no start condition
Guys, HELP! 2 month old problem. I have a 96 chevy van 350 v8, 120,000
miles. Runs perfectly (when its running). Than at ANY point (hours or days)
after i shut it off it may or may not start. If i leave it and try starting it over
the course of hours or days, it will just crank or just all of a sudden starts
(weather doesnt seem to matter). It never stalls once running, no
hesitation, no bogging or misfiring, no gas smell from spider injector
leaking. 18 months ago replaced fuel pump (it did go out). Turn ignition on
and always have fuel pump start up, pressure is bout 60, once running
bout 55. pressure always there. Checked spark, always have, even when i
have no start condition. Once when i had no start, injected starter fluid and
it caught, so i know its "no gas" related. Any ideas? Towed once when
stuck and mechanic replaced crankshaft sensor, but if was this would not
have spark and start fluid would make no difference. One mechanic
suggesting bad computer (another the spider injector system but than
would miss or smell gas leaking!). Throws NO codes and went and had
checked anyway when running...none. anyone know how to check see if
computer talking to spider injector system? Anything to check computer?
Anything else that would stop fuel getting to in injectors
Sounds like you may have a bad fuel pressure regulator working intermittently.
In the spider assembly,right? But than wouldn't i have other related issues, one mechanic proposed i would? Gas smell, bogging, missing, hard starting, etc. Before i take it all apart, any test for that? As i mentioned how do i know its not computer shorting out at times not sending signal? Any thoughts on 'no code' being thrown?
also before i go that route any sensor that would prevent gas getting to injectors to replace first?
That is why I used the word intermittently sometimes working and sometimes not check fuel pressure when problem occurs.
i have checked the pressure, it stay same. Start up, bout 60 than drops back to 55 or so and stays same, whether start or no start condition. When engine turned off pressure holds for bout hour than slowly backs down. Driving me Crazy. I dont mind replacing injector spider, but hate to tear it down (have to take intake manifold off, etc. in a van with room to move, aaarrrrgggg) and find it's not that! before I do that any other suggestions from you 'firebird' (or anyone else?!). I'd like to rule out computer or anything else.
I would start by doing a fuel pressure bleed down test. Hook up fuel pressure gauge to the Schrader vale on the intake, cycle the key on, off, until pressure builds up, (56 to 63 lbs. at idle if you want to check)...then with the key off, watch the gauge, it should not drop more than 5 lbs. in three minutes. If it does, then probably the injectors, spider lines, and regulator assembly is leaking.
'Rowefast' thanks for that, i'll try that too. Anyone know way to test input from computer to make sure getting a pulse signal from it to spider. Cant use 'noid light' cause has no outside connection.
Say there Mikbek, I was looking up fuel parts for your 96 5.7L G-series van, and it only shows a TBI set-up on there. Was that motor converted over to the MPFI?
Hey thanks for concern and ur even doin the research, nice to know there are friends out there like u guys! u guys are the greatest, really. As far as i've read i have csfi (central sequential fuel injection) with the spider injector system. Chevy realized they were pron to clog, problems,etc and recommended a MPFI to replace it, they are electronically actuated as opposed to pressure regulated is what I'm reading. the whole system is under the intake manifold with, thus the reason i'm looking to test things before i have to tear it apart.
Ok, then ya, I know all about fuel pressures, was just little confused on what the books were saying. So ya, fuel pressure gauge hooked to the Schrader valve and do a bleed down test. Also injector pulse voltage is like 5 to 8 volts. May very some.
problem is I'm mechanically inclined but no professional. is there an easy way to get injector pulse voltage tested. Cant even hookup 'noid' tester. can a professional do the test easily. from all that i'm reading it has to be done, after, intake manifold comes off...correct?
No, the plenum does not have to come off to check the injector voltage. There is a master plugin for the injectors behind the throttle body. Now I myself have never check before, but there should be a cover over the top of the master plug to gain access to the individual injector pin connectors. The hole plugin you pull out so you check from the underneath side of the plugin.
Or with the cover off and the wiring plugged in.
Rowefast, final question for now (I think...lol) Does that allow using a noid tester, do u know?
I don't know to be honest. I just know its ben done, never payed attention to how they check but I can find out if need be. Cause I was just thinking that the injectors do not pulse with just the key turned on, so I'm not sure what you would find checking from the underneath side of the plugin. I'm thinking maybe show up voltage with the meter cause you'll have one side of a lead grounded. So if there is just power there it would show. I hope... Otherwise it looks like the cover comes off of the plugin to be able to check when it is plugged in and running.
Yeah that's what i was thinking but lil concerned because was told if not using noid tester could cause to much amperage during a test to fry computer. if u come across a tried way of doing it please let me know...Thanks and anyone else havin ideas would appreciate it
I'll check it out, I have sources. In the mean time do a bleed down test.
I will, thanks and any other input is appreciated
Ok, got some answers on the testing. First can you post a picture of your noid light? Not sure if that would work but I see people using them for this test. Anyway, so yes, unplug that big harness behind the throttle body. Testing would be done from there. You can use a test light on this for sure. Using a test light you put the alligator clip on a hot source. All the solid pink wires are hot for each injectors. All the other different colored wires, even if they have a strip on them are ground wires for each injector. With someone turning the van over, you probe the ground wires to each injector. The light should flash. And it is 12V that run threw the hot wires.
Noid attached to spider injector cap worked, all injectors working, so computer talking to injectors. Cranked and still didnt start. Tried putting pedal to floor and cranking, still no start. Tried a burst spray of start fluid, caught and died. Tried again cranking with start fluid and when it started continued with bursts of fluid which kept it running. Than after 10-15 seconds caught and ran on its own. Any thoughts, ideas? What controls fuel to air ratio mixture at start? I'm thinking this may be off, but what is controlling it? Any other ideas Rowefast? Anyone?
