e38 NO SPARK, NO FUEL PULSE WHEN CRANKING...please help!

[Nkemp]

Hi guys, im having a terrible time trying to get a E38 computer to work in a project car im working on ...

I have tried both HPT and EFI live for removing the VATS and also tried the 100ohm resitor on x1 connector pin 52...no luck...im running out of things to check and try...hoping someone could steer me in a direction I havent tried yet...

thanks guys any help here would be amazing.

nkemp

[Taz]

Post your tune ...


Regards,
Taz

[Nkemp]

how do i post a tune?...im new

i can email it to you...

[Taz]

When you log in to reply ... click on the "Go Advanced" button at the bottom of the message window .... then in the Advance screen click on the attach icon (paper clip) .. follow the prompts to upload your file then click the insert button ... if you still have difficulty, there is a detailed explanation by Joecar of how to do this.


Regards,
Taz

[Nkemp]

12759

here she be...please help...:S...pulling my hair out...gone over everthing ...possible that the ecm doesnt like the os which was flashed in it?

[Taz]

Got it ... taking a look now ... what is the Service Number on the E38 ECM you are using ?


Regards,
Taz

[Nkemp]

the ecm doesnt have a service the sticker was ripped off....:(

[Taz]

the ecm doesnt have a service the sticker was ripped off....:(

Yikes !! Did the E38 ECM come from a 2008 Corvette ? Did you read the original calibration that was in the unknown E38 ECM ? If so, post that also.

Did you flash the 2008 Corvette calibration with a Tech 2 ?


Regards,
Taz

[Nkemp]

basically, the ecm came with the harness i bought from current performance... they purchase new computer from a/c delco and then flash an operating system in...but the stickers were gone when i got it...so this is the only file i have...:(

[Taz]

OK ... Jared knows what he is doing ... is the tune you posted the one the E38 had in it when you received it ?


Regards,
Taz

[Nkemp]

well...i pulled the file out first with hpt made some changes because of the large injectors but and then got frustrated because the car would not start...so i tried it with efi live...but the weird part was that when i orignally pulled the file with HPT i could clearly see he had turned off the VATS ect...but when i pulled it out with EFI it showed them to still be active...?...is that normal?

[Taz]

I need to know if you received the ECM with a 2008 Corvette calibration already loaded, or if you have tried to flash a Corvette calibration in over a truck calibration, etc.


Regards,
Taz

[Nkemp]

yes the very first time i pulled the file out when i recieved it from Jared it came up as 2008 corvette, so unless Jared had flashed over a truck os, im assuming that it was flashed by him a 2008 corvette OS.

I spoke to him today and he said he recieves the ecms empty and flashes in the OS for which ever he selects.

[Taz]

OK ... no worriies then ... try the attached tune ... for the VATS Patch to take requires a FULL FLASH (OS & Calibration), the thick red arrow on the right. When you request a Full Flash some warning screens may pop up .. read these and continue.

Do NOT interupt the Full Flash process.

When you try starting the engine use the Scan Tool to log GM.INJECTOR1 and GM.IGNCOIL1 - these PIDs will tell if the injectors and coils are active.

Good luck ...


Regards,
Taz

[Nkemp]

currently it has an HPT file in the ECM can i flash this over it?

[Taz]

Yes sir ... as long as the HPT file has not been upgraded to a custom OS.


Regards,
Taz

[Nkemp]

ok...loaded the file in ..

when i try to log it while cranking it basically stops the log and then starts again when i start cranking...:S

[Taz]

Does the battery show 12 volts ? If not charge it, then try again. Check all of the grounds in the wiring harness. Not sure how many PIDs you have selected - I usually log less than 20 when trouble shooting a no start.

Add GM.VOLTS and SAE.VPWR, if you have not selected these already.


Regards,
Taz

[Nkemp]

ok ill giver a go...yes battery shows 12v at the ecm while cranking...there is only one ground on the harness from jared...and its behind the cylinder head.

which pins should have grounds?...i only see the one on 73 the large one on x1 connector.

[Taz]

An OEM harness will have at least 3 ground connections - which have numerous grounds spliced in within the harness. If your harness is configured with a single ground connection that's OK ... just make sure there is good conductivity in the ground.

To know how many grounds there are built into your harness you would need to take a look at the ECM pinouts for a 2008 Corvette.

I have seen ignition switches (defective / worn out) that when in the crank position, cut off ignition (run) voltage. This manifests as the starter cranking the engine over, but there is no (or insufficient) voltage going to the ECM and / or injectors and coils to meet run criteria.

A no start condition could be caused by the battery, ignition switch (key switch), ground(s), power circuits to the engine sensors / components, CKP sensor, ECM, calibration (tune), or other issues.

Trouble shooting something like this means systematically confirming circuits / components, and moving on what else remains.


Regards,
Taz

[dlshandera]

I have seen this issue many times when doing engine swaps and starter replacements. 99% of the time a wire on the crank position sensor plug gets damaged, whether it be that it gets yanked out, or cut completely or broken. Id look there first as that causes the exact situation you are describing, trust me i learned this the hard way. 6+ hrs trouble shooting for such a simple issue.

[Nkemp]

I took the ignition switch out of the picture today after loading up your tune just to give it a try by going direct to the battery... Still same result... Is the a way to test and see how good your ground actually is ?... I can see that I have ground with my test light and my volt meter but is there a not so good of a ground that would cause like a false ground at the ECM?

I have my grounds as follows...

Battery mounted in trunk , ground from battery to frame

Engine grounds to frame

ECM grounded to engine cylinder head

PS: the car will be at the Mega Speed Show this weekend as a feature car...
You should swing by say hello... The car is a black fox body mustang.

Let me buy you a beer or something for your help, I really appreciate it...

[Nkemp]

I have seen this issue many times when doing engine swaps and starter replacements. 99% of the time a wire on the crank position sensor plug gets damaged, whether it be that it gets yanked out, or cut completely or broken. Id look there first as that causes the exact situation you are describing, trust me i learned this the hard way. 6+ hrs trouble shooting for such a simple issue.


I seem to have good cranking signal at the ECM pins so I can't see it being a broken wire... This Is driving me crazy:s....

[dlshandera]

I seem to have good cranking signal at the ECM pins so I can't see it being a broken wire... This Is driving me crazy:s....

what about cam position sensor?

[Nkemp]

Ok so after hours of trouble shooting the problem turned out to be a bad wiring harness pinning job on the cam sensor.

Basically , we found it by fluke... We ordered another GM cam sensor and had a hard time plugging it in when we realized the plug which came on the harness was not a GM style cam position sensor plug, but an aftermarket plug which I guess the harness manufacture thought was " close enough".... The problem was the aftermarket connectors pin lableing was not in the same order as the GM plug... Therefore when the pins were installed in slots " A,B,C"... They were actually in the wrong order... So with the new plug installed the car instantly fired up... This was the Second error in this harness I have fixed... I'm hoping the manufacture will step up to the plate and compensate me for some of my time... As now I have nearly 10 hours into this and it's not my fault nor my customers fault...

Thanks everyone for your help!

[Taz]

... the car will be at the Mega Speed Show this weekend as a feature car...
You should swing by say hello... The car is a black fox body mustang ...

One of the customs I tuned was at the show in Toronto - near the center of Hall 1. I recall seeing a black Fox Body Mustang with an LSx engine at the show - guessing that was yours.

Glad to hear you got it figured out.


Regards,
Taz