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Discussion Starter #1 (Edited)
Well, after a long haul, I have a 2001 5.3l in my son's 1978 K10... The engine ran well when it was removed from the Z71 donor. We just tried to start it for the first time in the k10 and no joy... We are getting fuel, but no spark... I'm guessing it is the computer not functioning properly, but I can't say for certain because I am unsure of how to functionally test the ECM... The ECM was reflashed to delete the trans, anti theft, emissions (AIR and EGR), but all other sensors were left alone. At least that is what I was told. The only sensor that is not connected is the VSS. I am waiting on a replacement adapter from Dakota Digital... I don't think that sensor will effect the stationary operation of the engine/ecu because it will just think it is in park. I am reusing the 2001 under hood fuse block. The IGN1 relay feels warm... Is this normal?

The connectors to each coil has 4 wires... One of them is hot 12v, the middle two are hot 8v (I found this to be a strange number), and the fourth wire has a very small amount of current. None of the terminal's voltage seems to change when the engine is being turned over... Would I be able to see the signal being sent from the ECM to the coil with a volt meter or would it happen too fast to register? EDIT: As the engine turns over, I attempted to test the coil itself and received no signal when the engine was being turned over...

I do have the OBD2 diagnostic port wired. Would that be able to tell me if the ECM is functioning and what, if any, codes are present even if the engine hasn't run since the reflash?

Sorry for the long post. Just thought I could give as much info as possible...
 

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Discussion Starter #2
I have also tested both the batt to ecm and hot/run/start to ecm and they are both supplying power.
 

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The coil plugs have four wires as you know.

Cylinders (2 4 6 8)
A ground
B Ref low volt (Brown to Brn/white C2 pin 61 PCM) (Control Grd)
C Ign control signal (these go to PCM to tell each coil to fire)
D 12v voltage (Pink wires all tired to E6 C2 under hood box)

Cylinders (1 3 5 7)
A ground
B Ref low volt (Brown to Brn C2 pin 60 PCM) (PCM Control Grd)
C Ign control signal ( these go to PCM to tell each coil to fire)
D 12v voltage (Pink wires all tired to E12 C2 under hood box)

The connectors to each coil has 4 wires... One of them is hot 12v, the middle two are hot 8v (I found this to be a strange number), and the fourth wire has a very small amount of current.
Check the grounds at pin A or at the coil extension harness plug by the valve cover. Ohm them out with engine off and battery disconnected just in case of a wiring problem. Or you could hook a test light up to pin A and the other end to batt 12v. If it lights then coil ground is good. Made sure they are good or it will not run. It sounds like something wired wrong as pin A should be ground its on the one end of the plug to the right if looking at the retainer clip. It should not have any voltage. Look at the picture below.

To test pin B PCM low ref control ground. Use a meter: place it in DC mode, place the black lead on pin b, and the red to 12v batt. should be proving ground during start so should read a voltage.

If that all checks out it could be the IC control wire, Bad PCM, or VATS not disabled. But usually it will fire for a few seconds if its VATS anti-theft.
 

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Discussion Starter #4
Excellent info, thanks! I will check it this afternoon and post up.
 

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Discussion Starter #6
Ok, I tested the coils, and all seems to be fine...
Pin A is grounded. Ohmed right and read 12v black lead to pin red to battery+

Pin B is showing 0 volts (black lead to pin, red to batt+) in all stages except when the engine is being turned over then it reads minuscule voltage.

You didn't mention how to or if I would be able to read anything on pin C

Pin D shows 12v at all times. Even with ignition is off.

Another observation: When connecting and disconnecting the batt+, the Ign 1 relay clicks... I assume it is closing the relay (switching it on). That it would explain why there is constant voltage to the coils. Is this normal operation?

I have two more questions...
I asked my programmer to turn off the park/neutral safety feature. In most cases, if that were still an active function in the ECM, it would not allow the starter to engage. We have the starter running off of the '78s wire harness so it is not controlled by the '01 computer or run through it's fuse block. If the P/N switch is still active, what is the best way to circumvent it?