In addition talked to mechanic I use sometimes with really big issues. He cant even get to it till next tuesday & even than condition has to be to be there or I have to leave it there till it starts to have a no start condition again. He told me probably not spider injection or diaphragm in spider because would display gas smell, bogging, misfire, lack of power, etc due to diaphragm, but i have none of these issues...but that was a guess by him!
Ya, you did a fuel pressure testing, and by the looks of it was good. Reading over your original post, this sounds to me like a fuel issue yet, since when you have the no start condition & spray starting fluid in the throttle body, it starts. It may be the fuel pump is starting to go... And I don't think there is a problem with the injectors, lines, & regulator since it did not bleed down fuel pressure. So, maybe carry a fuel pressure gauge in the truck, easy enough to check fuel pressure at this time when no start. Just an Idea. If I come across something I think contributes to your problem, I'll let you know.
Thanks! I did let the car just sit in the driveway for last week and just tried starting it at different times of day, different conditions, each time it started no problem. I did this cause didnt trust it (used wifes car, shes not happy!) Then like I said, all of a sudden, no start! The whole time had a pressure gauge hooked up but never fluctuation in pressure. Just when turn on ignition: about 60, then when start: 50s. this is whether it starts or not, pressure never changes. You can hear fuel pump kick in then off when it doesnt start, like its suppose to. After running and turn off, pressure slowly backs down after hour or so. Its got me bugged to say the least! Any ideas?! i'm still beating my brains. Rowefast your the only one giving me any ideas, i think maybe I scared everyone else away...lol, Thanks!
If you are getting power at the injectors and not loosing fuel pressure and vehicle still will not start sounds like you have dirty or bad injectors try adding some fuel injector cleaner to gas tank and let vehicle idle for awhile then take out on road and hit the passing gear a few times this will help clean out gum and carbon build up in engine and help clean injectors if they are dirty. Hope this helps.
firebird has a good point. Sometimes we over look the simple things, so have you looked at spark plugs, cap and rotor, wires? And one thing that kinda nags at me is the fuel pressure. I'm thinking it is a little low. If you are getting below 56 lbs fuel pressure, your going to have a hard start or no start condition. I have seen people say 45 lbs, but a sores I cam across says 56 to 63 lbs. and this has held true for me. I'm am leaning toward the fuel pump starting to get weak plus the dirty injectors.
you guys are great! yeah i checked the wiring, cap, etc.. But I am going to try the injector cleaning thing. Rowefast you said held true for you with the fuel pressure, what happened, where was pressure for you when it gave you trouble?
When you get under 56 lbs. to 50 lbs. you have a hard start condition. You are lucky if it starts when under 50 lbs.
what do you guys think would lead to a 60 or so start up pressure dropping gradually to 40 or so
You didn't say how much the fuel pressure dropped off with the engine shut off. Should not drop more than 5 lbs in 3 minutes. Lets say in your case the injectors, spider lines, & regulator are good. Then it would be the fuel pump. If you were just to test the fuel pump (dead head pressure check) it should hold at 80 to 90 lbs. Now if you are talking it goes from 60 to 40 lbs. while running, then it is a weak fuel pump.
no pressure actually rises after shut off from 52 or so, to 56 (probably from heat expansion). Than after hour or so goes to mid 40 range, but than on engaging fuelpump pressure rises to 54 to 64. Still hard to determine cause now stupid car is running every time i start! I'm waiting for condition again. now like you mentioned Rowefast i think its pressure related, but how is what i dont know or understand. Running it holds 52-54 steady. going to try seafoam in gas see if it may help, maybe injectors somewhat gummed up? watta u think?
I think you have a weak fuel pump. Seafoam is fine and good, not gonna fix the problem. If you run 1/4 tank of gas or less, this is hard on a fuel pump, gets hot, not submerged in gas to keep it cool.
Rowefast ur everywhere! Where do u find time to help out so much...lol? Its nice of u! Still try in to zero in on problem on mine. Can't get no start condition in days! Aaaarrrrgggggghhhhhh
Whaaaa.....lol....as in holy wha. This is something to do to get threw the winter here, summertime may be a different story...
Rowefast or anyone, still trying to figure this! Can anyone specifically tell me components involved in the INITIAL engagement of fuel pump and its pressurizing system.
Im dealing with no start conditions. Changed fuel pump, fuel filters, checked all the fuses i could get to. Fuel getting to throttle body. Injectors not spraying. Cleaned injectors and got new gaskets. Sprayed starting fluid into throttle body, runs long enough to burn off what i sparyed in n dies... sorry its no answer, but im in the same boat
Although mines a 94. Still a chevy g20 that hasnt ran for months now. Limited cash and help. Trying to do it myself. Broke down on a public street to top it off.
Long shot bout wat bout computer. I replaced relay next to computer, so far so good. Computer initiates injector. U still not getting activation of injectors?
Without reading threw all this again, if you are to the throttle body now, and I think you have a new fuel pump installed, still check the fuel pressure in the line running to the throttle body. Should be 9 to 13 lbs. If it is not, since the fuel pump has ben replaced, this would be an indication that the fuel regulator in the TBI needs to be rebuilt. As far as the injectors, you can check to see if there is voltage running to them with someone turning the key to start, cranking it over, with leads to a digital multi-meter at the injectors checking for voltage. This would verify if the computer is sending its pulse to the injectors.
Rowefast welcome bac! Tim rent a noid tester and check pulse to the injector
I check in every day, thanks.
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