Fuel Pump Check

[brentskibikeski]

I'm having an issue with getting my Tercel to start. Battery and Alternator are fine and I've gone through and checked for vacuum leaks, I'm fairly confident this isn't the issue. Next I'd like to check the Fuel Pump.

Going through #7 on this page: https://tercel4wd.com/forums/viewtopic.php?f=4&t=7442

Does anyone have a helpful video or step-by-step of how to preform the check on the fuel pump?

[jimcrazy]

take the top off the air breather and have a look down in the carb while giving gas cable a couple of pumps to see if there is a stream of fuel going in, do this with the motor not running, the little pump on the carb may be bad

[Petros]

you need to do a systematic check starting with the basics, if the engine cranks but will not start there are basicly two reasons: either no fuel, or no spark (or spark at the wrong time). Also, you recently were under the hood replacing parts or doing other maintenance, double check you got everything put back in the correct place, everything is plugged in correctly, etc.

Here is the order which I look for problems it it will not start: fastest test for spark is to take a spark plug wire off and put a screw driver, or large nail or some other metal conductor in it, and hold it about a 1/4 inch (6 mm) away from a metal part of the engine while someone cranks it (do not touch the exposed metal, you could get zapped!). You should get a strong whitish bluish spark that goes "snap!snap!snap!" as the engine cranks. If it is non-existent, weak or intermittent, and yellow, than you have may have an ignition problem (bad coil, bad sendor or pick-up, bad ignitor). Note that if there is no spark at all, it might be possible that the timing belt broke and the cam shaft is not turning (which drives the distributor, so if it does not turn you will get no spark). if this happens usually the engine will spin faster and unevenly because you are not building up pressure in the cylinders because the valves are not operating. You will also get no fuel either because the fuel pump is driven by the cam shaft. to verify if the cam is not turning if you suspect this issue, pull off the distributor cap (3 8 mm screws), or the valve cover or timing belt front cover, and crank it briefly to see if the dist rotor is turning, or with the valve cover off, the cam shaft is turning or not.

if you have a strong regular spark than likely you have no fuel. You can check this by doing one or more of the following: clean off the glass window on the front of the carb and see if you can see a fuel level line across the viewing port. If it looks dry, pull off the air filter assembly and than hold the choke open, shine a flash light down the carb and than crank over the throttle by hand, you should get a strong stream of fuel squiring down the carb barrel, if not could be no fuel. A final verification that it is no fuel supply is to spray some starting fluid down the carb (a short burst of about 2 to 3 seconds), and than crank the engine. If it starts momentarily and than dies off, it means spark is good, timing is good enough, and there is no fuel.

If no fuel, it could be leaky fuel line ahead of the fuel pump (it will suck air rather than fuel, and not leak much since this is the suction part of the fuel line), a plugged fuel filter, or bad fuel pump. Also slight chance that fuel pick up screen in the fuel tank is plugged with debris.

to test if fuel line is bad or leaky, and fuel pump is good, I run a length of fuel line from the fuel pump input line into a fuel can full of good fuel. if it will run off the fuel can, you have a leaky fuel line, bad fuel filter, or plugged fuel intake inside the tank. If it will not run off the fuel can, try running an extra length of fuel line off the fuel pump output into a fuel can and crank the engine. if you do not get a strong stream of fuel pumping into the can from the output line, than you have a bad fuel pump. The fuel pumps are very durable and long lived, but they do go bad occasionally. To verify the fuel pump is bad you will need a fuel pressure gauge (cheap to buy, or you can rent one for free from any Autozone and most Oreiley's auto parts store), put it on and it should show 2-3 psi when you crank the engine. No fuel pressure, the fuel pump is bad, replace it.

If you have spark and have good fuel supply, it is possible that the spark timing is off due to several factors: timing belt skipped a few teeth (you have to pull off the front timing cover and check the cam timing marks against the TDC mark on the crank shaft pulley), or it could be the timing gear or timing shaft on the distribuor somehow skipped or broke so it will not deliver the spark at the correct time. Both of these can be checked with a timing light (also from rental from auto parts stores if you do not have one), you will have to crank the engine and point the timing light at the timing mark to see where it is firing. It will usually start if it is within aobut + or - 10 to 15 degrees, if it is way off (or you can not see the timing mark at all), likely timing belt skipped.

check it all out, and get back with us.

good luck.

