Local garage installed a new fuel pump in my 90 IROC Z and also removed a Ford alarm that was preventing it from cranking. Now she starts but the injectors just flood out the plugs. The car starts once pressure drops after sitting but starts fouling out again. Is this a pressure regulator or ECU issue? She sat for 3 years in the desert heat and would crank and start only with starting fluid. We had power to the pump but it did nothing, the filter and injectors are new and so are the plugs, wires,cap and rotor and coil. When the alarm was removed there were three wires that they were not sure about. Is there an on line source for that circuit?

 

What injectors were used? And is this a 5.0L or 5.7L engine?

Welcome to TGO.

RBob.

 

Injectors were installed by the Vette Shop in San Diego along with the filter it is a 5.7 so it is all GM

 

So, what injectors?

What circuit? Kinda vague there.

 

They are Delphi C1000 147976 and all were replaced at the same time. The circuit for the ECU.

 

There are dozens of wires in that "circuit".

Find the other ends of them and hook them back up.

If you told us what wires they were, it might help... where they are in the car, what color they are, what kind of connector they go to if any, which harness they brake out of, how long they are, whether they're even factory at all or whether they're part of that .... other thing .... , or what.

Your description of the symptoms is not internally consistent: it contradicts itself.

and

mean opposite things; the first means "too much fuel", the second means "no fuel at all".

But however that may be, first thing to do is, if you think the wiring that works the computer is hacked up, is fix that; then once the computer has the ability to at least see and control what's going on around it, then maybe start to work on tuning issues (if any remain).

Always best to repair stuff you can see with your own 2 eyes is messed up FIRST before trying to troubleshoot farther; especially when it's something as dirt-simple and easy to set straight as wiring. Gotta be the easiest system of the car to work on. FIx that, then move on to the next malfunction.

 

At first the alarm worked properly it unlocked the car and opened the starter circuit however it would not start. I checked the relays and I
used some starting fluid and she spit out a flame and started briefly.
I was able to determine that I had power to the pump but the pump
was silent. After that the alarm would not go into valet and the key
would turn all the way without engaging the starter. Now we have a
new pump and the alarm is removed and she cranks good but they
say the plugs are drenched because the injectors stay open. Since
she fired at times after several days without any starting fluid this
is a new problem. I will try to talk with the guy who pulled the alarm
and get more info. I don't think that the ECU is faulty so it could be
the Code Alarm splicing into the harness. They have cleaned the
plugs twice and she keeps loading up. I will try to get more info in
the next day or two do you think I should look for a used ECU?

 

Probably not...

NO ECM, new, old, sat for 3 years, or any other, has any prayer of working right, if some of its wires are cut. Replacing it won't fix that.

FIx what you know is broke before spending huge amounts of money on swapping out big expensive parts. You may still get there eventually of course; but why start there. Don't go down that road until you have no other choice.

First thing to do, is un-hack the car. Once you have successfully accomplished that, move on.

The plugs are more likely "drenched" because there's no spark.

The absolute easiest kind of problem to fix that a car can have, if it has any problem at all, is a no-start. Too simple. It takes 3 magic ingredients for a car to run: air/fuel in anything resembling reasonable proportions, spark at the right time, and compression. Never forget that. It's just that easy. Now all you have to do is to logically and rationally deduce which one of the magic 3 has disappeared.

Compression rarely does; although it can happen. Most frequent cause of this is timing set ("set", not "chain") failure. Very easy to spot: take off the dist cap and watch the dist while somebody cranks the car. If the rotor doesn't turn smoothly at the same speed the engine is turning, then it probably needs a timing set. Although not "likely", the first crank after sitting for a while is when they are most prone to failure: the phenolic teeth on the cam sprocket get stripped off of the chinesium "gums". Worth a quick check to make sure this hasn't happened, but don't "expect" it.

You have fuel; no need to worry about that one. Move on.

Remaining one is spark. How's that? Do you have spark AT ALL? Got BIG FAT PURPLISH-WHITE sparks that look like they could jump out of your test spark plug and bite you, or do you have little weenie bluish-yellow ones that look about like what you get when you're putting on a sweater in the winter?

FOCUS. CONCENTRATE. TROUBLESHOOT. Be logical and rational. Avoid the temptation to just dink with things ("timing" is what people will have you mess with first) that don't ever just up and change of their own accord out of the blue, because if you do, then once you find The Problem, you'll just have to go back and UNdo whatever you DID. First re-assemble the car properly, then find the missing ingredient, and if any issues then remain, go from there.

See my signature for a helpful mental discipline that will keep you off of the "maybe it's this, maybe it's that" track.

 

Sounds good to me so I will get back to the harness and see what they did and go from there. So I went from getting spark and starting with starting fluid to a no crank and no pump. Now I have a pump and crank and wet plugs so I will check the spark.
Yeah it sounds simple but I need to ask some questions and take a look at what they did so far. Thanks will let you know

 

The injectors are the correct ones. Wanted to check that as some folks put higher low rated ones.

It may be that the injectors ground wires are now actually grounded. This will hold the injectors open all of the time. I mention this as it may have been how the alarm prevented the car from starting, by opening the injector ground wires.

Stock TPI has the injectors supplied with +12 volt ignition switched.

The ECM pulses the injectors by grounding the other injector terminal.

So if the wiring is now grounding the ECM signal to the injectors, they are always open.

Can check this easy enough. At key-on, engine-off, remove one injector plug. Measure the voltage from each pin in the plug to ground. Both pins should have +12 volts on it. If one has +12 and the other is ground... You found the problem.

Don't forget to change the engine oil once the problem is corrected. It is full of gas which thins it out.

RBob.

 

I have not paid for the work and they still have the car looks like they towed it to their other shop and are working on her. Tomorrow I will give them a call and find
out where they are. I will change all the fluids after I replace the heater core and
oil cooler tubes and AC seals. I told them when she is running to tow her to me
since the cooling fans are not working unless the AC is charged. I am forwarding
this response to their e mail.

 

This old style Ford Code Alarm would disable the starter unless it was put into Valet mode which is the bypass circuit to disarm. They might have crossed some wires in the harness which is shorting out the primary ignition or injector circuit so if they are still working on her I will just wait I am in no hurry as long as I hold the money.

 

spoke to the shop owner and he tells me that the cooling fans are inop so it cannot be driven and also the plugs are fouling. Tomorrow I will short the AC cycling switch
and the fans should come on regarless. If they do once the car starts I will see how
long it takes for the temp to climb. My ears will know the truth once she starts and
idles on her own. Either she comes home or to the boneyard

 

Went to see the car today and she started with no trouble but the fans were not coming on and the idle was really high. They claim that after a short time the plugs start fouling out. I tried shorting the AC cycling switch and also making sure that the harness connections were snug. Made no difference

 

Did you ever figure out what was causing the injectors to dump too much fuel?