- This topic has 15 replies, 6 voices, and was last updated 10 years, 9 months ago by
.
-
Topic
-
This one is tricky. My truck takes 3 or 4 times to start when it’s cold out, with a cold engine, but once it’s started it runs fine. what happens is when it’s the first start of the day, I go to start it and it starts then stalls like 1 second later, every time i give it gas and on the 3rd try it revs and stays running if i hold the RPMs at about 2000 for 20 seconds or so. Once it’s warmed up it starts right up.
It’s been happening since I bought the truck last year.
Some things to note:
I’ve replaced the battery about 6 months ago
Replaced the fuel filter about 4 months ago
the air filter isn’t dirty. changed 5 months ago.
Changed the plugs 4 months ago.
Replaced belt same time as plugs.
changed the wires about 2 months ago (pepboys moved them into the belt path while attempting to change oil)
replaced alternator 2 weeks ago (original just died)
There is no engine light on.I’ve done some searching and some people are pointing to the IAC sensor, what do you think? I don’t want to throw parts at it, if i don’t have to, although that part only costs about $47.
-
Replies
-
Could possibly be a failing crank / cam sensor. See if there is a spec for checking internal resistance, this would be your only option of testing them short of hooking them up to an oscilloscope and looking at the waveforms.
The other thing you might try is to leave a fuel gauge on it over night and see if the fuel system leaks pressure back into the tank. Sometimes the one way valve in the fuel pump goes and allows fuel to flow back into the tank. This would caused a delayed starting only in the morning.
does it matter if it only does it when it’s cold out? it doesn’t do it in the summer at all. starts right up and strong if the outside temp is above 50.
I’m thinking maybe it could be frozen fuel. Try filling up your tank to the top and then try to start it cold. But if you have your tank like half full then frozen fuel is not your problem.
yeah I know about the frozen fuel thing, I always keep it full in the winter. It’s been full since before it got cold outside.
when its the first start. Cycle the key on and off
3-4 times without starting the engine. Then try and
start it. If it fires right up.fuel pressure is the issue.
what does the vehicle idle at when cold without you touching
the pedal?I’ve tried that (cycling the key as to prime it) it didn’t make a difference. When I get it started after 3 tries with gas it idles at about 1100 RPM for about a minute then goes down to 700 RPM. and stays steady. (needle doesn’t jump).
Also I added some dry gas to the full tank tonight to see if it will help tomorrow morning. I also cleaned my MAF sensor as per Eric’s video. Tomorrow, I’ll be cleaning my throttle body just for good measure. If i can find a star bit to take off a plastic cover.If the engine has a separate cold-start priming injector nozzle, that may be the prob. Most cars have eliminated the separate injector and just have the computer squirt in more gas.
It could also be a bad temp sensor, so that the computer thinks the temperature is nice and warm so it doesn’t bother enriching the mixture. To check this you have to identify the temp sensor, look up its cold resistance, and check that with an ohmmeter. Don’t mix it up with the sensor for the dash temp gauge, they’re often a completely different sensor.
Do you mean the (IAT) Intake Air Temp sensor? or the Ambient Air Temperature Sensor?
In this vehicle the IAT is part of the MAF that I cleaned today. But the Ambient Air Temperature Sensor is just behind the grill. And I’m having a hard time finding out what that sensor does, some people say it has to do with the A/C. The good news is that it only costs about $17 if that’s the problem.[quote=”EdHall23″ post=84268]I’ve tried that (cycling the key as to prime it) it didn’t make a difference. When I get it started after 3 tries with gas it idles at about 1100 RPM for about a minute then goes down to 700 RPM. and stays steady. (needle doesn’t jump).
