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cold start problem


franlofter's Avatar
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06-22-02, 04:52 PM   #1  
franlofter
cold start problem

Hello, I have a 1996 Chevy, astro van, with 4.3 V6, It has 114000 miles on it i bought it 2 years ago at 75000 miles. It takes it about 5 to 6 turn over to get it to start in morning after it has been run it starts up fine. this problem has happened over a 6 month period it starting out as taking 2 or 3 turn overs to start and just keeps getting worse?? would bad wires cause this?? it runs fine warm and runs fine after the cold start?? spark plugs were changed 6 months ago ,EGR valve, fuel filter, pcv valve. took it to repair shop they say its mas air flow sensor but i dont think thats the problem because i has it unpluged for awhile and it started fine unpluged, this was awhile ago before cold start problem.


Last edited by franlofter; 06-22-02 at 05:37 PM.
 
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06-22-02, 08:09 PM   #2  
you probably have a weak fulepump that is slow to build up pressure after sitting for an extended period the injection system on that van requires 55psi of pressure to start cold , you might try changing the gas filter if you havent done it recently but i would suggest you check your fuel pressure when its hard to start and see if that is the problem.

 
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06-23-02, 01:56 PM   #3  
franlofter
thanks, that sounds more like the problem than a mass air flow sensor. I will try and check pressure and see what happens, I changed fuel filter 6 months ago so if thats good and my fuel pressure is low does this mean my fuel pump is going???

 
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06-25-02, 03:51 PM   #4  
kdogg
Hey Im not sure if you have a cold start injector on that v6, but if you do, you might want to check that...........and the timer switch for it.......

 
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06-25-02, 09:09 PM   #5  
Joe_F
I agree with BeJay. Check the fuel pressure. Also, the CPI vin W injector on this engine is known for giving cold start woes. GM has superseded the parts a few times.

 
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06-26-02, 08:17 PM   #6  
J. Papp
I have a 92 Astro that has just started doing the same thing. I put new wires, plugs, dist. cap, and rotor before the problem started. I checked to see if I had the wires in the right firing order when I noticed a clicking coming from the coil, so I repaced it too. It is still hard to start when cold but runs and starts fine after it is warmed up. I checked the fuel pressure (after confirming I had spark) and it was around 60lbs. A mechanic said that the CPI engine is known for having problems but a dealer price on a new CPI is close to $500! Is there another possible solution since I don't want to put that kind of money in it. Maybe the temperature sensor? Thanks, John

 
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06-27-02, 12:57 AM   #7  
well probably your best bet is to take it to a shop and leave it overnight so they can see the cold start problem and determine what is causing the problem, a coolant temp sensor can cause a hard to start cold problem but you really need a scanner to be able to read exactly what temperature it is reading and if it is reading correctly, that being said i wouldnt be replacing the injector until you had it confirmed that it was your problem, the main thing that i can think of that they had problems with on the injector was sticking poppet valves and leaking gas down the intake the main reason fuel pressure is so critical on the vortec it takes 55 psi to open the poppets there for your can have a fuel pressure reading of 54 psi and the engine will not start.

 
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06-27-02, 09:31 AM   #8  
Joe_F
BeJay is right...the poppet valves stick on the Vortec 4.3 vin W injector. It's a common problem and the part has been redesigned by GM a few times. Solution is generally to replace the injector....it should be a bit cheaper than that, but it's mostly labor (and the part's a bit pricey too) for the job. Very common on that engine.

 
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07-06-02, 06:52 PM   #9  
J. Papp
V6 with dirty intake

Thanks for your comments. Since I have spark and the fuel line pressure tested OK, I put in a temperature sensor . Unfortunately, it is still hard to start. I located a rebuilt CPI for about $140 so today I tore into it. Under the housing, I found everything covered with gritty oil deposits. I'm not sure whether to try and clean this out for fear of washing or knocking the gunk down into the intake or even the cranckcase. Should I try to wipe it out or just leave it? Also, I take it from the comments that the problem with the CPI is mastly leaky poppets. I pulled them out of their sockets and turned the key on "run" and they did not even drip. Does this mean the unit may be good? Thanks again, John

 
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07-07-02, 03:33 AM   #10  
Joe_F
Clean everything out completely and replace the CPI injector with a new one.

Change your oil and filter in case any debris got washed into the engine.

What did a fuel pressure check with a gauge reveal?

 
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07-07-02, 06:11 PM   #11  
J. Papp
A clean engine is a happy engine

Thanks Joe for the advice. The pressure read right at 60 lbs. I started the motor and it really didn"t change, it stayed right at 60lbs. Is it normal to have such a sooty oil buildup in the intake? I think I will change the PVC valves also. The only time I had a motor with that kind of buildup was when the rings were bad or the PVC valve wasn't functioning. It only produces visual smoke when it first starts, which I assume is from warn guides and /or seals. It has 151K on it so that does not surprise me, but it has never needed oil added between changes. Not even on 1500 mile trips. The build up in the manifold makes me feel like it should have been smoking up a storm all the time. Strange to me. John

 
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07-08-02, 03:42 AM   #12  
Joe_F
What color and odor is the smoke upon initial start up? Could be fuel or oil depending on what it is.

My guess is the former, fuel. Again, the CPI equipped vehicles are known for bad injectors.

