Fuel pump replacment
#1
Fuel pump replacment
Hey guys I'm having long starts after the truck sits for a few hours. I get 30 psi with key on and 28+ on rev. I've read on these forums it should be above of 34 psi. I replaced the fuel pump years ago when the check valve on the original old one failed and I replaced it with a cheap $50 pump off ebay to get me running.
I was wondering if the fuel pump is my issue? and if so can I keep the housing and just replace the pump itself with a better one? Trying to keep my costs down. $700+ for a new pump is not in the budget for this truck. Also I'm trying to keep costs low atm for a few years till I can pull and rebuild the engine.
Compression on all cylinders is about 110psi +- 3psi. 150k miles. Very sluggish power.
Thanks
I was wondering if the fuel pump is my issue? and if so can I keep the housing and just replace the pump itself with a better one? Trying to keep my costs down. $700+ for a new pump is not in the budget for this truck. Also I'm trying to keep costs low atm for a few years till I can pull and rebuild the engine.
Compression on all cylinders is about 110psi +- 3psi. 150k miles. Very sluggish power.
Thanks
#4
#7
On better "performance", that's a over used word just saying like a "heavy duty" replacement part. Made to run better overall yes that can be done.
Had to ask, did you receive a recall by LR involving NTSB a safety issue about possible fires caused by cracked plastic gas tanks that might of split leaking gas when topped off? If cracked a freebie tank replacement by LR and while out they would try and bribe you to replace the fuel pump while apart if you had 60K miles of higher as "their preventive maintenance". Yeah right LR pump price around $300+ a money maker for them. As mentioned above aftermarket pump replacements rather cheap.
With a fuel rail pressure test gauge tester is one of your best investments in checking running rail pressure plus the fuel pressure regulator to know when it's going into bypass. Also able to read max fuel pump output psi after blocking off the fuel return line from regulator. My 143K mile fuel pump still maxes out at 89 psi and a high volume output at 45 psi way above the Hp needs the engine can ever dream of producing.
The 2.5 BAR LR pressure regulators be it brand new or used maintain rail pressure right around the minimum of factory service manual specs of pressure.
Second flaw the single dribble plus add low pressure isn't producing the best spray pattern feeding any engine especially those Lucas single dribble injectors of old 80's design. They are what the Limey's speak as rubbish.
I installed a 89 BMW fuel pressure regulator of 3.0 BAR, same regulator covering several years on BMW's.
On the 94 & 95 OB1 LR's the regulator bolts to the ruel rail with a rubber hose connection which I believe is different on the 96 and newer OB2 LR's. That would require investigating with newer LR owners as I have no clue plus zero interst in 96 and newer OB2 LR's. I recall 96 and newer hard piped line vs rubber hose on 94-95.
The 3.0 BAR regulators go into bypass from arond the max factory servive manual spec to 1.5 psi above max spec, BFD!
With fluid pressure vessel used to clean and check injectors also used with vacuum pump and valving system to check regulators closed and into open bypass psi.
Second improvement item replacing Lucas injectors with 2000 plus era Bosch 4-hole injectors. Ford 351 engines I use. Four thin streams at a higher pressure more easily break up into smaller droplets and mist than any underpressured single dribble injector. Better atomization
Word of wise, used and new injectors can have producton variations up to 20% differences in flow amounts, this not so good with batch fired injected engines that LR use.
Talking left and right banks injecting with each bank controlled by one O2 sensor. You can have on any bank one below normal flow, one higher hence a lean cylinder and a rich one with the O2 sensor keeping the total F/A within normal running and smog regulation limits. These LR engines need all the help they can preventing leaned out self distruction issues.
This is where a balanced set of injectors really shines, all eight flowing equal volumes from simulated testing. I went from idle (below 350 rpm) up to max rpm's (7,300 rpm) checking volume amounts up to 95% duty cycle. This after checking flow paterns plus equal flow streams of all four holes each injectors. Not all streams flow the same from manufacture, this before having plugged up pr partially plugged holes as these four holes are a lot smaller than the single dribble Lucas. Lucas injectors with low or below minimum spec regulator flows like an old man with prostate issues.
