DS4 lift pump pressure gauge

[Sand]

Just installed my lift pump pressure gauge. Close to 4 psi at idle. 2-3psi driving at my old man pace. Hits 0psi (possibly negative pressure) on hard acceleration. Glad I did this. Looking for a lift pump soon.....

 

[ak diesel driver]

must be a Hummer?

 

[jrsavoie]

Fuel pressure gauges should have been factory. I think it's one of the best mods for the money - says somebody that has yet to install his

 

[Sand]

98 H1.
I love these things. Face mounted screws for all trim and dash. Why on earth did cars go to those stupid hidden fragile plastic clips etc.....
I do give Will credit for this. He has insisted on a pressure gauge for ages.

 

[Will L.]

Yeah, i learned the hard way about fuel pressure gauges in The 90's.

@Sand - please fill out your signature- it helps everybody. Nice clean install, what was there before- was that part of the panel blank? Also please do a write up and post it on the other forum, we need to get those guys on this ball. A rising tide raises all ships. Yea, you need to upgrade that LP if you are seeing it go below 1 psi. Just pretend everytime you see the gauge hit 0 psi- it is like sand in your IP.

Everybody else: his 98 is just like a 98 truck engine and transmission except the centermount turbo and maybe alternator & a/c on other sides.

 

[Sand]

It was a clock before. Dead clock.
While im planning a new lift pump - what is a good multi fuel compatible pump? Im looking at the walbro 10 from leroydiesel.

 

[JayTheCPA]

While I know that there is some back-and-forth about the 'desirable' psi, Stanadyne states that the DS4 for our motors should have 5 at the IP inlet under all loads (idle to WOT). The back-and-forth part is that others are running higher with no ill effect and in general there is commentary to not regularly run above 10.

The Walbro FRC-10 gives good pressure where it delivers higher psi at idle and the pressure lowers based on power request, and still is able to give positive pressure even at WOT (presuming no excessive restrictions in the plumbing).

IIRC, Leroy is looking into something new that both delivers good pressure and retains that steady pressure across the power band.

 

[Sand]

Just installed my AC Delco EP158 lift pump. Less than overwhelming as promised but better thsn the one I had. 9psi before starting the engine. 6 psi at idle. 4-6 psi with normal driving. I can make it hit 0.5 psi under full acceleration just before the transmission shifts. Its better than what I had, cost 75 dollars US and I can now keep an eye on it. Next one will be an upgrade but self admittedly I drive like an old man so full acceleration is a rare thing.
Sandy

 

[JayTheCPA]

Out of curiosity, what type of sending unit is the ague using and where is it reading the pressure?


Reason for the question is that I currently have electronic sending units mounted directly to the motor and am learning that they are not taking well to the heat. Am in the process of remote mounting the sending units (via hose) so that they get a little less heat.

For the fuel pressure sending unit, the current location is right at the IP inlet and soon it will move to just off the motor.

 

[Sand]

Mine is a mechanical gauge. No sending unit. The 1/16 tube is T'd into where there was a fuel pressure test port with a schrader valve just before the Injection Pump. I pulled the schrader fitting and plumbed the guage there. I have an isolator inline to keep fuel out of the interior.

 

[Burning oil]

FYI. Im releasing a Hummer specific fuel pump kit tomorrow. It uses the Walbro FRC10 and will have all the specific fittings for the Hummer (Hummers with dual tanks).
Its nice, and relocates the LP to the rear close to the tank. Fuel pumps push fuel better than drawing it.

 

[jrsavoie]

Mine is a mechanical gauge. No sending unit. The 1/16 tube is T'd into where there was a fuel pressure test port with a schrader valve just before the Injection Pump. I pulled the schrader fitting and plumbed the guage there. I have an isolator inline to keep fuel out of the interior.

Do you have any pics of your install?

 

[Sand]

Sure. Ill take a few and post tomorrow.

 

[Sand]

Here is the tie in I used on my H1. Its just before the IP. I unbolted it and turned it upside down - removed the test port and threaded in the 1/8 npt tube adapter. The tube coils around and weaves its way through a spare gromet on the firewall behind the dash. I cracked my fuel isolator tightening a leaking fitting so have bypassed it until I can machine a new part or get another one....

 

[Sand]

I love these trucks. So easy to work on. Just look at the cavernous amount of space beside the engine. I can nearly crawl in there between the engine and body.

 

[Will L.]

I love these trucks. So easy to work on. Just look at the cavernous amount of space beside the engine. I can nearly crawl in there between the engine and body.

I see I am not the only one who can't find the sarcasm font.

Looks good, just remember to bleed off the drain side with the engine running to flush out water once a year even if the dash light never comes on. Sux about the snubber/isolator.

For the pickup guys: on hummers the t handle drain battery that is normally on the engine is moved to the wheel well accessible with hood closed. On 1996 turbo/ds4 hummers, they put that block there you see with a schrader valve on it for fuel pressure gauge connection, but it is still tapped of the drain side of the ffm. The he driver side on hummers is way worse than in trucks even with the turbo moved to center mount.

 

[Quadstar Tuning LLC]

I'd definitely look into Leroy's new upgrade kit. 0.5psi under load while dragging around a Hummer is no good. You want to maintain 5psi even under the highest demand. Trust me.

And that 0.5 psi will turn into 0 or even worse after a few months when the EP158 starts to slowly die.