Major 7.3 Headscratcher

[Arisley]

Wow. Now that is one I have not seen or heard of before. Good luck.


Sent from my truck while eating, adjusting the radio and passing a Mustang sideways.

 

[CATDiezel]

Two things when checking resistance.

One is anything less than 1ohm is not very accurate for a sensor reading very precise pressure. It needs to be down below 0.5 ohms of resistance.

Residual electronic noise going to the PCM is also an issue. Shielded ground wires to carry the noise away need to be grounded from termination point (ie. frame) and capped. Not connected on both ends.

Alternator noise also amplifys when the battery acid (clean water) is LOW.

The batteries act as a noise buffer and softener for the electronic noise produced from the alternator.


Im going to throw out one suggestion--- Change the batteries.

This is a funny issue, When I am flashing a caterpillar ECM with whatever code I CANNOT run the Pinout harness I use to bench flash directly off a battery charger-- it has to be buffered through a battery or else I stand a very HIGH chance of the ECM not taking the code do to un-buffered electronic noise.

Give it a whirl... Im curious!!

 

[Marty]

Batteries have been changed. Already thought about maybe a dead cell problem. Kind of a given. My mistake for not listing. Not to mention... they were dead after the truck sat for 2 weeks or so awhile back.

 

[CATDiezel]

Then it's a grounding issue or noise issue. Man this could get complicated to trace down. Any solenoid can put noise in the line if it's not properly shielded and grounded. Try grounding the case of the alternator to the frame. And or start just randomly playing with grounds.

Make a pig tail and tap in and just start grounding all over everything.

I'm just trying to throw anything out there for you to maybe try if you haven't already.

Really this Is kinda cool. Lol (I'm sure not to you though)

Man, you have a dilly of a problem.

You know... I watched a similar problem to this on a 35liter cat one time. I checked voltage from Earth the the block and came up with 24 volts. The engine was NOT grounded and had become a giant static electricity generator causing all sorts of electronic weird feedback and the engine would act erratic.

Simple solution. 125 drilling rig engines. 125 pig tales. 250 bolts nuts and washers and alot of chasing engines down to install ground straps. All problems went away.

(Just sharing... disclaimer is ... I dunno what your problem is lol)

 

[lincolnlocker]

Then it's a grounding issue or noise issue. Man this could get complicated to trace down. Any solenoid can put noise in the line if it's not properly shielded and grounded. Try grounding the case of the alternator to the frame. And or start just randomly playing with grounds.

Make a pig tail and tap in and just start grounding all over everything.

I'm just trying to throw anything out there for you to maybe try if you haven't already.

Really this Is kinda cool. Lol (I'm sure not to you though)

Man, you have a dilly of a problem.

You know... I watched a similar problem to this on a 35liter cat one time. I checked voltage from Earth the the block and came up with 24 volts. The engine was NOT grounded and had become a giant static electricity generator causing all sorts of electronic weird feedback and the engine would act erratic.

Simple solution. 125 drilling rig engines. 125 pig tales. 250 bolts nuts and washers and alot of chasing engines down to install ground straps. All problems went away.

(Just sharing... disclaimer is ... I dunno what your problem is lol)

holy hell cat... thats a lot of grounds... I have often wondered if these would benefit from added grounds on everything?

live life full throttle

 

[lincolnlocker]

speaking of grounds, shouldnt there be 2 grounds on the block and 2 grounds on the heads of a 7.3?

live life full throttle

 

[Marty]

2 in the front on the bottom and then one in the back to the cab.

 

[lincolnlocker]

2 in the front on the bottom and then one in the back to the cab.

Thank you. wasnt quite sure... when I did headgaskets I only had 3..

live life full throttle

 

[TyCorr]

Thank you. wasnt quite sure... when I did headgaskets I only had 3..

live life full throttle

There is only 3..

 

[mandkole]

have you checked the starter relay? perhaps start it, disconnect the orange line and bypass the relay. That, and the links are the whats between alt and the batteries.

 

[Marty]

Yes, took the terminals off the stud.

 

[MOE]

Anything to report as of late?

 

[Black 02]

Ever resolve this?

 

[Countrycar]

Did this issue ever get fixed. I currently have the same Surging Idle going on, though I suspect it has more to do with Tuning. I'm currently in the process of contacting Matt to see what he can do to fix the problem. I'll post back on my progress.

 

[TyCorr]

Did this issue ever get fixed. I currently have the same Surging Idle going on, though I suspect it has more to do with Tuning. I'm currently in the process of contacting Matt to see what he can do to fix the problem. I'll post back on my progress.

Who is JG trans?

 

[Countrycar]

That would be Jimmy Galant. He builds race transmissions here in Sun Valley Ca.

 

[TyCorr]

Ahhhh...cool. Im trying to find someone local but im not having good luck.

 

[Countrycar]

Are you located in Ca? Jimmy builds and ships transmission's as well.
On Edit; Racetrans.com is his shop.

 

[TyCorr]

Nope...im in IL

 

[Uncle Salty]

Gotta love it when you read several pages and in the end...you fall off of a cliff.