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New member

Re: 3408E Starting Issues

Physically checked HEUI pump pressure. 0 psi. Ordered and installed OR pump and started like a dream. Thanks for the help.

Super Contributor

Re: 3408E Starting Issues

Yes, you need to dead head the pump and check HEUI pump pressure with a mechanical gauge. Also, read the instructions that came with the compensation plug kit.
New member

Re: 3408E Starting Issues

I figured the IAP was a false reading. CAT offers a plug kit for the HEUI pumps and a graph that shows which plug is longer or shorter than the current one. By dead heading the pump you mean to cap the outlets from the pump and tee in a pressure gauge capable of reading 4500 psi min?

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Super Contributor

Re: 3408E Starting Issues

At least 800 PSI IAP is required for starting. The 256 PSI IAP is false, that's actually the lowest the pressure will display. The actual IAP is probably zero. You need to dead-head the HEUI pump and check pressure. Should be around 4500 PSI. How did you select the compensator plug? Compensator pressure should be 700-840 with IAPCV disconnected with engine at idle.
New member

3408E Starting Issues

I have an 836 Landfill Compacter SIN# 7FR00315 that will not start. Intermittedly it will start however completly random. Checked speed sensors, changed IAP sensor and IAPCV, checked engine and ECM harness' for moisture and wear. Have installed different compensator plugs.  While starting "Disabled Injection" appears in the status flag section of CAT ET. Only active code is throttle lock lamp current below normal. While cranking; engine oil pressure according to CAT ET varies around 7-9 psi. IAP stays constant at 256 psi. Ground Level Shutdown Switch is working correctly and is off. Any help would be appreciated.