I have an ’84 4cyl.

Well here is my problem. My car will crank and crank and crank sometimes and not start. It runs fine, it usually starts right up without any problems. Lately it has been starting in the morning then at work, or when I want to go home it just won’t start.

I can hear the fuel pump turn on every time I turn the key over.
I have taken the line off the backside of the fuel filter and there was instant gas flowing as soon as the key was turned.
Looking at the injector I never see fuel actually “spraying” into it… (could this be a problem).
I have also taken a spark plug out to check and it wasn’t wet, I am pretty sure the car is not flooding.
Last time while troubleshooting the car I had a friend turn it over while I was trying to listen. It started on the third attempt….

I really have no clue what it is. I have tried cranking and cranking on it, I have tried intermittently cranking it over. I have tried it turning the car off and back on over and over trying to start it. I have no idea where to even begin to be honest. It has started to happen more and more though.

The car runs completely 100% just fine when running though. I have no idea… Please help.

No fuel spraying = Thats your trouble.

my GUESS - Vapor lock due to a low pressure fuel pump

Check your fuel pressure with a gauge - If low then check the voltage at your fuel pump connector. If the voltage is ok then lets talk about the fuel pump vs the fuel regulator.

Back in the seventies when cars were running mechanical fuel pumps and carborators this would happen kinda often. With electronic fuel injection, the fuel pump will pump more fuel than the engine needs. The fuel pressure regulator is located on the engine (In the throttle body in your case). Excess pressure/fuel is returned to the tank. They did that to get a consistant pressure at the engine.

This also fixed the vapor lock problem. Vapor lock occurs when the fuel in the fuel lines evaporates due to heat. Vapor lock occurs only after driving and then shutting down and "heat soaking" the fuel line. With the regulator and return line the vapor lock would be bled off and returned to the tank and cause no problems. Problem fixed right?

So if your fuel pump is marginal, it might pump enough fuel to run the engine, but not enough to return any fuel to the tank. When the heat soak problem occurs it just won't start when parked hot. Let it cool enough and the gas re-condenses and the car starts and runs fine. It could be a weak fuel pump, it could be a clogged fuel filter or low voltage to the fuel pump.

The fuel pressure test is the first item in diagnosing the problem. IF you want to go the route of just replacing parts, (NOT recommended) and the fuel filter hasn't ever been replaced, you could start there. It is however a great time to also check the fuel pressure on the 2.5 (which has no fuel pressure test point built in)

Also take a look at your fuel spray when the trouble is NOT happening. This guess is baised on the idea that you have fuel spray usually but no fuel spray when the trouble occurs.

Any chance under a sustained high load situation (going up an extended steep hill) that you also experence power issues?

[This message has been edited by phonedawgz (edited 06-24-2010).]

I have no issues at all with hills, even at slow speeds. It doesn't ever sputter, choke, or anything. When I took the fuel line off the filter (the line that is in between the fuel filter and the “throttle body” and turned the car on, gas shot out. I know fuel is getting to the throttle body, but maybe just not enough pressure? Every time I have looked though when the car wasn’t starting I really couldn’t feel or see any “spraying” into the damn butterfly hole from the injector.

This is the only problem the car has. It doesn't just do it when the car is hot though...because it regularly starts in the morning, then at 330pm when I go home it won't start. Today I drove it to work parked it at 7am. Then at 1040am I got into it drove it for 5 minutes to another building and parked it. Hour and a half later it won't start.....

I hear ya - I'm not sure what I am guessing is it either. Even when working directly on a car we propose "problems" in our minds and then test to see if that is/was the problem. When the trouble goes away we assume that last thing we did 'fixed' the problem. Who really knows. Maybe the problem was something else and that trouble just decided to stop giving trouble and yeah.

So you 2.5 guys - Can you unplug the connector at the top of the injector and put a 9V battery on the two pins to "fire" the injector? Of course this would have to be with fuel pressure (ie the fuel pump) on. Just wondering. I've never owned a 2.5 execpt to harvest it for an Isuzu 5 speed.

Might want to also look at Ogre's cave (The very very top of this page) to see what he says.

Well from reading around, I know there is no fuel being sprayed out of the fuel injector when it is not starting. Not even dripping... So now I guess I just have to figure out why sometimes it isnt when starting..and fix it.

Yep - Might want to start with that fuel pressure gauge. Someone told me that Harbor Frieght has them for $15.99.

You could also take a meter set to VOLTAGE and see if the injector is getting electrical pulses fromt the ecm. If you chose to do this I'd suggest testing first when its running to see what that looks like.

[This message has been edited by phonedawgz (edited 06-24-2010).]

http://www.harborfreight.co...mp-tester-92699.html

Does your tach read cranking speed while cranking and not starting? The GM ECM will not fire the injectors without a spark signal from the distributor and what you have described is a classic description of a failing HEI module.I had this same problem with my truck and it cost me a wrecker tow home in rush hour traffic before I finally caught on.

The tach will read 300-400rpm while cranking if the ignition is functioning or 0 if it is not.

Buy, or use loner tool, a Noid light.
Tells you if ECM send a signal to the injector.

No signal mean:
Something in Distributor is bad. module, pickup coil, Bad/loose wire, missing/loose module mount screws....
ECM is bad
Cam gear is bad. (Not your problem right now...)

Yes... See cave. HE ignition, More scanner tools

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave (It's also at the top and bottom of every forum page...)

Well I don't know anything yet. Problem hasn't happened again yet. I'm waiting for it though.

Damn - I HATE it when problems WON'T happen!

Anyways - try this - wiggle around the connector for the injector while the car is running. Wiggle around the wires - See if you can make it fail. If not - do this - take the connector off the injector and clean up the electrical connections. No splice in the injector wiring right? When pushing the injector connector onto the injector does it feel tight that last 1/8" of the push - the part where the pins of the injector are pushing into the metal connectors of the wires? Feel tight on both sides when you push it on?

I have YET to have it happen again. It's almost like it stopped completely. One thing I have done differently since is I have always waited for the car to get done priming. Everytime I go to start it I let it prime completely and when I hear the fuel pump kick off then I turn it over.