I am desperate

[zekinan]

i have a isuzu trooper LS DOHC 3.2L V6 i drove the car 3 days then i depresurized the fuel system to change the fuel filter since then the car is running rough the big white smoke made me think it was running rich so i sent the car to a mechanic. the guy checked the coil,spark,compression,fuel pressure,timing, the catalic converter, muffler, injectors, firing order and to finish he kicked me out of his shop with my car cause he couldn't figure the problem he even run straight LP eliminating the sensors and injectors but still running like crap the car run like it was only two cylinder firing. need big help any ideas is welcome thats how desperate i am.

[trooperbc]

1. the big white smoke made me think it was running rich

   white smoke is always a sign of water, not fuel, rich (black) or oil (blue). when does this occur? always? startup? once and only?

2. so i sent the car to a mechanic...

   no you didn't. any first-day mechanic knows what white smoke means (and it has nothing to do with the naming of a new pope, either).

3. need big help any ideas is welcome

   it's just impossible from the information or lack of information you are giving. come on...you really took it to a "mechanic" who couldn't track down a massive miss and we're supposed to guess based on that info?

Ok, then here goes. this is what could be wrong

1. fuel system
2. ignition sytem
3. computer system
4. engine mechanical.
5. homework assignment
6. massive trolling

if this is real, give us more to go on; the list of possibilities is endless.

i depresurized the fuel system

what did you do, how did you do it? what did the "mechanic" test/check? any changes, etc?

finally, of course, the first guess is head gasket, which would give the white smoke and cause massive missing. but an even bad mechanic could have told you that....and of course it has nothing to do with depressurizing the fuel system.

//bc

[zekinan]

i first took out the fuse of the fuel pump started the car let it run until it stop then i change the fuel filter put the fuse back and started the car again and that same day the car was backfiring on my way home but only when i stoped touching the gaz pedal so going to idle you could hear a backfire so i parked the car and the next morning. when i started the car again the car started but missfiring like crazy so i check the spark plug they were all black i clean them check them they all had spark i check the fuel pressure it was good, i check the firing order good, the timing belt is tight i took out the muffler just to check same. so i sent the car to the mechanic he checked the ignition coil, the spark plug, the spark plug wire, the fuel pressure, the timing belt, the timing,the compression, he told me he run straight LP bypassing the sensors and injectors but the car was still missfiring he runs straight pipe still missfiring
this is all we have done so far.

[trooperbc]

Originally Posted by zekinan

... still missfiring
this is all we have done so far.

damn. now that's a bunch of work.
what about the white smoke. still happening? what did the mechanic say about it?
are you getting water through the exhaust (after it's thoroughly up to running temperature)?
any indication of oil in the coolant?
any indication of water/coolant in the oil?

the backfiring is a new symptom that you either didn't state or i missed.

i'm still stuck on head gasket so far. . .maybe some of your answers to above questions will get others involved.

P.S. finally, everything was running ok before you did the fuel filter, or was this going on before that and you hoped it was the fuel filter?


//bc

[atfdmike]

Hi, thought I would weigh in on this one!

Is it possible that, if in the process of repressurizing the system, that you introduced enough air to cause misfiring which may have caused the timing belt to jump a tooth or two on the timing gear of either the Head or the Crankshaft pulley? That would result in a permanent misfire that might seem to go away at higher rpm but very obvious at low rpm. I don't know how many miles you have, but if you know that the timing belt and tensioner are new or were changed and checked at the proper interval then A good mechanic would have checked to see that the timing marks on the head pulleys and the crank pulley are timed right. Just one owners opinion. good luck

[trooperbc]

Originally Posted by atfdmike

....Is it possible that, if in the process of repressurizing the system, that you introduced enough air to cause misfiring which may have caused the timing belt to jump a tooth or two on the timing gear of either the Head or the Crankshaft pulley?....

mike, i'm ignorant about this, so my questions are:

you mean, got air into the fuel line? and that air then would cause a momentary misfire?
and that misfire would (could) cause the timing belt to jump a tooth or two, messing up the timing?

if i have this right, i doubt it. (but i don't know). it's just that cars have misfires all the time, and i've never heard that it could cause the timing belt to jump (but i'm open to hearing different).

i agree, that when the guy checked the timing, i assume with a light, that if it weren't spot on, then he'd have to check the alignment marks on the crank and on the cam gears.

//bc

[atfdmike]

Isuzu DOHC I am familiar with uses a crank sensor for timing, so the timing is controlled by the ecm, which does not care where valve timing is when it fires plugs. If timing belt jumps due to wear, tensioner breakdown, etc; then as long as it was not too far off, it might perfrom as described in this post. I have had another brand of vehicle have the timing belt jump due to a "cough" when the engine started. If it had a distributor which was driven by the camshaft, then you might see a problem with timing light. The air could have been introduced when new fuel filter was installed. I agree that that seems a stretch, but given the description and remedies applied, I just offered my own experience.

1994 Isuzu Truck Trooper (4 Door) V6-3165cc 3.2L DOHC (6VD1)

Vehicle Level Powertrain Management Ignition System Crankshaft Position Sensor Description and Operation Description and OperationCrank angle sensor sends information such as firing order and starting timing of each ignition coil, to ECM. A notch in timing disc on crankshaft activates sensor.

[bacchus_00]

hi , i have a 99 trooper 3.5 , i change the timming belt , replaced all seals , now the car doesn't want start , start for 1 second and then a backfire , i open the throtle body and i can see black smoke inside the intake manifold ,.... when i changed the timing belt first time i put wrong it now i'm sure that is right but backfire still there , before it car was running good .... i call to a machine shop and they told me that this car does have ENGINE INTERFERENCE .... any ideas??

[trooperbc]

Originally Posted by bacchus_00

hi , i have a 99 trooper 3.5 , i change the timming belt , replaced all seals , now the car doesn't want start , start for 1 second and then a backfire , i open the throtle body and i can see black smoke inside the intake manifold ,.... when i changed the timing belt first time i put wrong it now i'm sure that is right but backfire still there , before it car was running good .... i call to a machine shop and they told me that this car does have ENGINE INTERFERENCE .... any ideas??

IT IS A NON-INTERFERENCE ENGINE ! to keep this simple, here is a post by extechtrainer and isuzu expert JLEMOND http://forum.planetisuzoo.com/viewto...?p=98391#98391

ALL ISUZU V6 ENGS ARE NON INTERFERENCE ENGS FROM 92TROOPER ALL THE WAY TO 2002 AND THE RODEOS 93 THRU THE 2003 MODEL YEAR,

3.2 3.5 DOHC AND SOHC

2004 DI 3.5 IS AN INTERFERENCE ENG

NO EXCEPTIONS JERRY

ok, with that out of the way. your symptoms sure continue to sound like timing. want to talk about how you set the timing, what marks you line up, what info you used to do this? etc, ?
maybe it will lead to an understanding about what is wrong.

//bc

[atfdmike]

Originally Posted by bacchus_00

hi , i have a 99 trooper 3.5 , i change the timming belt , replaced all seals , now the car doesn't want start , start for 1 second and then a backfire , i open the throtle body and i can see black smoke inside the intake manifold ,.... when i changed the timing belt first time i put wrong it now i'm sure that is right but backfire still there , before it car was running good .... i call to a machine shop and they told me that this car does have ENGINE INTERFERENCE .... any ideas??

Sounds like you got the cams out of sync with the crank timing gear when you installed it wrong the first time. The cam gears require that they be in the correct position on your engine, and there is an explanation on the site that BC gave you on how to do it...Try a search there and you should find it.