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2001 Isuzu NPR

Coy Lancaster

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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?
 

Coy Lancaster

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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.
 

heymccall

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Western Pennsylvania
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.
 
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Coy Lancaster

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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.
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.
 

Coy Lancaster

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thepumpguysc

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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.?
 

thepumpguysc

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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.??
 

Delmer

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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.
 

OzDozer

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Semi-Retired ..
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.
 
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Coy Lancaster

Senior Member
Joined
Dec 19, 2014
Messages
2,028
Location
Arkansas
Occupation
service tech
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.
 
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