I love when i type all this and then lose it all

 

Happens to the best of us.

 

whole last post just vanished arghhhh!!!

ok so Ive cleaned the thottle body...replaced the hose (pcv)........also cleaned hose etc....coming off intake side of plenum to left bank ram housing. All of this was very dirty.....new hose seemed to be working well............started right up all day yesterday ............even the first start was surprisingly easy

Today warmer outside than yesterday.....and i mean like 68 degrees ...no start ..........tried over and over throughout day............wants to but no starting

tested intake air sensor by following method...........removed sensor from filter housing set ohm meter to 20k ohms applied a lead to either pin and breathed on the sensor to measure for change in resistance with temp change...............nothing just sits at 0............so I am thinking it is bad........found one cheap so ....ordered it.... anyone think I tested it wrong?? or agree it is bad? my only thought on this test method is that there would be no heat applied to the heated wire......


even so Ive been having this issue and starting so i tested for fuel pressure and had none........also thought i am not hearing the pump again so swapped fuel relays .........no change.......let pressure out of tank by removing gas cap......listen as someone turns to 2 I hear nothing..........?? put cap back on move key from 1-2 several times try to start several times.........now seems to be hearing pump very faintly open cap and have little pressure release......

need to open pump cover and confirm it is pumping I guess.......or try later when its quieter outside...I notice it is quieter when tank is towards empty which it is at present....just under 1/4 and I have never run it out of gas yet so just to be sure I put in a gallon from a gas can.....just in case its reading wrong......felt like it did get louder ....

Spike, I was thinking back to the night my plug tips came loose ..........the pump was hardly pumping then .......some signal was telling the pump to pump less.........after this was fixed ...I continued to get misfire (random) and P0420 left bank cat eff.........I re-gapped those autolites to .038 from .033 and erased the codes and didnt have any codes.....for a bit ......then I couldnt start when cold very well but still could start............while cold start issue was happening I got my new plugs (champion plat2s) and new wires...this was feb 9th........I gapped these at .035 at the advice of rovers north....and it was running great once started.....but my p0420 code came back on the 12 th and cel came on ..indicating several instances ....of this ( at least four correct?) which oddly equals the number of days since plug gap changed.................and starting seems to be worse now after cleaning throttle body.....my question .......I have on my vehicle under hood...... .033-.038 as the gap recommend
in the rave thats listed for austrailian versions with distributer.......
other wise I find this

ENGINE 4.0 V8
Type .................................................. ............................... 4.0 Litre V8
Firing order .................................................. ................... 1-8-4-3-6-5-7-2
Cylinder Numbers
Left bank .................................................. ........................ 1-3-5-7
Right bank .................................................. ...................... 2-4-6-8
No 1 Cylinder location .................................................. . Pulley end of left bank
Spark plugs
Make/type .................................................. ...................... Champion RN11YCC
Gap .................................................. ................................ 0.90 - 1.00 mm 0.035 - 0.040 in
Coils
Make .................................................. .............................. Lucas 2D1S2
Type .................................................. ............................... Twin coils, bank of 4
High Compression Low Compression
Compression ratio .................................................. .......... 9.35:1 8.2:1

however when i called rovers north and give them my vin they say .85mm or about .035

now I know it shouldnt be that big of a deal but It seems like it maybe is....cold start has gone from bad to worse........codes are back.......... Im thinking of re-gapping the new ones what your opinion......and your vote for gap?

Ok so to summarize.........info i seek =

did I test intake air sensor correctly?
agreement that sensor bad...

what is the result of this sensor having NO resistance ? from reading ....seems fuel injection is affected...fuel to air mix ..but what im wondering is would no resistance REDUCE pump output during the priming cycle...WANTING THESE TWO ITEMS TO BE RELATED...

concerning sensor........when I look in the pass through there is a little black bulb on the end of a wire.....and then it looks like there should be a wire attached to the collar near that bulb .........what I mean is it looks like there WAS a wire soldered there once ...

what plug gap do you recommend and do you think my p0420 is coming back from the gap change? or maybe just from the bad sensor? fuel air problems...............?

edit: thanks spike........but i bet no one takes this long to get it retyped !!!

