. Do you still think the check valve might be it??

I should just replace the fuel pump; which I will do as soon as I get a couple of sunny available days. This will remove the possibility of the pump being the culprit.

The pump check valve - unless you have a parts schematic for the fuel pump, you wonā€™t see it. It is inside the fuel pump, and most fuel system schematics only show the pump, not the break down of what is inside it. Replacing the pump is the only way to fix it. Since youā€™re doing the pump anyways, no sense i. Worrying about it.

I assume the EFI relay that was replaced provides power to the fuel pump. If that is correct then I would suggest that the voltage at the fuel pump be checked while the trouble is happening. Since the trouble seems to happen after the car has been running this may be indicating a possible trouble in the wiring to the pump. When the current for the pump heats up the bad wire connection the problem gets worse and the voltage drop across the bad connection goes higher, so less voltage gets to the pump motor to operate it. You already stated that the fuel pressure is on the low side so that may be another clue for this answer to the trouble.

I was aware the check valve was in the pump. Asking more what all symptoms and ā€˜howā€™ it would work to not allow the vehicle to start. Interesting idea on the pump bad wire connection. I will look at it when we replace the pump.

I donā€™t have a garage; and live close to Seattle. It is raining a lot around here right now. When I get a couple of sunny Tue & Wed - I will replace the pump. I will also let everyone know if that is the problem. If it is not - Iā€™m going to give up on it; live with it a bit longer till I acquire more funds; and then take it to a shop who promise they will find the problem and fix it - or no charge. Iā€™m fed up.

Currently, we are thinking that it IS the pump; and partially the check valve. But, I think the check valve in a way that is letting it startā€¦

I have a huge amount of construction, plumbing and yard work to do; and not a lot of funds. Been cutting some trees down; and driving the truck; not a lot of time in the Camry last few days.

As many have noted; check the pump. So, if the check valve is leaking - the pressure slowly drops when the car is not running. Go out to start the car; (pressure is now way down) the pump easily spools up; and voila - the car starts. Now, the system is much more pressurized; and if you go to start it again - the pressure has dropped a bit - but it is harder for the pump to run. Fuel is not flowing as it is when the vehicle is running; pressure is down for a start - but pressure is still also ā€˜upā€™. So the old pump has hard time pumping. (And when you do the fuel pressure tests; you have to bleed off the pressure first before starting the testā€¦)

As was suggested - I have now for a couple of times - got in and turn key on; off; on - off; for a few times. Because right when you turn the key ON - the pump is momentarily pressurized. Then the computer cuts the power to it. By On - off; on-off; a few times - you give the pump a few on cycles. It appears that this has ā€˜solvedā€™ the elusive starting problem. But really, I havenā€™t driven it enough the last few days to know. We have just been moving the car as need be - out of the way.

But right now, I do think it is the pump. Weā€™ll find out when I replace it. That will be just a bit; and I do appreciate the suggestions, interest, and help. Weā€™ll let you know.

And Cougar - your point on heating up connections is well taken. However, I am thinking in this specific situation - this applies more to the pump itself.

As the older pump runs - it gets hotter. (Even surrounded by cooling fuel - all pumps get hotter.) But as my older pump gets hotter - it then becomes even harder for it to pump. We drive somewhere; and then when we go to start up - the pressure is higher; and the pump has a difficult time pressurizing the system. Thatā€™s what I think is going onā€¦ So I definitely think heat has something to do with it; and I will of course look at the wires. When we purchased the pump and tank - we also purchased a New pump holding bracket - since that has new wiring which connects to the pump; and is immersed in gasoline. Because this pump installs into this ā€˜specialā€™ bracket assemblyā€¦ Thanks!

Whoa. Now there is an ugly car. 88 Camry wagon? 25 yr old car? Is the replacement fuel pump used or new? I bet you bought it at a swap meet?

test

Posting trouble. For a ugly car response and a bit of humor, and more info - please go to: http://skybreeze.com/camry/beautifulcar.pdf

Well before you go through the hassle of replacing your tank and fuel pump I suggest you first check out the voltage getting to the pump using a voltmeter and while the trouble is happening. Imagine the surprise if you replace all that and then find out the problem is still there because the actual problem is in the wiring to the pump. Check the simple things first before doing the harder things.

You canā€™t rely on just looking at the wiring and expect to find the trouble necessarily. Sometimes problems like this arenā€™t obvious to the eye but they are to a voltmeter. Doing this test before hand you might just find you save yourself a lot of time and money if the trouble is within the wiring to the pump. So check the voltage at the connector to the pump motor while the trouble happening and pump motor is supposed to be running. It is very important that the wiring has a current load on it if there is a fault in the wiring so a voltage drop will occur across the bad connection and the meter will see the low voltage at the pump. My thinking is you have a better than 75% chance that this is the real cause of the trouble.

Cougar - yes that would be good. Unfortunately, on the S/W - for access to the pump connections, etc. The tank must be removed. Impossible to measure the voltage drop without dropping the tank. On the sedan, you can remove a seat and have access. Not so on the S/W. Also, the actual pump connecting wires are part of a special bracket; and go into the fuel. The outside connector to the bracket has never been disturbed. I would like to do voltage checks first; but this requires dropping the tank. (And then you canā€™t do them.) I will examine the connector closely.

Iā€™m thinking - maybe Iā€™m wrong. Going to check a bit more on the access to the tank/pump connections from the interior.

I see. All this seems so easy while on the keyboard. Well you could try to find a place in the wiring that is accessible to get a reading with the meter, even if you have break into the wire insulation with the meter probes and then patch the small holes. Using pins to access the wires makes for small holes. Use some silicone to cover the hole up when done.

If there a wiring problem chances are that the trouble is at a point that is exposed to the outside environment and that could be at the connector on top of the tank so taking any meter readings before the bad connection point will be meaningless. Hopefully you can find a way to get access to things without having to drop the tank. Thatā€™s a dag-nab-it.

Tilting the seats; under the carpet; access to the fuel sender cover exists. Plus the connectors to the sender and the pump are inside the vehicle under the carpet. With vehicle running, pump voltage at connector is 13.45v - so not much of a voltage drop. That connector is OK. Good idea though. Plus, when I drop the tank - these connectors needed to be disconnected. I possess the FACTORY manual; plus two other manuals for this car. Had to spend a bunch of time in them; my manual from Australia - (has some great photoā€™s/ just can be backwards from US sometimes); was the one which discussed the access for the sender under the carpetā€¦

I guess I could drain the tank this way? Just pull out the sender and stick a hose into the tankā€¦ It has an anti-siphon system from the fuel door to the tank. Or just drive it for a week; and maybe it will stop raining.

For the voltage test to be valid the trouble has be occurring. If the trouble is happening and you still see the same voltage then the wiring to the pump isnā€™t a problem.

If I was working on this I would tap into the pump wires and run a lead to the front area where I could watch the voltage getting to the pump motor and hopefully catch the trouble when it occurs. It is a very good thing to have the factory service manual. You were wise in getting it and well worth the extra cost over a regular manual.