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HI Guys,
first time on here , seems a good site for knowledge.
I have just come across the club after searching via google for a manual for my 98 TFS 4ZE1 EFI engine. I found a link on another forum to a Gmail address for this club with a load of manuals on it, but I dont know if any of them are for the 2.6 EFI motor called the 4ZE1.
I have already purchased an Isuzu w/shop CD 97 - 2001 but it does not have anything on the EFI 4ZE1, only carburetter.
Is there anyone out there that knows of the manual I need?
I am in Aust, and the Holden rodeo manual if I can get it is about $495 .00 so I am looking at other options.
My problem is to do with fuel starvation in the 2-3000 rev range, and it is running as if it is missing, but it is not.
hope you can help.
cheers
Sails

from my experience with efi stuff in the falcons i've owned...

check fuel pump and lines.
check injectors and connections, even get yourself a bottle of injector cleaner and put that through the tank.
spark plugs/leads dizzy/coilpack.

if you have a friendly mechanic he may be able to test the injector pulse width to determine the possibility of a computer fault.

i don't know much about that particular engine but just perform these checks if you haven't already. just to eliminate the usual suspects.

it's not backfiring at all??

Sorry drew a blank on that engine. Even spent sev minutes looking at a Haynes book I had. Thought I was onto something as the fuel section covered injection. Then found this was for the USA version chevy v6

just cover the basics first then report here and we'll help as much as we can i guess...

HI kcsoft and geeves, thanks for the replies.
I have checked the compression and all 4 are pretty much the same.
I have replaced the fuel filter which was quity dirty.
I checked the distributer cap and gave the contacts a clean; all ok.
I checked the timing,;12' Btdc, all OK.
I have not checked the injectors as it is a bit of a trial to get to them as they are almost covered by the air inlet manafold.
I have been playing with the throttle Position Sensor (TPS) and could do with some guidance there. My manual says for closed throttle position and open throttle positions, continuity should be displayed at the connector points only when the throttle is fully open or fully closed. If I adjust the TPS so that I have continuity when the throttle is closed and it goes open circuit as soon as the throttle lever moves, I end up with continuity at the throttle open position when the throttle is only 3/4 open. I do find that the TPS adjustment does seem to have an effect on the performance and I think it could have a beneficial effect on the jerky ride, but it is difficult to really tell. What I need to know is whether a new TPS has continuity only at the extremities of its movement range or, if like mine, it comes in before the end range is met. Does anyone understand that part of the engine??
I have played around with the CO2 adjustor, just getting the engine to run at its best at idle.
There are no faults being displayed on the dash, which is a bit puzzlling as obviously there is something wrong as it some times really jerks when under throttle at 2-3000 revs constant. Perhaps it is the ECU, which I have not tested yet.
I dont have an exhaust gas analyser, or a fuel pressure guage, so those are things that I will have to get checked by a mechanic.
I will attempt to get to a mechanic this w/e and see what he can find with the instruments.
Any input is appreciated!
thanks guys
Sails

from my experience, a tps gives a resistance reading in ohms.
if it's showing continuity, it may be buggered. but i'm only going of what i know from working on efi henry's.

maybe unplug it and run it. the ecu should go into limp home mode and the engine will probably run rough, see if it keeps giving the same symptoms??

or wait till a mech looks at it. keep us posted. i'm interested as to what the problem is.

sails wrote:
There are no faults being displayed on the dash, which is a bit puzzlling as obviously there is something wrong
Any input is appreciated!
thanks guys
Sails
Did you bridge the wires under the dash to get the codes?
I have some info on the EFI 4ze1
I would check the plug leads and plugs first

I think he is just refering to the normal dash indicators below the speedo not any obd type codes

If you just want to check the fault codes there is a male and a female plug near the diagnosis plug that plug into each other and the faults will display on the check engine light
Fault codes:
12 no faults
13 oxygen sensor
14 coolant temp sensor
15 coolant temp sensor
21 throttle switch
22 starter signal
23 ignition system
25 pressure regulator VSV
33 fuel injectors
35 ignition system
41 crank angle sensor
43 throttle switch
44 oxygen sensor (lean)
45 oxygen sensor (rich)
51 ECU error
52 ECU error
53 pressure regulator VSV
54 ignition system
61 air flow sensor
62 air flow sensor
63 vehicle speed sensor
64 fuel injectors
65 throttle switch

To clear codes, disconnect battery for 20 seconds

Hi Pig75,Captcol and Kcsoft, thanks for the replies.
I bridged the male female plugs on the right side of the drivers position, and all that it gave me was 12, which is no faults.
I checked the plugs, quite clean; checked the gap, 1.1mm, all OK. Leads seem fine, no sparks at night.
I have come across an Isuzu TF w/shop manual on the internet from 1988 on, 3 volumes of original w/shop manuals, TF-WE-835AR, but I fear that it will not cover the TFS from 1998 on, so I am not too sure if I should buy it. Does any one know if the fuel injection from the 1998 4ZE1 TFS was the same as prior to the earlier TF models?

Pig75, What info do you have available on the 4ZE1 EFI? You mention the plugs and leads; there is no problem at idle, or at full throttle. She isnt missing, so much as surging,. THe most obvious area is between 2-3000revs, and it is worse when cold, but it carries on when hot also.

I,ve booked it into a mechanic for the 11/2 to test the fuel pump pressure and check the mixture.
thanks guys
Sails