Bought this 2003 not running. Guess it just died for prev owner. They had a shop look at it and quoted and entire new fuel system but I can find no evidence they did a single thing to it. Not even pull the fuel filter. Curious if anyone has experience with these? Wait to see if any knowledge here before I rattle on.
DONT TOUCH THE INJ. PUMP.!! Unless timing it to pull it off.. That’s the best advice I can offer.. The injectors are serviceable tho..
Well, let's assume I condemn the pump, do you have any procedures prior to removal? I intend to open the bleeder screw on the top of the pump to attempting priming when it gets here, but I don't intend to blindly mess with the pump until there is reason and a plan.
Finally killed an 4HE1 on one here. Definitely the injection pump on ours. Let's start with yours, though. There is screen in the top of the water separator mounted by battery, that is overlooked by many. Remove bowl retaining ring and drop bowl and Oring. Now, spin off the diffuser and pull off screen. If it has a steel tank, tank rust can block that screen (happened on many of mine). It may behoove you to simply remove the separator and place it in a vise. If the retaining ring is seized, you'll have to replace it and know that most aftermarket separators don't have that screen (but, with creativity, you can move the screen over). Next, once cleaned out, replace engine fuel filter, open bleeder on engine fuel filter and unscrew primer handle and pump till clear of air. Another killer on mine is the fuel stop. When key is turned on, stop cable must actuate. This cable is independent of throttle cable. The actuator is like a windshield wiper motor, so, at key on, for a second along with cable movement. Similar at key off along with cable moving other way. Final killer is the catalytic converter muffler. If plugged, engine will run up to 10 seconds and peter out. If attempted to restart right, it won't. If left sitting 30 seconds, it will give up to a 10 second run again. Cut muffler to exhaust brake bolts, leave a gap and restart engine. Should prove plugged muffler.
OK, so just talked to owner and I guess it started in the morning, then started to sputter, the died. They checked the fuel separator and bowl was dry! All good signs of a simple fuel delivery issue. Yes sir, I noticed what looked like a screen at the top of that bowl. When it gets here, I will make that the first thing to check. But on the cable you mention, this does have a fuel shut off solenoid on the pump, but you are saying there is another shut off cable? Truck is not here yet so I am just trying to get my bearings.
Also @heymccall , you say you killed a 4HE1? What happened and how many miles? I am trying to learn the limits on the engines and fuel systems. We have no way to know if the pump or injectors have ever been changed.
I've got 4 of them. The rest are 4hk1 (common rail injection). The 400k mile 4he1 unit that slobbered out the exhaust finally gave up its injection pump. Between the $4k injection pump, engine slobbering (rings from rusted through air filter housing years ago) and rear frame rot, I put that one out to pasture. These things are nearly bullet proof, though. Keep oil and fuel, along with cleaned air, in them and you're good to go. The shut off is only a lever, actuated by a cable. Cable no move= no go. Last one I pulled injectors on, at 250k miles, had them test good. It had restricted steel line from tank to separator.
That gizmo that you "think" is a stop solenoid is actually part of the rack control. Do NOT remove it. It will NOT go back in WITHOUT pump disassembly.
Lol… excellent advice..
LOL, I try not to touch unless I know. Let me drop the update. After getting details from the seller, I had more focus on the issues, and I had it running in 15min. I was going to open that separator but decided it had fuel in it at the moment and I want to see if I can make it sing first. No one even attempted to bleed the system! The primer plunger was puking fuel all over but it did the job, I primed the pump bleed screw, then the banjo on the filter housing because that stupid thing does not have a bleed screw.....***.... Anyway, I resorted to cutting the spanner nut on the separator to get it apart and I found the smoking gun. A huge glob of nasty in there that has probably existed for years. It must have finally lodged just right and blocked fuel flow. I have a new separator coming. Engine sounds perfect. There is a touch of blowby off the down tube but no freight train. Exhaust is clean. NEXT ISSUE. As I ran through the rig, I realized whoever they use for their maint checks is scamming them because there are chunks out of the belts, and the waste gate rubber tube is rotted off! It is puking boost air there and the waste gate rod does not want to move! I'd like info on that! With gentle pliers, it seems like the arm wants to move clockwise, but not counter. I am not sure if that means full boost and it just can't dump boost, or ? What is further annoying is they made that air can just so you can't even remove it! Other than that, I am just combing the system right now. AC does not work. No charge in the lines but I can see dye so someone was chasing it. I also do HVAC so I guess I will dig into that. I don't have high mode on the fan controls so I am trying to figure that one out. Usually high kicks a relay for full voltage but I am not that far yet. Nothing is labeled so I would be guessing.
PM your email to me. I has digital book that answers most engine questions.
