Hey everyone first time on this part of the site so bare with me please. I was checking out a 2001 Isuzu truck with a 4HE1-TCS 4cyl. engine that would crank but not start, owner said that it had been sitting for awhile but he would start it every week. The other day he tried to start it and the engine would crank over but not start. He changed fuel filters and added fuel to tank. He called me and I checked fuel from filters to inj. pump had good flow. I removed what I thought was the fuel shut off solenoid to test it. The solenoid did work out of pump grounded to frame. When I went to reinstall the solenoid I couldn't get it to start back into pump. The plunger seems to be hitting something in the pump. Can anyone give me some pointers on how to install the solenoid?
Do you know what IP it is?
No I don’t
I wont be any help here, but I bet if TPG knows what pump your dealing with............he will easily come up with your answer.
I'm hoping he can help also. I'll try and get some photos of pump and solenoid maybe that will help out.
You removed the the cold start advance (CSA). Don't turn anything in there or on there. Replacement of the CSA requires pump disassembly, I think. I'm not even sure that you can put that one back without teardown of the pump. On that truck, engine stop is handled by a cable attached to a electric motor. Turn key ON, electric motor moves cable attached to pump lever. Turn key OFF, electric motor moves cable and lever other way. It's a Zexel TICS injection pump.
HM is correct.. TICS PUMP
Well that sounds about right. I told owner I probably screwed up not knowing the system. Thank you for your help, I’ll let you know what happens.
If u can send me a picture of the problem, I think I know the answer.
Ok I’ll send you a photo tomorrow.
Here are some photos of IP and where solenoid goes
That CSD (cold start devise) scoops the control rack..(I think) If u can take the cover off 5mm Allen wrench, you’ll be able to see what ur doing.. Have a look at the plunger, can u see where it pushes/pulls the rack.?
Arrow points to where the Cold Start Device goes. Long oval shows shutoff cable.
Doesn’t look like there’s access.. I know this is a matter of “feel” but how did it come out.?? Did u have to “scoop” it out.??
It came out fairly easy it hung up a little bit but nothing too bad.
How about activating the solenoid and trying to screw it in.?? Sorry but it’s been awhile..and I haven’t done many of them..
I tried that to no avail. But will give it another shot, it may have not activated like I thought it did.
All that stuff on the front that's in the way can come off, can't it? How about pulling up on the mechanism and propping it with either a bit of wax, or a loop of monofilament fishing line/thread. Never been in one, and never will, just what I'd try. Obviously it will need a ground to activate the solenoid with any consistency.
The Cold Start Solenoid modifies the fuel timing advance when it is actuated. Once you remove the solenoid, you can't just replace it, simply by re-inserting it. Re-installation of the CSS means an IP technician is now required, because the IP now needs to be re-timed by a Zexel technician who knows his way around those quite complex Zexel TICS IP's. You're not the first player, nor the last, to be caught out by these cunning little Japanese devices. I tried to find a manual for you online - I found a pretty good Isuzu manual that covered the NPR and 4HE1-TC, that was quite informative - but it didn't cover U.S. models, which I suspect may have the CSS, whereas many other 4HE1 models didn't. Overall, despite being informative, the Isuzu manual I found did not cover any IP disassembly, repair or assembly, and I would have to say that is because all that work involves specialist Zexel IP technicians. As I understand it, the MI-TICS on the Zexel pump stands for Mechanical Injection, and Timing and Injection rate Control System. The Zexel pump is a modified Bosch-style in-line injection pump with electronics added, that control the quantity and timing of the injection process, and which electronics also contain self-diagnostic and backup abilities.
Thank you for your reply, so great then I really screwed up then. So I'll have to remove the IP and have the CSS reinstalled and calibrated.
Calibration is only if you've messed with the stem of the CSD.
