Engine dies out

[collinbrewer]

I have... it never got below 36psi.

 

[Viperwolf1]

You can rule out a fuel problem then. Concentrate on spark.

 

[collinbrewer]

Thanks Viperwolf. Can you speak to the loss of fuel pressure after shutoff? I'm concerned that maybe my injectors are allowing fuel to bleed pressure ultimately flooding the engine.

As for spark, I have spark but it doesn't seem very powerful. Not sure what would cause the car to spark fine from work to home, and then have weak spark 10 minutes after shut off. Any ideas there?

Another thought, my car does want to run hot(~220º) and I got to wondering if the ECT has any function in the computer?

 

[collinbrewer]

Anybody???

 

[Viperwolf1]

Thanks Viperwolf. Can you speak to the loss of fuel pressure after shutoff? I'm concerned that maybe my injectors are allowing fuel to bleed pressure ultimately flooding the engine.

As for spark, I have spark but it doesn't seem very powerful. Not sure what would cause the car to spark fine from work to home, and then have weak spark 10 minutes after shut off. Any ideas there?

Another thought, my car does want to run hot(~220º) and I got to wondering if the ECT has any function in the computer?

Its normal for fuel pressure to slowly bleed off when the pump isn't running. It should take quite a while, like hours, though. Hard to tell exactly where it might be bleeding. Could be injectors, fuel pressure regulator, pump, or any leaks in the system.

The ECT does have a function. The ECU uses it to determine engine temp and how much fuel to inject. If the ECT is way out of whack you should see a code. If its only half way out of whack you may not see a code but it will affect startup. Test it with an ohmmeter. Bounce the measurement off the chart on the bottom of this page: http://www.oldfuelinjection.com/index.php?p=28

For weak spark I'd be looking at the coil, cap/rotor, wires and plugs.

 

[collinbrewer]

Thanks Viperwolf.

I'll do a little more diagnosis and get back..

 

[collinbrewer]

I tested the range of my ECT and all seems to be well... reading .74vdc.

Tried to run the KOER test and the test would not initiate, in doing some searching, it seems that the code 67 during my KOEO test indicates that my painless engine harness ignores the neutral safety switch, and as such, the computer will not run a KOER test.

Did some more research and came across this thread: http://classicbroncos.com/forums/showthread.php?p=2207499

This thread describes me pretty exactly so I am working on getting rid of that code 67, by jumpering pin 30 to pin 46 if for nothing else than to just be able to run my KOER, though I'm hopeful it will fix my no start issue.

 

[70_Steve]

... so I am working on getting rid of that code 67, by jumpering pin 30 to pin 46 if for nothing else than to just be able to run my KOER, though I'm hopeful it will fix my no start issue.

I scanned back through this thread and didn't find a mention of what EEC your using. Pin 30 should be connected one of two places, depending on which EEC you have. Here's (part of) a diagram from oldfuelinjection.com that shows the differences. Either connect to signal common (Pin 46) or ground. I've verified this using the wiring diagrams in the Probst book.

 

[collinbrewer]

Thanks 70_Steve,

I'm using a D3D which according to a few resources is the equivalent of the A9L.

The painless 5.0 harness completely ignores pin 30 so I'm chasing that down now per the thread I linked and your diagram. I think this explains why I've never been able to KOER before, and maybe this issue as a whole.

Fingers crossed.

 

[collinbrewer]

So I got pin 30 patched over to pin 46 and I was finally able to run the KOER test. Among a few expected codes from things that have been deleted(EGR, Thermactor, etc), the only peculiar thing I got was a code 13, which relates to idle control.

I can't see why this would be related to the ongoing no start issue but maybe some of you can?

 

[Viperwolf1]

the only peculiar thing I got was a code 13, which relates to idle control.

I can't see why this would be related to the ongoing no start issue but maybe some of you can?

Yes it can. Take it off, ohm it out, clean it out, mount it back on in the correct orientation, make sure it has a good gasket.