Second question. I guess it is possible that the injectors are not firing... What is an easy way to test them? I don't have a stethoscope or node light... The old screwdriver to the ear method seems a bit risky with the engine turning over...

I am going to do another 5.3 swap in an obs chevy soon... I am buying a painless harness for that project... Screw this!
:shaking:
 

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Discussion Starter #7
i forgot to hook up crank sensor on my swap, pretty sure u have to pull starter to get to it. check it out.
We checked all the sensors and they are wired properly and connected. Are all of them functioning correctly? That is an entirely different quandary...
 

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Pin D shows 12v at all times. Even with ignition is off.

Another observation: When connecting and disconnecting the batt+, the Ign 1 relay clicks... I assume it is closing the relay (switching it on). That it would explain why there is constant voltage to the coils. Is this normal operation?
No this is not normal.
The Ignition relay should be energized with IGN on only. You may have fried the coils.
 

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I am going to do another 5.3 swap in an obs chevy soon... I am buying a painless harness for that project... Screw this!
:shaking:
I have heard lots of problems with the painless stuff.


WHO did you harness and PCM tune????


I don't think it would have fried the coils per-say but if it was left on all the time via the battery, they may have gotten hot and them smoked checked them.

Make sure the ground for the injectors is good as well. Or they will not work either. Verify fuel PSI at rail.
 

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Discussion Starter #10
No this is not normal.
The Ignition relay should be energized with IGN on only. You may have fried the coils.
That is what I was thinking... Got to figure that out... Need to find a better diagram for the under hood fuse block...

But.... I just picked up some ether from the local quick stop and with a spray, it fired up, all be it just a second... So, the injectors are not spraying. How likely is it that all the injectors go bad at once? I wouldn't think that is very common, so if the injectors were receiving signal, there should be at least some combustion... If they were spraying at the wrong time, there should be some residual fuel in the cylinder to cause a bang or two... Either they aren't receiving 12v, received 12v all night and are toast, or the computer isn't sending signal... VATS? P/N Switch? What else would cause that?

At least I know my enemy now...
 

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Look you need to see if you have fuel at the rails IE your fuel pump works. Then if getting the correct 58PSI at the rails, check for 12v at the injectors this should be 12v key on all the time to the pink wires. Then check the Pin B ground which comes from the PCM while cranking. Pin A pink is 12v ign and Pin B is ground from the PCM.


There should be a 15amp fuse in the under hood box for each injector bank as well.
LT1swap.com has pinouts for the under fuse box. Click link below
http://www.lt1swap.com/underhoodfuseblock.htm


It could be the injectors are gummed up if your getting correct PSI, pink 12v, and control ground that's the case. Remove them all and clean in Seafoam. Remove the orings before cleaning.
 

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Discussion Starter #12 (Edited)
I have heard lots of problems with the painless stuff.


WHO did you harness and PCM tune????
LT1 Swap did the PCM. Had some people recommend him... I did the harness... I really didn't do a bad job, other than the C1 A9 screw up... And hey, it still had power... Just stayed powered for about 14 hours... Long road trip, right?

Make sure the ground for the injectors is good as well. Or they will not work either. Verify fuel PSI at rail.
I think the way the injectors work is the computer completes the ground. I could be wrong though... The ECM has 4 ground wires... All are grounded...

I figured out the "always on" deal... I'm a bone head and wired the C1 A9 (fuse block run/start) to batt+ on the fire wall... Corrected and battery is on charge... Don't have any idea why I did that...
:homer:

Ok, I just checked the injectors... All ohm between 12.1 and 12.3... so that is normal... They all have 12v at run/start... I tried to ohm test the other pin on the injector connector with a ground, in run and in start, and got nothing... I'm not sure that is the proper way of checking for ECM signal, but it seemed logical...
 

