EFI Gurus, I need your help! EFI Trouble Diagnosis

[luderchris]

New EFI setup. Started up after install. Checked the codes with a light and from what I recall, all of the codes were "normal" for the EFI conversion.

From the beginning, the truck would not idle when cold, but idled pretty good after nursing the throttle for a couple minutes. This was at every start up. It also would run fairly well under 3000 RPMs, but over that would break up badly and fall on its face. Almost like a rev limiter.

So, with 2 spare ECUs, I switched out the ECU and it performed the same over 3000 RPMs. The engine was already warm, so I didn't know if it made any difference on cold start up. I waited until the next morning and started the Bronco with the 2nd ECU, and it didn't immediately stall, it was a bit better, but did stall after 8-10 seconds. I go to start it back up and it will not start now! It is cranking strong, but will not fire. I changed out the ECU to the original, and still the same. It will crank over and over but will not fire. I even tried the third ECU and still the same. I also put three more gallons of gas in the tank to be sure it had enough.

Fast forward a week, and I now have a Harbor Freight fuel injection pump tester and a Ford code reader. Because of where the upper intake sits over the fuel rail, I cannot get the fuel pressure gauge hooked up. So I have not yet tested the fuel pressure at the Schrader valve. It does have pressure, but I'm not sure how much.

I just ran the ECU codes and I'm getting the following codes – 31, 81, 82, 85, 84

I ran them a second time and a 10 popped in there. I didn't know what that was until I looked at the manual closer and it showed that is a code for the cylinder balance test.

I appreciate any insights and help with this, I would love to get this truck on the road and back on the trails sooner than later.

Thanks in advance for your help guys.

Chris

 

[ransil]

Need to check Fuel pressure

Pull distributor connector pins measure pins 3 & 4 with the key in run position only one should have 12 volts I would need to look up exactly which one

Starting issue turn the throttle plate screw in a bunch better to idle high than not at all, once running do the idle set procedure

If you can't check FP right now try starting it with carb cleaner

Is the distributor stabbed in correctly? Firing order correct

Auto/ manual jumper plug set for the computer its better unplugged than selected wrong

 

[ransil]

Did you get the breakout box from Eric? Your going to need that

 

[luderchris]

Thanks for the input.

I'll get it from Eric this weekend.

 

[chuzie]

Have you checked your firing order?

 

[luderchris]

Yes. Firing order should be ok. I will check it again though. It was running prior to this latest non-starting issue.

I did get my fuel pressure gauge to work. When I turn the key, the fuel pump comes on and it shoots to 41 psi, and down to 39 when the pump kicks off after 2-3 seconds. If I crank the engine, same thing.
Pressure then slowly drops over the course of a few mins of sitting to 35 psi or so.

 

[luderchris]

Ok. While adjusting out the throttle screw, I touched this (ignition coil?) and it is pretty hot. What is it and should it be so hot I can't keep my hand on it? After only turning the engine over a few times? The rest of the engine bay is cool.

 

[luderchris]

Ok. All I had done in relation to the ignition coil was hook up my tach. But that was weeks ago and it had run many times since. I had it spliced into the orange wire on the left in this picture. I unhooked the splice and tried to start it again. No luck. I guess it could just be hot from cranking it over, but I only cranked it for 10 secs, max.

 

[chuzie]

Do a cylinder balance test. Here is info courtesy of jrichker at stangnet.

Cylinder balance test:
Warm the car's engine up to normal operating temperature. Use a*
jumper wire or paper clip to put the computer into test mode. Start*
the engine and let it go through the normal diagnostic tests, then
quickly press the throttle to the floor. The engine RPM should exceed*
2500 RPM's for a brief second. The engine RPM's will increase to about*
1450-1600 RPM and hold steady. The engine will shut off power to each*
injector, one at a time. When it has sequenced through all 8 injectors,*
it will flash 9 for everything OK, or the number of the failing cylinder*
such as 2 for cylinder #2. Quickly pressing the throttle again up to*
2500 RPM’s will cause*the test*to re-run with smaller qualifying figures.*
Do it a third time, and if the same cylinder shows up, the cylinder is*
weak and isn’t putting out power like it should. See the Chilton’s Shop*
manual for*the complete*test procedure

Here's the link to dump the computer codes with only a jumper wire*
or paper clip and*the check*engine light, or test light or voltmeter.*
I’ve used it for years, and it works great.



See*http://www.troublecodes.net/Ford/
OR
Seehttp://www.mustangworks.com/articles/electronics/eec-iv_codes.html*

IF your car is an 86-88 stang, you'll have to use*the test*lamp or voltmeter method. There is no functional check*engine lighton the 86-88's except possibly the Cali Mass Air cars.

For those who are intimidated by all the wires & connections,*
seehttp://www.actron.com/product_detail.php?pid=16153*for what a
typical hand scanner looks like. Normal retail price is about $30 or so
at Walmart.