 

[collinbrewer]

The IAC is the only thing left on the engine that hasn't been replaced yet so maybe it's the cause...

1. For my own edification, would you mind explaining how the IAC can cause a no start situation when it's warm?

2. I have the IAC connector to the right and up(from the front of the engine), is that the correct orientation or should it be down and left?

I got the engine to operating temps then unplugged the electrical connector and witnessed no change in idle... per the text on oldfuelinjection.com, this indicates a faulty IAC solenoid. Headed up to the part store...

 

[Viperwolf1]

IAC controls the air going into the engine at idle and startup. Therefore it has a major effect on A/F ratio. The connector is normally oriented down. I've never seen one go bad completely, just get dirty inside. Easy to clean out with carb cleaner. No need to spend $80 on a new one.

 

[collinbrewer]

That makes sense... thanks for the explanation.

Before I installed my IAC a year ago it was pretty crudded up so I thoroughly soaked and cleaned it with carb cleaner and a wire brush, but I'm wondering if the electrical side is shot. I couldn't find any tips on oldfuelinjection.com on how to test it other than a hands on approach. Any suggestions there?

 

[Viperwolf1]

It's just a simple solenoid. If it measures 10-15 ohms I'd call it good.

 

[collinbrewer]

The old one read 10.2 ohms, and a brand new one I picked up read 9.4 ohms.

So I flipped the old one and the KOER code 13 cleared up, the idle slowed way down, and the drivability improved a bit since between shifting she idles down more.

More importantly, I drove around for a half hour and got it good and hot, then, after letting it sit for a bit, she seemed to start just fine!

I'm super pumped, but leery of trusting... Going to have a little faith and take her to the shooting range tomorrow. I'll report back.

 

[HGM]

I've always believed that far more PCM's are replaced on a regular basis than are actually bad.. They just dont fail that often.. However, reading your thread reminds me of my F150.. Just a sharp stall, no sputter, no loss of power, which tells me its not fuel or air.. My problem seemed like an ignition module or stator that I had seen many times before, but because it wouldnt stay broke, couldnt verify and threw a new set at it.. Worked fine for about a month then let me down again. Long story short, after about a year of tinkering and dealing with the intermitent issue that never really left me stranded, I took the PCM apart. Opened the box and found a burnt transistor on the board. Not open, just burnt and apparently overheating enough to open but come back when cool(sometimes!!!!).. I put a PCM in it a year and a half ago and its been running great ever since.. I absoloutely hate EECIV for this exact reason, because there is very little available for diag, short of throwing parts at it.. Sometimes you get no codes, few PID's to see and all the tests in the world wont help if the problem is gone.... Hense the reason mine is being wired as EECV, the trouble will be worth it in my opinion.. Might be worth a look if your problem happens to return..

 

[collinbrewer]

Thanks for chiming in HGM...

The report is overall pretty positive. I drove her around all day today, about 50 miles total, with several stops in between. Each time she started on the first go, which is more than I can say for my history with the ol' girl.

That said, she still seems a bit hesitant to start... she doesn't exactly leap to start, she still stumbles to get going.

I don't know what else to do other than to keep a brand new PCM and brand new IAC in the truck until I can't get her started, then swapping parts until she starts. Otherwise, I'm at a loss...

 

[collinbrewer]

Grrr! While the issue has improved, it still persists.

I ran a lot of errands and got her started pretty well the first couple times but finally she let me down... again. While stuck in the parking lot, I quickly swapped in a brand new PCM to no avail... that rules that out. Swapped the old computer back in, popped the hood, let her cool for a few, then got her to feebly start again. Drove home. Swapped in a new IAC just for grins, didn't seem to help.

Any other ideas?

 

[collinbrewer]

I thought about this some more. Maybe my question should be different. When I do get her good and hot, and am successful in getting her started, it's always a really fumbly start, never a good solid start. It's usually a fairly long crank, then a bumbly fire, and eventually smooths out to a nice running engine. So...

What would cause a really weak start when she's warm?