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Discussion Starter #1
Hopefully somebody here can help me figure this out......I have a 95 s-10 2.2 5spd and about 4 weeks ago my truck would not fire up right away if you let it sit for a day or two It would crank over just like normal but you would have to crank it for about a couple of minutes to finally get it to start, I took it to my local garage and they kept it over night and the next day they said that it had low fuel pressure so they changed the fuel pump....well for the last 3 weeks I had not had one problem until 2 days ago it started doing the same thing again I took it back to the garage and they checked the fuel pressure and it checked out just fine so then they said that a bad coolant temp sensor can cause what is going on with my truck also so they installed one of those yesterday and this morning it is still doing the same thing. I am stumped and so is the garage.... can anybody here shed some light on this subject and help me out...any responses would be very much appreciated.
 

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I have had starting problems as well (96 s-10 5-spd). Every once in a while i'd take a while to start. Normally i'd be 1/2 second on the key and release and i'd go right up. Now this still happens now that I replaced the starter over thanksgiving (The starter died and took out the ring gear on the flywheel with it). I have found no regular patten as to when my car will take a while to start. My truck has done this since I got it 80,000 miles ago (now has 113k on it) and the frequency has increased.

I know there are a lot of posts about starting problems. Though it isn't much fun to go through em all.


Have you done the tune up stuff? Airfilter, fuel filter, plugs, wires, ect --those would be the first things i'd do. I'd also get your self a volt meter and a Chiltons (haynes doesn't do as good of a job describing this type of testing) and test the sensors your self.
 

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Discussion Starter #3
Thanks for the reply..........The fuel filter was changed when the fuel pump was changed, I have been told by some that it might be the fuel pressure regulator??? does anybody know where this is located on a 94 S-10 2.2 motor and is it easy to replace???
 

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Same problem on my 96 Sonoma, 136k. Mine doesn't start (at times) and better yet, it will occasionally die while I'm driving it! I have tried replacing plugs, wires, relays, fuel filter. Haven't done the pump yet as it seems to be working. My money is on the computer, but I don't want to spend the $200 for a new one. You'd think that with so many of us having the same problem (I've read half a dozen posts like this) that a solution would present itself? I had one guy send a reply from the netherlands or somewhere saying that it was his pcm, which I assume is the computer, but thats the only definative reply that I have seen so far. If you do a search on starting you could probably find that post and read it. Otherwise keep us informed, I've been watching this site for a few months hoping to find an answer. I plan on testing sensors next myself like castiron said.
 

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Discussion Starter #5
I was reading on another forum that the problem could be the oil pressure switch, does anybody know exactly where the oil pressure switch is located at on my vehicle?
 

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Jolson,
When does your car die? as in low or high rmps? with no throttle or full? warm or cold? Or just randomly. Does it hesitate before hand or misfire? I've made a couple posts about my problems.

Mine misfires at low rpms, full throttle. Though, I have a feeling it is my fuel system that is causing all my problems.... Like it is flooding the engine. I am going to go through the 02, TPS, MAP, MAF, ECT, AIT, and prolly a few more sensors next week. I'll clean out the EGR valve too.

If you guys are just throwing money at any posible soltution, you might as well get an OBDII for 96+ or OBDI in the 95 and back(I think, I'd verify that one). Even though the good ones are
$250+, that's a fuel pump and a trip to the dealership to get your codes red. You can get either a scan tool or software for a laptop or palm pilot (I'm saving up for the software).
 

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The fuel pressure regulator is on the fuel rail and looks like a little vacum canister with a vacum line comming off it.

From memory I Think there might be 2 oil pressure (switches)/ sending units. One on the head near the fire wall with an oval 2 prong connector and I honestly do not recall where the other one was located.

There are several posibilities for hard starting and that is why there is no definative answer. There may be a fuel pressure problem or a bad injector. Could be spark issues due to weak coil, bad plugs, PCM, crank sensor, knock snesor, bad or crossed wires etc...
More commonly the IAC is clogged or sticking. (That's the Idle Air control Valve) It's on the back side of the intake behind the throttle body. It is held on by 2 screws and is easy to remove without removing anything else. It can be cleaned as well and the seat in the intake easily with a small toothbrush or simmilar and some carb/intake cleaner. It;s a cheap part to replace if it looks damaged. You still need to clean out the seat if you replace it or just clean it.

The temp sensory is a good sugjestion as many OBDII systems will retartd or advance spark timing dependant on the coolant temp. If the sensor tells the computer it's hot whne it's not. Then it may well retard the spark preventing a quick start.

A leaking injector could also fool the computer. When you go to start it the cylinder with the leaky injector pumps straight unburnt gas passed the O2 and the computer thinks your running way rich. Then the computer compensates actually causing such a lean condition that it barely fires.

Even something as small as a poor connection to the ignition module or starter solenoid can cause these symptoms.

Thurough troubble shooting it is really the only way to solve it. There isn't a magic bandaid or one solution for all poor start conditions.

The OBDII hook up can help find the problem on a OBDII 96 and newer vehicle. The OBD1 tool on the other hand is something I found useless and a multimeter and a manual was better for 95 and ealier. A check engine light on an OBD1 system tells you if there is a code and a paper clip is all you need to get the code then disconnecting the negative wire from the battery for a minute clears it. There wasn't much diagnostic info available from the older OBD1 systems to make a scan tool worthwhile in my book.
Even with the OBDII tool it will be difficult for someone with little experience to troubble shoot a problem that doesn't set a code. You need known good readings to compare to in many cases. Otherwise a 7% consistant lean correction might look normal. How would you know that 19% load at idle is high?
 

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Discussion Starter #8
Found the oil pressure switch yesterday afternoon it was on the passenger side just above the oil pan it had a connector with 3 wires on it plugged into the switch, the part was only $20 at advance auto so I said why not and I replaced it yesterday I will keep you guys updated on this to see if it fixes it....btw this morning it was very cold and it fired right up.
 

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My truck basically dies during normal driving, generally 8-15 min after its started. Its happened at idle, at 50 mph, turning corners, but no basic pattern. No hesitation that I can think of. Sometimes the relays in the dash go crazy, sometimes the fuel pump isn't running, sometimes it is. Have checked for codes and there are none.
?!!!!!
 

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Discussion Starter #10
It has been 1 week now and I have had no problems at all when starting it, It looks like the oil pressure switch was the problem...
 

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jolson said:
My truck basically dies during normal driving, generally 8-15 min after its started. Its happened at idle, at 50 mph, turning corners, but no basic pattern. No hesitation that I can think of. Sometimes the relays in the dash go crazy, sometimes the fuel pump isn't running, sometimes it is. Have checked for codes and there are none.
?!!!!!

try to test the ignition control module. most parts store can test them. whether it tests good or bad, clean the ground plate on it and make sure to put some di-electric grease on the plate as well
 
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