88astrotpi

1988 TPI.
New fuel Pump & Sending Unit. New Filter
I have fuel to the fuel rail check valve but do not seem to have any pressure, fuel pump is running & pumping, This vehicle has been sitting for 3 years what am I missing here, Does the fuel pressure regulator supply the pressure ?
Thanks,
Ted

oH HorizoN

Maybe the Fuel Pressure Regulator is bad? Or, f the vehicle sat for 3 years, I'd like to think plenty of varnish has been in the lines/ furl rails themselves.

88astrotpi

That was what I was thinking, This is the first TPI Engine i have ever owned so this is all a new learning experience for me.
Does the fuel pump supply the pressure or is the pressure actually supplied by the fuel regulator?
I"ll pull the fuel rail & completely clean the whole system, including all the injectors this weekend, I was told by the previous owner that it has an adjustable fuel pressure regulator on it, I'll check that also.
Thanks,
Ted.

oH HorizoN

The fuel pump always supplies the pressure. A good or new pump will usually be putting way more pressure in the lines that what you need, which is the point of the regulator. The regulator uses a spring on the incoming fuel to determine how much pressure the fuel will be in the rails, which go to the injectors, obviously.

IIRC you need special torx bits to take apart the regulator, don't ask me why they made it that way. I suggest taking apart the regulator too, just to cover your bases.

88astrotpi

Well, I"v pulled everything apart, checked & cleaned everything but to no avail, when I turn the key on the pump will run for about 3 seconds & then shut off, I suspected the fuel pump switch being it was the only thing that I had not replaced, so I replaced that & it still only runs for about 3 seconds & shuts off, the new switch will click as soon as I turn the switch on & then about 3 seconds later it clicks again & the pump shuts down.
Please tell me what I am missing here ?

oH HorizoN

If the key is in the ON position, the pump won't run forever - it will run until the pressure is built up in the line all the way to the regulator, then it will shut off. What happens when you attempt to start it?

88astrotpi

When I try to start it, it will just start for a second & shut down, then when I try to start it again the fuel will flow for about 3 seconds, it will try & start again but won"t.
same thing over & over.

88astrotpi

It"s like something is trying to shut my fuel pump down, it won"t stay on long enouigh to build up the pressure.

Supertex

The oil pressure sending unit supplies power to the fuel pump after the car starts. If it's not reading pressure when you let off the key, the pump won't run.

You may want to replace the pressure sensor. It's cheap, and easy to replace...right at the oil filter.

TTOP350

iTrader: (8)

I didnt read the whole post so if i missed somthing sorry..
new or old injectors? if they are the old ones they could b varnished up.

luvmy64

PAformula

iTrader: (1)

I replaced my bad oil pressure sender with one from autozone. Its reads the correct pressure now but now my fuel pump wont shut off. Could it be a bad sender from Autozone?

vetteoz

iTrader: (13)

Earlier you said "fuel pump is running & pumping"
You need to determine if
1. you have a pump running problem or
2. whether you are losing fuel pressure somewhere ; 2 different problems.

Do you have a gauge on the fuel rail to see what is actually happening to the pressure ?

If the rail is not being pressurized ,your pump is not running or you screwed up the new pump install and the small rubber line in the tank that joins pump to fuel line has come adrift
If you get pressure but it drops off fast , then you have a leak somewhere ( injectors , fuel reg )

Putting 12 volts to terminal G of the ALDL connector will make the pump run fulltime for testing

vetteoz

iTrader: (13)

Pull the connector of the sender and see if the pump stops
If so you have your answer ..............

vetteoz

iTrader: (13)

Wrong
The pump only runs for 2 secs when the key is first turned on through the pump relay ( controlled by the computer ) to prime the fuel rail. There is no feedback to the pump to tell it what the actual rail pressure is .
2 seconds run ONLY
Pump relay is then turned off and doesn't operate again until the computer sees the reference pulses from the dist indicating the engine is cranking over.

Wrong
The oil pressure switch closes at 4 psi OP and supplies power direct to the pump ( bypassing the relay )
any time the engine has over 4 psi oil pressure
A good engine should do at least 10 psi cranking so fuel pump should be running anytime the engine is being cranked over

86T/A_Ram_Air

For the Fuel Pump continuously running Check the Fuel Pump Relay. They Stick from time to time. And unplug the OP sender as stated above.

As for the original poster: Change the fuel filter, get a Fuel Presure tester, it will hook into the Schrader valve on the fuel rail and see how much preasure you have. Since you checked the regulator what was the condition of it? The next step after that is to check the injector power circut and then the injectors

PAformula

iTrader: (1)

yep, that was the problem

gregmy123

What was the problem?

ULTM8Z

My guess is the fuel pump relay went south.

If you pull the plug off the relay and jump the terminal from the orange wire to the tan wire, and you hear the fuel pump going and see pressure building in the rail, then you know the relay is bad.

gregmy123

Hi ULTM8Z,

I will try this tomorrow and will see.