[brentskibikeski]

Fuel flows up to the fuel filter no issues. I've added fuel directly to the Carb and nothing. Would spraying starting fluid make a difference?

As far as spark it seemed like 2, 3 & 4 weren't firing properly. I've replaced the ignition coil, distributor cap and spark plugs. I'm going to check for spark again soon.

As far as the timing belt goes it is at least on, not sure if it's on correctly.


Once the sun is up tomorrow I'll take another stab at it and let you know what happens. Thanks for the help!

[brentskibikeski]

Used Starter Fluid, New Distributer Rotor, New Spark Plug wires and gave it a boost. Still nothing.

Tomorrow is another day I suppose.

[dlb]

brentskibikeski, can you give us more info? specifically, i'm wondering

- did this starting problem begin suddenly or gradually?
- was any work done right before this problem started?
- is the engine cranking but not firing, cranking and sputtering, or cranking, firing, then dying?

at this point i'm leaning towards something with the distributor. check to make sure it is plugged in, and that all the wires are in good condidtion. do you have a spare dizzy you can swap in to test? you will also need a timing light if you do that.

[xirdneh]

if you pour gas in carb and it does not fire
you do not have spark or timing is way off
if timing is off a little or plug wires crossed it should fire once in a while

[irowiki]

Does RPM go up when you crank or does it stay at zero?

If it stays at zero, your distributor is at fault. Check timing belt to make sure, then check distributor, ESPECIALLY the wiring going into it.

[brentskibikeski]

brentskibikeski, can you give us more info? specifically, i'm wondering

- did this starting problem begin suddenly or gradually?
- was any work done right before this problem started?
- is the engine cranking but not firing, cranking and sputtering, or cranking, firing, then dying?

at this point i'm leaning towards something with the distributor. check to make sure it is plugged in, and that all the wires are in good condidtion. do you have a spare dizzy you can swap in to test? you will also need a timing light if you do that.

I did some work on the cooling system and it started to stall if I didn't rev the RPMs, it did this for two days. I then changed the oil and it wouldn't start after that. The engine cranks but it doesn't fire up.

[irowiki]

That doesn't really help us help you solve your problem. The cooling system has nothing to do with how the car starts, and changing the oil shouldn't do anything either, unless you cut (broke) some wires or created a short somewhere.

Read my post above yours. Actually, do you have a SR5 or a DLX?

[brentskibikeski]

That doesn't really help us help you solve your problem. The cooling system has nothing to do with how the car starts, and changing the oil shouldn't do anything either, unless you cut (broke) some wires or created a short somewhere.

Read my post above yours. Actually, do you have a SR5 or a DLX?

@dlb asked if I had done any work..I'm not sure how to answer your question about RPMs, the engine doesn't start and theirs no tach.

It's an 85 DLX

[irowiki]

Yeah that's why I amended my question. Might be worth seeing if you can pick up a tach to hook up to the diagnostic lead (the capped plug coming out of your distributor)

something like this:

http://www.amazon.com/Actron-CP7605-Tac ... tachometer

[brentskibikeski]

I was wondering what that capped plug was for, makes sense. If I hooked that up what would I be looking for?

The last thing I haven't checked on @Petros list is the ignitor. They seem a little pricey and I'm not even sure where it's located.

[dlb]

brent, do you have access to a good used distributor? i think it's easier and cheaper to swap that than replace the various components within it. there are a handful of other forum members in vancouver who may have such parts kicking around. toughtercel comes to mind, he might have one. look him up and drop him a PM. or try some of the wreckers. any distributor from any tercel hatchback 83-86 and any wagon 83-88 will work.

[brentskibikeski]

brent, do you have access to a good used distributor? i think it's easier and cheaper to swap that than replace the various components within it. there are a handful of other forum members in vancouver who may have such parts kicking around. toughtercel comes to mind, he might have one. look him up and drop him a PM. or try some of the wreckers. any distributor from any tercel hatchback 83-86 and any wagon 83-88 will work.

I was hoping to avoid that in order to prevent myself from messing with the ignition timing.