jbv808

Anyone had any low fuel pressure problems on their 22RE's? If so, what caused this low fuel pressure and what kind of symptoms did it creat? Thanks in advanced.

wyoming9

iTrader: (1)

Fuel pump on it`s last legs.

Fuel filter clogged by rust and dirt.

Crushed or kinked fuel lines.

Injectors not spraying correct due to rust and dirt.

Most times it is not so much a pressure problem but the volume of fuel being delivered can`t keep up with demands.

Can cause reduced performance to the point of the engine no longer running.

Without a fuel pressure gauge your only guessing .

Then don`t forget it also can be electrical nature .

Poor grounds

Loose fuses in sockets

Worn relay contacts .

tysen86

I do have a gauge on mine. Heres what has happened:

When engine was new, 5000 miles ago, fuel gauge read 33psi,
about 3000 miles into the new motor gauge dropped to 22psi
then about 4500 miles into it, gauge dropped to 18,
Now, at 5000 miles on new motor, gauge reads 12psi.

I have checked for proper voltage at the pump and its getting 12 volts.
unhooked the hose from the inlet side of the filter and ran the pump. it has lots of flow but no way to check pressure. I'm about to put a brand new filter on it and see if that helps. after that its a toss up between changing the pump or the regulator.

What y'all think?

scope103

I take it from your post that you have NOT tried to measure the fuel pressure, and instead have some (unstated) symptoms that you think might be connected to fuel pressure. My suggestion is a) tell us what those symptoms are; someone here can probably suggest some easy tests to figure out the cause, or b) measure your fuel pressure so you know. The Actron CP7838, for instance, contains the banjo bolt you'll need to connect that particular gauge.

Holy cow! The spec (at idle; the pressure changes with throttle position) is 38-44psi. I find it hard to believe it could run at 22, much less 12!

So, I would suspect your gauge. While the ECU can extend the injector open-time to compensate for running lean, I would be surprised it could overcome a factor-of-3 too low fuel pressure. What kind of gauge is it? Electrical? Brand/Model?

Testing the fuel regulator, though, if pretty easy. Just pull the fuel return line, and plumb it into a suitable container. When you start the fuel pump (I would jumper FP to B+; no need to have the engine vibrating everything) there should be a substantial flow in the return line. This is because the pump produces well over 44psi, and the regulator "dumps" what it doesn't need. If you get no (or very limited) flow on the return line, it means the pump is wheezing just to get 12psi, and the pump is probably toast.

tysen86

The gauge is an LC engineering, mechanical gage.

New fuel filter, still at 12 psi.

It runs great, I'm thinking the gauge is acting up....

I unhooked the fuel line at the pump just to see if the pump is putting anything out and I was actually surprised at the amount of flow that the pump is putting out.

Also, when i pull the vacuum line off, there is no change in in fuel pressure. again, thinking its the gauge....

scope103

Looking at the flow from the fuel pump is only part of the story; once it has to start pumping against pressure it could fall way off. That's way a pressure gauge plus the flow OUT of the regulator is a better test.

When you pulled the vacuum line off, was the engine running? If not, there's no vacuum, so the pressure should NOT change. (If the engine was running with about -5 to -7psi vacuum, the fuel pressure should be 5-7 psi lower, so when you pull the vacuum line it should jump back up by 5-7psi.)

tysen86

Yes, the engine was running. I talked to Mike at LC and he agrees, a 22re probably won't run on 12 psi.

scope103

tysen -

Sure sounds like a bad gauge setup.

But other than not knowing the number of your fuel pressure, why do you care? Are you having a problem?

By the way - where is your gauge mounted? You know mechanical gauges are not supposed to go in the cabin. (lines filled with pressurized fuel should be on the OTHER side of the firewall)

tysen86

youre absolutely right. Knowing the fuel pressure is the only issue. The thing is running great. I guess I'm just ocd. It's a gorgeous motor and I hate having to explain why the gauge is so low when I show it off.

It's located on the cold start injector. No fuel in the cab.

wallytoo

iTrader: (1)

probably the LCE gauge is failing. i installed one several months ago, and it worked for about two weeks - progressively lower readings, eventually down to zero, but engine still ran. LCE sent me a new gauge - thank you - but it also failed after bout two weeks. i sent the first one back to LCE so they could diagnose it, but have not heard any results.

wally

tysen86

They're sending me a new gauge also. We'll see how it does.

Chaviator

I had one of those gauges and had it replaced for another one because it just went all the way to zero, so at last LC engineering replace it once again for a liquid filled one and that's been holding up for the last 3 to 5 years. As of now I've noticed the pressure, as I accelerate, goes below 30psi, however I'm having issues with my truck hesitating so much when I apply gas and barely moves...so I'm going to swap the fuel pump to see if I fix that issue, I do not know what else to do since I have already done everything else... New denso spark plugs and wires, swapped coil and tps, new distributer cap and rotor, cleaned injectors using spray through the air intake, also Lucas treatment in the fuel tank for injectors and valve cleaning, checked for vac leaks, all checked. So I'm hoping the fuel pump is the issue because I do not know what else to do. That fuel pump is an aftermarket that lasted a while now, perhaps 5-7years, I Know original parts last longer than that...
Definatley the your issue is your gauge because they go bad after a few days or weeks, I know because I had to have two replaced witching a very few weeks...!

Chaviator

Update
I just swapped my fuel pump and solved my hesitation when accelerated. Definatley when you have low fuel pressure, first thing to check is the fuel pump. Unfortunately for me, that was the last thing I checked, lol

old87yota

But you know everything else is good to go now!

outdoorjunky

Old thread I know but for people that have this issue in the future I just had this issue last night. I replaced my old junky EFI wiring harness with one from a truck with low miles and everything worked fine for a couple of days but I must have bumped the rubber boot off of the wire that runs from the battery positive to the starter and after driving it around and going over some bumps it started grounding out on the starter housing. The truck started to have this horrible squelch when I activated the starter and then it went from that to not starting at all but I could tell it was something electrical because the charge gauge was dropping to zero when I turned the ignition. I reached down there and move the wire away from the housing and reinstalled the boot and it fires right up every time. Looks like I will need to run a new wire soon because there is exposed copper at the crimp that made it possible for this issue to happen.

From my reading it seems that sometimes the relay/configuration of the ignition system can be a problem with these but luckily I've only ever had the starter be the problem or in this case the wiring was grounding out and it was an easy fix.

wyoming9

iTrader: (1)

Unless the copper is melted from arcing heat shrink and call it good

outdoorjunky

random LOL I wasn't trying to reply to this thread ... I must have clicked on the next thread on the bottom of the page LMAO. I was referring to a no start thread not fuel pressure haha.