possible injection pump prolem

This topic contains 3 replies and was last updated by tommy-2 6 years 5 months ago
Author
tommy-2
November 1st, 2013 4:04am
Post
Hi have a 1995 toyota dyna diesel. When engine exceeds 3000 rpm a rattling sound is heard and revs increase without intervention from the driver but does not result in any speed increase a lot of white exhaust smoke is observed. After removing my foot from the accelerator pedal the revs will settle down and smoke will clear within 30 seconds of this event. Suspecting the VE injection pump is the course but confused with the symtoms of this problem and cant make any sense of this. would appreciate any suggestions.



Regards tommy
electronexciter
August 25th, 2015 12:12pm
Is the rattling coming from the injection pump or is it coming from the engine block? Could the rattling be detonation in the cylinder from incorrect injection timing? Perhaps you could start by loosening the injection tube union nut, where they connect to the nozzle, one at a time with the engine running at low idle. You should hear an rpm drop as each union nut is cracked open. If there is no rpm drop, that nozzle is not contributing to the power balance. Use a shop towel to contain any fuel that might squirt out as the union nut is loosened. Next I would probably check the injection timing of your VE pump. Dynamic injection timing is a more meaningful measurement since ii is measured with engine running at high idle, but it requires special tooling such as a Ferret loop that clamps onto your #1 injection tube and sends an electrical pulse through the ferret wire loop with each injection pulse. A timing light with an inductive pickup clamps around the Ferret wire loop and triggers the timing light with each injection pulse. I am not familiar with your Toyota but it probably has timing marks on the vibration damper that can be read with the timing light. These Ferret wire loops can be purchased at GXT.com or at Tooldiscounter.com. The Ferret part # is V765-02 for a 6.5mm injection tube clamp. Be aware there are different sizes of clamps available for the 0.25 inch, 6.0 and 6.5mm diameter injection tubes. The Ferret device costs about 150 USD.



If you do not want to get the tooling, about all you can do is measure static timing with the engine off. The VE pump on the pump flange has a single timing mark that aligns with a timing mark on the gear housing to which the injection pumps mounts. These timing lines should be aligned when timed correctly. The purpose of these injection timing lines is to get your timing close before starting the engine. Dynamic timing adjustment, with the engine running, is used to fine tune the timing. Rotating the injection pump housing in relation to the gear housing changes your injection timing. This adjustment should be made with the engine off; drive gear damage can result if the pump is loosened and rotated with the engine running. There is a more accurate way of measuring static injection timing which involves using a dial indicator that screws inrto the back of the injection pump and indicates the mm lift of your pump's cam lobe however this also requires special tooling and you would have to know the injection pump's cam lobe lift specification for your vehicle.



Since your problem only occurs above 3000 rpm I suspect a static timing measurement might not indicate a problem. A dynamic timing measurement would really be more appropriate for the problem. Since engine rpm increases, I think we can rule out a fuel supply issue.



That VE pump probably has a cold start advance solenoid. Does the problem disappear when the solenoid is disconnected?



Is there any fuel dilution in your engine oil? Is the oil thinner than normal and does it smell of fuel?
electronexciter
August 25th, 2015 4:04pm
Correction: GXT.com is wrong. Its GXTauto.com for the Ferret injection timing tool.
electronexciter
August 25th, 2015 6:06pm
On second thought, it might not be a bad idea to check your engine speeds to verify that the fuel supply system is ok. When the engine speed surges, is it increasing from a value that's lower than the specified high idle, up to the correct high idle speed? This could be fuel starvation issue. Or, is the engine speed increasing from the correct high idle specified speed up to a speed value that is higher than the specified high idle speed. This could be an overfueling or fuel metering issue. Since this is a highway vehicle, maybe there isn't a specified high idle speed since the governor might be regulated differently. Hopefully someone who's good with mechanical fuel systems can help you with this.

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