98 d1 not running help please

[TOM R]

OK this happened last week and sort of self corrected for a few days then happened again and won't go away

Vehicle started bucking while driving and will not idle, my TPS as displayed on the ultra gauge was 11.8 it is now .78,

It will go up and down as the pedal is moved like it should but only to something like 2.39%, so it is obvious the TPS is waay low and I am guessing the cause of the drivability issue

The only code is p0451

I checked the power and ground at the TPS sensor plug ground is good, power is only .50 volts which seems way low

I traced the red power wire back to the ecm and it is .50 volts at the ecm

I did attempt to use the old ecm and got the same measurement ( old ecm was stuck on high idle)

I attempted using 2 different TPS known good same reading

Now that red power wire splits off by the washer bottle goes into a large connector and through the firewall then I lose it

Any help is greatly appriciated

Am I looking in the wrong place?

I cannot locate the TPS test with values in the rave

 

[singingcamel]

Fuel pump hum with the ignition on ? You may have to have someone listen while you turn the key. may be a shot fuel pump . Ever change it?
Maybe a vehicle speed sensor?
Can't help with that TPS funkiness.

 

[TOM R]

It does crank and run if I keep my foot on the gas but runs real rough smells like it is loading up, IAt and coolant temp read correct to outside temp from sitting

 

[TOM R]

I have replaced, the fuel pump in the last 2 years, fuel filter last summer, rebuilt vss over the summer, and head gaskets, all done by me so I know nothing was skimped on and no wires pinched etc.

Guess I could crawl under and unplug vss, I do have the under hood abs pump fuse removed been like that a while

 

[TOM R]

Tried vss no change

 

[Flyfish]

Any problems filling up with gas?? (funky pressure kicking off pump?)

Since it's a fuel pressure sensor fault... bad cap, bad purge valve, loose evap canister fitting. Clean the multiplug from the purge control valve?

The EVAP control system pressure sensor circuit is open or shorted - Rubber hose to EVAP control system pressure is clogged, vent, kinked, disconnected or improper connection. - EVAP control system pressure sensor may be faulty - EVAP The Error code is generally activated on detection of the following conditions: - An improper voltage signal from EVAP control system pressure sensor is sent to ECM.

 

[TOM R]

I have had that code for years not sure it would cause this problem

Yes the pump kicks sometimes, I replaced the purge valve and cleaned out all vent lines, just have not replaced cap

 

[TOM R]

Fixed, TPS supply power is also tied to the sensor on the fuel sensor, it was shorted, unplugged and I am driving again

 

[XCELLER8]

now going thru this exact same problem !.......:banghead:

"power supply tied to sensor on fuel sensor "
Tom what exactly did you unplug ?....

really appreciate your help........this thing is driving me nuts on my '98 DI...
started out as a high idle, then went to a really high idle, then graduated to full blown chugging and dieing at idle, and dumping gas running rough same as you describe,( and I had the same code a week ago) fouled the plugs during this performance !

If i unplug the tps while its attempting to run.....it smooths out runs ok, but idles at 1500

thanks
in advance

 

[TOM R]

Pull up cargo carpet, remove round cover on floor to access fuel sensor, the plug closest to front of vehicle, unplug it is OK unplugged till new fuel pump assembly arrival

When you first start after unplug runs like crap for a few seconds will self correct, if this is the problem

TPS should be 5 volts at red wire key on, red/black is ground on tps

 

[TOM R]

My bad send or

 

[XCELLER8]

THANKS ! for the help, much appreciated !!
I'll get back here with the results.......cover me , I'm goin in !

 

[XCELLER8]

well...hoping not to jinx it....so far so good.
unhooked the tree hugging tank pressure sensor......instantly ran as it should . The idle is a little shaky but the ecu seems to be learning to contol it a little better....the more I drive it. After looking at a wiring diagram for this...some wizzard engineer hooked this sensor to the tps ( as tom mentioned) as well as the coolant temp sensor and the MAF !! when it shorted out ...no wonder ! the ecu couldnt compute.
thanks again for the guidance !