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1994 Isuzu Trooper ( Hard to start )

17 messages,  Last post on Feb 13, 2008 at 4:37 PM

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What is this discussion about? Isuzu Trooper, SUV

Messages Page 2 of 2

#8 of 17 Re: 95 trooper will not start [danco] by atfdmike

Mar 12, 2007 (5:47 am)

Replying to: danco (Mar 10, 2007 7:30 pm)
Repeated 12 code means no other codes set in memory.
(12 code refers to the reference signal that indicates motor is running....since memory is checked with engine off....12 code)

#9 of 17 Re: 95 trooper will not start [atfdmike] by danco

Mar 13, 2007 (7:25 am)

Replying to: atfdmike (Mar 12, 2007 5:47 am)
Last year I was told when I turn the key on I would get 8 flashes and then the next flashes would be the fault code.
If a 12 is the engine running with only the key on?

#10 of 17 Re: 95 trooper will not start [danco] by atfdmike

Mar 13, 2007 (9:03 am)

Replying to: danco (Mar 13, 2007 7:25 am)
The data link connector terminal "1" (diagnostic request) is pulled "Low" (grounded) by jumpering to data link connector terminal "3", which is a ground wire. This will signal the engine control module that you want to "flash" diagnostic trouble code(s), if any are present. Once terminals "1" and "3" have been connected, the ignition switch must be moved to the "ON" position, with the engine not running. At this point, the "Check Engine" malfunction indicator lamp should flash diagnostic trouble code 12 three times consecutively. This would be the following flash, sequence: "flash, pause, flash - flash, long pause, flash, pause, flash - flash, long pause, flash, pause, flash - flash". diagnostic trouble code 12 indicates that the engine control module's diagnostic system is operating. If diagnostic trouble code 12 is not indicated, a problem is present within the diagnostic system itself, and should be addressed by consulting the appropriate diagnostic chart.
Following the output of diagnostic trouble code 12, the "Check Engine" malfunction indicator lamp will indicate a diagnostic trouble code three times if a diagnostic trouble code is present, or it will simply continue to output diagnostic trouble code 12. If more than one diagnostic trouble code has been stored in the engine control module's memory, the diagnostic trouble code(s) will be output from the lowest to the highest, with each diagnostic trouble code being displayed three times.

#11 of 17 Re: 95 trooper will not start [atfdmike] by danco

Mar 14, 2007 (5:21 pm)

Replying to: atfdmike (Mar 13, 2007 9:03 am)
Flashes a 44 after the 12, what exactly is 44?

#12 of 17 Re: 95 trooper will not start [danco] by atfdmike

Mar 15, 2007 (3:41 am)

Replying to: danco (Mar 14, 2007 5:21 pm)
Code 44
 refers to the heated oxygen sensors in the exhaust system
Circuit Description:
 
The engine control module supplies a voltage of about 0.43 volt between terminals "B3" and "B2". (If measured with a 10 megohm digital voltmeter, this may read as low as 0.32 volts.) The Heated Oxygen Sensor (HO2S) varies the voltage within a range of about 1 volt, if the exhaust is rich, down through about 0.10 volt, if exhaust is lean. The sensor is like an open circuit and produces no voltage, when it is below about 360°C (600°F). An open sensor circuit, or cold sensor, cause "Open Loop" operation.
 
Test Description:
 
Diagnostic Trouble Code (DTC) 44 is set, when the O2S signal voltage is fixed below 0.100 mV and the following:
Throttle position sensor greater than 9.8%.
No DTC 21 or 33.
The engine has been running at least for 180 seconds.
System is operating in "Closed Loop".
Oxygen signal voltage is steady between 0.347 volt and 0.547 volt.
Engine Operation Temperature 69.5°C (155°F).
All of the above conditions present for 25 sec.
Integrator not at 128.
Diagnostic Aids:
 
Using the "Scan tool", observe the block learn value at different revolution per minute. The "Scan tool" also displays the block cells, so the block learn values can be checked in each of the cells, to determine when the DTC 44 may have been set. If the conditions for DTC 44 exist, the block learn values will be around 150.
 
Check for ground in wire between connector sensor.
Fuel Contamination - Water, even in small amounts, near the in-tank fuel pump inlet can be delivered to the injector. The water causes a lean HO2S signal and can set a DTC 44.
Fuel Pressure - System will be lean if pressure is too low. If may be necessary to monitor fuel pressure, while driving the car at various road speeds and/or loads to confirm. See Fuel System diagnosis CHART A-5.
Exhaust Leaks - If there is an exhaust leak, the engine can cause outside air to be pulled into the exhaust and past the sensor. Vacuum or crankcase leaks can cause a lean condition.
If DTC 44 is intermittent, refer to Diagnosis By Symptom.
Fuel Injectors - The wrong fuel injector(s) could be the cause of a lean HO2S signal condition. Verify that the correct fuel injector(s) are installed in the vehicle. Refer to the service parts manual for correct part and part number.

