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TH Cummins

'99 24v starting/priming issues

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I am having some troubles since rebuilding my engine and putting it back together. I'm not sure if the problem is caused by the lift pump, just not being primed, or the ECM. I put a new ECM in my truck do to the fact that my old one had a faulty wait to start light and thought maybe it was messing with the lift pump. I also tried priming it by bumping the starter and my pump does not run for the 20 or so seconds it's supposed to, and doesn't always run at all? It will crank but haven't got it to fire or start. Could this be from the lift pump being junk? The ECM not being flashed for my truck? Or just simply isn't primed yet? Any help is appreciated, thanks!

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The in tank pump is not stock. It is Dodges answer to the block mounted lift pump that was stock. They are both pretty crappy at best. I would check the voltage like Seth suggested. Is the ECM from Dodge? If so I would think they flashed properly when they installed it.

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The in tank pump is not stock. It is Dodges answer to the block mounted lift pump that was stock. They are both pretty crappy at best. I would check the voltage like Seth suggested. Is the ECM from Dodge? If so I would think they flashed properly when they installed it.

I was under the impression that some of the trucks actually came with the in tank pump. I don't know tons about these trucks so thanks for the heads up. So at some point this has had a lift pump put in it. The ECM is used out of a different truck but has the same part number. Wait to start light comes on immediately so I'm assuming it works as it should?

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I had one in mine. It was installed by dodge when the block mounted pump went. For the life of me I cant remember how it was wired. for some reason I dont think it was wired to the oe ECM connection which would have used the ECM for the relay trigger. I could be wrong however. You can look and see if it is being used. You should see it just to the rear and below the fuel filter canister. There should be a relay mounted on the firewall on the driver side that runs the in tank pump. If it si not using the ECM for the trigger you wont get the 25 or so second run of the pump. I knew so little about how this stuff works when I got rid of mine I did not pay any attention to how it worked.The ECM you are using sounds like it is working fine. Same part # and the wait to start light working are good signs.

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When they put the intank pumps in, they ran a wire up to a connector that was behind the drivers front wheel well. That's all I can remember doing, but there had to be more to it, I know we also had to flash the ecm.

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Good to hear. What did the problem turn out to be?

Just needed to run the pump, and crack some of the injector lines. Started right up and cleared out almost instantly

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