I'm not so sure the IP has to be removed. The tilt cab gives good access to any IP repair work needed, and I can't see where complete IP removal is needed. But you need to talk to an IP shop that deals with Zexel IP's and find out the exact process and cost required to re-install the CSD, and to retime the pump advance correctly. Busby Truck Parts seems to be pretty knowledgable on the 4HE1 engine, they have YooToob videos showing the 4HE1 IP removal/replacement and timing the pump to the engine - but nothing as regards that CSS.
Maybe I don’t know what I am talking about - but I don’t see how cold start can cause no start. Do you have fuel in the case of that IP?
Yes there is fuel in the IP case
Any pressure? Maybe overflow valve is stuck open. On those Isuzus they put them on the fuel filter return fittings sometimes.
It wasn't the CSD. That was removed simply from a lack of knowledge. The cable for fuel shutoff has a suspect circuit, fuse, motor, etc... Once the CSD gets reinstalled.
Okay thank you for your help and the information. I will have to do some research on what shops close to me that knows anything about these pump.
Hello.. all ya gotta do is get access to the front cover.. remove it and put the solenoid back in.. It’s already set.. all ya gotta do is scoop the rack on top of the solenoid “leg”..
And don't readjust the length of the stem (the "leg") on the CSS!
Ok guys I got the (CSA) solenoid back in by removing end plate and getting it to go back in place. Now back to original problem. The fuel shutoff isn’t working. I disconnected the cable from the lever and engine started after bleeding system. My question now is where is the relay that controls the fuel shutoff?
I took the CSA solenoid out as well, thinking it was the fuel shut off, which end plate do you take off? I recently bought a 2003 Isuzu NPR crew cab to use for hauling my equipment. 4HE-XS engine. Decent shape, did run, but has issues. My problem right now is as follows. I drove it home, died. Wouldn’t restart. Used a towbar and dragged it home. Pushed it into the shop and started the process of replacing the old lift pump. Previous owner provided a new one so I installed a new pump. I also installed an electric fuel pump right above the tank to prime the system. I can bleed the system, but it takes a very long time. Yesterday I was able to get it to run, this morning, nothing. Lost the prime. I can’t get fuel up to the injectors. I pulled what I thought was the fuel shut off solenoid and bench tested. Works. Tried to put the solenoid back in, nope. Having the same problem as the thread author. I bet I can get it back in if I know what to do. I don’t get fuel up to the injectors and it won’t start. I need to get it running so I can use my laser thermometer to see which injector is bad because she throws white smoke on acceleration. Any ideas?
I know nothing about that solenoid, or the internals of the pump, follow the advice given to get it back, then, don't touch the pump. Check the fuel inlet to the transfer pump for a banjo bolt with a screen screwed inside the hollow bolt. Then check the water separator, bypass it for testing purposes. Replace any original rubber fuel suction lines. The transfer pump should move fuel through the pump and to the return to the tank, then it should start, and run. Run it for a few hours on fresh biodiesel before you dig into the injectors.
I will get it back in. I have replaced the hoses already. I don’t know which pump is the transfer pump. Is that also the lift pump? If it is, I replaced the screen that is on the inlet side. I get plenty of fuel flowing out of the bleed screw on the back of the injector pump. I don’t think I am getting fuel to return to the tank, what should I look for? There is a banjo on the side of the injector pump that has a much thinner line coming out of it and it heads to the top of the injectors. I should add, that there is only one banjo line coming into the side of the lift pump. There are 4 ports on top of the lift pump and one large plugged port on the opposite side of the banjo line coming into the pump. Should there be a return coming out of the lift pump? Just curious, why biodiesel?
Can you send a photo or diagram of what cover needs to be removed? Is it towards the rear of the injection pump?
The end plate is right between the bell housing and the injection pump. There are 5 5mm allen head screws that hold the plate on.
biodiesel is a powerful solvent and gunk dissolver, until it gets old, then it turns to gunk. yes, transfer pump and lift pump are the same thing.
I have a half a tank of diesel in it now. I will pump some out and put in 5 gallons of bio diesel. Not going to get o to it today, but I can do it tomorrow afternoon.