#13 of 17 Re: 1994 Isuzu Trooper ( Hard to start ) [gpabear] by jfrozenh2o

Nov 28, 2007 (10:13 pm)

Replying to: gpabear (Dec 03, 2006 10:31 pm)
I want to add to this even though this seems to be closed and unanswered. I too have a 94 trooper LS with 168,000 miles with the excact same problem. I have problems starting my trooper after it sits for an hour or more. It will turn over but not fire up. it sounds like its starving for fuel. Although after cycling the ignition 10 plus times it will eventually start up, and once started, everything runs great even when i turn it off and fire it back up. It is very well maintained and everything has been replaced new/ filters,oil, pvc valve, plugs,wires, fuel pressure regulator, fuel pump, new battery, alternator. I have not hooked it up to any gauges because my check engine lights never go off. I have come to a conclusion as of now that after changing the fuel pump today, and it wasnt the fuel pump check valve that i had thought, i am now quite sure that what is going on is that there is a leaky fuel injector that when the car is off, the leaky injector fills the resovoir and it takes a while of trying to start the engine up, to burn all the excess leakage, and once that is gone it will fire right up. Now im just a carpenter, but feel ive become a full blown mechanic for how much work ive done on this trooper. so now my next step is to replace the fuel injectors to hopefully cure this horrible problem that has driven me batty. please any one resond to this if theyve run into this problem also, as in this blog between gpa bear and atfdmike. there was no resolution from gpa bear as to what fixed it, and he seemed to of headed towards the fuel injectors, so i hope this will fix the problem. i will be sure to post my end results. -jes

#14 of 17 Re: 1994 Isuzu Trooper ( Hard to start ) [jfrozenh2o] by atfdmike

Nov 29, 2007 (3:59 am)

Replying to: jfrozenh2o (Nov 28, 2007 10:13 pm)
"I have not hooked it up to any gauges because my check engine lights never go off." Do you mean that they are not lit or that they are on all the time?

#15 of 17 Plastic burning smell and hard to start by cuiosgeorge27

Jan 19, 2008 (6:09 pm)

Hey, i don't know if anyone else is here but i was wondering if somebody could give me a hand? I just bought a 1994 isuzu trooper 4x4 Manual 5 speed... and I LOVE IT. I wasn't sure at first but after driving it for a few weeks it won me over. Every once in a while (like 1 out of every 20 starts) it doesn't want to start. I have to really gas it! After i get it started it runs fine and cranks fine for 15 / 20 more cranks? Then just about 30 minutes ago I loaded up my daughters to run to the store and when i was putting my oldest in i noticed a very strong smell... like plastic burning??? Anybody have a clue??? I have noticed that I think there has been an electrical overhaul on it i believe because there is a lot of new wiring inside and under the hood.

#16 of 17 Re: Plastic burning smell and hard to start [cuiosgeorge27] by atfdmike

Jan 20, 2008 (9:28 am)

Replying to: cuiosgeorge27 (Jan 19, 2008 6:09 pm)
It is hard at this point to give a specific answer...it does not sound good to smell burning anything in a car, but the smell could lead you to the problem area. You don't say, but can we assume the Trupr started OK after you got ready to go? Did you try to locate the smell?
I think it is too early to assume the starting and smell are related, but it would help to know which engine you have SOHC or DOHC, and whether you have changed the fuel filter and air filter since you bought it. Information like this will help others pinpoint areas of concern. When you say you really had to gas it, do you mean that it started but would stall, or that you held the accelerator to the floor and or pumped it?
Welcome to the forum, there are good people here who will offer their input once a good description is provided. Good luck.

#17 of 17 Re: 1994 Isuzu Trooper ( Hard to start ) [jfrozenh2o] by landfill

Feb 13, 2008 (4:37 pm)

Replying to: jfrozenh2o (Nov 28, 2007 10:13 pm)
My 92 Trooper has the same problem. If it has been off for a few minutes, it fires right up and when it has been off overnight. When it has been off for a couple hours, it needs to be cranked for a long time before it fires.
 
Lately, on occassion, it has been chugging, stalling, blowing a lot of smoke and even backfiring. Then it runs perfecly except it seems to be running rich. These symptoms srarted a couple weeks after a complete exhaust system was installed from the manifolds in the fall.
 
Now it is colder and my trooper has flooded itself out twice now. I pulled the plugs to let it dry out and replaced the O2 sensor.
 
I've read your blog before (jfrozenh2o) and am leaning towards your idea of leaking fuel injectors, or some other fuel delivery issue. I've also read of others with hard starting issues and many trouble shooting possibilities, but no solutions or successful attempts to remedy these problems.
 
I love my trooper and just want it to run like it did a few months ago...and would like the gas mileage to go back to normal.
 
If the new O2 sensor helps, I'll post it. If you changed the injectors on yours, did the problem go away? My local dealer suggested a wiring harness at the front under the rad that typically turns green and cases problems. thanks, Kenny.

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