doogieboy

Hey folks just joined.
I have a 91 PU that will not start when the outside temp falls into the 50's or below. Been going on for 2-3 years. After the sun comes up and the temp warms up, it starts just fine.
Has to be a temp sensitive device ( a relay) or something that is not making good contact when it is cold.
please help resolve this burden.
Thanks

jason191918

Did you check the cold start injector?

doogieboy

No. I am no mechanic. i just wanted to know of anyone's experience of this problem so I will know "going in" what to suggest to the mechanic.

22mr2

cold start injector or the cold start injector time switch, both very easy to replace.

Bill54880

Yeah, sounds like the cold injecter isn't working for some reason

a4runnerfreak

I went thru the same thing with my old '91 truck. CSI and the CSI time switch are the culprets. The CSI time switch is something like $175 IIRC.....

doogieboy

Thanks all. I will try both of these.
Glad I found this place and lokk forward to more conversations.

Bill54880

Make sure to post if it gets fixed so others can find the solution too.

BrownsfaninMN

I had the exact same issue for the past 4 years, basically just lived with it instead of doing anything about it. This summer I put a new bed on my truck, replaced the fuel pump (precautionary) since I had easy access to it. Thought I had it, truck started fine (duh, summer, not cold enough), however once it got cold again, problem returned.

Was tired of the situation so I decided to shotgun both the timer and the injector (over $300 for the two items), replaced both, guess what, same stinking problem... What I finally did was took out the cold start injector, sprayed an entire bottle of carb cleaner in the hole (intake manifold), and guess what, it's started on the first crank every time since.

My suggestion, try the carb cleaner first (cheapest fix), and while you have the injector out, turn the key (when cold outside) and see if you get a mist of fuel out of the injector, if so, it's working. Clean the cold start injector and give her a whirl. If no mist, the timer isn't sending the signal to the injector to squirt.

The easiest way to test the timer (I found), rather than trying to attach the leads on your ohm meter with it installed, remove the damned thing, measure the resistance across the leads, then stick it in the freezer for about an hour and measure it again, supposed to be like 80ohms and 40ohms...

Good luck, if I can do it, you can too...

BrownsfaninMN

...to remove the timer is easy, remove the electrical connector, it's only like a 15mm socket, small extension and rachet, feed it between the lines, and take out. Don't take the radiator cap off and the vacuum in the system should prevent any coolant from coming out. Watch out, don't lose the washer that's on the threads of the timer when removing it.

Please note, my suggestions are for the V6 engine...