PM sent boss! Thanks for your help! I am now trying to find a few upgrade items as this will probably stay in the fleet and it needs a tune up! Wheels sims and LED headlights are what I am chasing at the moment. Did I mention cheap? lol
Oh the joy of junk parts.. Got the new water separator.... China.... Looks good. Could not get the spanner nut off at all so said screw it. Thought I noticed a little fuel around the spanner but seemed to stop. However, fired the truck and could see air in the fuel bowl. Bottom line, I chopped the new spanner nut off the new separator because it was FUBAR and I wanted to see that disaster. They galled the shi* out of that nut and the bowl was not tight and sucking air. Fun part is I got to chase my tail before circling back to that stupid separator. Thought we might have a plugged line, empty fuel tank with bad gauge, etc. In the end, I removed the new separator that was mostly full of fuel and tilted it sideways slightly and fuel came out of that stupid nut. If fuel can come out, air can go in. Thanks again China! Or OEM for 10x the price. Is there not a middle ground anymore?
Re the lack of bleed screw on the fuel system - most Japanese diesel engine fuel injection systems do not have a bleed screw, you just pump the primer and it pumps fuel through the whole system and bleeds air out the return line.
Isuzu 4H Series Introduction Since there isn't a specific area for the newer engines, I posted this here. I'll cite reference where I can. Most of the following information was pulled from the following thread: http://forum.ih8mud.com/diesel-tech-24-volts-systems/157856-isuzu-4he1-swap.html Manual with specs here... www.4btswaps.com 4btswaps has lots of info on the 4he1, if you dig a bit.
Wait until you need a wheel removed. Aside from being Budd nut style, with LH & RH threads on opposite sides, the inner hollow nut on the inner dual has a tendency to gallon to the outer nut. And, most tire shops don't even have the correct combination socket on hand for normal removal. If the inner nut stays with the outer wheel, I use a 1-5/8 combination wrench thru a hand hole, and a 15/16 12 point socket with a 3/4 gun to separate the two "nuts". Oh, and even if they has the correct socket, most tire shops don't tighten them sufficiently.
I always use a sniff of Never-Seez on the threads of Japanese truck wheel studs, sure saves a lot of pain and aggravation from galled threads. The threads are clearly marked with a big "L" or "R" on the outer end of the nuts, I don't know how anyone could miss that.
As I mentioned to mccall, I have found a turbo leak where the gasket has failed between the exhaust manifold and turbo housing, if anyone has experience how sucky this will be? Should I just order a new turbo now? I am imagining breaking every single bolt. I know CAT stuff has always surprised me so maybe Isuzu? I am trying to figure out if I start with the dotco now or make an attempt? Ideally I would like to just unbolt the turbo, replace gasket, drop back down and go. But thinking that is NOT likely. I will just braze the damn turbo on and be done with it.....lol
Here, in the rust belt, with a little patience, I have successfully unbolted the turbo from the manifold, on several. I have not, however, ever been successful at removing the downpipe. If you undo the first exhaust hangar, and, of course the turbo to manifold hardware, you can slip in a new gasket. If you're not in the rust belt, you may have it even easier.
Nah, she is far from rusted up but of course thr business side of that turbo is. Just not sure if I heat those bolts or what just yet. ? Never had luck with any spray until something moves. You understand my plan which is to leave down pipe on the turbo. Every bolt brings risk.
How many miles on the engine? That's the primary measure of whether you replace the turbo or re-use it.
175k. Otherwise solid as a rock.
That turbo should be just fine to put back, at those miles. Just check to see there's no excessive movement in the bearings, and that the housings on compressor and turbine are unmarked by the wheels. The bearings normally have a surprising degree of sloppiness, they tighten up with high temperatures. These engines will do over 400,000 miles before they develop any signs of wear. Isuzu engines are built like the old Allentown Macks - "robust" is the best description of them that I've heard.
Thanks! With a LOT of careful operating, I was able to get the nuts off the turbo flange. I will be replacing them to ensure the best chance of success here. The little bolt on the turbine side that bolts into the manifold was not so fortunate. Appears it has about 8 threads of engagement in which 4 on the end were galled when I finally got it out. My hope is to carefully chase the threads once the turbo is lifted up. But all this does bring the question of why the gasket failed. I noted the rubber waste gate actuator hose was rotted off so it was previously not able to relieve. But I have since replaced that hose. Then I tested the truck exhaust brake. I am wondering if that blew the gasket? Like if the gasket was weak or broke and my bump of the exhaust brake sent it to full failure? I am not sure how much exhaust pressure they can build.
That gasket and flange area can handle more pressure than you can throw at it. The gasket simply failed due to thermal cycling over its lifetime. Even the broken wastegate cannot create enough pressure to be an issue. The wastegate is there to A) allow faster spool up, 2) keep boost pressure limited for engine longevity, and iii) to maintain emissions standards.