Ok, I was able to sneak out to the shop and disconnect the return line going to the tank, no flow with the electric pump on, ignition key off. Same with key on. I blew air into the line and fuel will come out at the injector pump with the return banjo bolt lose. Should I see fuel circulating with the banjo bolt open? If so, what would prevent that?
The electric pump is probably 5PSI, the lift pump on the side of the injector pump is made for that pump, it's a small piston driven off the cam and is in the 20-30PSI range to overcome the relief/regulating valve. It doesn't surprise me that the electric pump won't return fuel. The lift pump should as far as I know, either priming or cranking.
What else would cause a no start if the system pumps?
If the shutdown actuator is working or disconnected to run position and air is bled out of the IP most likely one or more plungers are stuck causing the fuel rack to be locked up in shutdown position. I have had 6 or more injection pumps in the past year with the rack stuck because of varnish gumming up the plungers which sticks to the barrels and the fuel rack won't move. Sometimes I was able to carefully force the rack to move and with the injector lines loose spin the engine while working the rack and it freed up. Usually happens when they sit for 6 months or more, the fuel now days is garbage, if you keep an additive in the fuel it helps, I usually put Lucas Injector cleaner or Marvel Mystery Oil in every time I add fuel to help prevent the varnish.
Let me say in advance, I am not a diesel guy at all. I am pretty new to them. I teach auto tech at a local high school, but diesels are rarely seen in our shop, so I am learning as I go. THANK YOU for all of your help up to this point. First, I am betting that I have a problem with the engine is the fuel shut off. I am wondering if the fuel shut off isn't pushing enough. Second, I have no idea what the 'rack' is. How do I move it? Is there a way to pour something into the injection pump and let it sit for a while to loosen things up? Marvel mystery? Biodiesel? Finally, I just bought a manual for this unit so I am going to study that a little to try and get a better understanding of what to do with the pump. (Side note: once I get it up and running, any thoughts on what kind of diesel to buy and to continue to buy? I have access to a few kinds here in rural Wisconsin) Any recommendations are appreciated.
If it started, ran, and died three times, then I don't think you have an internal problem with the injection pump, unless there is water or really nasty fuel in it. If it gets air in the lines to the injectors, it will take a while to start, it will start easier if you loosen the injection pump line at each injector and crank until there is no more air bubbles, just fuel. Assuming you can do that on this engine, I believe you can.
Remove water separator bowl, then remove and clean screen in filter head. Just had same issue on my '00 Npr. Also had one, years ago, with plugged muffler. Started normal, petered out within 5 seconds, wouldn't restart until it sat for at least 20 seconds.
I can do that on this engine, however, regardless of how long I let it prime or crank, no fuel at the lines to the injectors. HAS TO BE the fuel shut off.
I am replacing my fuel filters very shortly. I ordered new units, I hope to get them in ASAP. I am pretty sure the muffler is good.
I was able to get the unit running today, I adjusted the fuel shut off cable, she started up pretty quick and then died after about 5 minutes. Tried again and no start. Checked and there was no fuel in the injectors lines. Bled the system again, started and ran for a while then stopped again. I'm going to wait on filters to try again. Anyone know if I do in fact have a bad injector, will that allow air into the system?
Minimal tools required.... Remove both fuel lines from water separator housing in front of batteries. Unbolt whole assembly, taking care to keep it upright. Carry it away and shake it upside down over a clean pan. Once all the crap is done falling out, take it apart and clean the screen. And, a faulty injector will NOT introduce air to the system.
I will do that. I am getting new Baldwin filters on tomorrow, when they show up, I will pull apart that unit, clean it up and install new filters.
After taking a look at the back of the pump, there are about 8 5mm bolts. Not all of them are easily accessible, especially along the bottom. Do I have to yank out the injection pump out to put the solenoid back in? Also, can I run this truck with the solenoid in, but without the little 'foot' on it? It starts without it, but will I have issues down the road?
