'91 cranks a long time before starting

[rhauf]

On my '91, when it's cold (or been sitting over night) it takes quite a bit of cranking (maybe 10 seconds, or several shorter trys) before it fires up.. i changed the fuel filter, and there is no CEL or codes. what should i check next?

 

[RedneckRambo]

On my '91, when it's cold (or been sitting over night) it takes quite a bit of cranking (maybe 10 seconds, or several shorter trys) before it fires up.. i changed the fuel filter, and there is no CEL or codes. what should i check next?

well when i disconnected my evap canister it took a little bit for it to fire up. i would check to make sure the hoses are connected to that

 

[rhauf]

checked - the canister is missing entirely (removed by previous owner i think)

is there a fix for this to make it start easily without the canister? what did you end up doing?

 

[Tbars4]

...What's the voltage on your battery after it sits for a while?

....What are your FPR pressure readings?

...Does your fuel pump prime every time you turn the key to the on position?

...And your canister is required in Calif.

 

[RedneckRambo]

checked - the canister is missing entirely (removed by previous owner i think)

is there a fix for this to make it start easily without the canister? what did you end up doing?

i hooked the canister back up. all i did when i disconnected it was splice the 2 hoses going into it together

 

[rhauf]

...What's the voltage on your battery after it sits for a while?

....What are your FPR pressure readings?

...Does your fuel pump prime every time you turn the key to the on position?

...And your canister is required in Calif.

battery is brand new, tons of voltage, cranks like crazy.

the fuel pump primes nicely

i didn't remove the canister, the previous owner did.. he also removed a bunch of other things i've had to reinstall (such as exhaust) the canister will be on my next junkyard run.
i tried splicing the lines together, and plugging them both, there was no change. (slow start every time)

i also found a vacuum leak... on that block of vacuum connectors at the back of the intake there was one vac hookup which had no hose on it.. i looked around and didn't see any hoses off, so i'm not sure what it goes to. i'll have to trace it out on my other explorer later. plugging the vac leak dropped the idle a bit.. it was idling slightly high before. but it didn't help the starting problem any.

i've also noticed that when it's cold, it tends to stumble a bit if you hit the gas too quickly. i've replaced the TPS and no change.

 

[Maniak]

I don't see how the evap canister will have any affect on starting Assuming the vacuum line that went to it was not just left open.. The Evap canister is a box with charcoal in it that is on the vent line from the tank. Certain times the computer will open a valve which will let the fumes that accumulated in the canister to be pulled into the throttle body by a vacuum line that is connected between the TB and the evap/charcoal canister.

Long cranks before starting is usually a fuel pump type issue or a leaking injector. Basically, there is a check valve in the fuel pump that is supposed to try to keep some fuel pressure in the line. If the injectors are leaking or the check valve is bad you will have to turn the key on/off a few times before starting to build the fuel pressure it to get it to start first try.

As far as I know, there is no way to change the check valve without changing the fuel pump.. Which is always fun since its in the tank.

Fuel pressure testers are cheap and are easy to use and will tell you if your loosing pressure when parked.

As for the missing vacuum line.. Depending on the year (1991 to 1994) you will have more or less capped off vacuum ports.

The 1991 and 1992's have the most capped off as they don't have EGR. If you have a manual trans you will have another one capped off since you don't have the vacuum modulator on the transmission. Some 1991's have MAP sensor (its in the firewall, up high, passenger side) which may have a vacuum line. IIRC, our 1992 had 3 capped off from the factory (had an auto trans)

It is pretty common to lose vacuum caps over the years.. Which of course makes it run poorly..

~Mark