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Gloomygoblin
Dodge Dakota
JOIN HERE
1/20/2005
21:05:41
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 Subject: Major Malfunction
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Message:
Ok.. heres a hard one for ya.. Yesterday I changed the waterpump on my 98 Dakota with the 3.9 V6 I parked it in the garage and it was idleing at 675 rpm. I did the waterpump change and fired it up... The idle was at 1500 RPM! 1200 In Park.. it's also missing at times and has a very lopy run at idle.. at speed everything is fine??? I didnt touch the distributor, wires, plugs.. they are all new anyhow.. I made sure everything is plugged in.., I looked for any vacume leaks and hear/saw none... I cleaned the IAC and nothing???? no differance at all.. I reset the PCM using the PCV valve trick without any change.. Im compleatly lost over whats goin on here.. I even changed the battery cables 2 make sure optimum voltage was acheved... also.. there is no check engine light on...I had unplugged the battery before I started.. have no water in the oil and never overheated it. Any Ideas would be appreatated.. One more thing.. the truck is parked outside in often -30 and cooler temps.. when I worked on it the garage was 75 degrees or so.. >>> what could it be???
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GB2000
GenIII
1/20/2005
23:35:53
|  RE: Major Malfunction
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Message:
What do you mean by resetting the PCM with the PCV valve trick?
Try resetting the computer again...start it, let it idle about 30 seconds and don't touch the gas, shut it off, repeat, shut it off, repeat (you can rev it up/whatever this time). See if that helps... could also be your TPS sensor possibly (I think that's the sensor I'm thinking of...), but I doubt it since you didn't mess with it. Did it start to do this before you cleaned the IAC or after? Before, right?
Josh
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Gloomygoblin
Dodge Dakota
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1/21/2005
01:32:31
| RE: Major Malfunction
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Message:
Hey a reply =).. kk What I did was pull the PCV valve hose off the PCV so the AIC motor would close as much as possable, then reset the PCM by dissonnecting the Neg cable and turning the key 2 start for 30 seconds. Then I rehooked up the hose and started it.I did clean the IAC very carefully after the problem began with no change in the idle condition. I spoke 2 a mechanic about it and he told me 2 check the EGR system..BTW I also replaced the timing gear and chain with a double roller one a few months ago with the new tentioner,it ran great with no probs afterwords. When I replaced the waterpump I also replaced the gasket for the timing chain cover since the gasket maker I had used wasnt all that great.. no leaks anywhere now... just this wierd Idle problem with the missing.. loping.. and high RPMs. This problem is really wierd and I could use all the help I can get, You know if this thing had a carberator on it Id assume the choke was stuck..but its EFI so I dunno whats going on with it =/, Also I checked the TB plates and cleaned them as well.. no cable hangups and proper operation was found there. And still no check engine light is present.
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GB2000
GenIII
1/21/2005
02:43:34
| RE: Major Malfunction
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Message:
Think it's possibly a vacuum leak? I'm really stumped... Hopefully someone else has more ideas for you.
Josh
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Gloomygoblin
Dodge Dakota
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1/21/2005
04:46:04
|  RE: Major Malfunction
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Message:
Well as far as I have checked I cannot find a vacume leak the MAP is connected and pvc,as well as the brake booster and other hoses, I even traced them looking for cracks and such, listened for any hissing and heard none. I wonder if a sparkplug decided 2 go out? Would the MPI try 2 give the remaining cylenders extra fuel if one cylender was not firing?,possably resulting in a very high Idle? This might explain why it's missing and loping a bit, However if it were a bad cylender why do I have normal power in driving conditions? Also my temp gauge is reading a normal operating temperature.
Gloomy
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gloomygoblin
Dodge Dakota
JOIN HERE
1/21/2005
07:49:39
|  RE: Major Malfunction
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Message:
Well I made some progress with it ..I went threw all the injectors with a wiggle test and found the #1 fuel injector produced an RPM drop..I guess when I put the compressor up there "making room" it tweaked it somehow. Dunno if it was leaking air or just not operating. When I unplugged it I could tell it definatly was unplugged. Now my curb idle starts out at 900 then rises too 1050 and 900 in park, better but evidently not the whole story.. I made sure its sealed and tryed 2 lower the RPM agian by reseting the comp and pulling the pvc hose agian with no luck. Ill be buying a new set of injectors and hopefully that resolves the matter.. Still wondering if somthing else could be involved. I never would have thought one injector could have such a dramatic effect.
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