No screen present. I think this is an aftermarket filter housing. There is a small black flap that seems to act like a one way valve. Not sure what that is for.....anti-drainback? Below is a photo of a VERY similar unit.
My '99, '00, and '01 NPR all have the separator on left, where #29 is said screen. You, apparently have a 1(b), the style on the right.
that has a primer on it, in order for the primer to work it needs two check valves, the rubber flap could be one of those check valves.
I do have the other unit. I have the bottom section of the water separator. I also have a 2003 NPR which might explain it.
UPDATE. I installed new Baldwin fuel filters, bled the system and she fired RIGHT UP! No hesitation, nothing. Ran pretty good and I wanted to clean out the mess underneath it. I pulled it outside drove about 200 feet and it died. No restart. I checked for fuel at the injectors, none. I have lots of fuel at the water separator, I have lots of fuel at the bleeder behind the injector pump and I have lots of fuel at the upper fuel filter. WHAT THE HELL IS GOING ON?!!! I changed the lift pump with a 'new' unit. It is totally a Chinese or similar build unit. Is it possible that the pump is trash? Could it be bad out of the box? Any way to tell? I keep losing fuel/fuel pressure.
The unit I have is just like this, but I had an issue. It came in the box assembled very similar to this, but it did not fit the engine. The fuel line from the fuel filter was only able to go on the back most right port. Does it matter what port is used for what? Is this just a universal pump and any port works? Do I have things in the wrong spot? Is there a way to pressure test? This is making me nuts......
Is it possible that the oil pressure switch is no good and causing a situation where it is a safety measure to kill the engine? I changed the oil yesterday, 14.8 quarts and a new filter, I still have the oil warning light on. There is a little box/panel to the right of the steering column that has red lights, one keeps flashing regardless and it is the oil light.
After doing a little looking on the web, I found that the little panel I have to the right of the steering column is an aftermarket device of some kind, not stock to the truck. I don't see any photos of other NPR's with the panel on it. It has 5 lights on it, indicating oil, temps, etc. It lights up with the ignition switch and seems to be some sort of fleet vehicle monitoring device. Could this thing be malfunctioning and causing all these issues? Could it be shutting down my truck? I will add a photo ASAP. Maybe this afternoon, maybe tomorrow.
Yes, an aftermarket "fleet monitoring" thingy could shut down the engine. I've never heard of a TRUCK that would shut down from oil pressure or temp. Do you know how the injection pump is controlled, I thought that injection pump would have been electronically controlled since the mid 90's, that is, more than just one solenoid to shut it off, a whole wiring harness to control timing etc. If it's only one wire to one solenoid, that's much easier to test for voltage while running, with the key on but not running, and after it dies. As for the pump, you'd have to pump it by hand to confirm it's working. I wouldn't think there are more ports, but I guess I've never looked that close. I'd think the other ports are access to the valves or mounting holes.
What solenoid am I testing? Fuel shut off? There is also the Cold Temp Solenoid that I still have a problem with, but I would think that it should still work regardless. Am I looking for a drop or loss in voltage?
Simplest way to test the solenoid, no voltage with key off I assume? turn the key on, does it have battery voltage? start the engine, does it have battery voltage? after the engine dies, does it have battery voltage? more complicated way, run a test lead into the cab, and watch the voltage on a multimeter as you turn it on, start it, run it, and watch it die. If there's only those two solenoids, then the fuel shut off is what you want to test. If the voltage is still present after the engine dies, then check the ohms of the solenoid before starting it, and again after it dies, in case it is an intermittent failure as it warms up, and works again when cold.
Ok, I can do that. I have a good meter. I have a couple broken and bad vacuum lines, could they be controlling this feature and shutting off fuel?
5% of full fuel rate will not kill the engine, it would be hardly noticeable in most driving.
Got it.
