Slow starting... (filters, plugs change?)

[Schrade]

How many fuel filters in a '90?

Should plugs be changed at 30k? Do they take a hit from 'time'? And plug wires?

She spins for 10-12 seconds before starting up. Sometimes a second attempt is necessary for 10-12 seconds.

Static fuel pressure holds 48, bleeds to 45 after 15 minutes.

Closed loop idle is perfect, no loping, no SES (except for CCM 72 / dash LED voltage).

Ideas?

 

[tmkassin]

Could be a bad fuel pump relay. When you turn the key the fuel pump activates momentarily and shuts off till the oil pressure comes up. If you have to crank it till the pressure gets high enough it will cause the very symptoms you describe.

 

[Hib Halverson]

Could be a bad fuel pump relay. When you turn the key the fuel pump activates momentarily and shuts off till the oil pressure comes up. If you have to crank it till the pressure gets high enough it will cause the very symptoms you describe.

"tmkassin" is spot on.

Get out your '90 Service Manual Supplement (sec 8A), look in the engine controls section and you'll find the circuit diagram showing the fuel pump relay and the oil pump switch. You need to verify the FP relay is working. If it's not, replace it and you're troubles will likely be over.

Also, only one fuel filter on a '90.

 

[Schrade]

If the FP Relay is bad, would the initial primed pressure go to 47 - 48 PSI, as mine does?

L98 would wait for an RPM signal (from started engine) to resume power to pump (after initial priming).

If this 'secondary / resume' signal, to fuel pump is bad, in mine, how would it even start at all? Could it be an 'intermittent' failure? Like a bad ground???

 

[scottfab]

...snip....

She spins for 10-12 seconds before starting up. Sometimes a second attempt is necessary for 10-12 seconds.

Static fuel pressure holds 48, bleeds to 45 after 15 minutes.

Closed loop idle is perfect, no loping, no SES (except for CCM 72 / dash LED voltage).

Ideas?

Sounds exactly like my LT5. Try this.
When you first turn the key go all the way over to the start position.
Do not hesitate at the ign on position.
Oh and make sure the clutch is pressed all the way in first before you turn the key
for an unrelated reason.
Now see if the car doesn't start quicker than if you hesitate at the ign on position.
We're not talking real quick but quicker that before. (5-8 sec)