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Discussion Starter #13
Look you need to see if you have fuel at the rails IE your fuel pump works. Then if getting the correct 58PSI at the rails, check for 12v at the injectors this should be 12v key on all the time to the pink wires. Then check the Pin B ground which comes from the PCM while cranking. Pin A pink is 12v ign and Pin B is ground from the PCM.


There should be a 15amp fuse in the under hood box for each injector bank as well.
LT1swap.com has pinouts for the under fuse box. Click link below
New Page 1


It could be the injectors are gummed up if your getting correct PSI, pink 12v, and control ground that's the case. Remove them all and clean in Seafoam. Remove the orings before cleaning.
Injectors were cleaned prior to install. Fuses have been quadruple checked (seriously). The PCM (ECM, ECU, whatever) ground seems to be the issue... While cranking it does not ohm out... Soooooooo, VATS, Park Neutral Safety Switch, or other PCM malfunction...

I guess I will contact LT1swap and see what he wants to do about it. All I know is that prior to removal, it operated correctly...
 

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Discussion Starter #15
Verify fuel PSI at rail.
It will be tomorrow before I have an instrument to check the fuel pressure at the crossover... It has good pressure... I know that is a very inaccurate and crude response, but it is the best I have until I know for certain.

What will occur in a low or a high fuel pressure state? Lean and rich, but the injectors will still operate, right?
 

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Discussion Starter #16
You stated that the PCM was tuned to remove VATS. If so WHO tuned it???
Post #12... LT1swap did the tune...

Remove VATS, Park/Neutral safety, EGR, Trans control, A/C, governor... I think that was all...
 

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Sorry missed that post on my small monitor. haha

The injectors fire off ground from the PCM as mentioned earlier. Really need a Noid light to check them to make sure they are pulsing at all a meter my not even pick it up. You might have blown the injector drivers in the PCM and fried it. But I doubt it never seen all them go bad at once. The fuel injectors ohms are good 11-14 is nominal.

The park neutral just really controls the starter which can be disable in the tune. So I doubt that's it. With VATS it will usually run 2-3 sec then cut off.

Now check that the C1 A9 PINK wire input in to the fuse box is getting power during crank as well. If it doesn't get power during crank that could be the problem some of the early ignition switch didn't provide the power during crank. But you had it on 12v Batt before just double check it has 12v during crank. Just to be safe.

Double check you crank sensor/cam sensor plugs and wires. The injectors drive off the Cam sensor.


Its either VATS not completely turned off or a cam sensor problem possibly.
 

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Discussion Starter #18
I checked the camshaft sensor plug yesterday for engagement, but pulled it off this morning to visually inspect it and the wires were destroyed... The 12v (red) was hanging on by one strand of copper, and the other two weren't much better... I'm going to the local JY to see if I can source another connector and pig tail... Hopefully this is the problem. I will post up results.
 

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I checked the camshaft sensor plug yesterday for engagement, but pulled it off this morning to visually inspect it and the wires were destroyed... The 12v (red) was hanging on by one strand of copper, and the other two weren't much better... I'm going to the local JY to see if I can source another connector and pig tail... Hopefully this is the problem. I will post up results.
That's it. :D
 

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Re wired the sensor and still nothing...

Another issue arose... I got an email back from lt1swap... I purchased a newer, used, intake with injectors and a TB to run. It was $50, who could pass that up. Well come to find out, the injectors that came with the intake were flex fuel... My harness didn't have the correct plugs for those 2004+ injectors... The PCM was flashed for those injectors... lt1swap says that even if everything was right, it would be very difficult to start the engine with the tune and stock injectors due to the fact they flow almost half of what the flex fuel ones do...

Damn... If it isn't one thing its another with this swap...

I have a 2007 5.3 that I just picked up, and the harness has the proper plugs for the other injectors, but I really don't want to cut it up... I could send the pcm back for a stock injector reflash, but that will take a week turnaround minimum... There is a local place that I just discovered does GM PCM tunes... I will talk to them on monday to see what they can do and charge...

PITA!
 
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