1998 Jimmy ... no guts.....

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warwagaon

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Might just roll it ove a cliff.....I hav posted her a few times on the gremlin infestation...a few more onths of work and back to square one...so let me start the list and Info..

1998 sls jimmy 2wd
v-6 vortex
heads reconditioned/rebuilt.
fresh oil and 91 octane gas,w 1/2 bottle of SeaFoam in each
ALL filters replaced.
New battery,fully charged., Extra grd added.
all new gaskets on the intake manifold,No vacuum leaks. no fuel leaks.
Fuel Pump Pressure checked , 62psig. during start drops alittle , WHEN running at Idle ,reads 62 psi. steady.
Oil pressure normal,temp normal , etc.
New Cap and Rotor, New spark plugs properly gapped.
Does not blow ant black exaust..very clean,,little grey smoke when Cold,goes away.
New MAP sensor.
New MAF sensor.
New TPS sensor

symptoms
intermittent PO108, only when trying to increase Eng RPM does it code.
Eng will 1st fire start cold in one eng rotation ..as long as i dont do anything it idle like a kitten.
I move the it throttle 1/8" , It will either surge , drop rpms( barely run) or die . like I said when idle its smooth, and may or may not throw a code oif it does its P0108,, listed is the FF data after a 5-10 min idler period,,never touching the Acceleration pedal. OAT 65-70 High humidity (clouds , no rain)

fuel sys1 CL
fuel sys2 CL
Calc Load %4.2
ECT *C 92
stft b1 -24,22
ltft b1 -14.06
stft b2 -24,22
ltft b3 - 17.97
MAP. 98.00
Eng rpm (750-800 at start) 403
MAFs 7.48 gs
TPS 0.0


Take your best Troubleshooting guess ,.I am all ears.. spoke w CAR repair shop for cost ON REPROGRAMMIN>$150. and thru the INTERNET?? wonder If could find that program and do it myself w/ a laptop?
 
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update,,.... replaced the Pressure regulator,,checked complete fuel system for leaks, NO -LEAKS ,,65 psi .upon removal of plenum onl leak (wet area) was under the FPR ,hence replacement ..rechecked for leaks after replacement ,NO-LEAKS,,,eng Runs the same same NO Change... as it did before replacing the FPR...


Removede and checked plugs ,,Because i cant get it do do anyhting but idle..they were on the black sooty side at the base a ceramic,,but dry,, the electrode was Tan..,,thay looked perfect to me.
 
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Update # 3
the fuel pressure upon turning the Ign, switch , an installed gauge gives a reading of 62-65 psi. As soon as the pump stops ,,it will drop to 30m psi ,then slowly bleed off to 0 psi.. this was still AFTER instlin a new pressure reg
Even though the pressure will read 62-65 psi while eng is running.

I was told by a shop that the fuel filt has no check-valve but the FUEL PUMP inside the tank does ....I dont see how...

either way it looks like internal leakage..

anyone have experiance w/ these pumps to confirm these findings...?

also the OB2 recorded in FF an " OL" (open loop) in the fuel banks now ..can someone also explain this..???????
 
Replaced fuel pump.....NO CHANGE ..holds pressure WTF?????!!!! CAT and Muffler and whole ex system ..no blockage.
 
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REALLY , REALLY?? nothin? com'on guys ...i guess ur just a stumped as i am..Where are all the experts ??
 
warwagaon said:
REALLY , REALLY?? nothin? com'on guys ...i guess ur just a stumped as i am..Where are all the experts ??
Click to expand...

There is a sensor on top of the fuel tank that looks exactly like a map sensor. Its a fuel tank pressure sensor, unplug it and see if it runs good any better.

These can short out and bring down the 5v reference on the map sensor causing the issues your having. Keep us posted and good luck

Molson02536;)
 
Ok just tried the suggestion,,ob2 thru a code p0452 (emissions low volt) No change.
wont start,,tries to ,,thumps over - wont finish,,,,
replugged in sensor on top of fuel pump/level housing...po452 gone.

but the P0108 generic code says HIGH input..not low....????

and as long as DO-NOT TOUCH the gas pedal to start...NO OB2 CODES WILL be recorded.

DAMN !!
%50 Ether doesnt help//
 
ZER0, "0" NADA as in NO-CODES ...only time I get p0108 now is if i hold the throttle wide open during cranking.....
 
Disconnected wire at fuel pump as suggested ..NO-CHANGE..tied another batter , twice twice the cranking amps,,still no start.
 
I have spark from the coil,,I have spark from the dist to the plugs, I have fuel to the spider, plugs are black, and dry ..I spray ether and can also pour gas down the throttle body,,still try to but wont light off.
ONLY time it sound like it going to start WOT..:(

Used another battery ,twice the crankin amps.
 
ANYONE lookin for a GMC parts car,,come get this POS,,,,I dont think Ill ever own another GMC/CHEVY again.....
 
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