1986 Chevy Camaro hard starting

J.P. DURAIN

MEMBER
1986 CHEVROLET CAMARO

Engine Performance problem
1986 Chevy Camaro V8 Two Wheel Drive Automatic

please help im trying to fix a 1986 camaro with a tpi it is hard to start cold or hot seems to be flooded have to hold throttle open to clean out then it throws a 33 code have replaced maf, tps, maf relay, cleaned and inspected maf relay connector and fuel pump realy and connector have installed a new regulator, new injectors, holds fuel pressure pretty good now was losing presure fast before and injectors were noisy set tps at 5.4 volts yet still it starts hard cold or hot, if you fire it right back up its ok if it sits five or so min its hard to start again, please help me

1 Reply

MMPRINCE4000

MECHANIC
8,548 POSTS

If the MAP/MAF were bad it would barely run hot or cold. The ECM would (if the MAP/MAF were bad) set a default setting of WOT, which would be very rich.

You may try a different MAF, or scan the ECM with a scanner to see what voltage or kilopascals the MAF is reading. Also see what the injector pulse width is.

Also 5.4V is too high for the TPS, the reference voltage is 5V so WOT on the TPS should be 4.5-4.75V.

I would also check the ignition module (have it tested).

It also sounds like the injectors are leaking (you mentioned it started back up after turn off, but if you let it sit it won't) or the fuel pressure regulator is leaking. You said you changed the injectors and regulator, look in the regulator vacuum line for gas which would indicate a ruptured diaphram. Also fuel pressure above 70psi would cause the injectors too leak. Maybe the return line is clogged/pinched.