Or for a nicer scanner seehttp://www.midwayautosupply.com/detailedproductdescription.asp?3829*– It has a 3 digit LCD display so that you don’t have to count flashes*
or beeps.. Cost is $33.

Do a compression test on all the cylinders.
Take special note of any cylinder that shows up as weak in the cylinder*
balance test. Low compression on one of these cylinders rules out the*
injectors as being the most likely cause of the problem. Look at cylinders*
that fail the cylinder balance test but have good compression. These*
cylinders either have a bad injector, bad spark plug or*spark plug wire.*
Move the wire and then the spark plug to another cylinder and run the*
cylinder balance test again. If it follows the moved wire or spark plug,*
you have found the problem. If the same cylinder fails*the test*again,*
the injector is bad. If different cylinders fail the cylinder balance test,*
you have ignition problems or wiring problems in the 10 pin black &*
white electrical connectors located by the EGR.

 

[luderchris]

Can't do a cylinder balance test - it won't start!

Once I get it started, I can run through some other tests.

 

[luderchris]

Randy, although I think I have it correct, I unplugged the auto/manual jumper plug and still no start.

 

[chuzie]

Oh ya. Little details. Well, if you have fuel pressure and the eec isn't coding anything other than balance, and you have air....
Have you visually checked for spark?

 

[luderchris]

Not yet. Wife pulled me out if garage. I am going to check spark/ignition tomorrow. Any tips on what to check? I will be out there again in the morning.

 

[Broncobowsher]

Everyone is looking at spark. I don't think that is it. I see your profile lists the engine as a 5.8 and you say you have EFI. I have a LOT more questions before I send you onto a parts chasing spree.

Is this a stock 351, slightly modified, built?
What intake?
What computer code (A9L, etc.)?
What MAF?
What injectors?
How is the PCV hooked up (including the fresh air for the crankcase)?
Anything else about the intake or EFI that you feel we should know about?

My thoughts...
You are running out of fuel. If for some reason you are running a speed density computer for a 5.0 but it is breathing 5.8 worth of air, that is pretty simple. But I am going to guess (since I am still waiting to know what parts you have) that the MAF/ECM/injectors are not properly matched. You didn't do anything silly like port the MAF for more airflow, did you? Did you take a MAF sensor from one vehicle, and a housing from another and put that onto a computer that isn't programed for any of it? Maybe an aftermarket "tuned" MAF? How about an open element crankcase filter instead of pulling metered air from between the MAF and throttle body for the crankcase fresh air?

 

[luderchris]

Is this a stock 351, slightly modified, built?

Stock 5.8L from 97 F250HD

What intake?

Gt40 upper/lower

What computer code (A9L, etc.)?

A9L, also have 2 A9S

What MAF?

Mustang, I believe. (Maybe Explorer?)

What injectors?

19 lb (orange)

How is the PCV hooked up (including the fresh air for the crankcase)?

Have to check.

Anything else about the intake or EFI that you feel we should know about?

Nope

My thoughts...

You are running out of fuel.

I had it running, although not great, now it won't start.

If for some reason you are running a speed density computer for a 5.0 but it is breathing 5.8 worth of air, that is pretty simple. But I am going to guess (since I am still waiting to know what parts you have) that the MAF/ECM/injectors are not properly matched. You didn't do anything silly like port the MAF for more airflow, did you?

No

Did you take a MAF sensor from one vehicle, and a housing from another and put that onto a computer that isn't programed for any of it?

Don't think so.

Maybe an aftermarket "tuned" MAF?

Nope

How about an open element crankcase filter instead of pulling metered air from between the MAF and throttle body for the crankcase fresh air?

Don't think so, I will make sure though and take some pics.

This thing was running, although not great, after the efi install, prior to it stalling and now not starting a week ago. I put 15-20 miles on it.

Thanks for the thoughts. Keep it coming, I want to get this thing going again.

 

[TN1776]

A little off from your main point but do yourself a favor and get some explorer rails such that your schrader valve isn't blocked by the upper manifold. You may need to extend the lines between the two sides to make it fit but its worth it.

I don't like that your ign coil is getting so hot that you can't touch it, in only 10 seconds Mine's over on the fender well and it stays cool.

Check fuel pressure, check for spark. When it was running, where was the timing set to? Perhaps the clamp isn't tight and the distributor rotated while it was running? when I first fired mine post-EFI conversion, I had my distributor off an entire tooth. It ran but very rough and would backfire. Different than what you describe but a possibility anyway.

Good luck

 

[chuzie]

Post a pic of the maf housing. looking into the tube. And a pic of the maf sensor

 

[luderchris]

Post a pic of the maf housing. looking into the tube. And a pic of the maf sensor

I will in the morning.

 

[Broncobowsher]

Also check the MAF for an airflow direction arrow. It needs to point into the engine, not toward the air filter.

 

[EFI Guy]

Does it spit, sputter, cough, like it's lighting off fuel or does it just crank?

Verifying spark should be step one. The "too hot to touch" ignition coil is a huge red flag.