Thank you

Gregmy123

gregmy123

Hi ULTM8Z,

I pulled off connector and jumped orange to tan wire and did not hear pump turn on and no pressure on pressure tester. You wanted me to have key turned on during this test?

I put a new relay in anyway.

So I tried something I think I read on these forums.
I ran 12 Volts to G terminal on ALDL with fuel pressure tester on and I get 42 to 47 psi on tester. Then I tried to start engine with the 12 Volt connected to G Terminal and engine tried to start but no go. Also the SES Light lit up with 12 Volt to G Terminal on ALDL. Without it connected the SES light does not turn on. Any Ideas? Maybe ignition switch or wiring?

ULTM8Z

Shouldn't need to. I believe that orange wire is always hot. The relay gets turned on by the green/white wire and allows that orange wire to put 12V into the tan wire.

If you're getting rail pressure and it's not starting, it may be ignition related.

Try getting an extra spark plug, removing the #1 sparkplug wire and putting the spare plug into the boot. Then touch the metal part of the spark plug to some metal on the engine (maybe the intake manifold). Then have a friend crank engine over while you observe the spark plug. Should be getting spark jumping the gap.

gregmy123

I already have put 8 new spark plugs- gap -.035, in engine. And I inserted a spark tester between each plug and wire and had someone crank engine and I get a spark on each.
I will try this test also. I will post result soon! I do not want to give up on this.

Thanks!

ULTM8Z

Sounds like my suggestion may be redundant to what you already did then

gregmy123

Thats OK. I am thinking this is a Fuel problem that looks like a ignition problem. I will start checking everything again. This cannot be that difficult.
But now I am wanting to check out: All wiring and connectors and ground circuits; Pressure Regulator; Fuel Injectors; Electronic Spark Control; ECM; Check compression to see if I have a broken timing belt. etc.

Thanks

jkris53406

iTrader: (5)

A couple of questions:

1: Have you checked pressure yet? When the pump primes before the start you should have around 45psi.
2: If you have pressure, does it bleed off?

If you pinch the return hose, will it stay running? If so, replace your pressure regulator.

Good luck!

gregmy123

Hi jkris53406,

Engine cranks but never starts!

I get 0 pressure and do not hear the pump prime for the 2 seconds when i just turn the key to on. And engine cranks but will not start.

I hear pump turn on and get pressure at the fuel rail fitting - (42 to 46 PSI) when I run 12 V to G Terminal on ALDL. Engine cranks and almost starts when I connect 12 V to G Terminal.

Also my fuel pump tester hose was leaking at the gauge connection - so pressure dropped, so I tightened connection and will try pressure test again, but will have to connect !2 V to G Terminal again. So some component or wiring or connector is obviously bad.

Thanks!

jkris53406

iTrader: (5)

Can you hear the relay click on when you turn ign switch to on?

gregmy123

Yes I can. And it is a new relay- Right next to MAF Power Relay. What do you think?

jkris53406

iTrader: (5)

The next question is are you getting power out of the relay to the pump?

gregmy123

That I will check tomorrow and will post result.

Thank you!

gregmy123

I tested 11 Volts at the orange wire leading to fuel pump relay. Why won't this 11 volts light up my 12 volt light tester. But I have not jumped the orange and tan/w white wire at fuel pump relay connector.

jkris53406

iTrader: (5)

Any updates?

gregmy123

Hi jkris53406,

Yes I am getting power to fuel pump when i connect hot orange wire to tan/white strip.I replaced the fuel pump relay but still will only crank over and not start.
I came across this article on internet that claims this non starting may be caused by bad ignition switch. Can you look at it and comment? Here is link:

http://www.faqqq.com/fix/severe-volt...amaro-2945822/

Thank you!

jkris53406

iTrader: (5)

You need to check if there is "trigger" voltage to the relay from the ignition switch. I don't recall which wire it is.
You should have the power from the fuse box through the orange wire, which you do, and the power from the ignition switch to close the relay on one of the smaller wires. The top of the relay always shows the wiring diagram of the internals. The actual power side has only two connections, the orange wire is the feed and the relay pulls closed to complete the circuit on the other wire. The trigger side has three wires and one of those should get 12v when you try to start the car.
At this point you know the circuit from the relay to the pump is good. You now just need to figure out why the relay isn't being triggered.
As for the article, it is impossible to troubleshoot an issue like this over the internet unless you have a lot more info than they had. That seems like someone's shot in the dark but you never know. LMK what you find.

gregmy123

OK I will check this out later this week. I have a spare ignition switch so I may try it out.

Thanks Again!

rusty vango

ha ha , he said auto zone

jkris53406

iTrader: (5)

Have you got this running?

gregmy123

Hi jkris53406,

I have not. weather sucks - I am working outside. Waiting for slightly warmer day. I have a ignition switch I am going to install and I want to do a test on two leads on connector to ECM to see if I have a bad ECM. I guess I should have gone by the shop manual to test: "There is no SES light and engine won't start". Thanks for checking back with me! I will post when I have engine running.