Elec./ Computer... lingering problem

[GSP7]

I have a long time issue

 

'99 CTD 4x4 with 170,000, Ive owned the truck for a long time

 

When I turn on the ignition key to 'On',,, the truck alot of times the lift pump and "wait to start" light have a 3-4 second delay before they get power. So it will crank but not fire up unless you wait to here the lift pump turn on and the 'wait to start" light to go on. Its like a 3-4 second delay for the computer to boot up or something is the best way I can describe it.

 

It is a electric issue not a fuel issue sence I mentioned the lift pump, dont get the wrong idea

 

Any ideas what causes this?

 

[Mopar1973Man]

4 minutes ago, GSP7 said:

Any ideas what causes this?

 

AC noise failure on the ECM. In other words, the alternator AC noise cooked the RAM or the PROM chips in the ECM. So now at boot time (key on), the ECM struggles to boot up so the truck is actually brain dead till that WAIT TO START light comes on. You need to verify your alternator is clean, grounds are good. Not the body ground but the passenger main ground for the computers. Then you need to see about having your ECM remanufactured. There is an article started for known good listing of shops.

 

 

Edited November 27, 2017 by Mopar1973Man

[dripley]

What he said.

[GSP7]

Ok,

You guys told me this before, 2-3 years ago, And Mopar man had a thread on Alt noise and bad diode that I saw

I had my alternator checked and it had a bad diode so I had my alternator rebuild with new diode pack and brushes a couple years ago, So my Alternator is good

 

Did my bad Alternator diode damage my ECM?

 

So I need to get my ECM rebuild or get another rebuilt/ good  ECM ?

 

  What / Where exactly is the passenger main ground for the computers.

 

Ill read the link

[Mopar1973Man]

Don't be so confident that your alternator is still good. I've seen alternators fail in under 3 months. Yes it very possible that the ECM got wiped out by excessive AC noise again. I would still retest the alternator and see where you are at. 

[GSP7]

On that link I see only One good shop listed.,

Auto Computer Specialist,,, I called the phone number and it wont accept calls     .....

 

 

Im is Calif. is there any ECM repair places western US?

I called Auto Computer Specialist in Florida and talked to the girl , They seem pretty knowledgable

 

I told her the delay of the "wait to start" and lift pump

 

Where is the

"passenger main ground for the computers" ?

Edited November 27, 2017 by GSP7

[JAG1]

Keep trying they might be a bit slow to go since it was Thanksgiving holidays.

 

I think where you live in Cali. that it would be a benefit to unhook your grid heaters. Anyhow it's warm climate and you don't need them. There was a discussion about how using them can cause excessive AC noise hurting the ECM and another problem...... the fuseable links can melt if grid heater starts going bad. Anyhow I know there is good reason the forum owner, while living in cold climate, unhooks them when temps average above 32* something like that.

 

GSP7, Are you saying you are bumping the starter when it takes awhile to hear the lift pump and see the wait to start??

Edited November 27, 2017 by JAG1

[GSP7]

Where is " passenger main ground for the computers "

 

Do you mean the ground wire on the PCM ? not the ECM

Edited November 27, 2017 by GSP7

[Mopar1973Man]

4 hours ago, GSP7 said:

Where is " passenger main ground for the computers "

 

Do you mean the ground wire on the PCM ? not the ECM

 

 

All the information you need to know...

[GSP7]

Mike , I found what your are talking about and every thing is good tight and clean. In the picture your hand is on a ground wire that has a plug connection. Is that plug something that should be pulled apart and plugged back in? Mine plug looks in great condition. I also have new military battery terminals and up graded cable ends

3 hours ago, Mopar1973Man said:

 

All the information you need to know...

 

[JAG1]

I know of a few cases where they did that and solved a problem.

 

In my case I read about a guy that cut those connectors out and solved the trouble he was having by wrapping them together like a  licorice twist and soldered them together with shrink tubing, but Mike says it's not necessary to butcher up the wires like that so I have not done it to my other second gen.

 

when I pull them apart, tho, they don't feel like a very tight connection to me.

 

Edited November 28, 2017 by JAG1

[Mopar1973Man]

 

I look at it from a simple solution. First of you have to think these truck ran for 10 plus years without any issues. Then all of sudden you have transmission shift issues. Then people start butching the electrical system attempting to fix this problem. Just remember that the truck ran fine for 10 plus year why do you need to do wiring mods or install noise filters? Why not fix the problem and leave the wiring alone that worked fine for so many years.

[JAG1]

I know that too..... but what about those connectors not being very snug and the battery grounding right there to help protect the electronics from some of the AC ripple...... that is my thought because when you slide those apart they really don't feel like a real good connection.

[Mopar1973Man]

27 minutes ago, JAG1 said:

the battery grounding right there to help protect the electronics from some of the AC ripple......

 

You got that backwards...

 

You need to stop the production of AC ripple. You can produce AC ripple on the negative side as well as the positive side. So no matter what you do you still stuck fixing the source of the AC ripple. Because if a diode on the negative side fails it can potentially feed AC ripple down the negative side or into the block. AC ripple doesn't matter if it on the positive or negative side. It has ZERO references to the actual earth ground like house electrical does which will direct that energy to a safe place. On vehicles there is no such place. So the AC ripple continues till the problem is fixed.

 

This is why on some truck the noise filter doesn't work because the fact the noise filter is installed on the positive line but what if the noise in on the negative side? Make you think... 

Edited November 28, 2017 by Mopar1973Man