1995 Buick Stalled and Won’t Start After Replacing Intake Manifold

Hi ,I’m new to the world of fuel injection and sensors such as a knock sensor. I have a 1995 Buick Century with a 3.4L Pontiac engine. I used the 3.1L intake manifold system and have been driving the car for several months now without any problems till 2 nights ago, I was doing nearly 10mph when the car died without any type of warning. Here what I’ve done, hot wired the fuel pump and it gets fuel only when hot wired it does have spark and if I pour fuel into the intake plenum it will fire and start till it consumes what I pour in, it does not have a VATS system I’m told to check the knock sensor. Any help and ideas is greatly appreciated, thank you. Austin.

Austin, how about checking the fuel pump fuse and fuel pump relay? if you can power up the the pump by hot wiring it, then I would say the pump is good and you have either a wiring problem to the pump itself or a blown fuse, bad relay, or even possibly a faulty PCM. The knock sensor would NOT cause this type of problem.

Yes I have checked the fuse ist good and I switched the relay,(i think) it has 5 relays right behind the passenger side headlight two are name brand so I assume that they are for the headlights so I let them be and the other 3 I switched by rotating them out one time in reference to each other. I could not find any difference in them such as the numbers that were embedded in there case, but am not positive that one of them was actually the fuel pump relay.

The fuse box should have a cover that tells which is which on a diagram, also if you can find which one it is, have someone turn the key on while you hold your finger on the relay and see if it clicks…if it does it’s good.

OK this sounds like a good possible cause because it seems as though that i am missing a noise that usually takes place at power up of ignition switch, I’ll try to track it down, but what I’m sorta baffled at is i can jumper the fuel pump and it will push the fuel out of the relief valve on the fuel rail when i relieve the fuel rail, but it wont give fuel to cylinders to start it when its wired, to say seems like the injectors aren’t operating is also in my thoughts?

Fuel Injectors

You said before that it will run if you put some gas into the intake? You could have a problem with the injectors too. If you can get at one of the connectors to an injector, I would check for power with a test light, or a ‘noid’ light if you have one to see if they are getting a signal from the computer. If not, I would tend to think you probably have a PCM issue, or wiring problem somewhere.

Yes I introduced it into a vacuum port between the throttle body and combustion chambers. I’ll check that out, I have a set of injectors of the original motor could one help with diagnostics of my problem?

No another injector wouldn’t help you in this case, because if you’re losing the signal to them, switching them won’t make a difference. I’d get checking the relay to see if it click, and checking to see if you have an injector signal. If you have neither, you may want to replace the PCM.

I thank you very much for your knowledge, I wish i could make a donation to the site but I have been unemployed for over two years ,not trying to get any symphony, just want to give reason I’m not able to donate, but i also would like to say its been realy enjoyable conversing with some one who has obvious knowledge behind them, you know how it is, around here every friend of a friend has the solution. I had one person tell me a friend had said the plastic timing cover had a scratch in it, I’m pretty certain mine is aluminum, thanks again.

No problem at all, have a great night!


1998 Buick Century

My 1998 Buick century leaks coolant like behind the power steering pump close to the hoses for it ?

Most likely it is the intake gasket that is leaking coolant.

If by any chance its not that do you have any other suggestions? Yes because it will leak by itself and when i press on the hose more comes out dripping from the power steering hoses down towards the belt tensioner to the bottom.

That is really the only thing that can leak coolant in that particular area, unless it’s worse and it’s a head gasket leaking. I would pretty much bet though that is the intake leaking. I’ve seen that a thousand times. that is a pretty bad leak. The timing cover also has a paper gasket that can leak coolant in that area too, although they do tend to hardly be a problem, but you might want to look there as well.

I also have a 91 civic with a 1.6 in it , It wont start it cranks but it wont start ? fuel goes through maybe the distributor doesn’t work.

Yes you should check to make sure you have spark first.

Yes i checked that pulled the spark plug wire out put a extra one i had on it cranked it but seen no spark so that’s a good sign of a new one ?

No that is a bad sign. You could have a bad coil, or distributor, or just a bad set of wires and plugs.

Thanks for all your help.


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