Harbor Freight CIS fuel pressure tester review

[bpu699]

Well, I am working on making sure my fuel system is up to snuff. I have a Harbor Freight near me, so I went and bought their "Master Fuel Injection Pressure tester." 89$, with a 25% off coupon, it was $75 or so with tax.

I thought I would share my experience for folks considering buying one of these.

First, you get an aweful lot for the money. Other testers can run $300 or so. Thats a lot for a tool you may not use often. The tool set is nicely packaged, and does include all of the connectors you would need.

I read a lot of the online reviews, and some folks complained that it leaked at the fittings. I used teflon tape to prevent this, and had zero issues.

I connected mine between the fuel distributor and the WUR. The pressures I was getting were somewhat wacky, and I knew they couldn't be right.

I had a system pressure of 100 psi (that sounds about right), and a cold pressure of 90. THAT can't be right. Switched the ball valve to the other side, no change. Put the ball valve back on the side nearer the WUR.

The pressure guage also didn't seem to go down once the valve was opened… odd.

Each connector of the kit has a tiny one-way shrader (?spelling) valve. These have absolutely tiny orifices. For the fuel to go throught the connectors to back to the WUR, it had to go through 4 (!!!) of these. The function of these is to keep fuel from shooting into your face, when you use the quick disconnects.

I figured these valves must be creating massive resistance, so I removed them. This made a world of difference. Now, it worked like it was supposed to!!!

I checked to make sure there was no further resistance, by leaving an open line and running the fuel through to an open container. Flowed easily, no issues.

With this modification, the gauges worked beautifully. The Shrader valves screw out easily with needle nose pliers. The gauge now worked well, and the results were repeatable. And, if I wanted, I can screw the schrader valves back in - no damage done.

For anyone looking for a fuel pressure tester, this one is highly recommended. Helluva value!!!

Bo

[kostya.lyt]

I went through the same issues you did with the Schrader valve, didn't even think to remove them! I immediately returned the set and purchased a higher quality unit on Amazon.

You're right, can't beat the value!

[Robey5]

Bo:

I picked up the same set; and I am not sure I understand what you did: removed the quick disconnect pieces? Or just the pin from inside the small side of the quick disconnect part?

Also, when you did this, did the gauge return to -0- when you removed the pressure from the system with these connections removed??

Can you post a picture of what you removed from the equation?

[bpu699]

I left the quick disconnects on, but removed their guts. On the female end, it pops out when you unscrew it. On the male end, the little valve unscrews easily.

Now, I can blow through all the connectors with no issues. Did the same for the connector on the gauge.

Works great.

Bo

[RDM]

Originally Posted by kostya.lyt

I went through the same issues you did with the Schrader valve, didn't even think to remove them! I immediately returned the set and purchased a higher quality unit on Amazon.

You're right, can't beat the value!

My experience also.

[dos531]

Did the same with mine. Works great now

[dicklague]

I have one and did the same mod.

How can you go wrong for $20.00!!

[bpu699]

Just wanted to wrap this up. Looks like I fixed my cis issue, the hf kit worked great. I am really pleased.

I just realized it also can be used to measure oil pressure, as it has the attachments.

Go buy one, hard to go wrong here.

Bo

[universeman]

Question about fuel pressure gauges: I am looking at this kit and also one on Amazon...neither seems to have the 3-way fitting with the open/shut valve that Bentley describes (they have T-connectors but no valve.)

Question - do you really need the valve or will a simple T work?

[ossiblue]

Originally Posted by universeman

Question about fuel pressure gauges: I am looking at this kit and also one on Amazon...neither seems to have the 3-way fitting with the open/shut valve that Bentley describes (they have T-connectors but no valve.)

Question - do you really need the valve or will a simple T work?

You absolutely need a shut off valve to isolate the wur from the fuel distributor. Without a picture of the sets you are considering, it's hard to know if they have a valve connected to one side of the "T" connector. The gauge sets I've looked at (for CIS) all had a shut off valve. As long as you can shut the flow off to one side of the gauge, the set will work for CIS. It doesn't need to have a special 3-way valve.

[rusnak]

Great value priced kit. The gauge is OK, but all of the hoses and connections are very good.

Works well for both 911SC and 3.2 Carrera.

To answer the above, yes there is a 3-way connector and a shut off for the CIS test of the WUR.

[bpu699]

As a bonus, you can use the same kit to manually check your oil pressure!!!

Go buy the Harbor Freight kit. Helluva deal, no complaints.

Bo

[88911coupe]

Can I assume this tool from HF would work on a Motronic engine as well?

[T77911S]

here is something else to consider.

i bought a new fuel tester. about $110. they sent me 2 by mistake. one reads .5bar lower than the other when i check system pressure but read the same for the lower control pressure. the pressures were also bouncing up and down.

now i dont know what my system pressure REALLY is.

[Derek911]

All these posts and no one own a camera??

[nickd]

Does this help? Harbor Freight deluxe kit. Worked great on my 964 checking pressure at the fuel rail. It does have a hose set with an inline valve, so should work fine with CIS.

[T77911S]

that schreder valve is in that quick disconnect so that fuel does not shoot out when the gauge is not connected.

i cant tell if that gauge has a pressure relief valve on it so that fuel does not spray everywhere. (perhpas also why it has the schreder valve).

[sugarwood]

Which one is the fitting that is M12x1.5 female that connects to the fuel rail ?

[bpu699]

Take the Schroeder valves out. They screw up the readings big time.

Bo

[wicks]

Question about the shrader valves - I removed all of them and got a reading of zero, then put them all back in and get a proper system pressure, but opening the valve to WUR I get no change - stays at system pressure. I can’t figure how this behavior could happen - seems like with no valves in lines I should be able to see both system and control...any clues?