 

when i do get started again should i go ahead and do an induction cleaning?

 

soz youz knowz... The IAT only has an effect on the ECM's fuel, air, ignition management if it senses incoming air temps over 131*F

If you are 100% positive your probe leads are making good contact with the two tabs on the sensor and you are getting 0 or OL (out of limit) that signifies a broken circuit ... bad sensor.

Here is a list of sensor values you should see with your multimeter. I stole this from another thread.... stole it from myself actually.

IACV - both circuits should measure between 40 and 60 ohms
circuit 1 is pins 1 and 26
Circuit 2 is pins 28 and 29

MAF output voltage - 1.7 (idle) - 4.5 (full throttle)
(Disclaimer on this one---I think!!!!! Those are the values for the 5AM but gems uses a 20AM SAGEM)

TPS
throttle closed - 0.6 v
throttle open - 4.5v

ECT
0.7v @ 185*F -----V will increase as temp decreases
28,000 homs @ -22*F
300 ohms @ 185*F ----Normal op temp.
90 ohms @ 266*F


IAT *[note - ignition timing retarded above 131*F]
23,000 ohms @ -22*F
290 ohms @ 176*F (hope you never drive in those conditions )

Fuel Temp
1,100 ohms @ 104*F

HO2's -
1.0 to 4.99 v
high volts = rich
low volts = lean

 

wow cosmic thats alot of info..... so to keep me on track...and no i did not know that.....I was told by a mechanic that helped me push my car out of an intersection that my cold start problem was due to bad IAT he said this because I told him .....it runs and starts great after the first warm up of the day......but before that rise to operating temp (which takes forever) I stall ....turning on the heat before temp is up will cause a stall....this is sitting still or moving........also I stall mostly when taking off from stop, coming to stop, and on random speed bumps.....but not once its warm

1) did i test it right? Sensor removed, not hooked up to wiring....set ohm meter to 20k ohms lead on each tab....i get zero.....breath on it on stays at zero...
or
should I have tested it with sensor connected?

my test method comes from ehow or some such place....

also just to understand better
"IAT *[note - ignition timing retarded above 131*F]
23,000 ohms @ -22*F
290 ohms @ 176*F (hope you never drive in those conditions ) "

my reading of 0 then indicates a temp above 176F ?? is this right? - or it indicates no temp reading at all-thus leading to default value (normal operating value) ?

"Intake air temperature sensor (IAT Sensor)
This is another resistive sensor, located in the body of
the air cleaner. The resistance varies with changes in
air temperature. The signal from the IAT Sensor is
used to retard the ignition timing if the air temperature
rises above 55°C. If the sensor is disconnected or
failure occurs a default value will be supplied to the
system. The default value selected will represent
normal operating conditions. The fault may not be
evident to the driver, there may be slight power loss in
high ambient temperatures. The fault is indicated by
illumination of the malfunction indicator light (MIL) on
North American specification vehicles."

what code would this throw ? current codes p0420


At any rate I have opened the fuel pump hatch again yesterday....since i could not hear it and the pump was running however if I bump the pump wiring it cuts off............I separated the wires just enough so that they do not touch each other and tapped on each one as pump was running and the white wire when tapped or bumped cuts off the pump......opening that connector and re-soldering/checking out those wires today..........this would explain my stalling when taking off from stop and stalling over speed bumps......and probably the misfires and low cat codes also yes? The only thing I do not understand is why it would happen sitting still and why it stops happening when the vehicle is warm......(maybe the wires get hot and the expansion holds the connection?) thinking back now ....I do recall power losses.....from time to time while driving (hesitation type power loss and what has felt like odd shifting)

thanks



thanks for all the great info ....

 

update .............fixed up my fuel pump connector today...it fits nice and tight and started right up....tapped it, thumped it, jum,ped on the back bumper .....still working.....took it through speed bump alley...still no problems......so.....now I guess I wait for cold whether again to see if it starts when cold out............

 

That is great news... congrats (for now).

Another prime example of KISS, although finding it was far from simple.

 

The collective information in this thread might make a good "starting/stalling issues" troubleshooting sticky in the tech section.