Ok, tried it all over again. 1) Inspected the fuel lines, found a tiny leak, ran new line again. No change, runs for about 3-4 minutes, shuts off. 2) Removed the fuel lines from the water separator, connected that together to bypass the water filter, no change. No change, runs for about 3-4 minutes, shuts off. 3) Checked all the connections to make sure no air leaks, bled the system again. I mounted my camera on my toolbox to record the fuel shut off cable. Cable doesn't move, runs for about 3-4 minutes, shuts off. I'm at the end of my knowledge on this kind of thing. Thinking about taking it in and having an experienced diesel mechanic look at it.
Unbolt the muffler from the exhaust brake and retry.
I will try that, any thoughts on what that might be doing?
Let it idle and be ready with a can of ether, when it dies give it a snort and see if ether keeps it alive, do a few more puffs to make sure you are well past the period when it normally dies
Fuel compression or heat, well it runs so it's not the last two, I'm wondering if it's running out of air, either by air in or air out.
I have to bleed it every time.
How do you find air leaks in a fuel system? Could it be the fuel pickup in the tank?
There's so much going on here it's hard to tell what's what. How about a picture of the "fleet monitoring" device, and trace some of those wires in the wiring diagram to see if it ties into the ECM. I'm assuming this has an ECM that controls the pump in some way, since it's Japanese and 2003. Have you ever walked away from it for an hour when it dies, and see if it starts up without bleeding it then? so that it's only time, and not bleeding that makes it start. If it still needs to be bled the next day to start, then a vacuum/pressure gauge, and clear tubing will help you find air and blockages if that's the last resort.
There is a lot going on. Hard to determine sometimes what to do. I forgot to get some shots of the fleet monitor. I will get that ASAP. I have walked away and tried, still needs to be bled. Every time it dies, there is no fuel at the injectors. I am considering running all new fuel lines and not using any of the old solid lines. I replaced all of the hoses that were connected to the solid lines running to the tank. I have 3/8" hose, I am going to replace all of it soon and see if that changes anything. Is there anyway to intentionally pressurize the system with air and search for leaks?
I've been an interested bystander in this since the start. FWIW I would be ruling out a problem in the tank before going any further, even if that meant taking it off and turning it upside down. If something is floating around in there it could easily be producing the symtoms you are experiencing.
I am thinking about pulling the tank, cleaning it out and putting a new pick up assembly in to ensure I am not sucking air. Any experience with issues like this in the past?
Might I be better off trying to plumb a remote tank with an electric pump and see if I get the same issue?
Basic diagnostics for me is that when diagnosing a fuel system you start from the tank and work towards the engine. Until you can definitively rule out the tank as a possible source of the problem you shouldn't be moving forward. My 2c, YMMV.
You don't need a remote tank and electric pump. A gallon jug half full of diesel with the supply and return lines stuck in the top will work. The other thought I forgot, use a stop watch when you start it, if the shut off is near exactly an even minute mark, then I'd suspect the "monitor" and try it again to see if it runs the same time.
I have been using a stop watch, we are right around 3:30-4:30 minutes. I’m going to try the tank tomorrow. I will also add some photos of the monitor and see if you guys know what it is.
It's a purely mechanical injection system. The only electrical interface, of consequence, is the fuel shut off cable. Unless someone has installed an electric shutoff solenoid in the fuel line. Earlier, I suggested disconnecting the muffler, as, technically, it's a catalytic converter of sorts. They can get plugged/ restricted.
Ok, I'm going to remove the muffler as well.
Well, you were right. The most logical way to approach a lack of fuel, start at the tank. I drilled a hole in a 5 gallon bucket, put in a fitting, ran a hose to the electric fuel pump, bled the system. Started right up and ran. RAN for over an hour. Started to clear up a little too in regards to the white smoke. It blows white smoke when I accelerate, but it is starting to have a little RPM as well. Doesn't stumble as bad it did before. I ran about 2 gallons of new diesel in it, a couple ounces of Howe's Meaner and Kleaner. Seems to be working on getting that injector a little better than it was. I'm hoping to find some biodiesel, but I can't find any in my area. Seems like one of those things that you see all the time, but can't find when you need it. I have a side tank as well on the unit, I plan on cleaning it out, putting a new sender in it and give it a try. THANK YOU GUYS FOR ALL OF YOUR HELP UP TO THIS POINT!!!!!!
