Last post on Feb 13, 2008 at 4:37 PM
You are in the Isuzu Trooper
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Isuzu Trooper, SUV
#6 of 17 Re: 1994 Isuzu Trooper ( Hard to start ) [gpabear]
Dec 04, 2006 (10:28 am)
your problem sound familiar, I run into the same problems and alway happened in different ways that needs to be repaired, cleaned or replaced. You said that already replaced the fuel pump, can you read fuel pressure while you turn the ignition on?, can you check if you have firing at the ignition coil while you cranck the engine? and please if the engine runs read the following values whit a scanner the ECT (electronic coolant temperature sensor) while the car is even not running and the switch on you can get this readings and of course when your engine runs too. I need this values and also your trim values in the scanner so I will tell you from there what else we need in order to diagnosus your problems!
#7 of 17 95 trooper will not start
Mar 10, 2007 (7:30 pm)
This is the second time in two years that the car will not start. First time no codes flashed, mechanic changed spark plugs, started, but every once in a while on the road it would act like it was getting to much gas, black smoke, sputtering, back off the gas okay. This time, exactly one year later, will start in the morning, but not any other time of the day. Took it to the mechanic, said my hot/cold engine sensor was covered by blow by, cleaned it, worked great for a day. Now it will not start again, night here, and when I check the codes a 12 flashes. Took the sensor out and that looks good as well. What is a 12 and any other ideas?
#8 of 17 Re: 95 trooper will not start [danco]
Mar 12, 2007 (5:47 am)
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]
Mar 13, 2007 (7:25 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]
Mar 13, 2007 (9:03 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]
Mar 14, 2007 (5:21 pm)
Flashes a 44 after the 12, what exactly is 44?
#12 of 17 Re: 95 trooper will not start [danco]
Mar 15, 2007 (3:41 am)
refers to the heated oxygen sensors in the exhaust system
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.
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.
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]
Nov 28, 2007 (10:13 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]
Nov 29, 2007 (3:59 am)
"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
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.