bleeding injection pump

gary in neb. · Oct 12, 2015

wasn't sure where to post this so thought I'd try here. friend of mine called me Saturday to look at his new purchase. a jcb 1550b backhoe. fella he bought it from said he could not get the air out of the injection lines.
so, I went through the bleeding of the system. took out both vents (it's a CAV pump)took injection lines loose and could not get any fuel. buddy says it runs on either. he had it running on either/wd-40 combo for about 30 seconds two or three times and no fuel out of injection side of pump. told him to replace injection pump.
he did not believe me and says he things it's the transfer pump not putting out enough pressure so he ordered one. transfer pump would not blow my finger off the line when he pumped it, but still had fuel at injection pump and electric shutoff is working.
took timing cover off pump, shaft is turning.
thoughts???
Gary

RM-MN · Oct 12, 2015

Injector pump plungers stuck?

Billy Shafer · Oct 12, 2015

Did you bleed the air out of the pump.

Tx Jim · Oct 12, 2015

Is fuel control of IP manual or electric controlled? Also it's possible the metering valve in IP is stuck.

JF in MI · Oct 12, 2015

I have run my CAV pump dry several times. The only way to bleed it (after letting the air out of the pump bleeder screws) is to crack the tubes up at the injectors and crank it at FULL throttle. Cranking it at idle setting does practically nothing.

gary in neb. · Oct 12, 2015

pump is bled at least out of the vent ports. it has an electric selonoid right after the inlet side of the pump, thought that was bad but took it out and still would not get fuel out of high pressure side. have throttle open to wide.
possible metering valve stuck but also wonder as I was looking at a pic of this without the electric solenoid, if the manual shut off arm is hooked up in the pump and is "off". not sure how the electric would shut the motor down very fast as fuel would still be in the metering valve side of things.
but I'm pretty sure it's not the manual fuel pump.

Al Baker(pumpman) · Oct 12, 2015

Most CAV DPA pumps bleed a little hard. You will always have better luck if you loosen the bolt through the fuel line at the pump. Most DPAs have a check valve in the bolt that makes pushing air out difficult. MAke sure you have a full 12 volt to the electric shut off. Plungers or metering vale only stick if machine has sat a long time Good luck,,, Al

gary in neb. · Oct 12, 2015

Al, took the plunger out of the seloniod and still no fuel. I took every line loose starting at the filter inlet and worked all the way back to the return off the injection pump back to the filters. got fuel everywhere. I'm starting to question the shut off on this pump. the only one it has is the electric one and that to me don't make sense as even if that shuts down fuel,the motor should still run awhile correct? I think the thing did set for a couple years but I still question the shut off.
Gary

Dieseltech · Oct 12, 2015

I agree with Al, bet the plungers and/or metering valve are stuck. Have been seeing this trouble more lately, even on pumps that have not set very long, especially with any water in fuel or biofuel..

Al Baker(pumpman) · Oct 12, 2015

Cav-Roosa-or bosch rotary pumps with electric shut off are kind of strange. If you dont have a full 12 volts BEFORE you roll them over they will not let fuel to the high pressure side. If I have one on the test bench and kill the power while spinning to check the shut off,, It will not make fuel again until it comes to a complete stop. Check your power supply with a jumper wire. I rebuilt a DPA off a JCB a few weeks ago and it had a two wire shut off so make sure you also have a good ground. If it does not come alive you will need to get it off and have someone look at it. I would be glad to help you out if you cant find someone in your area or in your budget. Good luck,, feel free to give me a call if you need more trouble shooting details. AL

gary in neb. · Oct 13, 2015

last night I tried putting some pressure to the tank and that made no difference. took top cover off to see if metering valve was stuck and it seemed ok. just seems to me like something in the pump rollers, or something are stuck. when I took the side cover off there was like a fine covering of dirty fuel all over. could wipe off with a rag, so I think best to pull pump.

gary in neb. · Oct 13, 2015

I forgot to mention I took the plunger out of the selonoid to make sure that was not the issue and it made no difference. I started to take the pump off last night. took the little side cover off to time the engine and pump but am use to stanadyne pumps that have the little lines under the cover to time them. this pump don't have that. has A B C up to H.
so, how do I time this to make sure its correct before I take it off? Any guess on a cost to rebuild this style pump?

bleeding injection pump

gary in neb.

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RM-MN

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Billy Shafer

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Tx Jim

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JF in MI

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gary in neb.

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Al Baker(pumpman)

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gary in neb.

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Dieseltech

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Al Baker(pumpman)

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