So.....Here is my issue. The tank is full of sludge. Like a LOT. I can get quite a bit out by hand, but it does not dissolve with gasoline or mineral spirits. I have a pretty potent degreaser that seems to work pretty good, but I need to get this thing clean. Any thoughts?
Had the fuel in the tank when this all started (not the fresh fuel you added since) been in there for an extended period of time.? Is it really "sludge" or algae growth.? Does it have a greenish tinge.? You need to consider the possibility. If it is algae the treatment process will be totally different.
No idea how long this truck sat, but it sat. No idea what this stuff is on the bottom of the tank. Not really a green tinge, but nothing really dissolves it that I have laying around. Could be algae, but not sure. How do you tell?
I would assume it's algae (more correctly described as microbial growth) and treat it accordingly. Disinfecting Heavily Contaminated Fuel Systems – Biobor Fuel Additives www.biobor.com
Could all of that build up be what is plugging up my injectors?
Not my area of expertise I'm afraid. I know it will plug fuel filters, beyond that - no idea. As I say assume what you have in the tank is algae and treat it (and then the rest of the fuel system) accordingly.
It is if you bypassed the frame mounted filter and ran your "questionable" fuel to the pump without a filter.
The plugged up injector was an issue prior to purchase.
And somehow you don't think that all the cr@p you found in the tank wasn't also there before you bought it.?
The stuff in the tank most likely came from the fuel itself, either algae growing or the fuel breaking down and forming crud. That same old fuel was in the pump and injectors and they are coated with the same bits. It might work through without problems, or it might not. I've never seen permanent damage from this sort of thing, but I'm not a pump expert either. I've certainly seen injection pumps ruined by waste vegetable oil, which is one possibility for what you have, depending on who you bought it from, or just old biodiesel blend.
That’s what I am saying. I’m betting the issue I have with the injectors is related to all of the stuff in the tank.
$300 gets 4 new injectors, but, if you're fortunate like me, you'll have a local injection shop that can test them. Until the fuel supply is cleaned up, it would all be for naught.
I have a shop nearby that rebuilds pumps and injectors. The smoke has cleared up a lot since the other day. I'm going to run the truck for a few hours and see what happens.
Agreed. First get the tank cleaned out and treated with biocide on the assumption that you have algae present. It can't hurt even if the "sludge" is nothing more than contamination from dodgy quality/stale fuel. Then fit all new fuel filters and clean out any screens that might be in the system between the tank and the fuel inlet to the IP. You'll probably need extra filters if you do not get 100% of the sludge out of the tank, which you most likely won't. The filters are where it will land. Get some fresh fuel in it and see how it goes from there. Oh, and maybe do a check of the valve adjustment at some point BEFORE you start thinking about pulling injectors.
Here is my current plan. I have pulled out about 80% of the sludge with my hands. It sat overnight with Zep Purple Degreaser in it and LOTS of stuff loosened up. I drained that out this morning, filled with 5 gallons of E85 and it has really softened things up. I am going to drain and fill it again with E85 two more times. In the meantime, I will keep running the truck out of a 5 gallon bucket and new diesel. I am going to replace all of the plumbing to and from the tank. I am going to reinstall the tank, fill with Biocide and new diesel and run for several days at my farm. Change the filters and repeat. If the injectors don't clear up, pull them and I will take them to a shop for rebuilding.
Tank is clean, running much better than before. Going to have a local shop rebuild the injectors, they are better, but still not the best.
Sounds like a plan. I’d still suggest to set the valves before pulling the injectors, just in case. Far cheaper than having the injectors rebuilt as well.....
Will do!