1990 Toyota Pickup Starting & Running Problems

1990 TOYOTA PICKUP
Avatar
EIGHTRAC2
  • MEMBER
  • 4 POSTS
1990 Toyota Pickup 240000 miles

my 90 toyota pickup will sometimes start & run just fine.other times it won`t start right away if i click the starter about 20 times it will start.this has nothing to do with the starter or battery it cranks over good.i jumped the diagnostic fuel pump terminals like you said & the truck runs just fine.how long can i run this truck in that mode till i can repair it & do have any ideas whats causing this problem maybe a relay or wiring ?.

90 toyota pickup / 22re / fi / 2wd / 4 speed stick

thank you
Oct 24, 2010 at 1:27 PM
Advertisement
Avatar
RASMATAZ
  • CAR REPAIR CONTRIBUTOR
  • 75,992 POSTS
Hi eightrac2, Welcome to 2carpros and TY for the donation

Remove the jumper from the DLC and block wide open the airflow meter vane flap and see what happens-let me know.

As long as you want -mine was a defective airflow meter and the jumper is still in place its almost 3 yrs now-

Could also be the circuit opening relay-the airflow meter has to ground the Fc terminal of the COR to power the fuel pump
Oct 24, 2010 at 1:54 PM
Avatar
EIGHTRAC2
  • MEMBER
  • 4 POSTS
will my truck pass a california smog test with jumper wire left in.i`am not sure what your talking about blocking wide open airflow meter vane flap & then trying to start.
Oct 24, 2010 at 9:07 PM
Avatar
RASMATAZ
  • CAR REPAIR CONTRIBUTOR
  • 75,992 POSTS
If there's no CEL On, you should be able to make it thru. Description and Operation Air Flow Meter


https://images.2carpros.com/forum/automotive_pictures/12900_maf_5.jpg

A Bosch vane type airflow meter is mounted in the air induction system near the air cleaner. The airflow meter measures intake air volume, and converts these readings into voltage signals by means of a variable resistor (potentiometer). These voltage signals are then sent to the ECU and used to determine injection duration and proper fuel delivery. When intake air volume is low, the voltage is high; when the intake air volume is high, the voltage signal is approximately zero.
Oct 24, 2010 at 9:29 PM
Avatar
EIGHTRAC2
  • MEMBER
  • 4 POSTS
can i bypass the maf : mass air flow meter till i can find a replacement part.

thank you
Oct 25, 2010 at 9:53 PM
Avatar
RASMATAZ
  • CAR REPAIR CONTRIBUTOR
  • 75,992 POSTS
You don't have to worry about bypassing the airflow meter all it does for the fuel pump is to ground the circuit opening relay to power the fuel pump-you can keep your jumper in the diagnostic link connnetor hooked-up
Oct 25, 2010 at 10:05 PM
Avatar
EIGHTRAC2
  • MEMBER
  • 4 POSTS
the maf is damaged i tryed to inspect it & now my truck runs bad & won`t idle.
Oct 25, 2010 at 10:32 PM
Avatar
RASMATAZ
  • CAR REPAIR CONTRIBUTOR
  • 75,992 POSTS
The computer has to see an input signal ( airflow volume ) to control the fuel as needed also with other sensors-Dunno how to bypass it w/o the signal-Sorry
Oct 26, 2010 at 12:09 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.