Car will not start

pontiac
bonneville

#1

I have a 2000 Pontiac Bonneville ssei (Supercharged) 3.8L V-6. I had a issue with the fuel injectors now that problem is fixed. I can’t get the car to start on it’s own. I and a auto garage have replaced the MAF,MAP,Camshaft Pos Sensor, Crankshaft POS Sensor, FPR, ICM, IAC, Someone had the TPS in wrong and I was missing 5 volts at pin B of the TPS. I corrected that and now it’s ok. The engine cranks but it will not start on it’s own, I have about 54 psi on the fuel rail. The ECM was relaced by the dealer before i fixed the fuel injector problem but that did not help so the original is back in place. The car runs like a top after I shoot some starting spray down the intake and will run until I shut it off. I try to restart it and it won’t start until I spray it again. I am very careful not to spray on the MAF sensor. Even with that being said I use Electronic spray cleaner to start it. All Sensor wires have been checked with the exception of the crankshaft position sensor which I’m going to do today going to the icm. ANY help would be appreciated.


#2

You must have spark since motor runs with spray fuel. Can u verify injectors are firing as you crank?


#3

That’s a lot of parts to throw at it. Presumably that has come from some mixture of guessing and - perhaps - some error codes? Is the check engine light on now? If so what are the current codes? What codes have come up in the past? The specific “Pxxxx” codes - not whatever words have been used to describe them.

When you say you have 54psi at the fuel rail, under what conditions? Is it static pressure with the car off? Does the 54psi hold well with the car off? Or does it drop right off?


#4

Cavell I have not pulled the fuel rail off to see if the injectors are firing when i crank, maybe a bad assumption but I thought that they were because of the running after it was sprayed.


#5

cigroller Yes a little of both. I’m going to hook up my obd2 comp to it today after work and see what if any codes are present. Yes on the psi both off after i crank it and while it’s running. Oh I replaced the fuel pump as well, sorry i forgot about that one. No ses light on as of right now.


#6

With the car off does the fuel pressure hold it’s 54psi? What I’m getting at is that the fuel pump only primes when you first turn the key. It doesn’t just run continuously until the car is actually running. So I would want to put the fuel pressure gauge on, prime the pump up to the 54psi max by cycling from off to run a bunch of times (without cranking), watch it for a few minutes to see if it holds, and then watch what happens if you have an assistant crank it over.

Fuel injectors, btw, make a fairly audible click when they run. You can usually hear it pretty easily using something like a piece of vacuum line or other hose as a “stethoscope”


#7

ok thanks I’ll try that. I have to wait until Tuesday for my asst. I can tell you that when we did crank it over without priming it it did hold at 54. Then we pimed it and it started and the psi held. After we shut it off and before we had to prime it again. I believe he said that the psi stayed the same. I did take the hose off of the PFR to see if fuel came out and it did not.


#8

we had recent post of 3800 with bad map sensor causing no run. and a 2nd car with bad maf. but you have changed both. your car is also known for funky fuel pressure issues. usually a few posts online of fuel pump relay bypass or hotwire but that might be a grand prix issue.


#9

Doesn’t the oil pressure switch come into play for starting purposes on some GM vehicles?


#10

Sounds like the injectors aren’t getting power when the key is in the start position.


#11

i checked the fuel psi and at key on engine off, the gauge reads 55 psi when i turn it to start then drops to about 48 or 49 psi when i release it to the run position. Each time I turn it to the off pos and back to start it reads 48 psi the to start55 psi. I tried this several times to see if psi bled off it stayed the same. Ive checked the wiring to the ecm and they all check out. I can’t seem to find where the grnd wire goes though from the fuel injectors. Anyone who might have wiring problems and uses the info from all data or some other refererence the wiring diagrams might not be correct. I verified this when I t/s the tps wiring. I went to the GM dealer and they had the same wiring diagrams as all data. It took me awhile but I figured out what’s what. I just plugged the obd2 comp in and it came back with nothing. Once the car is running, some people have been saying that the crankshaft pos sensor has to relearn the info from the ecm… If the fuel injectors were not getting power, is it different than when the key is in the on pos. I will check again while it is running and just if the key is “on”.


#12

@Tinybubba

The engine control module grounds the injectors


#13

The easiest way to find out if/when the injectors fire is to get your hands on a noid light - or “injector signal tester.” Then you don’t need to muck around with pinouts and wiring diagrams - unless, of course, you do find a problem. You just plug the noid light into the injector harness and it flashes if the firing power is coming through.

Sets look like this: http://www.ebay.com/bhp/noid-light

  • although I think you can also buy them individually, and you might be able to “borrow” one from an auto parts store that has a loaner tool program.

#14

I have checked the icm for power and ground signals and they are there. I weather cooperates, I will hand crank the motor today to check for the voltage at the icm connctor from the ckp.


#15

From what has been stated it does seem the injector circuit isn’t working while the ignition is in the START position. I like @db4690 suggestion of the oil pressure switch if there is one. I also wonder about the security system possibly coming into play on that if there is one.


#16

I just checked the crankshaft signals at the ICM. I have 5-6 volts at the plug to the ICM. I will check the oil psi switch today. From the other fixit web site they say that the ICM is BAD if you have the voltage at the ICM from the CKP. Either way I will check both today. I’m going to pull the fuel rail and see if ANY fuel sprays out, even a trickle.


#17

Checked for ref low voltages, and they are there. I’m going to start checking grounds. at G103


#18

@Tinybubba finnally fixed his car. It would start if you sprayed starter fluid, but would not start without it. Disconnected MAP and it would start, MAP is new part from O’Rieley’s. Plug it in and no start. Replace MAP and car runs good. @Stoveguyy had it correct.


#19

Thanks everyone for your ideas, It helped me eliminate somethings.