Hard to start when hot

[22sonoma]

Hey guys just joined this forum and am looking for some help with my wife truck. its a 2000 sonoma with the 2.2 flex fuel.
The truck will start good when the motor is cold, and runs good once started, but if you stop and try to restart wile the motor is hot it will crank for about 15-30 seconds before firing. just put a new battery in it last month and starter seem to crank hard. just takes a while to fire. i dont want to go buy a bunch of part and start throwing money at it. i hope some one has had same problem thank you for any help

[Fr8 Train]

there are a couple of us working on trying to fix this problem check the slow to start thread...

[beandip]

Check the coolant temp sensor...when bad it reads -40ºF and the computer just DUMPS fuel in to compensate for the cold temps...but its not cold...its hot so it floods the motor a little bit making it hard to start ONLY when hot.

[22sonoma]

Ok guys i will give that a try i hope it works.

[Fr8 Train]

mine unfortunatly wasnt the temp sensor i changed it out and still having the same problem..the last thing i can think of for mine is the injectors leaking into the cylinders and basically flooding the motor.. hope yours is just the temp sensor 22sonoma its much cheaper..

[fast68chevy]

try another crank sensor they break down when hot, timing is supposed to retard when cranking, but wont if CS is failing

also does the FP prime for a couple seconds do you give it enough time to prime before cranking it over?

i always flip key on and wait a few seconds before cranking so i have full pressure to start with

[Fr8 Train]

yup always let it prime... even tried priming it a couple times before starting and to the same effect.. i might look into that crank sensor im sure thats cheaper than injectors... always liked the whole working my way from cheapest to most expensive fixes even if it turns out to be the most expensive one then at least ive got the other little minor fixes out of the way as well..

[22sonoma]

Just wanted to update you guys. tried the coolant temp sensor, with no results going to try cps. i hope that will fix the problem.

[22sonoma]

ok changed the cps i hope this fixes the problem. if not what in the world could it be i am going to change the plugs and wires this weekend cause it just rolled over 100xxx so they are do anyway. any thing else to try that is low cost. Also does the 2.2l flex fuel have a PCV valve.

[ridatchevy]

i was having this same issue and it was even causing a running lean code on the dash. i dealt with issue for about 2 years after installing an "advance auto parts (purolator) fuel filter. i finally decide to order a A/C DELCO filter from rock auto. it corrected my hard start issue and the lean code went away. i dont think the issue was the actual filter through, becuz i have the flex fuel the fuel regulator is built into the filter, thats why its so pricey compared to other fuel filters. im pretty sure the regulator was the problem. been driving it for about 3 weeks now with no hard start issues. fires right up. its nice

[22sonoma]

OK i am going to give that a shot. if i recall the problem started when i changed my fuel filter also. i used a fram. so i will go buy a new ac delco. has any one used wix filters before i can get them for cheap was wondering if they are any good on this style filter i have used them in my diesel truck for years and had good luck with them.

[serpentracer]

dude I've put all new sensors and injectors on my 97 new with the rebuilt motor i put in it and it still starts slow after it's hot.
not like what some of you guys say, but it's just doesn't burst to life like it does when it's cold.
I even went as far as having the computer "case learned". it runs a lot better, but it still starts up like it's a old tired hag.
I kind of leaning toward my fuel pump. truck runs just fine and all but the pump is original (190k miles)
and the IAC valve. I have a scan tool that will allow me to do things to the sensors as the engine is running. on my 02 I can open or close the iac valve, but on my 97, the valve doesn't respond. the valve works though because the computer is using it to crank up the idle when I turn on the AC. and I can see it move with the scan tool. there are a few wires that go to the IAC valve and I think one of them to the computer or wherever it goes to might be bad. I did have a few wires in the harness that were melted to my manifold that I tapped up but never actually spliced in a new section.
I might just do that and see if it works.

[payne4life]

Quote: Originally Posted by ridatchevy

i was having this same issue and it was even causing a running lean code on the dash. i dealt with issue for about 2 years after installing an "advance auto parts (purolator) fuel filter. i finally decide to order a A/C DELCO filter from rock auto. it corrected my hard start issue and the lean code went away. i dont think the issue was the actual filter through, becuz i have the flex fuel the fuel regulator is built into the filter, thats why its so pricey compared to other fuel filters. im pretty sure the regulator was the problem. been driving it for about 3 weeks now with no hard start issues. fires right up. its nice

wow, i had the same issue with the same everything. it was a bad FPR in the fuel filter. i bought the purlator filter cause it was half the price of the AC Delco one. luckly i only delt with it for 2 months but my truck was getting to the point where i couldnt even drive it. i could only use a quarter throttle or it would bog down.

22sonoma i would check and see if your fuel filter is an AC Delco one or not. it seems like the ac ones are the only good ones, from the auto parts store is about $90 but i think rock auto has it for $67 or so.

[payne4life]

Quote: Originally Posted by 22sonoma

OK i am going to give that a shot. if i recall the problem started when i changed my fuel filter also. i used a fram. so i will go buy a new ac delco. has any one used wix filters before i can get them for cheap was wondering if they are any good on this style filter i have used them in my diesel truck for years and had good luck with them.

i wouldnt mess with the wix one for this problem. spend the extra on the AC Delco one and be done with it.