Speaking of emissions.....lol What emissions? That's one thing I love about that truck! So much easier to work on, and less to worry about. When that that muffler flange finally gives up (she close), I just want to know what these sound like on the straight pipe.
"Maintain emissions standards" also means operate cleanly, which also translates to operate efficiently.
Yeah, that is one thing I had concerns about with a turbo leak but it at least appears the injection pump does have a manifold pressure input? To compensate injection events based on boost?
All the Japanese diesel truck and 4WD engines have utilised an aneroid-controlled rack for many years. The aneroid can be used to compensate for altitude, and to limit rack travel under full throttle application at low revs to prevent excessive black exhaust smoke. An aneroid can also be used in conjunction with a turbo to control rack movement according to boost levels. Some injection pumps have two aneroids. However, the 4HE-1 utilises a Zexel injection pump with a modern design, and it contains electronics to produce variable injection rates and variable fuel injection timing, from an old-style jerk type pump. Zexel called it TICS technology - (Timing and Injection rate Control System). This pump also contains electronic circuitry to provide self-diagnosis and back-up. This design was the final frontier in jerk-type pump design, before fully electronic common rail injection took over fuel injection design - because CR injection provided a massive boost in injection pressure that the old jerk-type pumps could never produce in a million years. These Zexel TICS pumps are pretty high-tech, and you don't fool with them, they require attention from an experienced injection pump repairer if they're displaying faulty operation, and if you want them fixed properly. They need specialised test and repair equipment. Here's the TICS outline from Zexel - "TICS is a sophisticated system that detects engine conditions, vehicle speed, coolant temperature, accelerator angle, etc to control the fuel-injection engine and vehicle to the highest efficiency at all times. To control the volume and timing of injection, TICS has an electronic governor with a linear DC motor, and an electromagnetic rotary actuator. In addition, it has a movable timing sleeve for prestroke control to realize a variable injection rate (pressure). At low speed, the prestroke is increased to raise the injection pressure so that smoke emissions and improved while increasing the torque. At high speed, the prestroke is reduced to advance the injection timing, while suppressing an excessive increase of the injection pressure to decrease NOx emissions." Zexel was taken over at a corporate level by Robert Bosch GmbH in 1997 and on July 1, 2000, Zexel Corporation changed its name to Bosch Automotive Systems Corporation. The company then went from Zexel-branded pumps, to the Zexel-Bosch brand name. Not sure if the Zexel name is still on any injection systems any more, the company got broken up by Bosch, who sold off various Zexel divisions. Zexel - Wikipedia en.wikipedia.org
As far as I know, that injection pump system rotates the cylinder as well as the plunger to control the beginning and end timing of the injection stroke. It is very much electronically controlled, but will also run surprisingly well with none of the electronics working, with certain increased emissions.
Thanks for the deep dive on the injection system!!! I am eager to learn more about that system before I ever have to deal with issues with it. I did note that system is far from simple, with a bank of vacuum and pressure valves. One matter that I am investigating is if that injection system has any limits set on it because that truck is a former rental truck and we have experienced these types of trucks with speed or power limits on them. I have not had to truck running fast enough to see if I hit a wall yet. I did note the lack of power past about 40mph which would make sense as it appears the aneroid system would not be able to achieve proper pressure for increased fuel. It still hit highway speed without too much issue and I have to realize it is a 175hp 4cyl, so I am not expecting to burn up the roads! But if the rack is partially controlled with electronic means, that could complicate bringing the truck up to full power/speed.
Well this turd seems to run like a dream! Been out burning up the roads and it has brought some new questions for you NPR guys. This truck is a HAND FULL on the road! Id like to know any tricks with them? I have already pulled some of the backlash out of the steering box but I intend to do more and better inspect all the links. I notice I take quite a ride sitting right on top of the front wheels. Somewhat a pogo stick so I'd like to try some new shocks. I checked tire pressure at 70psi which I would think would be spot on the decent ride and loading. It does have a sway bar but not real well designed, or at least it would not have much torsional stiffness. Just trying to spot some ways to help me drive this thing! In a 20mph cross wind, it is a 2 hand, white knuckle driver. Maybe tighter steering will help manage it? Almost like the back needs a sway link! That is a lot of wind loading on that box.
Check your front wheel alignment, and especially the front wheel caster angle. If the box is light, there may not be enough weight to keep the back end down. A back end sitting high reduces caster angle. Big boxes have a lot of wall area that is badly affected by crosswind, more so if they're tall. The smaller Japanese trucks tend to be a bit narrow in the track, so that doesn't help.
It's a truck acting, driving like a truck in 20 mph winds.