 
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07-09-02, 08:53 AM   #13  
J. Papp
The smoke is blue from oil, not black from fuel. I really don't think the poppets were leaking because the fuel pressure always read 60lbs. Even when I pulled the poppets out of their holders and turned the key on, they didn't leak. Anyway, I odered the CPI and when I get back from a trip to Canada I will install it and see if the cold start problem goes away. I'll post my results next time I try it. John

 
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07-10-02, 06:26 AM   #14  
franlofter
Hi. I did fuel test its ok 60lbs, Is there any chance it could be the mass air flow sensor like the shop said??? that was only trouble code they found, would the mass air flow sensor cause hard starting when cold?? the part cost $150 for new mass air flow sensor but i can change it myself but dont want to spend $150 on something that wont solve trouble??

 
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07-10-02, 06:35 AM   #15  
Joe_F
The parts store can easily send the MAF out for testing before you spend the money on it. Yes, it does cause starting problems.

 
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07-10-02, 07:09 AM   #16  
franlofter
does the check engine light need to be on for a trouble code?? because my check engine light only comes on when i unplug the mass air flow sensor, when i plug it back in check engine light goes off after few min. now the dianostic scan shows a trouble code p0102.... Mass or volume air flow circut low input.

 
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07-10-02, 09:43 AM   #17  
Joe_F
May not set a code and could still be bad...that's why I say have it tested first before throwing money at the problem.

 
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07-10-02, 10:30 AM   #18  
franlofter
ok thanks for all your help, I have a new one i can throw in my van to see if it is the trouble, I just cant keep it borrowed out of new van i use for work. I really need to wrap this up this week getting so i dont know if its even gonna start in the morning. I sure if they send the part out could take some time. I unplugged the one in the new van i use for work before i start it in morning and it starts right up, so i kinda have my doubts thats the trouble let you know what happens with new sensor in there..

 
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07-11-02, 01:04 PM   #19  
franlofter
Well today I was walking to work, will not start at all now. put new MAS in there no help. guess i will have to pay a mechnaic to play a guesing game and change out parts till they find problem, what a joke when you take your car to shop and there guess is as good as yours, guess the mechanics from 20 years ago are all gone.

 
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07-11-02, 04:22 PM   #20  
Joe_F
Sure it's the right one? It won't run if it's not the right one.

Where did the new one come from? What brand is it? Did you match the OEM # off the old one to the listing in the catalog? If you didn't, you could have gotten the wrong part and it won't run

 
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07-11-02, 04:33 PM   #21  
franlofter
nah its the same one same numbers and all, i even tried the old one to still no go, i am just getting frustrated cause it so hot here 112 today and would you know it i park in driveway last night when i allways pull in garage lol. thought i be nice and let wife park in there hehe now i paying for it. I am not hearing the startup sound that the fuel pump has allways made, so i going to try fuel presure test again, if its the fuel pump i will pay someone to do it to hot for me outside. check it in a couple hours .

 
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07-11-02, 05:42 PM   #22  
franlofter
I checked fuel pressure again and it took me 7 off an on with ignition to get it up to 50 lbs would not go higher than that. so I am going to replace fuel filter and retest it again, if it still same pressure it would be fuel pump that going???

 
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07-11-02, 07:03 PM   #23  
Joe_F
Sounds like a weak pump. Was it ever changed? If replacement is needed go with an AC Delco pump and replace the in tank strainer too.

 
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07-11-02, 08:14 PM   #24  
franlofter
well i installed brand new fuel filter and cant get above 50 lbs on fuel test, my repair book says something about a fuel regulator and tells how to test it but you need to have a running engine to do it. also says something about strainer could be clogged up, the pump was never changed as far as i know. looks like i be calling tow truck tommorow.

 
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07-11-02, 08:30 PM   #25  
franlofter
Thanks for all your help joe let you know what happens in the shop, i will tell them i want a AC delco, and new strainer but I will never know if thats what they put in there, hehe, to big of a job for me to take on now not enough time. have to pay someone.

 
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07-12-02, 04:21 PM   #26  
franlofter
I had it towed to shop today should be done by tommorow i am having them change fuel pump I hoped to god thats the trouble cost me $300 with the tow parts labor.

 
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07-12-02, 07:20 PM   #27  
franlofter
Got it back tonight all done its running now got AC delco pump and strainer, hopefully all will be good in morning, thanks again for all the help. was running better than it has rough idle not so bad now.

 
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08-14-02, 07:55 PM   #28  
J. Papp
cold start solved

My cold start problem has been a long ordeal, but now it is finally over. I decided to gamble and order the CPI for $140 instead of adding another $80 for someone to diagnose the problem and tell me what everyone else thought it could be- the CPI. I should have listened to bejay because it turned out the $140 unit was no longer available. I ended up paying about $300 for an AC DELCO unit and after putting it in, it still would not start. I tried a fuel filter also with no luck. Then a friend came over with some nice scanners and a pressure guage. The mas flow read 5 volts like it was suppose to but the fuel pressure read low. My guage was inaccuarate and just happen to read 60lbs when it was 36lbs. Lucky me. Today I tackled draining the tank, (I found that by running a hose from a 5 gallon can to the presure line from the tank, then removing the fuel pump relay and added a jumper wire, the old pump would empty the tank.) Dropping the tank was even more fun as three of the four welded nuts hidden inside the frame broke loose. I had to improvise and drop bolts in through nearby holes. Then I tried it and it started! No leaks. To make the job even more fun we finally got rain after weeks of drought. So most of the job was done under a leaky tarp. Anyway, it is done and I hope someone else can learn from my experience.

 
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