Out of 27 used Bosch injectors cleaning first by ultrasonic then flushing backwards and forwards plus checked spray patterns ending up with eight injectors flowing within 3/4% of each other. Matched set of racing injectors use 1% as the standard, I chose 3/4% because it just me.
Cold starts by the 2nd or 3rd cylinder over a complete compression firing right up, smoother idle with overall running up to 5,500 rpm's. It's stupid why push it beyond 5,200 rpm's once in a while anyway being out of the Tq range? Cleaner smog sniff tests besides other simple mods like cold ram air, restriced throttle plate heater for cooler plenum temps and intake charge.
Intake under ram tube base an extension machined out of 1 1/2" thick aluminum plus a 1/4" plate raising the plenum cover allowing more room for air to turn 90 degrees for smoother airflow to the ram tube velocity stack bells at both ends of the plenum cover.
If blessed with a 94 or 95 with a distributor this allowing altering mechanical advance when and how much plus a non U.S. vacuum advance unit having more total vacuum advance degrees, more gains in performance. Tune engines to what they can handle as each engine is different like women.
Port matching intake manifold, heads and exhaust manifolds, that alone making a big performance increase even before doing any mild head porting not wild porting.
Cats, MagnaFlow's 94305 Cats, (94-95 OB1) vs LR's with Borla's stainless Cat back exhaust vs stuffed up, expensive plus heavy OEM LR exhaust. Let the little engine breathe.
First months of D1 ownership every morning it would rattle rods 7-11 seconds before oil pressure developed then went silent.
Rod bearings into the copper, babbitt missing on the upper shells. Michrometer measured crank, within spec, installed new rod berings in the 3.9 of 61K miles.
Still dry starts before oil pressuer was established. Forget an oil change with 20 plus seconds rattling before oil pressure and this with a new oil pump installed. Didn't matter brand of oil filters either as some have better anti drainback qualities.
Installed a 3 quart MasterLube pre-oiler before the 4.6 install with a new timing cover and oil pump from LR. Extended warranty from PO paid for 4.6 and timing cover.
Stripped shortblock, I supplied roller timing chain set.cam and lifters with lifter pre-load shims.
At least I keep same the brand engine in my vehicles and not install a 350 Chubbie into a LR. A 4.9 stroker crank in the 4.6 would be the final upgrade w/ "Top Hat" liners.
With 32 to 38 psi pre-oiler then timer set to six seconds once pressure was established a "wet engine dripping internally", crank slinging oil onto the cylinder bores even after an overnight oil drain with a 33 oz. capacity oil filter installed dry. Designed system with Red/Green LED with a mini NO switch a simple pre-oling system the wife activated when she drove the D1.
First cold start or parked more than two hours then pre-oiled again the rules the wifey followed.
Performance increase, Mark Adams chip installed that stays in even during smog sniff tests. Throttle response plus better mpg all positive gains, fuels normally to 5,900 redline. LR's fuel lean before the leanout getting worse at around 4K rpm's. Engine damage anyone? Several itens adding up to the increased driving fun factor. From a slow turd (bearly lived with) to a normal performing vehicle. Can slow roll a stop sign in front of a cop (testy one) in 2nd, clutch fully engaged then pulls away light throttle at first a very flexible engine the stock engine could never perform. LR's demo rock pile years ago I could chug over in 1st or 2nd as well in reverse in high range. Still keeps pulling past 5K rpm's.
After driving other Discos with automatics I can not imagine owing one vs the 5 speed D1 plus after several upgrades 21 years ago.
Rubber flex joint first thing replaced after ownership with a RR driveshaft sporting a real U-joint, vibration issues permanently solved.
End of novel.....~~=o&o>......
#9
#10
With a couple friends plus a sister owning jeeps nothing makes sense with them, I understand their problem.
Sister's 69 CJ5 V6 with 3 spd and OD since new always wrenching on it until I finally quit. It became yard art 25 years and counting......~~=o&o>.......
Sister's 69 CJ5 V6 with 3 spd and OD since new always wrenching on it until I finally quit. It became yard art 25 years and counting......~~=o&o>.......