Started yesterday

I swapped in 3 MAF I have all same result

I see no vacume leaks, but the exhaust smells wrong no cats I can tell

O2, TPS both look normal on the ug

At idle MAF is .08
TPS is 11.8
O2 are both moving 995/1000
Idle keeps 650/750 ish

Sounds like it wants to die on startup

Unplug the vacume to fuel reg and it makes no difference, plug the intake port and possible minor improvement no smell of raw fuel

I have not checked fuel pressure

 

Same thing here. After replacing the ivac, tsp, maf (twice), fuel temp, air temp, and crank sensor, I had a brit shop put it on their scan tool to set the idle & they found the air temp at the ecu was reading -38 even though the UG was reading close to ambient temp. Checked with a few other brit shops who confirmed the -38 was a computer issue and would read different than the UG. Waiting for my replacement ecu & alarm ecu to get here from WA since that was the only place who had both parts as a matched set. Yours is a 98 & if you have the type 01 80801A they are hard to find.

 

I have my original ecu it needs reset this is the replacement I had reflashed, iat does display correct on ug

 

Air Mass Flow Rate which means your not getting enough air through the engine under load. Look at restrictions, filter, openings, plenum/trumpets covered in oil......

 

My MAF reading is to low?

 

I have 32 psi on fuel rail

 

Measured while running or off? Should be between 34.8 - 37.7 (2.4 - 2.6 bar) according to the Rave.

 

That's running, everyone I hookup same reading, I knew that looked low tried moving plug and wires no change, hell I unplugged it no change how the engine ran

Could something be shorting MAF like what happened to my TPS before?

 

You have too much oxygen in the A/F ratio and the ECM is telling the injectors to max pulse to put more fuel into the cylinders. A dirty MAF, dirty O2's, low fuel pressure or vacuum leaks are the items to chase. I know you put O2's in so it's not them, you've tried three MAF's with no change, you haven't looked for a vacuum leak that I know of and you just posted the fuel pressure and it's lower than it should be by almost 3 pounds per square inch at the minimum spec level. Fuel filters, pump, vacuum........

 

Saw no vacuum leaks

Probly Monday I will put in the replacement pump need to buy a sock and filter

Could it simply be the fuel pressure regulator at the rail is bad?


But why is the MAF reading so low? What should the reference voltage be at the sensor and which pin?