HELP!!! It won't start...

[ronaconda]

Just a little over a week ago i was driving to work and it was running fine while cruising. I pressed the gas to pass someone (not hard, but it did unlock the converter) and as soon as the converter unlocked, i was dead. I determined early that i had a fuel problem; thought the fuel pump was dead. Swapped the pump yesterday and it still didn't start. I am getting fuel to the schrader valve (sprays hard as it should). Swapped computers and still have the same problem - swapped PROMs as well and nothing. Also ran both computers with and without the WOT chip. In fact, i think there is nothing wrong with either computer; spraying starting fluid in the intake makes it want to start. I'm at a loss as what the problem is. All fuses are good.

Thanks in advance for the help guys.

[SuzukiGhostRider]

An engine needs three things to run.

1. Compression

2. Spark

3. Fuel

We'll assume you have compression for now. You said you've got fuel at the Schrader valve. That's good, but what kind of pressure?

Have you verified spark? Tested the coils? Tested the ICM? If no spark is existent at all, I'd start with the CKPS.

[3X00-Modified]

Did you say it wants to start with starting fluid though? If so that puts spark there... I would check fuel pressure and also see if any wires got damaged going to the injectors or ensure that they are spraying.

[ronaconda]

An engine needs three things to run.

1. Compression

2. Spark

3. Fuel

We'll assume you have compression for now. You said you've got fuel at the Schrader valve. That's good, but what kind of pressure?

Have you verified spark? Tested the coils? Tested the ICM? If no spark is existent at all, I'd start with the CKPS.

I have all three...to some extent. I have no idea what my fuel pressure is as i don't have a fuel pressure gauge. I suppose that will be the next tool purchase...

Spark is verified...tested the coils and the ICM as i didn't want to over look anything and the crank sensor is new.

[DTMAce]

Reseat the fuel rail power connectors?

Just for giggles, check your main connections for power and grounds. See if you have a bad ground on the firewall, etc. Make sure they are all tight, make sure your wiring connections are tight on the fuel system too. Since it did it during a shift, (and I am surmising here) I'm willing to bet something simply came loose. After all, you did do an engine swap, its possible something didn't get tightened properly.

[90GTZHO]

According to what he has been telling me, fuel pressure is not an issue as when he goes to hit the schrader valve, it pretty much hits his hood, so we know he has good pressure. The problem he is having is the injectors will not fire. I have NEVER heard (especially on an OBDI car) of fuel pressure not allowing a car to fire. Its already obvious that hes got spark as it wants to fire on starting fluid. The problem he is having is the injectors have no power going to them. Now, according to what i have seen in the diagrams, the computer is the only and direct influence on the injectors. If the injectors do not fire, the computer is bad. It wont be in the EPROM as the injector circuit is hardwired to the main computer board. If the injectors do not fire at all, its has to be computer yes?

[3X00-Modified]

Not always true, He swapped motors meaning wires were moved around... Anything can happen then. When Geoff did his 3400 swap he pinched something somewhere and nothing was right till he swapped to OBDII and rid the car of the engine harness.

I would strongly suggest tracing wires and circuits to see if anything has been pinched or broke from movement, especially on the fuel injector circuit, because with the MPFI... three injectors are firing at once so its got to be the main power feed, or ground as Ace mentioned.

[SuzukiGhostRider]

Agree. Check and RE-check wiring circuits leading to the FI system. Make no assumptions. On fuel pressure or anything else.

Also, easiest way to see if your injectors are getting power or not is to ohm them out. If they're dead , then you know you have one of two problems.

1. A wiring fault or dislocated/pinched wire.

2. A faulty ECM.

[SuzukiGhostRider]

........... The problem he is having is the injectors will not fire. I have NEVER heard (especially on an OBDI car) of fuel pressure not allowing a car to fire. Its already obvious that hes got spark as it wants to fire on starting fluid. .......................

Not sure where you heard this Geoff, but it's completely FALSE. Almost all newer cars will NOT fire if a sufficient fuel pressure is not present at the injectors. And, YES, weak fuel pressure will even keep an OBDI car from firing. OBDI , OBDII has jack crap to do with it all. Carb'd cars will sometimes not fire due to a lack of fuel pressure.

As to "wanting to start on ether" so it must be obvious it has spark. NO. If it "obviously had spark" it WOULD fire on Ether, not ALMOST.

A car I just bought and sold recently , as an example. '97 Chevrolet Lumina , 3100/Auto. Bought NON running. A fuel pressure test was well below expectations and car would NOT FIRE because of it. I started, note I said STARTED , and ran the car on Ether (starting fluid) for 30 seconds to verify the engine was good before I revamped and replaced the fuel system. A new pump, filters, and lines in tank later, and bam car fired right up on it's own.

So as I said, yes weak fuel pressure will keep a car from firing.

[Carson21R]

this is my problem. ive done everything you have and mine still wont start. tried 3 computers, new pump, new fpr, everything.

[3X00-Modified]

this is my problem. ive done everything you have and mine still wont start. tried 3 computers, new pump, new fpr, everything.

You've messed with your motor multiple times though... have you traced every wire in your FI system? If not then you have not done everything. These cars are 100% electronic ignition wise and fuel wise so if you have not done trouble shooting on your ENTIRE harness then you still have 75% of the system un tested.

And SGR to an extent a car will fire with weak pressure, but agreed NO pressure the car wont fire, so if he is getting enough to spray out the shrader for example 20psi or something then the car should stumble similar to spraying ether in the intake, but it may not idle or rev.

[90GTZHO]

Okay, understandable. But Rons problem was immediate. There was no leading up to it, no studdering, just deadness. If his fuel pressure went out, it usually starts with some kind of signal before it will just drop dead. And not to add insult to injury, but when i had the FPR in my 88 Calais go out on me (blew out the diaphragm), it was just circulating fuel back to the tank and not so much in in the rail, never built pressure, the car still ran, but very lean, and weak (i was able to drive it home 12 miles). Now, even if he was getting some fuel in the rail, the injectors dont know how much pressure is in the lines, all they are is a solenoid. Computer tells them to open they open, whether theres 45psi behind them or not. If the injectors were working properly, he should get atleast one spit or some kind of life, but does not.

We see this kind of problem sent in to this site all the time with the older motors and 95% of the time, the ECM has taken a crap.

[SuzukiGhostRider]

In Ron's case , I too, am leaning towards the ECM.

[DTMAce]

Swapped computers and still have the same problem - swapped PROMs as well and nothing. Also ran both computers with and without the WOT chip.

I'm only assuming, but doesn't this mean the ECM has been swapped already?

I really think this issue is a wiring problem someplace. It makes more sense.

[Carson21R]

if it were wiring it wouldnt have started to begin with.