what controls the "wait to start light"

[James T]

 Base Info, 1999 FASS fuel pump on the block new injectors at75 hp new tubes and lines on all injectors, new exhaust manifold 3 piece with new banks intake. Quadzilla Adrenaline Daily driver tune

The issue I have is....   there is an inconsistent time for the WTS light to come on. there is also a duration the light stays on 

Some time when I start the Dodge she fires rite up half a turn and she comes to life other times she will turn over and not start until the second and some time the third try I am thinking the module that controls the WTS light seems to be in league with the issue. I don't remember it taking so long to come on. when I put the key in the ignition and turn to start without cranking, it takes 3-5 beeps before the light come on.  all other dash lights come on as soon as the key is turned to the start position but the WST does not always come on at the same time as the rest of the instrument lights. then when it goes out it cranks but does not start like it should,  2-3 attempts before it starts. Does not seem to matter warm or cold

it almost seems like fuel starving.  I have noticed that as soon as the light goes out on the second or third time it comes to life like it should.   any guidance would be appreciated 

 

[Max Tune]

I believe your ECM is going out.

[Silverwolf2691]

@Mopar1973Man, 24v powertrain might be a better spot for this. Can we move the thread?

 

@James T, I agree with @Max Tune. The wait to start light is driven by the ECU. It serves as a health check of the ECU on every start and the "timer" for the grid heaters when they are needed.  

[Mopar1973Man]

21 hours ago, Silverwolf2691 said:

@Mopar1973Man, 24v powertrain might be a better spot for this. Can we move the thread?

 

Presto, chango... Moved to 24V Powertrain forum.

 

In a nutshell if the WTS is not on... The ECM did NOT boot up yet and having errors during boot up.so it keeps trying till the ECM boots up fully. Boot up time should be instant with the key so if the WTS light isn't coming on then the ECM is going south for sure. 

 

Cause: Most likely don't have the W-T ground wire mod and have excessive AC noise from the alternator which typically cooks the chips in the ECM. In this case its messing with the EPROM that stores the code for the ECM so when power is ON the processor boot strap request the data stored in the EPROM the actual run code. The first instruction of code is to check for IAT temps and turn on the Wait To Start and the grid heater if needed. So you going to need to do AC noise check and most likely replace the alternator. Then do the W-T ground wire mod, then send the ECM to @Auto Computer Specialist to be rebuilt. You can then notify the staff that you already replaced the alternator, W-T ground wire mod and other mode to insure no future damage which they will ask about. So get that done first thing. 

[Auto Computer Specialist]

We are here to help in any way we can, feel free to call and chat about your issues. Sounds like your ready for an ECM rebuild, contact us, 954-513-8359. Hope to hear from you soon. Best Regards ACS

[Doubletrouble]

8 hours ago, Auto Computer Specialist said:

We are here to help in any way we can, feel free to call and chat about your issues. Sounds like your ready for an ECM rebuild, contact us, 954-513-8359. Hope to hear from you soon. Best Regards ACS

 I am curious, what does an average ecm rebuild cost. I am not in need of one, just asking. Thanks 

[James T]

Lots of great information thanks. I now have many more questions.

what is the W-T ground wire mod and it would appear that there two ECM or ECU's, one on the engine 

and one on the fire wall. which one is the WTS light issue linked to??

How do you do an AC noise ck on the alternator?? if the alternator is replaced is there a larger output Alternator over the standard OEM

is there any advantage of repairing vrs replacement of the ECM /ECU other than cost, any programming differences

has anyone used ACS for the upgrade how were the results??

 

 

[wil440]

Search in articles

here is the link to the WT mod  

Engine ECM, on the drivers side of the block,,  the one on the passenger side firewall is the Powertrain Control Module or PCM so not this one

 

New ECU not available, repair what you have if possible, ASC will sort you out, never had to use them YET but that's where mine would go if it failed and I'm in the UK, company of choice for the guys on here for ecu/pcm etc

[Max Tune]

Testing for AC is very simple. You need a meter that can read AC voltage on a low scale. Positive probe to output stud on back of alt and negative to negative post on passenger battery. Should read less than 0.05. I think test is to be done after driving truck for awhile to top up batteries after starting and to be sure grid heaters are off. I'm sure someone will chime in to correct or verify what I said as I may have something not completely right, but that's the jist of the test.

[Mopar1973Man]

8 minutes ago, Max Tune said:

Testing for AC is very simple. You need a meter that can read AC voltage on a low scale. Positive probe to output stud on back of alt and negative to negative post on passenger battery. Should read less than 0.05. I think test is to be done after driving truck for awhile to top up batteries after starting and to be sure grid heaters are off. I'm sure someone will chime in to correct or verify what I said as I may have something not completely right, but that's the jist of the test.

In a nutshell it is correct. Only difference I might check the black probe directly to the alternator case.

[Auto Computer Specialist]

On 2/18/2022 at 9:31 PM, Doubletrouble said:

 I am curious, what does an average ecm rebuild cost. I am not in need of one, just asking. Thanks 

@Doubletrouble Our price depends on the service needed, we have multiple services provided for the problem at hand. Example, there is a wait to start service, a general repair service and a P0600 removal service. General repair service is $399 plus a 15% discount for our Forum members. 

On 2/19/2022 at 1:31 AM, James T said:

Lots of great information thanks. I now have many more questions.

what is the W-T ground wire mod and it would appear that there two ECM or ECU's, one on the engine 

and one on the fire wall. which one is the WTS light issue linked to??

How do you do an AC noise ck on the alternator?? if the alternator is replaced is there a larger output Alternator over the standard OEM

is there any advantage of repairing vrs replacement of the ECM /ECU other than cost, any programming differences

has anyone used ACS for the upgrade how were the results??

 

 

We would be happy to assist you, contact us at 954-513-8359