Also I added some dry gas to the full tank tonight to see if it will help tomorrow morning. I also cleaned my MAF sensor as per Eric’s video. Tomorrow, I’ll be cleaning my throttle body just for good measure. If i can find a star bit to take off a plastic cover.[/quote]Next clean the throttle body and the IAC and its passages.
sounds IAC related due to the fact you have to crack the throttle
plate to start it.Well I cleaned the throttle body and IAC and it’s passages today, even changed the air filter for good measure. Put it all back together and I didn’t notice too much of a difference. It’s a warm day today, over 50 degrees, so I won’t have an issue starting it today. I bought some Sea Foam because people say it does wonders. I put it in the vacuum line coming off the brake booster, in the oil and some in the tank. I was worried because I already cleaned the throttle body and IAC that it wouldn’t do much. WOW was I wrong, the smoke poured out like a BBQ pit. for a good 3 minutes. I took it for a drive and noticed the engine overall was a LOT smoother, and what I thought were worn engine mounts turned out to be a rough idle, which is now gone. The real test will come when it gets cold again and I try it out. I also looked for where the PCV valve is and I think it’s in the back of the engine, a job I think, I’ll leave to the real mechanics.
Just for fun I’m gonna put my bets on grg8888’s response to what the issue could be. 🙂 Please keep us posted on what you find out.
Also, I supposed you can try spraying break fluid in to the PCV hole before first cranking on a cold day. See if that starts right up. If so, then it’s a lack of initial fuel that’s the problem.
Thanks!
JulianWell it’s still doing it. of course it’s 12 degrees outside right now, had trouble even starting this morning. About that temp sensor, you never answered which one it was. also I can’t spray anything in the PCV valve because it’s in the back of the engine, behind and under the intake. I did notice a coolant smell outside of the vehicle I figured it was just the overflow, and it didn’t overheat. But when I checked it yesterday night it took a full gallon. I checked the oil for white foam, you know the coolant in the oil for a blown head gasket but nothing but clean oil. There’s no leaks under the truck so I have no idea where the coolant went…lol.
You can spray in the throttle body too– just more to remove. Make sure you put the hose back on before starting. Btw, you know what a PCV looks like, right? It just pulls out– not clamped or screwed in. My 89 mustang has a PCV on the back part of the engine as well. If you really lean in, you can get to it 🙂
Also, did I understand correctly that when it’s cold you first start it, it starts, then you give it gas and it dies? Then after doing the same thing 3-4 times it finally starts?
Finally, one more important thing. Since you cleaned the IAC and ran SeaFoam and stuff, the computer needs to relearn the new status of things. I’d unplug the battery for 1 hr and let the computer clear. Then plug it back in and drive it for 20 min and let the computer re-learn.
Let us know how it goes.
Julian
[quote=”juels98″ post=84463]
Also, did I understand correctly that when it’s cold you first start it, it starts, then you give it gas and it dies? Then after doing the same thing 3-4 times it finally starts?
Julian[/quote]Yeah it starts for about 1/2 a second then dies, try that 3 times, on the 3rd time it starts I hold the rpms at 1500 for 10 secs and let go and it stays running.
I found out where the coolant is going tonight when I picked up my daughter from daycare. The belt started to squeal, it’s a new belt. So when I got home i popped the hood, and was greeted with some steam. It looks like it’s leaking from behind the thermostat housing, not really on the thermostat housing behind it what looks like a seal under the intake. I don’t exactly know what it’s called. Valve cover gasket? Intake gasket? Anyway I checked the oil, still no white stuff, so that’s good.
I guess tax season is close and I’ll have to see if I can take it somewhere to find out if it’s worth fixing and finding out what the issue with starting is. I wonder if the coolant and the starting issue are related. I only paid 3k for it last year, I don’t know if I want to give up on it yet, at least I’ll know what the problems are, vs getting another truck and not knowing what the problems are. It only has 147k miles on it.Lets try this test. With the engine cold and off.
unplug the ECT (engine coolant temp sensor) Bridge
the connector with a small paper clip or wire. see
if the truck starts. if so replace the coolant sensor.
If you get a check engine light we can reset it later
by disconnecting the negative battery terminal.
- You must be logged in to reply to this topic.