Jump to content
Sign in to follow this  
TH Cummins

Gauges went crazy!

Recommended Posts

So I finished rebuilding my truck the other day. Started right up and took it out a few times, ran and drove great. The last time however, I took a corner and accelerated and my gauges went nuts. The water in fuel, check engine, check gauges lights all came on and my oil pressure gauge also reads 0. I have no idea what's going on or why that happened? Ran the truck a little after the fact and it still runs and idles fine without any excessive noise so I don't think it really has no oil pressure. Any insight would be appreciated. Thanks!

Share this post


Link to post
Share on other sites

It also has a new ECM, well it's just out of a different truck, but new to mine. Didn't have it flashed but it worked right when I plugged it in, don't know if for some reason after a couple days of driving it this could be affecting it or not? I'll check for loose connections tomorrow though, seems kind of odd for something to actually be wrong

Share this post


Link to post
Share on other sites

It also has a new ECM, well it's just out of a different truck, but new to mine. Didn't have it flashed but it worked right when I plugged it in, don't know if for some reason after a couple days of driving it this could be affecting it or not? I'll check for loose connections tomorrow though, seems kind of odd for something to actually be wrong

That explains a lot, unless the ECM came off the same year and same option pickup, it will cause the gauges to go funky, it is a good tell tale you didn't have the ECM flashed to your rigs specs. Many folks have ran into this exact problem with ECM swaps.

Share this post


Link to post
Share on other sites

That explains a lot, unless the ECM came off the same year and same option pickup, it will cause the gauges to go funky, it is a good tell tale you didn't have the ECM flashed to your rigs specs. Many folks have ran into this exact problem with ECM swaps.

Even after it ran fine for a day or two and none of those lights/errors were on? Just thought it was weird that it wouldn't have happened right away and been wrong from the get go

Share this post


Link to post
Share on other sites

That is weird, but is the ECM actually from the exact same model year and specs?

The date of manufacture is really close, exact same part number. I'm not sure if it was an auto or manual. The guy I got it from just receives parts in bulk and supposedly checks them to make sure they work and whatnot but doesn't know the ins and outs of the vehicle they come out of.

Share this post


Link to post
Share on other sites

I would check connections again and then pay a dealer an hour labor to have it flashed just to be sure. It will save a lot of time and headache in the troubleshooting scheme and then you can rule it out for sure.

  • Like 1

Share this post


Link to post
Share on other sites

Ok, So it seems that every time I dig into my truck to figure out the issue something else comes up.. I'm at a loss and have no idea where to go from here. The water in fuel light, check gages, check engine lights are all on. The oil pressure gauge sometimes works, and sometimes doesn't, radio cuts in and out. The tach also will come and go as it pleases. Now I am also having trouble with the truck starting. Some days it fires right up, and others it will crank til the batteries are dead. If I leave it sit for a day or two it won't start when I try. Idk if it's the ECM, the gauge cluster itself, wiring, a sensor, multiple sensors? The truck runs PERFECT, nothing was wrong when I pulled the motor, had it rebuilt, stuck it back in, plugged everything back in, and now issue after issue.. Any help? Thanks

Share this post


Link to post
Share on other sites

Idk if it's the ECM, the gauge cluster itself, wiring, a sensor, multiple sensors? The truck runs PERFECT, nothing was wrong when I pulled the motor, had it rebuilt, stuck it back in, plugged everything back in, and now issue after issue.. Any help? Thanks

Until you rule out the ECM by re-flashing it to the correct parameters it will be hard to go any farther with your issues, Your issues are classic symptoms of others who have done the same swap and put on a different ECM.
  • Like 1

Share this post


Link to post
Share on other sites

Until you rule out the ECM by re-flashing it to the correct parameters it will be hard to go any farther with your issues, Your issues are classic symptoms of others who have done the same swap and put on a different ECM.

Yeah, I actually had an appointment to get it to a guy that does that this last weekend but didn't want to bring it down there and have it be dead in his way because it won't start from day to day. Wanted to get that squared away before I cruised down there. Makes sense though, I'll try to get it there. Thanks

Share this post


Link to post
Share on other sites

Does he have a factory DRB computer with capability to do this sort of re-flash? Never heard of any private individual having the access to this tooling or factory files / usually a dealer only type of info. The only other places that I thought did this are ECM repair companies or Bob Wagner from Smarty can have this done.I am very interested in this if there are other sources who can do this.

Share this post


Link to post
Share on other sites

Does he have a factory DRB computer with capability to do this sort of re-flash? Never heard of any private individual having the access to this tooling or factory files / usually a dealer only type of info. The only other places that I thought did this are ECM repair companies or Bob Wagner from Smarty can have this done. I am very interested in this if there are other sources who can do this.

To be completely honest I'm not very familiar with the any type of electrical work, wiring, checking for codes, or computer related problems. I just know a guy that used to work at a chrysler dealership and has a scan tool and said that some of the older models just had a vin on the ECM and if you punch in the vin on the new ECM it will sync to the truck it is now in. He said I may have to end up bringing it in but being that he could check it for no charge first I figured it was worth a shot

Share this post


Link to post
Share on other sites

Ok so now my main concern is the issue with it not starting. I atleast want to be able to start it and move it around before I bring it somewhere to have the ECM flashed. The batteries will barely crank the truck over, sometimes it starts and others it will crank for a short period until they are dead. If I check them they read 12.8 or higher every time but still barely crank the truck.. Does this mean the batteries are junk? Just seems weird that they read good on a tester

Share this post


Link to post
Share on other sites

Check the connections. Time to clean ALL battery connections and see what happens.

Share this post


Link to post
Share on other sites

Check the connections. Time to clean ALL battery connections and see what happens.

I've cleaned, and checked all connections to make sure they're tight. Everything was good

Share this post


Link to post
Share on other sites

I went and got new batteries, my old ones were junk. All was good for a while but now my lift pump isn't running, at all. You can bump the key and I don't get a cycle, and if you try and start it, it will just crank. I'm not sure if it would just be the relay, the ECM, or the lift pump itself? Any of those things a common problem? Thanks

Share this post


Link to post
Share on other sites

Ok so now my main concern is the issue with it not starting. I atleast want to be able to start it and move it around before I bring it somewhere to have the ECM flashed. The batteries will barely crank the truck over, sometimes it starts and others it will crank for a short period until they are dead. If I check them they read 12.8 or higher every time but still barely crank the truck.. Does this mean the batteries are junk? Just seems weird that they read good on a tester

When batteries fail they don't have to fail with low volts but then can fail where they no longer have CCA ability to twist the engine over. As battery age they will continue to charge but the plate will degrade and amperage power will degrade. It's possible. I would have the batteries load tested.

Share this post


Link to post
Share on other sites

If it was me, I'd be thinking about ruling out the instrument cluster. Have you tried swapping out the instrument cluster? I know that most people might not have a spare instrument cluster laying around, but if you can find a known good used one, try swapping it out. If issue continues then the instrument cluster is ruled out and start looking elsewhere.I know I asked this before, but have you checked all of the ground to body terminals? There are quite a few under the hood alone. Did you check the ground terminals on the drivers side below the headlamp? (kind of in front of the battery) My truck has 2 in that viciniity. one looks like it's grounding a whole cluster of circuits, more than likely electronics. Grounding issues can cause all kinds of problems. A faulty ground could easily cause the issue you describe.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  



×