So we have some miles on this truck now. Been running like a top! However, I have a couple simmple questions. 1. I detect an audible 'tick' sound of the engine once warm, which I suspect might be valve lash? Do these engine normally just have a slight valve noise? Nothing alarming but might be something we should look at? 2. Finally got a chance to do cold weather start testing. She will start in 30s for sure, but little slow to start and smokes a bit. Curious if these have a factory block heater? I can't find one anywhere. Sure would help ensure we can run it when cold out. I noticed the glow plug indicator does not stay on near long enough to actually do much so wondering if they have the same BS as the old GM 6.5s where you need to manually glow them or something? Even at 30F, the glow lamp was on for like 2sec. That should be more like 10s IMO
IIRC I installed lower radiator hose heaters in 7 of those for food distributor vendor because none had block heaters.
It doesn't hurt to do valve clearances every 100,000 miles. You will often be surprised how a valve clearance adjustment will improve the power level - particularly if they were all out of spec. A light tick is bound to be valve lash, a heavier knock is wrist pin bushing wear, the Isuzus tend to get this type of wear with age. I have an '89 Isuzu FSR500 with the 6BG-1 engine, it's done 720,000 kms (450,000 miles) and while it runs sweetly, it has a steady but light wrist pin knock from worn little end bushings. It doesn't use much oil, but the exhaust smells of oil upon startup, and the oil gets black quite quickly, so there's a moderate level of ring wear in it. It doesn't breathe all that badly, and most operators around here tell me they get well over 1,000,000 kms out of their 6BG-1 engines. Isuzu make good engines.
The truck has like 175k on the clock. I know I can see a touch of blowby from the vent tube, but I recall putting my finger on it with nothing I would be concerned about. I do know it is not a race truck! It is a 14ft box truck with 14.5k gvw and I typically am close to floored when accelerating but it will do 70mph if I need it to. I guess I would have to drive another one to know how well it runs. Certainly no stumbles, glitches, or smoke. But sitting right on that engine, I can hear that slight tick and being a wrench head, I am pretty certain it is valve noise. Probably safe to say those valves have never been touched in its life. But I will have to evaluate the cold starts. Like to be able to fire it at 15-20F if needed. I'm sure I could get it to light but I don't like clumsy cold starts. Would be nice to just get some intake air heat. That is what CAT and my Duramax like to use. They seem to work really well rather than glows alone.
I did an oil change on it to get a clean baseline and if memory serves, it was a 14qt capacity and I think I got about 10qt out of it. Now that dip stick!!???? Who TF designed that! It is a nightmare to use and causes me to not check oil like I should because I know it is a 5min affair! The cable that the Duramax uses seems to work well but I have heard of the bulb on the end coming off!
Have you even tested the glow plugs and relay?
I quickly tested the glows with a meter to ensure they were all reasonable resistance but beyond that, I guess no! But it would see the dash tells me when the glows are on and if you blink you will miss it! IMO, that just can't be right! Possible a temp sensor is not reading right? Now that I think of it, this could be an issue with the super fast cycle. Problem is when it is cold and blowing 50mph, I am less excited to test anything.....lol
I am now studying the glow circuit as you got me thinking. My gut tells me something is not right with that. Glow light should be on for several seconds to get good heat in there! Looks like they use a CTS to determine heat timing. I need to find that and test it.
Hmm, so with some testing, I am showing that all 4 glows are junk. I can't get continuity on the main wire relative to ground. Nothing. But, there is also no voltage going to that wire either. That is more puzzling as it seems the glow controller pulls one leg to ground for the relay coil, and that is not happening. I can't find the elusive coolant temp switch or glow controller at all. The books I have don't match my USA 12V truck. The drama continues....lol
Well, we had to use the truck today but took some time to try to troubleshoot the glow system and could sure use some help!!! Seems our service manuals are not correct and it probably matters right now to get the right schematics and such. Basically even though the books were wrong, I found a fuse blown in the dash that I suspected as being related. We know they don't blow for no reason but I needed to know. Once new 10A fuse was in, dash indicator for glows came on and I confirmed the glow relay behind cab was on for approx correct amount of time. I flipped cab to confirm voltage to the glow wire and had nothing. It blew the fuse again. I didn't know if the cab flip meant something or not so later we tested carefully with our meters in series with another fuse and the behavior is odd. that circuit starts up at like 3A and builds up to 8.5A or so. We confirmed with bench testing the glow relay only pulls about .4A and that should be the only device on that circuit other than this elusive "glow controller". So we know for sure there is way too much current on that circuit. We don't know if this is a partial short, glow controller is bad, or what. I need to find the glow controller for more testing!!!! What I did further confirm is the book was again wrong on my coolant sensor. Book shows a 1 wire "temp switch", but the only thing I could find appeared to be the 3 wire thermisor that is likely used by the ECM. I confirmed the glow circuit uses that so I have concern there is no glow controller and the ECM just sends power to that relay. What is odd is the timing and other behavior is perfect so would be very hard for me to say the ECM or other controller is bad. I just don't know without accurate schematics and such.